HK1245402B - Apparatus and method for fluorescence grading of gemstones - Google Patents

Description

Apparatus and method for fluorescence grading of gemstones

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Patent Application No. 14/673,780, filed on March 30, 2015, and entitled “APPARATUS AND METHOD FOR FLUORESCENCE GRADINGOF GEMSTONES,” which is incorporated herein by reference in its entirety.

Technical Field

The apparatus and methods disclosed herein generally relate to fluorescence grading of gemstones, particularly cut gemstones. More specifically, the apparatus and methods relate to fluorescence grading of cut gemstones having irregular or fancy shapes. The apparatus and methods disclosed herein further relate to digital image processing based on color component analysis.

Background Art

Diamonds and other gemstones are typically analyzed and graded by multiple trained and skilled individuals based on the diamond and its visual appearance. For example, the foundation of diamond analysis includes analysis of the Four Cs (color, clarity, cut, and carat weight), two of which (color and clarity) are traditionally assessed by human inspection. Gemstones are also evaluated for unusual visual properties. For example, certain gemstones produce fluorescent emissions under UV illumination, and the degree and distribution of this fluorescence are also used to grade such gemstones. Like color and clarity grading, fluorescence grading was previously assessed primarily based on human visual perception. Analysis and grading require the practice of judgment based on visual comparisons, the formation of opinions, and the ability to draw subtle distinctions.

The testing and analysis process is typically time-consuming, involving multiple rounds of testing, measurement, and inspection by trained and skilled individuals. The process also involves quality control and may include various non-destructive tests to identify treatments, fillers, or other defects that may affect the sample's quality. Finally, the process involves intensive visual comparison of the diamonds with a reference set of diamond master stones that serve as historical standards for diamond color and fluorescence.

Instruments have been developed to improve efficiency and allow gemstone analysis in the absence of trained and skilled personnel. For example, U.S. Patent No. 7,102,742 to Geurtz et al. discloses a gemstone fluorescence measurement device comprising an ultraviolet ("UV") emission chamber, a UV radiation source, and a light meter assembly. The UV radiation source comprises an upper light emitting diode ("LED") and a lower LED, which irradiate the gemstone from both above and below the gemstone under test. However, current instruments are unable to provide consistent and reproducible fluorescence grades for fancy-shaped cut stones; such gemstones are classified as step-cut, heart-shaped, egg-shaped, oval, pear-shaped, triangle-shaped, princess-cut, or any other cut except a round brilliant cut (RBC). Additionally, current instruments fail to provide hue information, and the operator must manually enter the color of the fluorescence. This results in incorrect grading because weakly fluorescent colors are not easily visible to the human eye.

There is a need for apparatus and methods that can provide gemstone evaluations and grading (eg, fluorescence grading) that are consistent and accurate with evaluations and grading provided by trained and skilled individuals.

Summary of the Invention

In one aspect, an apparatus for evaluating the fluorescence properties of a gemstone is provided. The apparatus includes a light-tight platform, wherein the platform has a surface configured to support a gemstone to be evaluated; a light source shaped to at least partially enclose the platform, wherein the light source is approximately level with or below the platform surface and is designed to provide uniform ultraviolet (UV) radiation to the gemstone on the platform; an image capture assembly, wherein the image capture assembly is positioned at a predetermined angle relative to the platform surface supporting the gemstone, and wherein the image capture assembly and the platform are configured to rotate relative to each other; and a telecentric lens positioned to provide an image of the illuminated gemstone to the image capture assembly.

In one aspect, an apparatus for evaluating the color characteristics of a gemstone is provided. The apparatus includes: a light-tight platform, wherein the platform has a surface configured to support a gemstone to be evaluated; a light source above the surface of the platform, wherein the light source is designed to provide uniform ultraviolet (UV) radiation to the gemstone on the platform; an image capture assembly, wherein the image capture assembly is positioned at a predetermined angle relative to the surface of the platform supporting the gemstone, and wherein the image capture assembly and the platform are configured to rotate relative to each other; and a telecentric lens positioned to provide an image of the illuminated gemstone to the image capture assembly.

In some embodiments, the apparatus further comprises a collimating lens, wherein the collimating lens and the light source are coupled to provide uniform UV illumination to the gemstone on the platform.

In some embodiments, the apparatus further comprises an optical diffuser, wherein the optical diffuser and the light source are coupled to provide uniform UV illumination to the gemstone on the platform.

In some embodiments, the apparatus further comprises a collimating lens and an optical diffuser, wherein the collimating lens, the optical diffuser, and the light source are coupled to provide uniform UV illumination to the gemstone on the platform.

In some embodiments, the apparatus further comprises a reflector device having an interior surface that is at least partially spherical and comprises a reflective material. The reflector device at least partially covers the light source and the platform surface and directs UV radiation from the light source toward a gemstone positioned on the platform surface. In some embodiments, the interior surface of the reflector device has a hemispherical shape.

In some embodiments, the device further comprises a computer-readable medium for storing images collected by the image capture component.

In some embodiments, the apparatus further comprises an interface between the light source and the platform surface for adjusting the output intensity of the UV radiation.

In some embodiments, the apparatus further comprises a UV filter between the image capture assembly and the telecentric lens to eliminate all UV components.

In some embodiments, the UV radiation provided by the light source includes transferred radiation, direct UV radiation, and combinations thereof.

In some embodiments, the light source further provides uniform non-UV illumination to the gemstone.

In some embodiments, the telecentric lens is an object-space telecentric lens or a bi-telecentric lens.

In some embodiments, the platform is configured to rotate about an axis of rotation that is perpendicular to the side of the platform in which the gemstone is positioned.

In some embodiments, the platform is configured to rotate 360 degrees about the rotation axis.

In some embodiments, the platform is a flat circular platform, and wherein the axis of rotation passes through the center of the circular platform.

In some embodiments, the platform surface comprises a UV reflective material.

In some embodiments, the platform surface comprises a diffuse UV reflective material.

In some embodiments, the platform surface comprises a white diffusely reflective material.

In some embodiments, the light source is configured as a ring light surrounding the platform surface. In some embodiments, the light source includes a plurality of light-emitting LEDs. In some embodiments, the LEDs emit fluorescence at 365 nanometers or 385 nanometers.

In some embodiments, the LED is coupled to a bandpass filter. In some embodiments, the bandpass filter is set at 365 nanometers or 385 nanometers.

In some implementations, the LEDs are configured as a ring light surrounding the surface of the platform.

In some embodiments, the light source comprises a near-daylight light source and a plurality of light-emitting LEDs. In some embodiments, the LEDs are coupled to a bandpass filter. In some embodiments, the bandpass filter is set at 365 nanometers or 385 nanometers.

In some embodiments, the predetermined angle between the image capture assembly and the platform surface is between approximately zero degrees and approximately 45 degrees. In some embodiments, the predetermined angle between the image capture assembly and the platform surface is between approximately 10 degrees and approximately 35 degrees.

In some embodiments, the image capture component is selected from a color camera, a CCD camera, and one or more CMOS sensors.

In some embodiments, the image capture assembly captures a plurality of color images of the gemstone illuminated by UV radiation, each image comprising a full image of the gemstone.

In some embodiments, the image capture assembly captures a plurality of color images of the illuminated gemstone, wherein each image is taken when the image capture assembly and the platform surface are at a different relative rotational position, and wherein each image comprises a full image of the gemstone.

In some embodiments, the plurality of color images comprises 4 or more color images, 5 or more color images, 10 or more color images, 15 or more color images, 20 or more color images, or 800 or more color images, and wherein each image is taken at a unique image angle and comprises a plurality of pixels.

In some embodiments, the fluorescence characteristic is a fluorescence intensity level, a fluorescence color, or a combination thereof.

In one aspect, a method for evaluating fluorescence characteristics of a sample gemstone is provided. For example, the method includes the steps of: (i) determining a fluorescence shield for a fluorescence image in a plurality of fluorescence images based on a contour shield determined from an image in the plurality of images and based on an apparent fluorescent area in the fluorescence image; (ii) quantifying individual color components in each pixel in the fluorescence shield in the fluorescence image in the plurality of fluorescence images, thereby converting the values of the individual color components into one or more parameters representing color characteristics of each pixel; (iii) determining an average value of each of the one or more parameters for all pixels in a defined area in all of the plurality of fluorescence images; and (iv) calculating a first fluorescence score for the sample gemstone based on the average value of the one or more parameters for all pixels in the defined area in all of the plurality of fluorescence images.

Here, each of the plurality of images includes a full image of the sample gemstone illuminated by a non-UV light source. Each of the plurality of fluorescence images includes a full image of the sample gemstone illuminated by a uniform UV light source. Furthermore, the images and fluorescence images were captured under identical conditions, except for the illumination light source.

In some embodiments, the method further comprises the step of: (v) calculating a second fluorescence score for the sample gemstone based on pixels in the contour mask for all of the plurality of fluorescence images.

In some embodiments, the method further comprises the step of: (vi) evaluating the fluorescence characteristics of the sample gemstone by comparing the first fluorescence score or the second fluorescence score to corresponding fluorescence scores of one or more reference fluorescent gemstones previously determined.

In some embodiments, the first fluorescence score reflects the color of the fluorescence and wherein the second fluorescence score reflects the intensity.

In some embodiments, the method further comprises the step of collecting a plurality of images of the sample gemstone using the image capture assembly at uniquely different image rotation angles while maintaining a constant image viewing angle.

In some embodiments, the method further includes the step of collecting a plurality of fluorescence images of the sample gemstone using an image capture assembly at uniquely different image rotation angles while maintaining a constant image viewing angle. Here, each fluorescence image in the plurality of fluorescence images corresponds to an image in the plurality of images and both are captured at the same image rotation angle and image viewing angle.

In some embodiments, the method further comprises the step of determining fluorescence masking for each of the plurality of fluorescence images.

In some embodiments, the method further comprises the step of quantifying individual color components in each pixel in the fluorescence mask in each fluorescence image of the plurality of fluorescence images.

In some embodiments, the method further includes the steps of: collecting a new plurality of fluorescence images of the sample gemstone using an image capture assembly at uniquely different image rotation angles while maintaining a constant image viewing angle, wherein there is a time gap between the time the plurality of fluorescence images were collected and the time the new plurality of fluorescence images were collected; assigning a new fluorescence grade based on the new plurality of fluorescence images by applying steps (i) to (vi); and comparing the fluorescence grade to the new fluorescence grade based on the time gap.

In some embodiments, the time gap is between 2 minutes and 5 hours.

Those skilled in the art will understand that any embodiment described herein may be used in conjunction with any aspect of the apparatus or method, where applicable.

BRIEF DESCRIPTION OF THE DRAWINGS

Those skilled in the art will appreciate that the drawings described below are for illustration purposes only and are not intended to limit the scope of the present teachings in any way.

FIG1 depicts an exemplary embodiment of a gemstone optical evaluation system comprising an optical unit and a gemstone evaluation unit.

FIG. 2A depicts an exemplary schematic embodiment of a gemstone optical evaluation system in a closed configuration (light source not shown).

FIG. 2B depicts an exemplary schematic embodiment of a gemstone optical evaluation system in an open configuration (light source not shown).

FIG. 3 depicts an exemplary embodiment of a sample platform with surrounding ring light illumination.

FIG. 4 is a schematic diagram illustrating an exemplary image viewing angle and an image rotation angle.

FIG. 5A depicts an exemplary embodiment of a top reflector having an internal reflective surface.

FIG5B depicts an exemplary embodiment of a top reflector having an internal reflective surface.

FIG. 5C depicts an exemplary embodiment of a top reflector having an internal reflective surface.

FIG. 5D depicts an exemplary embodiment of a top reflector having an internal reflective surface.

FIG. 6A depicts an exemplary embodiment of a connector module for linking a gemstone assessment unit with an optical unit.

FIG6B depicts an exemplary embodiment of a connector module for linking a gemstone assessment unit with an optical unit.

FIG. 6C depicts an exemplary embodiment of a connector module for linking a gemstone assessment unit with an optical unit.

FIG. 7A depicts an exemplary embodiment showing an RBC diamond illuminated by a near-daylight light source.

FIG7B depicts an exemplary embodiment showing an image of an RBC diamond illuminated by a near-daylight light source after contour masking has been applied.

FIG7C depicts an exemplary embodiment showing extraction of a contour mask.

FIG7D depicts an exemplary embodiment showing the extraction of regions of significant fluorescence.

FIG. 7E depicts an exemplary embodiment showing extraction of a contour mask.

FIG7F depicts an exemplary embodiment showing the extraction of regions of significant fluorescence.

FIG8 depicts an exemplary organization of a computer system.

FIG9A depicts an exemplary procedure for data collection and analysis.

FIG9B depicts an exemplary procedure for data collection and analysis.

FIG9C depicts an exemplary procedure for data collection and analysis.

FIG. 10 depicts exemplary images taken under regular and UV illumination.

FIG. 11 depicts an exemplary embodiment, illustrating varying intensities in fluorescent emissions.

FIG12 depicts an exemplary embodiment illustrating inhomogeneous fluorescence emission.

FIG. 13 depicts an exemplary embodiment illustrating fluorescence emission in gemstones having different shapes.

FIG. 14 depicts an exemplary embodiment showing fluorescent emission in different colors.

FIG. 15 depicts an exemplary embodiment showing fluorescent emission in different colors.

DETAILED DESCRIPTION

Unless otherwise indicated, terms are understood according to common usage by those of ordinary skill in the relevant art. For illustrative purposes, diamond is used as a representative gemstone. Those skilled in the art will understand that the apparatus, systems, and methods disclosed herein are applicable to all types of gemstones capable of fluorescing upon UV exposure. Systems and methods for color grading based on similar apparatus are disclosed in U.S. Patent Application No. XX/XXX,XXX, entitled "APPARATUS AND METHOD FOR ASSESSING OPTICAL QUEALITY OF GEMSTONES," filed concurrently with the present application, which is incorporated herein by reference in its entirety.

As mentioned in the background, current automated instruments are unable to provide accurate, complete, and consistent assessments of the fluorescence properties of certain gemstones, such as those with irregular or fancy shapes. One reason for this failure is that a gemstone's fluorescence intensity is significantly affected by factors such as the gemstone's orientation relative to the detector, its position, and its size. Furthermore, even if some gemstones are regular round brilliant cut (RBC), these gemstones exhibit heterogeneous fluorescence distributions, and current instruments are unable to provide reproducible fluorescence grades for such stones.

To overcome existing problems, an improved fluorescence grading instrument as disclosed herein has the following features: (1) provides consistent and reproducible fluorescence grades for gemstones regardless of their size and shape; (2) provides consistent and reproducible fluorescence colors; and (3) provides consistent and reproducible fluorescence grades with ease and quick operation (e.g., the operator does not need to keep the stone in the same position).

In one aspect, an improved fluorescence grading apparatus for evaluating the fluorescence of gemstones, such as cut diamonds, is provided herein. The apparatus is suitable for grading gemstones, such as cut diamonds, including gemstones with irregular shapes, sizes, colors, and fluorescence distributions. An exemplary apparatus 100 is illustrated in FIG1 and includes, but is not limited to, for example, a gemstone assessment assembly 10, a light source 20 with a UV filter, a telecentric lens 30, and an image capture assembly 40.

Based on functionality, the components of the apparatus disclosed herein can be divided into two main units: a gemstone presentation unit and an optical unit. The gemstone presentation unit provides uniform illumination to the gemstone under analysis and the optical unit captures an image of the presented gemstone.

Additionally and not depicted in FIG. 1 , the exemplary apparatus further includes a computer processing unit for analyzing information collected by the image capture component.

As shown in FIG1 , an exemplary gemstone presentation unit comprises at least two parts: a gemstone evaluation assembly 10 and a light source 20. The gemstone evaluation assembly is where the gemstone is presented. As depicted in FIG2A and FIG2B , the gemstone evaluation assembly has a closed configuration and an open configuration. Here, light source 20 is omitted from FIG2A and FIG2B for clarity of illustration of the different configurations. In the closed configuration (e.g., see FIG2A ), the gemstone undergoing analysis is completely concealed and invisible to the observer. In some embodiments, to avoid inconsistencies caused by ambient or other light, the gemstone evaluation assembly is an isolated and closed system that excludes ambient or other light. The gemstone evaluation assembly and the optical unit engage in a complementary manner, thereby excluding ambient or other light from the hidden sample chamber within which the sample gemstone is housed. Although a fluorescent light source is not depicted in FIG2A and FIG2B , those skilled in the art will appreciate the need for such a light source for fluorescence grading of gemstones.

In the closed configuration, image information about the gemstone under analysis is received and captured by an optical unit comprising a telecentric lens 30 and an image capture device 40 (eg a camera).

In the open configuration (see, for example, FIG. 2B ), no image information is collected. Instead, the gemstone undergoing analysis is exposed to the viewer. In the open configuration, the exposed gemstone presentation unit has two parts: a bottom presentation assembly 50 and a top reflector assembly 60. In some embodiments, as shown in FIG. 2B , the top reflector assembly is mounted on movable side rails. When the top reflector is moved away from the optical unit on such rails, the bottom presentation assembly 50 is exposed. As shown in FIG. 2B , the shape and design of the opening of the top reflector assembly 60 complements the shape and design of the optical connector module of the optical unit (e.g., assembly 70 in FIG. 2B ). In some embodiments, the optical connector module is a lens cover to which the telecentric lens 30 is attached.

An exemplary bottom presentation assembly 50 is shown in Figure 3. A circular white reflective platform 510 serves as a base on which a sample gemstone 520 is placed. Concentric ring lights 530 are placed outside the circular platform so that the platform is completely enclosed within the ring lights 530.

The platform 510 (also referred to as a stage or sample stage) is important to the system disclosed herein. Importantly, it provides support to the gemstone being analyzed. In some embodiments, the top surface of the platform is horizontal and flat. In addition, it serves as a stage for data collection and subsequent analysis by the telecentric lens 30 and the image capture device 40. To achieve data consistency, the telecentric lens 30 is positioned at a first predetermined angle relative to the top surface of the platform 510. In some embodiments, the image capture device 40 is positioned at a second predetermined angle relative to the top surface of the platform 510. In some embodiments, the first predetermined angle and the second predetermined angle are the same and have been optimized for data collection. In some embodiments, the first predetermined angle and the second predetermined angle are different, but both have been optimized for data collection. The first predetermined angle and the second predetermined angle can be referred to as image viewing angles or camera viewing angles.

An exemplary illustration of the relative configuration of the top surface of platform 510 and the optical unit (e.g., telecentric lens 30 and camera 40) is depicted in Figure 4. Here, the optical unit including both telecentric lens 30 and image capture device 40 is positioned at a predetermined angle (α) relative to the platform surface.

In some embodiments, the circular reflective platform is rotatable. For example, the platform can be mounted on or connected to a rotor. In a preferred embodiment, the gemstone to be analyzed is placed at the center of the platform surface, as shown in FIG3 . The platform is then rotated relative to the optical unit, allowing the image capture device to collect images of the gemstone at different angles.

In some embodiments, the platform surface is rotated about an axis of rotation that passes through the initial center of the circular platform surface and is perpendicular to the platform surface; see, for example, axis Zz depicted in FIG. 4 .

In some embodiments, the platform is rotated relative to the optical unit by set angular variations. The magnitude of these angular variations determines the extent of data collection; for example, how many images of the gemstone will be collected. For example, if the platform is rotated by an angular variation of 12 degrees, a full rotation will allow 30 images of the gemstone to be collected. The angular variations can be set to any value to facilitate data collection and analysis. For example, the platform can be rotated by an angular variation of 0.5 degrees or less, 1 degree or less, 1.5 degrees or less, 2 degrees or less, 3 degrees or less, 4 degrees or less, 5 degrees or less, 6 degrees or less, 7 degrees or less, 8 degrees or less, 9 degrees or less, 10 degrees or less, 12 degrees or less, 15 degrees or less, 18 degrees or less, 20 degrees or less, 24 degrees or less, 30 degrees or less, 45 degrees or less, 60 degrees or less, 90 degrees or less, 120 degrees or less, 150 degrees or less, or 180 degrees or less. It will be appreciated that the angular rotation variation can be set to any value. It will also be understood that the platform can be rotated to any total rotation angle and is not limited to a full 360 degree rotation. In some embodiments, data (e.g., color images) are collected for rotations less than a full 360 degree rotation. In some embodiments, data (e.g., color images) are collected for rotations greater than a full 360 degree rotation.

In some embodiments, the platform or a portion thereof (e.g., the top surface) is reflective using a reflective surface coating. In some embodiments, the platform or a portion thereof (e.g., the top surface) comprises a reflective material. In some embodiments, the platform or a portion thereof (e.g., the top surface) is made of a reflective material. In some embodiments, the reflective material is a white reflective material. In some embodiments, the reflective material is Teflon ^™ material. In some embodiments, the reflective material includes, but is not limited to, polytetrafluoroethylene (PTFE), Spectralon ^™ , barium sulfate, gold, magnesium oxide, or a combination thereof.

Preferably, the rotatable platform is circular and larger than the size of any sample gemstone to be analyzed. In some embodiments, the platform is horizontal and remains horizontal as it rotates.

In some embodiments, the height of the platform is fixed. In some embodiments, the height of the platform is adjusted manually or via the control of a computer program. Preferably, the platform can be raised or lowered by the control of a computer program run by a computer unit.

In some embodiments, the platform is flat. In some embodiments, a central region on which the gemstone sample is positioned is flat and a more peripheral region on the platform is not flat. Confirmation that the entire platform adopts a flat dome-like structure.

In some embodiments, the relative position between the platform and the illumination source can be adjusted. For example, the illumination source can be moved closer to or further away from the platform.

The platform can be made of any rigid and non-transparent material, such as metal, wood, black glass, plastic or other rigid polymeric materials. In some embodiments, the platform and/or the area surrounding the platform is coated with a non-reflective or low-reflective material.

In the broadest sense, light source 20 includes, but is not limited to, a source for generating light, one or more filters, components for directing the generated light, and components (e.g., a ring light) for emitting the generated light as UV illumination. In the embodiment depicted in FIG3 , ring light 530 provides UV illumination to the sample gemstone. As disclosed herein, a source for generating light is sometimes referred to as a light source. Those skilled in the art will understand that the illumination components are also part of the light source.

In some embodiments, the light generating source is separate from the final illumination assembly, for example, it is connected to an external ring light (e.g., by a light transmission cable) to provide the illumination source. In such embodiments, a short-pass filter and a band-pass filter are applied before or after the illumination source reaches the ring light for UV light selection. Thus, the illumination ultimately provided by the ring light has a defined ultraviolet characteristic; for example, having one or more wavelengths in the UV range. Such wavelengths can be any wavelength from the range of 400 nm to 10 nm, 400 nm to 385 nm, 385 nm to 350 nm, 350 nm to 300 nm, 300 nm to 250 nm, 250 nm to 200 nm, 200 nm to 150 nm, 150 nm to 100 nm, 100 nm to 50 nm, or 50 nm to 10 nm.

In one aspect, the light generating sources disclosed herein are capable of producing fluorescence excitation (e.g., at 365 nm). In another aspect, the light generating sources disclosed herein provide light illumination for gemstone outline identification. This dual functionality is achieved by using a combination of specialized light sources and different types of light sources.

In some embodiments, a tunable light source capable of emitting both UV and white light is used. For example, this tunable light source includes one or more LEDs. Advantageously, this light source can be used for both contour recognition and fluorescence measurement. For example, a built-in mechanism can be used to allow the user to switch between two operating modes. In some embodiments, the light source (for example, emitting UV LED) emits UV illumination at a desired wavelength (for example, at 365 nanometers). For example, a UV LED emitting UV light at a single wavelength (for example, 365 nanometers or 385 nanometers) is available (for example, from Hamamatsu). In some embodiments, the light source (for example, emitting UV LED) emits UV illumination at a certain range and emits a desired wavelength by applying a UV-pass filter (UV-pass filter) that is set at, for example, 365 nanometers.

In such an embodiment, the tunable light source provides uniform top illumination or uniform bottom illumination. For top illumination, there is no restriction on the shape and size of the light source. For example, the light source can be circular, partially circular, or completely non-circular (e.g., elliptical, square, or triangular). There is also no restriction on the distance from the gemstone sample. For example, the tunable light source is attached to the reflective interior surface of the top reflective component 60 (e.g., FIG. 2B ). A combination of light sources can be used; including (but not limited to) one or more UV LEDs; one or more UV LEDs with an optical diffuser; one or more UV LEDs with a collimating lens; or one or more UV LEDs with a collimating lens and an optical diffuser. Those skilled in the art will understand that any combination of light sources and optical components that can provide uniform illumination will be suitable for use as a light source in an apparatus as disclosed herein.

For bottom illumination, the light source is preferably a ring light compatible with the shape of the sample platform 50 (e.g., FIG. 2B ). Here, the components that can generate UV illumination are arranged in a circular or nearly circular shape. For example, UV LEDs that emit UV light at a single wavelength (e.g., 365 nm or 385 nm) are available (e.g., from Hamamatsu). In some embodiments, the ring light is embedded within one or more UV LEDs.

In some embodiments, more than one light source is used. At least one of these light sources is a UV light source (such as one or more UV-emitting LEDs). At least another of these light sources is a white light source. Any suitable white light source can be used, including but not limited to a fluorescent lamp, a halogen lamp, a Xe lamp, a tungsten lamp, a metal halide lamp, laser-induced white light (LDLS), or a combination thereof.

Many combinations can be used in such embodiments. For example, two ring lights can be used: one providing uniform UV illumination and one providing uniform near-daylight illumination. In this combination, in some embodiments, both light sources provide bottom illumination. In some embodiments, one ring light provides bottom illumination while the other provides top illumination.

In another exemplary combination, the light source includes a ring-shaped UV LED light source and a white light source. In some embodiments, the ring-shaped UV LED is used to provide bottom lighting, and the white light source provides top lighting.

In another exemplary combination, the light source includes an annular white light source and an LED light source. In some embodiments, the annular white light source is used to provide bottom lighting, and the UV LED source provides top lighting.

As mentioned, white light sources include daylight-like light sources. Exemplary daylight-like light sources include, but are not limited to, one or more halogen lamps with color-balancing filters, a plurality of light-emitting diodes arranged in a ring-like structure around the platform surface, fluorescent lamps, Xe lamps, tungsten lamps, metal halide lamps, laser-induced white light (LDLS), or combinations thereof. In some embodiments, a color-balancing filter is used to produce a daylight-equivalent light source.

In some embodiments, either the white light source or the UV light source can be a ring light, where applicable. For example, with respect to the UV light source, the components that can generate UV illumination are arranged in a circular or nearly circular shape. For example, UV light emitting diodes that emit UV light at a single wavelength (e.g., 365 nanometers or 385 nanometers) are available (e.g., from Hamamatsu). In some embodiments, the ring light is embedded within one or more UV LEDs.

In some embodiments, a cable (such as a gooseneck light guide, a flexible light guide, each containing one or more branches) is used to connect the ring light to the light generating source.

The UV illumination source can be of any shape and size suitable for optical analysis of a sample gemstone. For example, the illumination source can be a point light, a circular light, an annular light, an elliptical light, a triangular light, a square light, or any other light of suitable size and shape. In some embodiments, the illumination source is annular or circular in shape, having a diameter greater than the diameter of the circular platform.

A UV illumination assembly provides input light under which sample gemstones can be analyzed. Advantageously, gemstones that fluoresce under UV illumination can be analyzed with high sensitivity in an environment with little or no interfering light (e.g., from ambient or other sources). Exposure to UV illumination results in the emission of visible fluorescence. When the effects of UV illumination are eliminated (e.g., by setting the optical filter on the detector or image capture assembly to the visible light range only), the emitted fluorescence is compared to a zero background (e.g., no fluorescence). Here, the signal-to-noise ratio is very high due to the low or near-zero noise level.

A modular approach to the design of the apparatus has been adopted to provide experimental flexibility.In some embodiments, the intensity of the UV illumination can be adjusted to optimize image collection.

A modular approach to the design of the apparatus has been adopted to provide experimental flexibility.In some embodiments, the intensity of the UV illumination can be adjusted to optimize image collection.

As shown in Figures 2A and 2B, the top reflector module can be moved over the area in which the sample gemstone is positioned. In the closed configuration shown in Figure 2A, the internal chamber of the top reflector module serves as a sealed and isolated sample chamber, wherein the sample gemstone is analyzed in a controlled environment. For example, ambient light or other light is excluded from the chamber. The user can adjust the light intensity within the chamber to optimize data collection. In some embodiments, the collected data includes color images of the gemstone viewed from different angles.

Figures 5A-5D illustrate exemplary embodiments of a top reflector assembly 60. Generally speaking, the top reflector has an exterior shape that resembles that of a short cylinder, except that portions of the cylinder are carved out to form a curved slope (e.g., see assembly 610 in Figures 5B and 5D). Portions of the slope are removed to allow access to the interior of the reflector assembly. For example, as shown in Figures 5A-5D, the lower portion of slope 610 is removed to form opening 620. In some embodiments, the top port of opening 620 is circular in design; for example, having a diameter through which a lens from an optical unit is mounted. In some embodiments, the diameter is the same as the diameter of a telecentric lens to prevent ambient or other light from entering the interior of the reflector. In some embodiments, the diameter is slightly larger than the diameter of the telecentric lens, requiring an adapter module to prevent ambient or other light from entering the interior of the reflector.

Inside the top reflector module 60 is a reflective surface 630. This internal reflective surface is at least partially hemispherical. In some embodiments, the internal reflective surface takes a shape that is a portion of an involute of a circle having a radius R. In a preferred embodiment, the circle is positioned at the center of the platform surface and has a diameter greater than the size of the gemstone being analyzed. The shape of the involute surface is described based on the following equation:

x＝R(cosθ+θsinθ)

y = R (sinθ - θ cosθ), where R is the radius of the circle and θ is the angular parameter in radians. The involute surface will reflect light towards the central circular area so that the illumination of the gemstone being analyzed is optimized.

In some embodiments, the reflective surface 630 or a portion thereof comprises a reflective material. In some embodiments, the reflective surface 630 or a portion thereof is made of a reflective material. In some embodiments, the reflective material is a white reflective material. In some embodiments, the reflective material is Teflon ^™ material. In some embodiments, the reflective material includes, but is not limited to, polytetrafluoroethylene (PTFE), Spectralon ^™ , barium sulfate, gold, magnesium oxide, or a combination thereof. Additional reflective coating materials include, but are not limited to, zinc salts (zinc sulfide), titanium dioxide, silicon dioxide, and magnesium salts (magnesium fluoride, magnesium sulfide).

In some embodiments with bottom UV illumination (such as when a ring light of UV LEDs is used), one or more reflective materials are used to reflect the UV illumination toward the gemstone. In some embodiments with top UV illumination, no reflective material is required.

As shown in FIG. 2B , the optical connector module 70 links the gemstone assessing unit with the optical unit to allow data collection by the image capture device 40 , while simultaneously preventing ambient or other light from entering the gemstone assessing unit and interfering with data measurement.

Figures 6A-6C provide a more detailed illustration of an exemplary embodiment of an optical connector module. In this case, the connector is a lens cover for receiving a telecentric lens 30. On the side that contacts the telecentric lens, the lens cover has a flat surface 710. On the opposite side that contacts the reflector, the lens cover has a curved surface 720. In some embodiments, the curved surface 720 has a shape that complements the curved surface 610 on the reflector.

Additionally, the connector also has an opening 730; see Figures 6A, 6B, and 6C. In some embodiments, opening 730 has a configuration that accommodates a telecentric lens while preventing interference from ambient or other light. For example, the opening 730 depicted in Figures 6A-6B has a cylindrical opening whose size is non-uniform. For example, the diameter of the cylindrical opening on the contact lens side is smaller than the diameter of the cylindrical opening on the contact reflector side.

The lens cover or other optical connector module allows the integration of two different functional components. It is designed so that no or very little ambient light or other light enters the sample chamber. In some embodiments, additional components (such as sealing tape) can be used to exclude ambient light or other light.

Another key functional component of the system is the optical unit, through which data from the gemstone being analyzed passes. The optical unit provides a sample chamber that enables the collection of the visible spectrum from the area containing the sample gemstone while excluding light from outside the chamber. Optical measurements (such as images) are captured of the area containing the sample gemstone, and detailed structural analysis of the images can provide insights into the causes of previously anomalous grading results for certain stones.

The exemplary embodiments disclosed herein include, but are not limited to, two important functional modules in the optical unit, a telecentric lens 30 and an image capture component 40 (such as a color camera). Those skilled in the art will understand that additional components may be present to facilitate data collection.

Telecentric lenses are used to provide an image of an illuminated gemstone to an image capture assembly. Telecentricity refers to a unique optical property in which the principal rays (the oblique rays passing through the center of the top of the aperture) passing through a certain lens design are collimated and parallel to the optical axis in image and/or object space. A telecentric lens is a compound lens that has its entrance or exit pupil at infinity. Advantageously, a telecentric lens provides constant magnification over a range of working distances (object size does not change), virtually eliminating solid angle errors. For many applications, this means that object movement does not affect image magnification, allowing for highly precise measurements in measurement applications. This level of accuracy and repeatability is not achievable with standard lenses. The simplest way to telecenter a lens is to stop the aperture at one of the lens' focal points.

There are three types of telecentric lenses. An entrance pupil at infinity makes the lens object-space telecentric. An exit pupil at infinity makes the lens image-space telecentric. If both pupils are at infinity, the lens is bi-telecentric.

A telecentric lens with a high depth of field is used in the systems disclosed herein. In some embodiments, the telecentric lens used is an object-space telecentric lens. In some embodiments, the telecentric lens is a bi-telecentric lens. In a preferred embodiment, the zoom should be fixed for all images collected of a given gemstone stone to further ensure consistency.

Advantageously, the present apparatus and system do not require the sample gemstone to be placed at the center of the platform surface. Additionally, the telecentric lens does not discriminate between the sizes of the sample gemstones. The same telecentric lens can be used to collect images of very small gemstones and significantly larger gemstones.

The optical unit further comprises an image capturing component or detector such as a digital camera.In order to capture only the fluorescence emitted from these gemstones, filters are applied to exclude interference from UV illumination.

In some embodiments, image capture component 40 comprises one or more photodiode arrays of a CCD (charge coupled device). In some embodiments, image capture component 40 comprises one or more CMOS (complementary metal oxide semiconductor) image sensors. In some embodiments, image capture component 40 comprises a combination of one or more photodiode arrays and a CMOS sensor. In some embodiments, image capture component 40 is a CCD digital camera, such as a color digital camera. When analyzing images from different fluorescence grading devices, more consistent results may be obtained if the devices use the same type of detection method; for example, all CCD arrays, all CMOS sensors, or the same combination of both types.

For more accurate analysis results, the resolution limit of the collected digital image is 600 pixels x 400 pixels or greater. In some embodiments, each pixel has an 8-bit value (e.g., 0 to 255) for each color component. The analog-to-digital converter (ADC) of the digital camera is 8 bits or greater to efficiently process the information embedded in the pixels with little or no loss in image quality. In some embodiments, the ADC is 10 bits or greater, depending on the dynamic range of the image capture component. In some embodiments, the ADC is between 10 and 14 bits.

In some embodiments, the color components of a pixel include, but are not limited to, red (R), green (G), and blue (B). In some embodiments, the color components of a pixel include, but are not limited to, cyan (C), magenta (M), yellow (Y), and key (black or B). In some embodiments, the color components of a pixel include, but are not limited to, red (R), yellow (Y), and blue (B).

Image viewing angle: As depicted in Figure 4, the image capture device of the optical unit (or the telecentric lens 30, or both) is positioned at a predetermined angle (α, also referred to as the image viewing angle) relative to the platform surface. In some embodiments, the image viewing angle is 65 degrees or less, 60 degrees or less, 56 degrees or less, 52 degrees or less, 50 degrees or less, 48 degrees or less, 46 degrees or less, 44 degrees or less, 42 degrees or less, 40 degrees or less, 39 degrees or less, 38 degrees or less, 37 degrees or less, 36 degrees or less, 35 degrees or less, 34 degrees or less, 33 degrees or less, 32 degrees or less, 31 degrees or less, 32 ... In some embodiments, the image viewing angle is between about 10 degrees and about 45 degrees. For consistency, the image viewing angle for a given gemstone will remain constant as the images are collected.

Image Rotation Angle: As also illustrated in FIG4 , the relative rotational position between the imaging capture assembly and a predefined location on the platform (e.g., point 540) can be described by an image rotation angle β. For example, the image capture assembly and the platform surface can be rotated relative to each other so that the image rotation angle is changed by a set angular change between consecutive images. For example, the angular change between two consecutive images can be 0.5 degrees or less, 1 degree or less, 1.5 degrees or less, 2 degrees or less, 3 degrees or less, 4 degrees or less, 5 degrees or less, 6 degrees or less, 7 degrees or less, 8 degrees or less, 9 degrees or less, 10 degrees or less, 12 degrees or less, 15 degrees or less, 18 degrees or less, 20 degrees or less, 24 degrees or less, 30 degrees or less, 45 degrees or less, 60 degrees or less, 90 degrees or less, or 180 degrees or less. It will be appreciated that the angular rotation change can be set in any number.

It will also be understood that the platform and image capture assembly can be rotated relative to each other by any total rotation angle, not limited to a full 360 degree rotation. In some embodiments, data (e.g., color images) are collected over a rotation of less than a full 360 degree rotation. In some embodiments, data (e.g., color images) are collected over a rotation of more than a full 360 degree rotation.

When collecting a set of images of the same sample gemstone, the angular rotation variation can be varied. For example, the angular difference between Image 1 and Image 2 may be 5 degrees, but the difference between Image 2 and Image 3 may be 10 degrees. In a preferred embodiment, the angular difference between consecutive images remains constant within the same set of images of the same sample gemstone. In some embodiments, only one set of images is collected for a given sample gemstone. In some embodiments, multiple sets of images are collected for the same gemstone, where the angular difference remains constant within each set but varies from set to set. For example, a first set of images may be collected by varying the image rotation angle by 12 degrees for consecutive images, while a second set of images may be collected by varying the image rotation angle by 18 degrees for consecutive images.

The number of images collected for a given sample gemstone varies depending on the characteristics of the gemstone. Exemplary characteristics include, but are not limited to, shape, cut, size, color, etc.

A visible spectrum is selectively collected from an area on the surface of the platform containing the sample gemstone. In some embodiments, multiple color images are collected for each gemstone. In some embodiments, multiple colorless images are collected for each gemstone. Color images are useful for determining the color grade of, for example, a cut diamond.

In some embodiments, as will be discussed further in the following sections, images captured by a CCD camera are processed to identify regions of varying color or fluorescence intensity. Furthermore, colorimetric calculations can be performed on these distinct regions using the red, green, and blue signals from the camera pixels. In some embodiments, such calculations are sufficiently accurate to provide a fluorescence grade. In some embodiments, such calculations are sufficiently accurate to provide a color distribution across the diamond, and comparison of these color calculations with those obtained from measured spectra can help identify diamonds that may be giving anomalous results.

In some embodiments, the fluorescence grade is determined based on a color value calculated from the entire sample gemstone. In some embodiments, the fluorescence grade is determined based on a color value calculated from a color region of the sample gemstone.

The resolution and capacity of a detector can be determined by the number and size of pixels in the detector array. Generally speaking, the spatial resolution of a digital image is limited by the pixel size. Unfortunately, while reducing pixel size improves spatial resolution, this comes at the expense of the signal-to-noise ratio (SNR). Specifically, the SNR improves when increasing the image sensor pixel size or cooling the image sensor. At the same time, if the image sensor resolution remains the same, the image sensor size is increased. Higher-quality detectors (e.g., better digital cameras) have large image sensors and relatively large pixel sizes for good image quality.

In some embodiments, the detectors of the present invention have an area of 1 square micron or less; 2 square microns or less; 3 square microns or less; 4 square microns or less; 5 square microns or less; 6 square microns or less; 7 square microns or less; 8 square microns or less; 9 square microns or less; 10 square microns or less; 20 square microns or less; 30 square microns or less; 40 square microns or less; 50 square microns or less; 60 square microns or less; 70 square microns or less; 80 square microns or less; 90 square microns or less; 100 square microns or less; 200 square microns or less; 300 square microns or less; 400 square microns or less; 500 square microns or less; 600 square microns or less; square micrometers or less; 700 square micrometers or less; 800 square micrometers or less; 900 square micrometers or less; 1000 square micrometers or less; 1100 square micrometers or less; 1200 square micrometers or less; 1300 square micrometers or less; 1400 square micrometers or less; 1500 square micrometers or less; 1600 square micrometers or less; 1700 square micrometers or less; 1800 square micrometers or less; 1900 square micrometers or less; 2000 square micrometers or less; 2100 square micrometers or less; 2200 square micrometers or less; 2300 square micrometers or less; 2400 square micrometers or less; 2500 square micrometers or less; 2600 square micrometers or less; 270 0 square microns or less; 2800 square microns or less; 2900 square microns or less; 3000 square microns or less; 3100 square microns or less; 3200 square microns or less; 3300 square microns or less; 3400 square microns or less; 3500 square microns or less; 3600 square microns or less; 3700 square microns or less; 3800 square microns or less; 3900 square microns or less; 4000 square microns or less; 4100 square microns or less; 4200 square microns or less; 4300 square microns or less; 4400 square microns or less; 4500 square microns or less; 4600 square microns or less; 4700 square microns or less In some embodiments, the pixel size is greater than 10,000 square microns, for example, up to 20,000 square microns, 50,000 square microns, or less.

In some embodiments, the exposure time for the detector can be adjusted to optimize image quality and to facilitate determination of the grade of the gemstone's optical properties, such as color or fluorescence level. In some embodiments, the fluorescence emission is quite weak and therefore requires a long exposure time for evaluating the fluorescence quality. For example, the exposure time for the CCD detector can be 0.1 milliseconds (ms) or longer, 0.2 ms or longer, 0.5 ms or longer, 0.8 ms or longer, 1.0 ms or longer, 1.5 ms or longer, 2.0 ms or longer, 2.5 ms or longer, 3.0 ms or longer, 3.5 ms or longer, 4.0 ms or longer, 4.5 ms or longer, 5.0 ms or longer, 5.5 ms or longer, 6.0 ms or longer, 6.5 ms or longer, 7.0 ms or longer, 7.5 ms or longer, 8.0 ms or longer, 8.5 ms or longer, 9.0 ms or longer, 9.5 ms or longer. long, 10.0 ms or longer, 15.0 ms or longer, 20.0 ms or longer, 25.0 ms or longer, 30.0 ms or longer, 35.0 ms or longer, 40.0 ms or longer, 45.0 ms or longer, 50.0 ms or longer, 55.0 ms or longer, 60.0 ms or longer, 65.0 ms or longer, 70.0 ms or longer, 75.0 ms or longer, 80.0 ms or longer, 85.0 ms or longer, 90.0 ms or longer, 95.0 ms or longer, 100.0 ms or longer, 105.0 ms or longer, 110.0 ms or longer, 115 .0 ms or longer, 120.0 ms or longer, 125.0 ms or longer, 130.0 ms or longer, 135.0 ms or longer, 140.0 ms or longer, 145.0 ms or longer, 150.0 ms or longer, 175.0 ms or longer, 200.0 ms or longer, 225.0 ms or longer, 250.0 ms or longer, 275.0 ms or longer, 300.0 ms or longer, 325.0 ms or longer, 350.0 ms or longer, 375.0 ms or longer, 400.0 ms or longer, 425.0 ms or longer, 450.0 ms or longer, 4 1 or more seconds, 1.6 or more seconds, 1.7 or more seconds, 1.8 or more seconds, 1.9 or more seconds, 2 or more seconds, 2.5 or more seconds, 3 or more seconds. It will be appreciated that exposure times may vary with respect to, for example, the intensity of the light source.

In another aspect, the methods and systems disclosed herein are used to detect or assess changes in the fluorescence properties of a sample gemstone over time. For example, the color of a gemstone's fluorescence may change over time. Similarly, the intensity of a gemstone's fluorescence may change over time.

In such embodiments, multiple sets or images (e.g., color images) are collected over a period of time. For example, using the system disclosed herein, sets of images are automatically collected at multiple image angles. There is no limit to how many sets of images can be collected over time. For example, two or more sets of images can be collected; three or more sets of images; four or more sets of images; five or more sets of images; six or more sets of images; seven or more sets of images; eight or more sets of images; nine or more sets of images; 10 or more sets of images; 15 or more sets of images; 20 or more sets of images; 30 or more sets of images; 50 or more sets of images; or 100 or more sets of images can be collected.

In some embodiments, all sets of images are collected of the same gemstone using the same system configuration; for example, using the same camera, same image angle, same reflector, same platform, etc.

In the multiple image sets, two consecutive image sets are each used for a time interval ranging from a few minutes to a few hours or even days, depending on the nature of the color change in the stone. The duration of the time interval is determined by how quickly the color change occurs in the sample stone. There is no limit to how long or short the time interval can be. For example, the time interval can be two minutes or less; five minutes or less; 10 minutes or less; 20 minutes or less; 30 minutes or less; 60 minutes or less; 2 hours or less; 5 hours or less; 12 hours or less; 24 hours or less; 2 days or less; 5 days or less; or 10 days or less.

In some embodiments, calculations are performed for each set of images to assign a fluorescence grade to the sample gemstone.The fluorescence grades from multiple sets of images are then compared to determine changes in fluorescence over time.

In another aspect, a data analysis unit is also provided herein, comprising both hardware components (eg, a computer) and software components.

The data analysis unit stores, converts, analyzes, and processes the images collected by the optical unit. The computer unit controls various components of the system, such as the rotation and height adjustment of the platform, the intensity of the illumination source, and the exposure time. The computer unit also controls the zoom and adjusts the relative position of the optical unit and the gemstone platform.

8 illustrates an exemplary computer unit 800. In some embodiments, computer unit 800 includes a central processing unit 810, a power supply 812, a user interface 820, communication circuitry 816, a bus 814, a non-volatile storage controller 826, optional non-volatile storage 828, and memory 830.

The memory 830 may include volatile and non-volatile storage units, such as random access memory (RAM), read-only memory (ROM), flash memory, and the like. In some embodiments, the memory 830 includes high-speed RAM for storing system control programs, data, and application programs, such as those loaded from the non-volatile storage 828. It will be appreciated that at any given time, all or a portion of any module or data structure in the memory 830 may actually be stored in the memory 828.

The user interface 820 may include one or more input devices 824 (e.g., a keyboard, keypad, mouse, scroll wheel, and the like) and a display 822 or other output device. A network adapter card or other communication circuit 816 may provide a connection to any wired or wireless communication network. An internal bus 814 provides interconnection of the aforementioned components of the computer unit 30.

In some embodiments, the operation of computer unit 800 is primarily controlled by an operating system 828, which is executed by central processing unit 810. Operating system 382 may be stored in system memory 830. In addition to operating system 382, a typical embodiment of system memory 830 may include a file system 834 for controlling access to various files and data structures used by the present invention, one or more application modules 836, and one or more databases or data modules 852.

In some embodiments according to the present invention, the application module 836 may include one or more of the following modules described below and illustrated in FIG. 8 .

Data Processing Application 838: In some embodiments according to the present invention, the data processing application 838 receives and processes the optical measurements shared between the optical unit and the data analysis unit. In some embodiments, the data processing application 838 utilizes an algorithm to determine the portion of the image that corresponds to the sample gemstone and eliminates extraneous digital data. In some embodiments, the data processing application 838 converts each pixel of the digital image into its individual color components.

Content Management Tool 840: In some embodiments, the content management tool 840 is used to organize different forms of data 852 into multiple databases 854, such as an image database 856, a processed image database 858, a reference gem database 860, and an optional user password database 862. In some embodiments according to the present invention, the content management tool 840 is used to search and compare any database hosted on the computer unit 30. For example, images of the same sample gemstone acquired at different times can be organized into the same database. Additionally, information about the sample gemstone can be used to organize the image data. For example, images of diamonds of the same cut can be organized into the same database. Additionally, images of diamonds from the same source can be organized into the same database.

The database stored on computer unit 800 includes any form of data storage system, including (but not limited to) flat files, relational databases (SQL), and online analytical processing (OLAP) databases (MDX and/or its variations). In some specific embodiments, the database is a hierarchical OLAP cube. In some embodiments, the database has a star schema that is not stored as a cube but has dimension tables that define the hierarchy. Furthermore, in some embodiments, the database has a hierarchy that is not explicitly broken in the underlying database or database schema (e.g., the dimension tables are not arranged hierarchically).

In some implementations, the content management tool 840 utilizes an aggregation method for determining ranking characteristics.

System Management and Monitoring Tool 842: In some embodiments according to the present invention, System Management and Monitoring Tool 842 manages and monitors all applications and data files on Computer Unit 30. System Management and Monitoring Tool 842 controls which users, servers, or devices have access to Computer Unit 30. In some embodiments, security management and monitoring is achieved by restricting data download and upload access to Computer Unit 800, thereby protecting data from malicious access. In some embodiments, System Management and Monitoring Tool 842 uses one or more security measures to protect data stored on Computer Unit 30. In some embodiments, a random rotation security system can be applied to protect data stored on remote Computer Unit 30.

Network application 846: In some embodiments, the network application 846 connects the computer unit 800 to a network and thereby to any network device. In some embodiments, the network application 846 receives data from an intermediate gateway server or one or more remote data servers before transferring the data to other application modules (such as the data processing application 838, the content management tool 840, and the system management and monitoring tool 842).

Computational and analytical tools 848: The computational and analytical tools 848 may apply any available method or algorithm to analyze and process the images collected from the sample gemstone.

System Adjustment Tool 850: The system adjustment tool 850 controls and modifies the configuration of various components of the system. For example, the system adjustment tool 850 can switch between different masks, change the size and shape of the adjustable mask, adjust the zoom optics, set and modify the exposure time, and so on.

Data Modules 852 and Databases 854: In some embodiments, each of the data structures stored on the computer unit 800 is a single data structure. In other embodiments, any or all of such data structures may include multiple data structures (e.g., databases, files, and archives), which may or may not all be stored on the computer unit 30. One or more data modules 852 may include any number of databases 852 organized into different structures (or other forms of data structures) by the content management tool 840.

In addition to the modules identified above, various databases 854 may be stored on the computer unit 800 or on a remote data server addressable by the computer unit 800 (e.g., any remote data server to which the computer unit can send information and/or from which the computer unit can retrieve information). Exemplary databases 854 include, but are not limited to, an image database 856, a processed image database 858, a reference gemstone database 860, an optional component code data set 862, and gemstone data 864.

Image database 856 is used to store images of gemstones before they are analyzed. Processed image database 858 is used to store processed images of gemstones. In some embodiments, processed image database 858 also stores data converted from the processed images. Examples of converted data include, but are not limited to, individual color components of pixels in an image; a two-dimensional or three-dimensional map representing the color distribution of pixels in an image; calculated L ^* , C ^* , a, or b values for pixels in an image; and an average of the L ^* , C ^* , a, or b values for one or more images.

Reference Gemstone Database 860: Data (e.g., grade values or L ^* , C ^* , a, or b values) for existing or known reference or master gemstones is stored in the reference gemstone database 860. In some embodiments, information about known reference or master gemstones is used as a standard for determining the grade value or L ^* , C ^* , a, or b value of an unknown gemstone sample. Optical qualities (such as color or fluorescence grade) have already been determined for the known reference or master gemstones. For example, optical measurements of a brilliant-cut sample diamond are used to calculate L ^* , C ^* , a, or b values, which are then compared to the L ^* , C*, ^a , or b values of multiple known reference or master diamonds of the same cut. The grade of the sample diamond is determined by the closest match to the reference gemstone. In preferred embodiments, the reference gemstone is of the same or similar size or weight as the sample gemstone.

Optional User Password Database 862: In some embodiments, an optional password database 862 is provided. Passwords and other security information about users of the system can be generated and stored on the computer unit 800 where the user's password is stored and managed. In some embodiments, the user is given the opportunity to select security settings.

In one aspect, methods are provided herein for system calibration, data collection, data processing, and analysis. For example, a color digital image of a gemstone is obtained, processed, and calculated to provide one or more values for evaluating and grading the quality of a cut gemstone, such as a diamond.

Not all gemstones fluoresce upon UV exposure. Even for gemstones that do fluoresce upon UV exposure, the fluorescence level is highly unlikely to be uniform, as fluorescent material is typically not evenly distributed within the gemstone. Furthermore, not all parts of the gemstone may fluoresce. An important aspect of fluorescence grading is precisely identifying the regions within which fluorescence is emitted and focusing data analysis within these regions to improve accuracy.

For fluorescence analysis, at least two sets of test data are used. For example, for a given sample gemstone under identical conditions (e.g., at a set image angle and a set image rotation angle), at least two images are captured: one image under regular non-UV illumination (e.g., under a visible near-daylight source), and another image under UV illumination (e.g., a fluorescence image or a fluorescence image, also referred to as a UV image). In some embodiments, the set of images captured under regular non-UV illumination is used to extrapolate contour masks. In some embodiments, the set of images captured under UV illumination is used to extrapolate regions of fluorescence (e.g., Figures 7C and 7D). In contrast, a single set of test data is used for color analysis. For example, multiple color images of the sample gemstone are captured under identical illumination conditions (e.g., under a near-daylight source) using a telecentric lens, at the same image angle, and with the image rotation angle varied at set intervals.

Figures 7A and 7B depict images of a diamond in which the background white color has been masked to highlight the presence of the diamond. As shown in Figure 7B , a contour mask is formed around the dark region of the diamond. In some embodiments, the contour mask corresponds to the physical boundary or edge of the sample gemstone, as viewed at a given image viewing angle and a given image rotation angle. Thus, the opening of the contour mask encompasses the full image or entire region of the sample gemstone at a given image viewing angle and image rotation angle. As described in the methods section of the analysis section, such a contour mask can be defined for each image to isolate the region for analysis and extract measurements (such as width and height).

FIG7C depicts a gemstone illuminated under a visible light source before (a) and after (b) contour extraction. As shown, the resulting contour mask corresponds to the physical size of the diamond in two dimensions under the specific image capture conditions. FIG7D depicts the gemstone illuminated with a UV light source in a fluorescence image before (a) and after (b) fluorescence extraction. It is important to understand that the area appearing fluorescent in a fluorescence image (i.e., the apparent fluorescent area) can be different in size (e.g., larger) than the area within the gemstone capable of fluorescing, since the fluorescence emission, when captured in the image, can extend from the area emitting fluorescence. As shown in (b), the apparent fluorescent area is, in fact, larger than the physical size of the diamond itself due to reflections of the fluorescence from the sample platform. Therefore, the apparent fluorescent area is significantly larger than the opening of the contour mask, as shown in the comparison between FIG7C(b) and FIG7D(b). In some embodiments, the contour mask is used to calculate fluorescence intensity; for example, as represented by the parameter L according to the Commission Internationale de l'Eclairage (CIE or Commission Internationale de l'Eclairage). Here, the entire area of the gemstone is evaluated to accurately quantify the gemstone's total fluorescence emission level.

Fluorescence masking is used to define regions within a gemstone that are subject to further analysis or calculation. In the cases depicted in Figures 7C and 7D, the region of apparent fluorescence is significantly larger than the physical dimensions of the gemstone (e.g., as indicated by the openings in the outline mask), suggesting that the region of apparent fluorescence includes areas that do not correspond to any part of the gemstone. To eliminate inaccuracies, any fluorescence beyond the physical boundaries of the gemstone is removed from further data analysis. Only fluorescence measurements from within the boundaries of the gemstone are subject to further calculation and analysis to provide an estimate of the fluorescence emitted from the gemstone. When fluorescence is emitted from the entire gemstone and the region of apparent fluorescence covers the entire gemstone, fluorescence masking is identified by overlaying the region of apparent fluorescence (e.g., Figure 7D(b)) onto the gemstone's outline mask (e.g., Figure 7C(b)). Any area outside the boundaries defined by the outline mask within the region of apparent fluorescence is eliminated. The remaining portion of the region of apparent fluorescence corresponds to the fluorescence masking. In effect, the fluorescence masking is calculated as Figure 7C(b) × Figure 7D(b). In the context of the above description, inhomogeneous, highly fluorescent diamonds cannot be masked.

In other gemstones, the apparent fluorescent area may also be smaller than the physical boundaries of the gemstone, as defined by the contour mask and shown in Figures 7E and 7F. Figure 7E illustrates the contour extraction from (a) to (b), which is similar to the contour extraction of Figure 7C. In Figure 7F, fluorescence is emitted only from a limited area within the gemstone. The area is small and incoherent. After applying fluorescence extraction, the apparent fluorescent area is obtained, as indicated in Figure 7F(b). In this case, the apparent fluorescent area also contains patches of incoherent smaller areas. The entire apparent fluorescent area is much smaller than the contour mask shown in Figure 7E.

In the cases depicted in Figures 7E and 7F, the area of apparent fluorescence is significantly smaller than the physical size of the gemstone (e.g., as represented by the openings of the outline mask). Additionally, the fluorescence in the area of apparent fluorescence is discontinuous, meaning that non-emitting regions have been excluded from the area of apparent fluorescence. To eliminate inaccuracies, in some embodiments, a fluorescence mask with openings matching the smaller area of apparent fluorescence will be used to define areas within the gemstone for further analysis. Again, the fluorescence mask is identified by overlaying the area of apparent fluorescence (e.g., Figure 7F(b)) onto the outline mask of the gemstone (e.g., Figure 7E(b)). Any areas within the area of apparent fluorescence outside the boundaries defined by the outline mask will be eliminated. The remaining portion of the area of apparent fluorescence corresponds to the fluorescence mask. Only the fluorescence measurements within the openings of the fluorescence mask will be further calculated and analyzed to provide an estimate of the fluorescence emitted from the gemstone.

In some embodiments, the fluorescent shield comprises continuous openings; for example, see FIG. 7C(b). In some embodiments, the fluorescent shield comprises discontinuous openings; for example, see FIG. 7F(b). In some embodiments, the total open area of the fluorescent shield corresponds to the physical size of the gemstone. In some embodiments, the total open area of the fluorescent shield is substantially smaller than the physical size of the gemstone.

An exemplary procedure based on the devices and systems disclosed herein is summarized in Figure 9 A. Those skilled in the art will understand that the steps provided are exemplary and can be applied in any order or used in any possible combination.

At step 9000, system calibration is performed. For example, to provide reproducible results and offset fluctuations in the non-UV light source, the white balance of the image capture component (such as a color camera) is adjusted. At this step, the pixel gains of the individual color components (e.g., RGB) are adjusted so that the background image of the platform surface becomes white. Background adjustment is performed using a bare platform surface; that is, the sample gemstone has not yet been positioned on the platform surface. Preferably, background adjustment is performed after the light source has stabilized. In some embodiments, background adjustment is performed a short time period before collecting images of the sample gemstone. In some embodiments, background adjustment is performed after the light source has stabilized and shortly before gemstone images are collected. White background adjustment is performed while the top reflector module 60 is in the closed configuration. Next, the top reflector module is opened and the user can place the sample gemstone in the center of the platform surface. Care should be taken here to ensure that the lighting and other conditions and settings of the platform surface, in the sample chamber, and for the optical unit remain the same before and after the sample gemstone is placed.

Fluorescence measures the visible light emitted by a fluorescent material (eg phosphor) when it receives input energy from UV illumination. In general, it will be understood that the more intense the UV illumination, the more intensely the fluorescent material will emit visible light.

In some embodiments, the intensity of the input UV illumination is adjusted to optimize fluorescence measurements. For example, a power meter (e.g., a PM160T thermal sensor power meter from Thorlabs) is used to measure the light intensity from the UV light source. The UV intensity is adjusted to the same intensity level to provide reproducible fluorescence measurements.

At step 9010, color images of the sample gemstone are captured at different image rotation angles while maintaining the image viewing angle constant. At each image rotation angle, at least two images of the gemstone are captured: a regular image when the gemstone is illuminated by a non-UV light source (e.g., a near-daylight light source) and a fluorescent image when the gemstone is illuminated by a UV light source (e.g., set at a predetermined intensity).

In a preferred embodiment, the angular difference between consecutive color images remains constant throughout the collection of all images. Any configuration disclosed herein (e.g., relating to image viewing angle and image rotation angle) can be applied to the image collection process. For example, if the camera is set to take 30 pictures per second and one full rotation of the sample platform takes 3 seconds, then 90 images will be collected after one full rotation. In some embodiments, the platform surface completes at least one full rotation relative to the image capture assembly. In some embodiments, the rotation is less than a full rotation. In some embodiments, the rotation is more than a full rotation; for example, 1.2 full rotations or less, 1.5 full rotations or less, 1.8 full rotations or less, 2 full rotations or less, 5 full rotations or less, or 10 full rotations or less.

At step 9020, a contour mask is extracted for the non-UV illuminated image. Generally speaking, the contour mask corresponds to the physical area occupied by the sample gemstone, which is represented by the full image of the sample gemstone. Figures 7A and 7B illustrate the difference in images of the same diamond before and after the application of the contour mask. As depicted in Figure 7B, the contour mask highlights and clearly defines the edges of the diamond, making parameters such as width and height easier to measure. The contour mask extraction process is completed for all non-UV illuminated images acquired for a given sample gemstone.

There are many methods for edge detection, and most of them can be grouped into two categories: search-based and zero-crossing-based. Search-based methods detect edges by first computing a measure of edge strength (usually a first-order derivative such as the gradient magnitude), and then searching for local directional maxima of the gradient magnitude using a computed estimate of the edge's local orientation (usually the gradient direction). Zero-crossing-based methods find edges by searching for zero crossings in second-order derivatives computed from the image, typically zero crossings of the Laplacian or a nonlinear differential.

The main differences among edge detection methods known to date lie in the type of smoothing filter applied and the method used to calculate the edge strength measure. Because many edge detection methods rely on the calculation of image gradients, they differ in the type of filters used to calculate the gradient estimates in the x- and y-directions.

Here, any applicable method for extracting the contour mask can be used, including, for example, edge detection filters in commercially available software products such as Photoshop ^™ . Alternatively, for example, a sample algorithm can be developed in which any continuous region in the image having a color value matching the background white color (as previously calibrated) is defined as black. Thus, the continuous black region will form a contour mask with an opening corresponding to the full image of the sample gemstone.

Based on the contour mask, the values of geometric parameters (e.g., the width and height of the gemstone, as depicted in FIG7B ) are determined for each open area corresponding to the full image of the sample gemstone. The contour mask is used for more accurate or automated measurement of the geometric parameters. Essentially, the geometric parameters are determined based on each contour mask, or more precisely, each opening within the contour mask. Measurements are performed for each image. Following this step, multiple sets of measurements are determined for the multiple color images (or their corresponding contour masks), including, for example, multiple width measurements and multiple height measurements.

At step 9030, regions of apparent fluorescence are extracted from images of the same sample gemstone captured under UV illumination. Regions of apparent fluorescence are defined by the extent of fluorescence emission from portions of the sample gemstone capable of fluorescing. As illustrated in Figures 7D and 7F , regions of apparent fluorescence may be larger or smaller than the physical size of the gemstone. Specifically, regions of apparent fluorescence may be discontinuous, due to discrete portions of the gemstone emitting fluorescence.

At steps 9040 through 9060, the apparent fluorescent region is overlaid on top of the corresponding outline mask to identify the fluorescence mask. An important aspect of the overlay step is identifying the portion of the apparent fluorescent region that falls outside the physical boundaries of the sample gemstone (as defined by the outline mask). Because this portion of the fluorescence emission does not correspond to any physical area within the sample gemstone, including it in the fluorescence assessment may lead to errors. Thus, in some embodiments, when any fluorescence exists outside the physical boundaries of the sample gemstone, the corresponding fluorescence outside the physical boundaries of the sample gemstone is removed in step 9050. In contrast, in other embodiments, when no fluorescence exists outside the physical boundaries of the sample gemstone, the fluorescence mask may be calculated directly at step 9060, typically as the apparent fluorescent region itself.

For example, in FIG7D(a), the fluorescence now passes through the entire gemstone, resulting in the large, continuous area of apparent fluorescence depicted in FIG7D(b). In this case, the fluorescence mask is a composite of the contour mask and the apparent fluorescence area, obtained by removing all areas beyond the physical boundary of the sample gemstone (i.e., the contour mask). The fluorescence mask is identified by superimposing the apparent fluorescence area on the contour mask and then removing any fluorescence that exceeds the physical boundary of the contour mask. The fluorescence mask is the intersection of the apparent fluorescence area and the contour mask. In a specific example, because the apparent fluorescence area is continuous and the contour mask is always continuous, the resulting fluorescence mask is essentially the contour mask, as outlined in steps 9050 and 9060. The situation depicted in FIG7E and FIG7F is slightly different. Here, fluorescence is emitted by discontinuous portions of the sample gemstone, resulting in a discontinuous area of apparent fluorescence, as shown in FIG7F(b). Again, the fluorescence mask is identified by superimposing the apparent fluorescence area on the contour mask and then removing any fluorescence that exceeds the physical boundary of the contour mask. In this particular example, there is no fluorescence outside the solid boundaries of the sample gemstone (i.e., the contour mask). The resulting fluorescence mask corresponds to the apparent fluorescent area in Figure 7F(b), as outlined in steps 9050 and 9060.

It will be appreciated that if the extracted apparent fluorescence region is non-continuous but also extends beyond the physical boundaries of the sample gemstone (i.e., the outline mask), the resulting fluorescence mask will be the apparent fluorescence region with the areas outside the boundaries of the outline mask excluded (e.g., steps 9050 and 9060). Again, the fluorescence mask is identified by overlaying the apparent fluorescence region (e.g., FIG. 7C(b)) onto the gemstone's outline mask (e.g., FIG. 7D(b)). Any areas within the apparent fluorescence region that are outside the boundaries defined by the outline mask are eliminated. The remaining portion of the apparent fluorescence region that intersects the outline mask corresponds to the fluorescence mask.

In some embodiments, the fluorescence shielding corresponds to 20% or less of the entire gemstone, 25% or less of the entire gemstone, 30% or less of the entire gemstone, 35% or less of the entire gemstone, 40% or less of the entire gemstone, 45% or less of the entire gemstone, 50% or less of the entire gemstone, 55% or less of the entire gemstone, 60% or less of the entire gemstone, 65% or less of the entire gemstone, 70% or less of the entire gemstone, 75% or less of the entire gemstone, 80% or less of the entire gemstone, 85% or less of the entire gemstone, 90% or less of the entire gemstone, or 100% or less of the entire gemstone. In some embodiments, the fluorescence shielding corresponds to the entire physical area of the sample gemstone.

To improve accuracy and consistency, only pixels within the fluorescent mask will undergo calculation and further analysis (eg, step 900). An exemplary data collection, calculation, and analysis process is depicted in Figures 9B and 9C.

At step 910, a plurality of images of a sample gemstone are captured under non-UV illumination. Color images are captured at different image rotation angles while the image viewing angle remains constant. Considerations affecting data collection are all available.

At step 920, multiple fluorescence images of the sample gemstone are captured under UV illumination. Color images are captured at different image rotation angles while the image viewing angle remains constant. All considerations affecting data collection are applicable. The terms "fluorescent image" and "fluorescence image" will be used interchangeably.

At step 930, a fluorescence mask is applied to each of the plurality of fluorescence images. An exemplary method for calculating a fluorescence mask is illustrated in FIG9A and previously described.

At step 940, the pixels within the fluorescent mask undergo a quantitative analysis of the fluorescent image. For example, each pixel may be analyzed to quantify the values of all color components in a particular pixel. The number of color components is determined by an algorithm, and the pixels are encoded according to the algorithm when the color image is first captured. In some embodiments, the image is converted from its capture color mode (e.g., CMYK) to a different color mode (e.g., RGB). After quantizing the values for each color component in each pixel within the fluorescent mask, an average value may be calculated for each color component in a given fluorescent image. This process may be repeated for all images to calculate the average value for each color component in all fluorescent images. Ultimately, a final average value may be calculated for each color component based on information from all fluorescent images.

At step 950, a conversion process is performed on all pixels within a defined region in the image to calculate an average value of one or more parameters. Steps 910 through 950 can be repeated for all images in the plurality of color images. Ultimately, an average value of one or more parameters (e.g., L ^* , a ^* , and b ^* ) can be calculated for each color component based on information from all images.

At step 960, a first fluorescence score is calculated based on the values of one or more parameters. For example, here, the first fluorescence score can be chromaticity (C ^* ) and hue (h) values, which are calculated based on CIE color space values (e.g., L ^* , a ^* , and b ^* ); for example, based on the following equation ( FIG. 10 ):

In some embodiments, color images are analyzed using standards published by the CIE (e.g., tables of color matching functions and illuminants as a function of wavelength). The curve for a standard daylight illuminant has an associated color temperature, _D65 , of 6500 K. Here, this illuminant is represented by the function _HD65 (λ). These color matching functions are used to calculate colorimetry parameters.

In some embodiments, the first fluorescence score represents a color or hue characteristic of the fluorescence emitted by the sample gemstone.

FIG9C continues with an exemplary process for fluorescence grade analysis. At step 962, individual color components are quantified in each pixel within a solid area of the gemstone in the fluorescence image (e.g., defined by a corresponding outline mask). In some embodiments, each pixel is segmented into three values representing the colors red (R), green (G), and blue (B). In some embodiments, each pixel is segmented into three values representing the colors cyan (C), magenta (M), yellow (Y), and black (K). In some embodiments, the image is converted from its capture color mode (e.g., CMYK) to a different color mode (e.g., RGB) or vice versa. The individual color components are then used to calculate one or more parameters, such as CIE color space values (e.g., L ^* , a ^* , and b ^* ).

At step 964, one or more parameters (e.g., L*, a*, and b*) are calculated for all fluorescence images collected for a particular gemstone during one session (e.g., under the same lighting conditions with the image capture assembly ( ^e.g. , camera) configured at ^the same settings ⁾ .

At step 970, a second fluorescence score is calculated for the same gemstone. In some embodiments, the second fluorescence score represents the fluorescence intensity of the gemstone. In some embodiments, the second fluorescence score represents the average fluorescence intensity of the gemstone based on all fluorescence images acquired; for example, the average L ^* value.

At step 980, the fluorescence grade is assigned to the sample gemstone by comparing the values of the first fluorescence score and/or the second fluorescence score (e.g., L ^* , C ^* , h ^* ) with previously determined standard values for corresponding reference gemstones. The previously determined standard values for the reference gemstones are obtained using the same or similar procedures. For example, one or more groups of sample stones (which share the same or similar color, proportion, or shape characteristics and whose fluorescence grading values have been previously determined) serve as reference gemstones or grading standards. In some embodiments, the fluorescence color is distinct. In other embodiments, the fluorescence color may be too weak to be used for accurate identification. In such cases, the first fluorescence score and/or the second fluorescence score of the sample gemstone may be compared with multiple groups of reference gemstones, each having a different color.

An example of calculating color characteristics (e.g., L ^* , C ^* , and b ^* ) is as follows. Since diamond is a transparent material, the sum of the transmission spectrum T(λ) and the reflection spectrum R(λ) is used in the calculation of the tristimulus values X, Y, and Z:

The chromaticity coordinates x and y are then defined as: An attempt to achieve a "perceptually uniform" color space is the CIE 1976 color space, also known as the CIELAB color space. Its parameters are calculated from the tristimulus values as follows:

brightness,

Red and green parameters,

and yellow-blue parameters,

where _XW , _YW , and _ZW are the tristimulus values for the white point corresponding to the chosen illuminant (D65 in this case).

Saturation or hue is expressed as: and the hue angle is expressed as: h _ab =tan ^-1 (b ^* /a ^* ).

Resources are available for image/color conversion and transformation. For example, the OpenCV project hosted at docs<dot>opencv<dot>org can be used to convert RGB values to CIE L, a, and b values. Additionally, the same or similar resources allow conversion between RGB values and Hue-Saturation-Value (HSV) values, between RGB values and Hue-Saturation-Lightness (HSL) values, and between RGB values and CIE Luv values in the Adams color difference color space.

The present invention may be implemented as a computer system and/or computer program product comprising a computer program mechanism embedded in a computer-readable storage medium. Furthermore, any method of the present invention may be implemented in one or more computers or computer systems. Furthermore, any method of the present invention may be implemented in one or more computer program products. Some embodiments of the present invention provide computer systems or computer program products that are encoded with or have instructions for performing any or all of the methods disclosed herein. Such methods/instructions may be stored on a CD-ROM, DVD, magnetic disk storage product, or any other computer-readable data or program storage product. Such methods may also be embedded in a permanent storage device such as a ROM, one or more programmable chips, or one or more application-specific integrated circuits (ASICs). Such permanent storage may be localized in a server, 802.11 access point, 802.11 wireless bridge/station, repeater, router, mobile phone, or other electronic device. Such methods encoded in a computer program product may also be distributed electronically via the Internet or otherwise, by transmission of a computer data signal (with the software module embedded therein) digitally or on a carrier wave.

Some embodiments of the present invention provide a computer system or computer program product containing any or all of the program modules disclosed herein. These program modules can be stored on a CD-ROM, a DVD, a magnetic disk storage product, or any other computer-readable data or program storage product. The program modules can also be embedded in a permanent storage component, such as a ROM, one or more programmable chips, or one or more application-specific integrated circuits (ASICs). Such permanent storage components can be localized in a server, an 802.11 access point, an 802.11 wireless bridge/station, a repeater, a router, a mobile phone, or other electronic device. The software modules in the computer program product can also be distributed electronically by the Internet or otherwise by transmission of a computer data signal (in which the software module is embedded) digitally or on a carrier wave.

After describing the present invention in detail, it will be apparent that modifications, variations and equivalent embodiments are possible without departing from the scope of the present invention as defined in the appended claims. In addition, it should be understood that all examples in this disclosure are provided as non-limiting examples.

Example

The following non-limiting examples are provided to further illustrate embodiments of the invention disclosed herein. It will be appreciated by those skilled in the art that the techniques disclosed in the following examples represent methods that have been found to function well in the practice of the present invention and, therefore, can be considered to constitute embodiments of modes for its practice. However, it will be appreciated by those skilled in the art in light of this disclosure that many changes may be made in the specific embodiments disclosed and still achieve the same or similar results without departing from the spirit and scope of the present invention.

Example 1

Fluorescence Grading for Regular Stones

Figure 10 shows images of a sample gemstone taken under both a near-daylight light source (top 3 images) and under UV illumination (bottom 3 images). Under UV illumination, portions within the gemstone that fluoresce at different intensities are apparent.

Example 2

Confirmation of fluorescence emission levels in reference stones

In this example, four reference stones with varying fluorescence emission intensities were analyzed. The imaging viewing angle was set at 32 degrees. A Point Grey GS3-U3-28S5C camera was used to capture images under both regular and UV illumination. Here, top UV illumination was provided by a UV LED in combination with a bandpass filter and a collimating lens.

FIG. 11 shows that in addition to the C value, both the L value and the h value (particularly the L value) are correlated with the intensity of the fluorescent emission observed in the reference stone.

Example 3

Gemstones with heterogeneous fluorescence distribution

The images in Figure 12 show a gemstone with a non-homogeneous fluorescence distribution. At different image rotation angles (0, 120, and 240 degrees), different levels of fluorescence emission are observed. When each image is evaluated individually, the resulting L, C, and H values suggest different mechanical gradings of fluorescence intensity. However, when the L, C, and H values are calculated by averaging the effects from all images, the mechanical and visual grading scores become consistent.

Example 4

Fancy-shaped stones with blue fluorescence

Figure 13 depicts a gemstone with a fancy shape, all with blue fluorescence. Here, the image viewing angle was set at 32 degrees. A Point Grey GS3-U3-28S5C camera was used to capture images under both regular and UV illumination. Here, top UV illumination was provided.

The stones have different shapes and sizes. After applying the analysis disclosed herein, the resulting mechanical fluorescence grading score for each stone is the same as the fluorescence grading score provided by human visual inspection. Here, the stones emit different levels of blue fluorescence.

Example 5

Gemstones with different fluorescent colors

Figure 14 depicts two gemstones emitting different fluorescence colors: the gemstone on the left fluoresces green, while the gemstone on the right fluoresces yellow. Here, the image viewing angle was set at 32 degrees. A Point Grey GS3-U3-28S5C camera was used to capture images under both regular and UV illumination. Here, top UV illumination was provided.

Again, after applying the analysis disclosed herein, the resulting mechanical fluorescence grading score for each stone was identical to the fluorescence grading score provided by human visual inspection. Here, the stones fluoresce different colors.

Example 6

Gemstones of varying sizes and fluorescent colors

Figure 15 depicts two gemstones emitting different fluorescence colors: the gemstone on the left fluoresces yellow, while the gemstone on the right fluoresces orange. Here, the image viewing angle was set at 20 degrees. A Point Grey GS3-U3-28S5C camera was used to capture images under both regular and UV illumination. Here, top UV illumination was provided.

After applying the analysis disclosed herein, the resulting mechanical fluorescence grading score for each stone was identical to the fluorescence grading score provided by human visual inspection. Here, the two sample stones had significantly different sizes: one was almost three times the size of the other. In addition, the stones emitted different fluorescent colors.

The various methods and techniques described above provide several ways to carry out the present invention. Of course, it will be understood that not all of the objects or advantages described may be achieved according to any particular embodiment described herein. Thus, for example, one skilled in the art will recognize that these methods may be performed in a manner that achieves or optimizes one or a group of advantages as taught herein, without necessarily achieving other objects or advantages as may be taught or suggested herein. Various advantageous and disadvantageous alternatives are mentioned herein. It will be understood that some preferred embodiments specifically include one, another, or several advantageous features, while other preferred embodiments specifically exclude one, another, or several disadvantageous features, while other preferred embodiments specifically mitigate current disadvantageous features by including one, another, or several advantageous features.

In addition, a skilled person will recognize the application of various features from different embodiments. Similarly, the various components, features, and steps discussed above, as well as other known equivalents of each such component, feature, or step, can be mixed and matched by a skilled person to perform methods according to the principles described herein. Among the various components, features, and steps, some will be specifically included and others will be specifically excluded in various embodiments.

While the invention has been disclosed in the context of certain embodiments and examples, those skilled in the art will appreciate that the embodiments of the invention extend beyond the specifically disclosed embodiments to other alternative embodiments and/or uses, modifications and equivalents thereof.

Many variations and alternative components have been disclosed in the embodiments of the present invention. Further variations and alternative components will be apparent to those skilled in the art.

In some embodiments, the numerical values used to describe and advocate certain embodiments of the present invention, such as the amount of components, properties such as molecular weight, reaction conditions, etc., should be understood as being modified in some cases by the term "about". Accordingly, in some embodiments, the numerical parameters listed in the written description and the appended claims are approximate values that may vary depending on the desired properties that a particular embodiment attempts to obtain. In some embodiments, numerical parameters should be interpreted in light of the reported significant figures and by applying general rounding techniques. Although the numerical ranges and parameters setting forth the broad scope of some embodiments of the present invention are approximate, the numerical values listed in the specific examples have been reported as accurately as possible. The numerical values presented in some embodiments of the present invention may contain certain errors that are necessarily due to the standard deviation found in their respective test measurements.

In some embodiments, the terms "one" and "an" and "said" and similar references used in the context of describing specific embodiments of the present invention (especially in the context of certain claims below) may be interpreted as covering both the singular and the plural. The numerical ranges recited herein are intended only to be used as a shortcut for individually citing each individual value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into this specification as if it were individually recited herein. Unless otherwise indicated herein or clearly contradicted by the context, all methods described herein may be performed in any suitable order. The use of any and all examples or exemplary language (e.g., "such as") provided herein with respect to certain embodiments is intended only to more fully illustrate the present invention and not to limit the scope of the invention originally claimed. The language in this specification should not be understood as representing any non-claimed elements necessary for implementing the present invention.

The grouping of alternative components or embodiments of the invention disclosed herein should not be construed as limiting. Each group of components may be referenced and claimed individually or in combination with other components of the group or other components found herein. For convenience and/or patentability purposes, one or more components of a group may be included in or deleted from the group. When any such inclusion or deletion occurs, the specification is deemed herein to contain the group as modified and thus fulfills the written description of all Markush groups used in the appended claims.

Preferred embodiments of the present invention are described herein, including the best modes known to the inventors for carrying out the present invention. After reading the above description, variations to those preferred embodiments will be apparent to those skilled in the art. It is expected that such variations may be utilized by those skilled in the art as appropriate, and the present invention may be practiced in other ways than those specifically described herein. Accordingly, many embodiments of the present invention include all modifications and equivalents of the subject matter recited in the appended claims of the present invention as permitted by applicable law. Furthermore, unless otherwise specified herein or otherwise clearly contradicted by the context, the present invention encompasses any combination of the above elements in all possible variations thereof.

Additionally, various references have been made throughout this specification to patents and printed publications. Each of the above-mentioned references and printed publications is hereby incorporated by reference in its entirety.

Finally, it will be understood that the embodiments of the present invention disclosed herein illustrate the principles of the present invention. Other modifications that may be utilized are within the scope of the present invention. Thus, by way of example and not limitation, alternative configurations of the present invention may be utilized according to the teachings herein. Accordingly, the embodiments of the present invention are not limited to those precisely as shown and described.

Claims (34)

1. An apparatus for evaluating the fluorescent properties of gemstones, comprising: An opaque platform, wherein the platform has a surface configured to support the gemstone to be evaluated; The platform is configured to rotate about a rotation axis at a set angular variation and is height-adjustable. A ring-shaped tunable light source, shaped to at least partially surround the platform, wherein the height of the ring-shaped light source is adjustable relative to the platform. The tunable light source is approximately at or below the level of the platform surface and is capable of emitting uniform light at multiple wavelengths in the ultraviolet (UV) and white light ranges. An image capture assembly, wherein the image capture assembly is positioned at a predetermined angle relative to the surface of the platform supporting the gemstone, and wherein the image capture assembly and the platform are configured to rotate relative to each other; and A telecentric lens, positioned to provide an image of the illuminating gemstone to the image capture assembly; A reflector device comprising a reflective hemispherical interior, wherein the reflector device partially covers the light source and the platform surface, and directs UV radiation from the light source toward the gemstone positioned on the platform surface. 2. The device of claim 1, wherein the UV radiation provided by the light source includes transferred radiation, direct UV radiation, and combinations thereof. 3. The device of claim 1, wherein the light source further provides uniform non-UV illumination to the gemstone. 4. The device of claim 1, wherein the telecentric lens is an object-space telecentric lens or a double telecentric lens. 5. The device of claim 1, wherein the platform is configured to rotate about a rotation axis perpendicular to the side of the platform where the gem is positioned. 6. The device of claim 2, wherein the platform is configured to rotate 360 degrees about the rotation axis. 7. The device of claim 2, wherein the platform is a flat circular platform, and wherein the rotation axis passes through the center of the circular platform. 8. The device of claim 1, wherein the platform surface comprises a UV-reflective material. 9. The device of claim 1, wherein the platform surface comprises a diffuse UV reflective material. 10. The device of claim 1, wherein the platform surface comprises a white diffuse reflective material. 11. The device of claim 1, wherein the light source is configured as a ring light surrounding the surface of the platform. 12. The device of claim 1, wherein the light source comprises a plurality of light-emitting LEDs. 13. The device of claim 12, wherein the LED emits fluorescence at 365 nanometers or 385 nanometers. 14. The device of claim 12, wherein the LED is coupled to a bandpass filter. 15. The device of claim 14, wherein the bandpass filter is set at 365 nm or 385 nm. 16. The device of claim 15, wherein the LED is configured as a ring light surrounding the surface of the platform. 17. The device of claim 1, wherein the light source comprises an approximate daylight source and a plurality of light-emitting LEDs. 18. The device of claim 17, wherein the LED is coupled to a bandpass filter. 19. The device of claim 18, wherein the bandpass filter is set at 365 nanometers or 385 nanometers. 20. The device of claim 1, wherein the predetermined angle between the image capture component and the platform surface is between zero degrees and 45 degrees. 21. The device of claim 1, wherein the predetermined angle between the image capture component and the platform surface is between 10 degrees and 35 degrees. 22. The device of claim 1, wherein the image capture component is selected from a color camera, a CCD camera, and one or more CMOS sensors. 23. The apparatus of claim 1, wherein the image capturing component captures multiple color images of the gemstone illuminated by UV radiation, each image comprising a full image of the gemstone. 24. The apparatus of claim 1, wherein the image capturing component captures a plurality of color images of the illuminated gemstone, wherein each image is acquired when the image capturing component and the platform surface are at different relative rotational positions, and wherein each image includes a full image of the gemstone. 25. The device of claim 24, wherein the plurality of color images comprises four or more color images, and wherein each image is acquired at a unique image angle and comprises a plurality of pixels. 26. The device of claim 24, wherein the plurality of color images comprises five or more color images, and wherein each image is acquired at a unique image angle and comprises a plurality of pixels. 27. The device of claim 24, wherein the plurality of color images comprises 10 or more color images, and wherein each image is acquired at a unique image angle and comprises a plurality of pixels. 28. The device of claim 24, wherein the plurality of color images comprises 15 or more color images, and wherein each image is acquired at a unique image angle and comprises a plurality of pixels. 29. The device of claim 24, wherein the plurality of color images comprises 20 or more color images, and wherein each image is acquired at a unique image angle and comprises a plurality of pixels. 30. The device of claim 24, wherein the plurality of color images comprises 800 or more color images, and wherein each image is acquired at a unique image angle and comprises a plurality of pixels. 31. The device of claim 1, further comprising: A computer-readable medium for storing the images collected by the image capture component. 32. The device of claim 1, wherein the fluorescence characteristic is a fluorescence intensity level, a fluorescence color, or a combination thereof. 33. The device of claim 1, further comprising: An interface, located between the light source and the platform surface, is used to adjust the output intensity of the UV radiation. 34. The device of claim 1, further comprising: A UV filter is placed between the image capture assembly and the telecentric lens to eliminate all UV components.