HK1168068B - Diamond sorting system - Google Patents

Description

Diamond sorting system

Technical Field

The present invention relates generally to a diamond sorting system and in particular, but not exclusively, to an automated diamond sorting system.

Background

Diamonds are natural stones that are graded according to characteristics such as color and clarity. The grading of a diamond can be used to determine its value for use, for example, in the manufacture of jewelry.

Grading is usually performed by trained professionals who view the diamond under ten times magnification. The professional can grade the diamond by observing its color and clarity, and determine the clarity by looking for imperfections on the diamond surface and impurities within the diamond. After a professional observes and grades a large number of diamonds for a period of time, the eyes of the professional become fatigued. Furthermore, the vision of the professional deteriorates with age. These factors can lead to erroneous diamond grading.

It is an object of the present invention to provide an improved diamond sorting system or at least to provide the public with a useful choice.

Disclosure of Invention

In a first aspect, the invention resides broadly in a diamond sorting system comprising:

a diamond source for supplying one or more diamonds to be graded;

a vision system arranged to receive diamonds from a diamond source for grading and having:

one or more cameras arranged to acquire one or more images of the diamond, an

A processor arranged to receive data representing one or more images from one or more cameras and to perform operations on the data to grade the diamond;

a diamond collection unit configured to receive graded diamonds from a vision system; and

an electromechanical diamond transporter arranged to transport diamonds to be graded from a diamond source to a vision system and further arranged to transport graded diamonds from the vision system to a diamond collection unit; and wherein the transporter comprises at least one robotic arm, each arm being movable to transport diamonds from the source to the vision system or from the vision system to the collection unit.

Preferably, the diamond source comprises a diamond feeder arranged to transport diamonds orientated for grading to a diamond transporter. Preferably, the diamond feeder comprises: a container for holding one or more diamonds to be graded therein and a vibratory platform extending from the container for transporting one or more diamonds along the platform to a location adjacent the diamond transporter.

Preferably, the diamond transporter comprises a robotic arm moving between the diamond source and the vision system for transporting diamonds from the diamond source to the vision system for grading. Preferably, the robot arm includes: a body portion rotatable between a pick-up position adjacent the diamond source and a delivery position adjacent the vision system. Preferably, the arm extends from the body portion and includes a suction cup at an end of the arm, wherein the suction cup is configured to: suction is applied to pick up a diamond from the diamond source when the body portion is at the pick-up location, and at least part of the suction is removed when the body portion is at the delivery location to release the diamond onto the vision system for grading. Preferably, the arm is pivotally coupled to the body portion to enable the suction cup to pivot towards or away from the diamond when the body portion is in the pick-up position or the drop position.

Preferably, the diamond transporter comprises a robotic arm movable between the vision system and the diamond collection unit to transport the graded diamond from the vision system to the collection unit. Preferably, the robotic arm comprises a first body portion rotatable between a pick-up position adjacent the vision system and a drop-in position adjacent the collection unit. Preferably, the arm extends from the body portion and includes a suction cup at an end of the arm, wherein the suction cup is configured to: applying suction to pick up the diamond from the vision system when the body portion is at the pick-up location, and removing at least part of the suction to release the diamond at the collection unit when the body portion is at the deposit location. Preferably, the arm is pivotally coupled to the body portion such that the suction cup can pivot towards or away from the diamond when the first body portion is in the pick-up position or the drop position. Preferably, the robotic arm further comprises a second body portion to which the first body portion is rotatably coupled and which is rotatable about an axis generally parallel to and spaced from the axis of the first body portion.

Preferably, the diamond transporter comprises two separate robotic arms.

Preferably, the diamond collection unit is divided into a plurality of sub-sections, each sub-section corresponding to a particular diamond grade. More preferably, the diamond collection unit comprises a segmented platform, each segment corresponding to a particular diamond grade. Preferably the diamond collection unit comprises a segmented platform, each segment having a receptacle for storing a particular grade of diamond. Preferably, a robotic arm movable between the vision system and the diamond collection unit is movable over any one of the receptacles of the collection unit. Preferably, the containers are arranged in a matrix.

Preferably, the system further comprises a computer arranged to drive the diamond transporter in motion. Preferably, the computer drives the diamond feeder to vibrate.

Preferably, the vision system is arranged to grade the diamond by colour or clarity. More preferably, the vision system is arranged to grade the diamond by colour and clarity.

Preferably the vision system comprises at least one camera and an imaging area for storing diamonds to be imaged by said at least one camera. More preferably, the first camera comprises a lens arranged to capture an image suitable for colour grading of a diamond and the second camera comprises a lens arranged to capture an image suitable for clarity grading of a diamond. Preferably, to grade a diamond, only one image needs to be taken from each of the first and second cameras.

Preferably, each camera comprises a charged-couple device.

Preferably, the vision system comprises an integrating sphere arranged to receive the diamond and provide a substantially uniform distribution of light around the diamond to be imaged. More preferably, the integrating sphere comprises a movable platform for transporting the diamond into the integrating sphere for imaging and outputting the diamond from the integrating sphere for transport to the collection unit. Preferably, the platform is rotatable and passes through a slit in the integrating sphere to move the diamond on the platform into and out of the integrating sphere. Preferably the platform is a disc with at least one recessed step for storing the diamond. More preferably, the disc has three radially spaced embedded steps such that during imaging one step is within the integrating sphere, one step is adjacent the transport system for receiving a diamond from the diamond source and one step is adjacent the transport system for transferring the graded diamond to the collection unit.

Preferably, the vision system comprises a light source arranged to illuminate the diamond to be imaged.

Preferably, the vision system comprises one or more optical fibers arranged to transport light from the light source to the integrating sphere.

Preferably, the system further comprises a housing for storing the vision system, diamond source, transport system and the data collection unit.

Preferably, the system further comprises a dust ionizer in the housing for neutralizing the electrostatic charge in the housing.

In a second aspect, the invention resides broadly in an automated method of sorting diamonds comprising the steps of:

a step of transporting the diamond from the diamond source to a vision system;

a step of acquiring one or more images of the diamond;

a step of processing data representing the image to grade the diamond;

a step of transporting diamonds into a zone of a diamond collection unit corresponding to a grade of said diamonds so as to sort diamonds into diamond collection units according to their grade, and wherein said step of transporting diamonds from a source to a vision system or said step of transporting diamonds to a collection unit or both utilizes at least one movable robotic arm to transport diamonds.

Preferably, the diamonds are graded by their color. More preferably, a saturation value of the image of the diamond is extracted, thereby grading the color of the diamond.

Preferably, the diamond is graded by its clarity. More preferably, large intensity variations in the image of the diamond are identified, thereby grading the clarity of the diamond.

The term "comprising" as used in the present specification and claims means "consisting at least in part of. When interpreting each expression in this specification that includes the term "comprising", features other than or in addition to those expressly recited may also be present. Terms such as "comprising" and "comprises," etc., are to be interpreted in the same manner.

The invention resides in the foregoing and also includes the following constructions by way of example only.

Preferred embodiments of the present invention will be described by way of example only and with reference to the accompanying drawings.

FIG. 1a is a perspective view of a diamond sorting system according to a preferred embodiment of the present invention;

FIGS. 1b, c and d are top, front and side views of the diamond sorting system of FIG. 1 a;

FIG. 2 is a more detailed perspective view of the diamond sorting system of FIG. 1a without the housing;

FIG. 3a is a perspective view of a first robot arm of the transport system of the diamond sorting system of FIG. 2;

drawings

FIG. 3b is a perspective view of a second robot arm of the transport system of the diamond sorting system of FIG. 2;

figure 4 is a perspective view of a first robot arm collecting diamonds from a diamond feeder of the diamond sorting system;

FIG. 5 is a close-up perspective view of a first robot transporting the diamond of FIG. 4 to a vision system of a diamond sorting system;

FIG. 6 is a perspective view of a first robot arm for delivering the diamond of FIG. 5 to a vision system;

FIG. 7 is a perspective view of a second robot arm of the transport system collecting graded diamonds from the vision system;

FIG. 8 is a close-up perspective view of a second robot arm transporting the diamond of FIG. 7 onto a diamond collection unit of a diamond sorting system;

FIG. 9 is a perspective view of the second robot arm of FIG. 8 delivering graded diamonds into the appropriate collection receptacles of the collection unit;

figure 10 is a perspective view of a diamond feeder of an alternative form of diamond sorting system;

FIG. 11 is a perspective view of the exterior of the vision system of the preferred form diamond sorting system;

fig. 12 is a sectional perspective view showing the interior of the vision system of fig. 11;

FIG. 13 is a close-up perspective view of a first robot arm placing a diamond to be graded on a platform of the vision system of FIG. 11;

figure 14 is a close-up perspective view showing rotation of the platform of figure 13 as the diamond enters the integrating sphere of the vision system;

figure 15 is a close-up perspective view showing rotation of the platform of figure 14 as the diamond exits the integrating sphere of the vision system;

FIG. 16 is a perspective view of the vision system showing a diamond within the integrating sphere of the vision system from above;

FIG. 17 is a perspective side view in cross-section of the diamond of FIG. 16 shown inside an integrating sphere;

FIG. 18 shows a series of diamonds of various color grades and clarity grades;

FIG. 19 is a flow chart of an algorithm for determining the color grade and clarity grade of a diamond;

FIG. 20 is a flow chart of an algorithm for determining the color grade of a diamond; and

FIG. 21 is a flow chart of an algorithm for determining the clarity grade of a diamond.

Detailed Description

The present invention generally relates to an automated diamond sorting system that can sort diamonds into different grades by an electromechanical diamond movement system and vision system based image processing.

Referring to fig. 1a-1d, diamonds can be graded by an automated process using a diamond sorting system 100. The diamond sorting system 100 comprises an electromechanical system for transporting diamonds within the system. The diamond sorting system 100 also includes a vision system 160 that ranks each diamond according to its particular characteristics. Each diamond may be graded by its color, clarity, or both, or any other suitable characteristic. Typically, the electromechanical system 140 transports diamonds from the diamond source 150 to the vision system 160 for grading. Once graded, the electromechanical system 140 transports the diamond from the vision system 160 to the diamond collection unit 180.

The diamond sorting system 100 may be disposed within a housing or box 200. The box may enclose the processor or computer of the system and the actuators, such as the engine, within a lower portion 210 made of metal, wood, plastic or any other suitable material. The lower portion also provides a platform 215 for supporting the system components 130, 140, 150, 160, and 180. The housing also includes an upper glass section 220 so that the system components can be viewed when the sortation system is in use. The upper portion 220 and the lower portion 210 may be supported using a frame 230 made of any suitable material.

In the preferred embodiment shown, the diamond sorting system 100 is enclosed in a structure 910mm high, 560mm wide and 560mm deep. It will be appreciated that the system may be packaged in other sized configurations depending on the complexity of the system and the size of the components used.

Referring to fig. 2, the system 100 is shown without the housing 200. The electromechanical system 140 includes two robotic arms 141 and 145. The first robot 141 may move between the diamond source 150 and the diamond vision system 160 to transfer diamonds from the diamond source 150 to the vision system 160 for sorting. The second robot 145 may move between the vision system 160 and a diamond collection unit 180, where the graded diamonds are collected and grouped according to their grade in the diamond collection unit 180. A dust ionizer 130 is provided in the housing 200 for neutralizing the electrostatic charge in the housing 200.

Electromechanical system and diamond collection unit

The electromechanical system 140 comprises a diamond transporter arranged to transport diamonds from the diamond source 150 to the vision system 160 for grading. Once the diamond is graded, the diamond transporter is also configured to transport the diamond from the vision system 160 to the diamond collection unit 180. The diamond transporter may comprise a single apparatus arranged to transport diamonds around all areas of the system. Alternatively, the diamond transporter may comprise two or more devices, wherein each device may be arranged to transport diamonds around a particular area of the system. The diamond transporter may comprise one or more robotic arms or any other suitable mechanism or device arranged to move a diamond.

In the preferred form of diamond sorting system shown, the diamond transporter comprises a first robotic arm 141 arranged to transport diamonds from a diamond source 150 to a vision system 160. The diamond transporter also includes a second robot 145 configured to transport the graded diamond from the vision system 160 to a diamond collection unit 180. Other embodiments of the diamond sorting system may comprise only one robot arm arranged to move a diamond from the diamond source 150 to the vision system 160 and then to the diamond collection unit 180.

Referring to fig. 3 and 3b, the first robot arm 141 includes a body part 142 rotatable in clockwise and counterclockwise directions as indicated by an arrow AA'. The second robot arm 145 includes a lower body portion 146 and an upper body portion 147 that are rotatable in clockwise and counterclockwise directions as shown by arrows BB 'and CC', respectively. The rotation of the body portions 142, 146 and/or 147 may be driven by a motor controlled by, for example, a computer of the diamond sorting system 100. The first robot arm 141 may further include an arm assembly 143, the arm assembly 143 being pivotally coupled at a proximal end thereof to the body portion 142. The second robot arm 145 may also include an arm assembly 148, the arm assembly 148 being pivotally coupled at a proximal end thereof to the lower body portion 146. Each of the arms 143 and 148 can pivot upwardly and downwardly about a pivot axis as indicated by arrows DD 'and EE'. The pivot axes of the arms 143 and 148 are preferably substantially perpendicular to the rotational axes of the main body portions 142 and 146/147, respectively. The pivoting movement of the arms 143 and/or 148 may be driven by motors controlled by, for example, a computer of the diamond sorting system 100. The above mentioned computer for controlling the motor may be enclosed in the lower part 210 of the housing 200 in fig. 1a or any other suitable location.

In particular, the first robot arm 141 comprises a single articulated joint a to which the body 142 is coupled, which allows a free circular movement of the body 142 in a clockwise direction and in a counter-clockwise direction. An arm assembly 143 extends laterally from the body portion 142 and is pivotally hinged to the body portion 142 to effect an up and down movement DD' of the arm 143 for picking and dropping a diamond. The transport system 140 is designed such that the degree of rotation of the body portion 142 and the length of the arm 143 is at least suitable to enable the end of the arm 143 to reach both the diamond source 150 and the vision system 160. At the end of the arm 143 is provided a vacuum suction head 144 for picking up diamonds from the diamond source 150 and placing the diamonds on the vision system 160.

The second robot arm 145 includes two articulated joints B1 and C1. These joints allow free circular movement of body portions 146 and 147 in both clockwise and counterclockwise directions, respectively. Body portions 146 and 147 are coupled at joint B1 with their axes of rotation spaced apart but parallel to each other. This allows the arm 148 to extend into any X-Y coordinate system within its working range, reaching the defined area and retracting or "folding" unimpeded from the rest of the system 100. In addition, up and down motion for picking and placing the diamond is achieved with the aid of a Z-axis vacuum tip 149 at the end of the arm 148. This facilitates the transportation of the graded diamond 10 from the vision system 160 to the collection unit 180.

As shown in fig. 4, 5 and 6, the first robot 141 may be controlled to move its chuck 144 into contact with a diamond 10 waiting at the diamond source 150. The suction cup 141 will then apply suction to the diamond 10 causing the first robot 141 to pick up the diamond and move it to the vision system 160. The suction is then removed from the diamond 10 to release the diamond 10.

Similarly, referring to fig. 7, 8 and 9, the second robot 145 may be controlled to move its chuck 149 into contact with the graded diamond 10 waiting at the output of the vision system 160. The suction cup 149 may then apply suction to the diamond 10 causing the second robot 145 to pick up the diamond and move it into the diamond collection unit 180. Suction is then removed from the diamond 10 to deposit the diamond on the appropriate location 183a of the collection unit 180.

The suction cup 144/149 may be made of plastic, rubber, or any other suitable material. The diamond sorting system 100 may include a pneumatic system connected to the suction cup 144/149 by, for example, a hose or the like, such that the suction cup 144/149 is capable of generating suction. The pneumatic system may be controlled by a computer. Any method suitable for picking, transporting and placing diamonds other than suction may be used. In this specification, the term "throw" or "throwing" is intended to cover situations where the diamond is released gently to or on a surface and does not have to be released from a certain height.

Referring again to fig. 4 and 5, in a preferred embodiment the diamond source 150 comprises a diamond feeder 151 arranged to supply diamonds 10 to the first robot 141 in a known position and orientation. The diamond feeder 151 may comprise a container 152 for holding a plurality of diamonds 10 to be graded. Typically, the diamonds 10 held in the receptacle 152 are in a chaotic manner (not shown). The diamond feeder 151 may comprise a vibrating track 153 which vibrates to position the diamond 10 and facilitate transport of the diamond along the length of the track. The diamond feeder 151 may vibrate to cause one or more diamonds 10 to vibrate from the container 152 onto the bottom of the vibration track 153. The diamond is then vibrated along the length of the vibration track 153 until it reaches the end of the top of the container wall, ready for pick up by the robot 141. During the movement of the diamond 10 along the orbit, the diamond 10 is positioned to a known position. For example, a diamond cut to make one end larger or heavier (polished engraving) than the other end may end up on its smaller, lighter end when vibrated along the length of the rail 153. Initially, the diamond is 10 volts on one side in the container 152. By the time the diamond vibrates along the vibration track 153, the diamond may change direction, thereby allowing it to rest on the table. Generally, if multiple diamonds are vibrated along the vibration rail 153, they are eventually all in the same orientation before reaching the end of the rail 153, so that they are ready to be picked by the first robot 141 for transport to the vision system 160.

The supply machine and the container need not be of the form shown and may take any shape, such as the bowl 155 shown in FIG. 10. The vibration track may also take different shapes, such as a spiral 156 around the bowl 155. Any suitable length of track may be employed if desired by the system 100.

Alternatively, a hopper or any other suitable diamond source 150 may be used that adjusts the diamond 10 into an orientation suitable for grading.

Referring to fig. 4, 5 and 6, the body 142 of the first robot 141 may be rotated towards the top of the vibration rail 153 while transporting the diamond 10 from the diamond feeder 151 to the input of the vision system 160. The arm 143 can then be pivoted so that the suction cup 144 comes into contact with the diamond 10 on top of the vibration rail 153 (figure 4). Suction is then applied to the diamond 10 and then the arm 143 can be pivoted in the opposite direction to pick up the diamond 10. The body 142 may then rotate the arm 143 holding the diamond 10 towards the input of the vision system 160 (fig. 5). Once adjacent the input of the vision system 160, the arm 143 can be pivoted towards the input of the vision system 160 to place the diamond 10 in position (fig. 6). The suction is removed leaving the diamond 10 in a known orientation at the input of the vision system 160. The body 142 and arm 143 can then be rotated away from the vision system 160 and await instructions to pick the next diamond from the supply machine 150.

Referring to fig. 8 and 9, the diamond collection unit 15 comprises a zoning platform 181, the zoning platform 181 having a collection bin 183 for storing a particular grade of diamond in each zone. In a preferred embodiment, the diamond collection unit 180 comprises a table 181 provided with a plurality of apertures 182 arranged to receive a collection bin or receptacle 183 for collecting the graded diamonds 10. Each collection container 183 corresponds to a particular diamond grade. For example, one collection container may correspond to a blemish grade clarity and a nearly colorless diamond grade, while another collection container may correspond to a blemish grade clarity and a yellowish diamond grade, and yet another collection container corresponds to a slight grade clarity and a nearly colorless diamond grade. The number of collection containers provided should be equal to the number of possible clarity classifications multiplied by the number of possible color classifications. One collection container may be provided for each combination of a possible clarity grade and each possible color grade. As shown, the holes 182 and collection receptacles 183 are arranged in a matrix to organize the diamond grading in rows and columns of clarity and color. The computer may have a database or address table in memory indicating where each collection container 183 corresponding to a particular grade of diamond is located on the table 181. With this information, once a diamond 10 is graded to a particular grade, the computer will extract the row and column address of the appropriate collection receptacle 183 and instruct the robot 145 to move it to the appropriate position and place the graded diamond 10 in the collection receptacle 183. Repeating this procedure multiple times for multiple diamonds 10 allows the same graded diamond to be sorted in the same collection container 183. The user may then retrieve the diamonds 10 sorted by their grade.

The second robot 145 is preferably able to reach all of the collection receptacles 183 on the table 181 so that a diamond 10 can be deposited in any suitable collection receptacle 183.

Referring now also to fig. 7, during transport of the diamond 10 from the output of the vision system 160 to the diamond collection unit 180, the body portions 146 and 147 of the second robot 145 may be rotated towards the vision system 160. Once adjacent the output of the vision system 160, the arm 148 can be pivoted to bring the suction cup 149 into contact with the diamond 10 at the output of the vision system 160 (fig. 7). Suction is then applied to the diamond 10 and then the arm 148 can be pivoted in the opposite direction to pick up the diamond 10 (figure 8). The body portions 146 and 147 may be rotated towards the diamond collection unit 180 to align the diamond 10 with and suspend the diamond 10 above the appropriate collection container 183 of the diamond collection unit 180 (figure 9). The suction may be removed so that the diamond 10 falls into the appropriate collection container 183 a.

In the preferred embodiment, the second robot arm 145 includes two body portions 146 and 147, each rotating about parallel but spaced axes. This arrangement enables the arm 148 (and in particular the end of the arm 148 where the suction cup 149 extends) to move across all areas of the table 181 carrying the collection container 183.

In addition, or in the alternative, the table 181 may also be movable or rotatable so that it can be moved appropriately before, during or after the movement of the robot 145 to assist in alignment with a diamond 10 suspended above an appropriate collection container 183.

Referring to FIG. 9, the table 181 may include a plurality of stacked trays 181a-c for storing collection containers 183 therein. The trays 181a and 181b may contain a set of identical but offset holes 182a and 182b, respectively, for receiving each collection container 183 in a diagonal fashion through a pair of offset holes as shown. This causes each collection container to rest on the periphery of its corresponding aperture 182 a/b. A base plate 181c for supporting the bottom of each collection container 183 is provided. The pins 184 extend between the trays 181a-c to space, couple and align the trays 181a-c with one another. Any other method or arrangement suitable for collecting graded diamonds 10 may be used.

Typically, the diamond sorting system 100 may grade diamonds from 0.8mm to 3mm, but may grade diamonds of any suitable size. For systems configured to grade diamonds from 0.8mm to 3mm, the control accuracy or control precision of the robotic arm 140 and the electromechanical vision system 160 may be as low as 0.08 mm.

It should be noted that any suitable means of transporting diamonds from the diamond source 150 to the vision system 160 and, once graded, from the vision system 160 to the diamond collection unit 180 may be used without departing from the spirit and scope of the present invention.

Any suitable means may be used to drive all of the moving parts or mechanical devices of electro-mechanical system 140. For example, the motors may drive the movement of the robotic arms 141 and 145, or the movement of any moving parts in the system 160 as described further below, as well as the movement of the table 181 (if it is movable/rotatable). A motor with an asymmetric weight associated with diamond feeder 151 may drive vibrations in diamond feeder 151. The actuators may be controlled by one or more computers or processors associated with the diamond sorting system 100. Alternatively or additionally, a hydraulic system connected to any moving part may be employed.

Dust ionizer

Referring again to fig. 2, in a preferred embodiment, a dust ionizer 130 is provided for neutralizing the electrostatic charge within the housing 200. In a preferred form, the dust ionizer 130 is continuously operated once the machine/system 100 is turned on. The ionizer 130 generates a flow of positive and negative ions that causes an electronic exchange with the dust and anti-mixing filter (an-equalizing filter) to provide a neutralizing charge to the dust particles. In the absence of an electrostatic charge, the particles do not stick to each other, thereby enabling easy removal of all dust from the system 100. This ensures the cleanliness and brilliance of the diamond surface for color and clarity grading.

The dust ionizer 130 also helps to dissipate static charges within the rails 153 of the vibrating feeder 151 in operation. In the absence of electrostatic charge, the diamonds do not stick to the top of the rail 153 of the feeder 151. This ensures a stable supply of diamonds during the automated process.

The dust ionizer 130 need not be employed in the system 100, but is a preferred feature because it facilitates measuring static electricity, neutralizing static charge, continuously monitoring dust particles, and protecting production areas in the factory's processing and testing environment from dust particles.

Vision system

Referring to fig. 11 and 12, the vision system 160 is arranged to receive a diamond 10 from the diamond source 150 via the electromechanical system 140. The vision system 160 comprises one or more cameras (not shown) arranged to take one or more images of the diamond 10. The image processing system may process the image or data representing the image captured by the camera to grade the diamond 10. Preferably, the vision system 160 includes two cameras located on either side of the vision system 160. One camera is arranged to capture images for the colour grading of the diamond 10 and the other camera is arranged to capture images for the clarity grading of the diamond 10. Each camera may have a corresponding lens 161 arranged to assist in capturing information relating to the colour or clarity of the diamond 10. Preferably, the camera is digital and comprises a CCD chip, a CMOS chip or any other suitable device. Alternatively, the diamond sorting system 100 may include three or any other suitable number of cameras.

The diamond 10 may be placed within an integrating sphere 162 for capturing an image. The integrating sphere may be a container or collection box configured to receive the diamond from the inside to provide an imaging region, and within the integrating sphere, its interior is substantially sealed or sealed from outside light and other interference. Integrating sphere 162 may be fabricated using plastic, metal, or any other suitable material. The interior surface 163 of integrating sphere 160 may be coated with a reflective coating to promote diffuse reflection. The interior surface 163 of integrating sphere 162 may be coated with barium sulfate or any other suitable coating.

The interior of integrating sphere 162 may be illuminated by a light source (not shown). An LED lamp can be used inside the integrating sphere to reduce the amount of specular reflection from the diamond. Typically, the integrating sphere provides a uniform light distribution that is projected onto the diamond 10 when capturing an image of the diamond 10. This avoids areas of the diamond 10 that are over-illuminated or under-illuminated which may affect the grading of the diamond 10. For example, a white coating may be used inside integrating sphere 162 to provide a uniform light field. Light from the light source may be directed to integrating sphere 162 by one or more optical fibers (169 shown in fig. 15). However, the light may be introduced into the integrating sphere in any suitable manner. Alternatively, a light source may be provided within integrating sphere 162 itself.

Referring to fig. 13 to 15, the diamond 10 may be introduced into the integrating sphere 162 by rotating the platform 164, where the rotating platform 164 is in the form of a disk in the preferred embodiment. As shown in fig. 13, the diamond 10 may be placed on a rotating disk 164 by an electromechanical system 140, such as a first robot 141. As previously discussed, the arm 141 carrying the diamond 10 is arranged to release the diamond 10 from the suction 143 and place it at the input of the vision system 160. Then. The rotating disc 164 may then be rotated (as shown by arrow RR' in figure 14) and carry the diamond 10 into the integrating sphere 162 for imaging. The rotating disk 164 may pass through a slit in the integrating sphere 162 (covered by the rotating disk 164 in the figure). The rotating disk may contain one or more recessed steps 165 for the diamond to rest on so that the diamond can move through the slot without being brushed off the rotating disk. The rotating disk 164 may include three or more inset steps 165 so that an unfractionated diamond 10 may be placed at the input 160 of the vision system 160 (see fig. 13 and 14) on the rotating disk 164 at any one time, one diamond may be positioned within the integrating sphere 162, and one graded diamond 10 may be positioned at the output of the vision system 160 and ready to be removed from the rotating disk 164 (see fig. 15). Each recessed step 165 may include a further flat recess 166 for seating a diamond 10 therein. The flat recess 166 may comprise a window through the rotating disk 164 to enable images to be taken from below, for example if a camera is provided below the rotating disk 164. The recessed step 165 including the flat groove 166 may be formed as a sapphire step. The rotary disk 164 may be driven to move by a motor 167, such as a stepper motor. The action of the rotating disk 164 may be controlled by a computer. If there are three equally spaced steps 165, the rotating disk 164 can be set to rotate 120 degrees per instruction from the computer. Once graded, the rotating disc 164 rotates, exposing the graded diamond 10, as shown in fig. 15, ready to be picked up at the vision system 160 output.

Referring to fig. 16 and 17, the interior of integrating sphere 162 may be substantially spherical. Integrating sphere 162 may include an aperture 168 for the light source and camera lens 161. Rotating the disc 164 moves the diamond 10 into the bottom of the integrating sphere 162 to image the diamond 10. Preferably, the vision system is arranged to move the diamond into a central position at the bottom of the integrating sphere 162, thereby performing image capture and acquisition. A coating 163 is provided within the inner surface of the integrating sphere for promoting diffuse reflection.

The rotating disk 164 may be considered as both an input and an output of the vision system 160. For example, a diamond that has been oriented may be placed on the rotating disk 164 by the electromechanical system 140 (particularly the robotic arm 141). The diamond 10 can then be moved into the integrating sphere 162 by rotating the disk 164 to be imaged. The diamond can then be moved out of the integrating sphere 162 and removed by the electromechanical system 140 (particularly the arm 145).

It is noted that any suitable system for imaging the diamond 10 may be used without departing from the spirit and scope of the present invention. For example, the diamond 10 may be suspended or resting on a platform for imaging, and any number and type of suitable cameras may be used to image the diamond. In addition, vision system 160 may be adapted to image and process/grade two or more diamonds at a time, thereby increasing the speed of operation of the overall system 100.

Image processing

Referring to fig. 18, the diamond 10 may be graded according to one or more of several characteristics, including diamond color and diamond clarity. For example, the american jewelry association (GIA) diamond grading standard grades diamonds from D (colorless) to Z (pale yellow) in color. Similarly, the GIA diamond clarity grading Standard grades diamonds clarity as FL (flawless) to I₃(flawed). The diamond sorting system 100 can grade a particular diamond color and purity with similar criteria.

Once the vision system 160 captures one or more images of the diamond, the images, or data representing the images, are fed to a computer or processor for execution of image processing algorithms to grade the diamond according to color and clarity. In a preferred embodiment, real-time analysis of the image of the diamond is performed by a processor, thereby grading the diamond. The processor may have in memory information or a database or look-up table representing a large number of diamond samples with known colour and cleanliness ratings. The clarity grading information or data may contain a large amount of information about a diamond sample with known inclusions or surface imperfections, such as clouds, feather cracks, boils, cleavage cracks, wear lines, grain boundaries, scars, pins, chips, and the like, or any other inclusions or surface imperfections. The clarity grade or information or data may also contain information about the size of inclusions or surface imperfections. A database or look-up table may be established to compare or correlate the color and clarity information captured from the diamond 10 to classify the diamond into a particular color or clarity grade. In the preferred embodiment, only one digital image of the diamond is required for real-time analysis and grading of color, and only one digital image of the diamond is required for real-time analysis and grading of clarity. This reduces the treatment time required for diamond grading.

Referring to fig. 19, a general algorithm for grading the color and clarity of a diamond is shown. In this system, vision system 160 includes two cameras, however in alternate embodiments any suitable number of cameras may be used. The first camera 36a may be used for color grading and the second camera 36b may be used for clarity grading. Each camera takes an image of the diamond and then pre-processes each image. The pre-processing may comprise extracting an image of the diamond from the background. Image processing algorithms may then be performed on each image or on the data representing each image to obtain the colour and net grading of the diamond. The image processing techniques employed may include filtering, edge detection, image segmentation, defect detection, compositing, or any other suitable image processing technique. For example, a diamond edge may be detected using an edge threshold algorithm, such that no data outside the diamond is used to determine the grade of the diamond. The image may be filtered to remove any noise. The data is then used to determine the color grading and clarity grading of the diamond 10. A color grading algorithm 50 may be performed to determine the color grading. Similarly, a clarity ranking algorithm 52 may be executed to determine a clarity ranking.

Referring to fig. 20, the color of the diamond can be evaluated by looking at the blue color in the RGB (red-green-blue) color domain of the pre-processed image. This is due to the fact that diamond can absorb blue light. However, there may be slight color differences between the different diamond color grades. Thus, alternatively, the colour of the diamond can be assessed by looking at the saturation values in the HSV (hue-saturation-purity) colour domain of the pre-processed image. Different sized diamonds having the same color grading have different saturation values and it may therefore be necessary to select a calibrated color saturation value from a look-up table or database based on the known size range of graded diamonds (step 50 a). The image at this point, or even before, may be segmented to separate the diamond from the background (step 50 b). The most stable saturation value can then be calculated in the HSV gamut of the diamond image (step 50 c). Finally, the saturation value is compared or otherwise correlated with information contained in a database or look-up table to determine the final color grade of the diamond (step 50 d).

Referring to fig. 21, an edge detection algorithm may be performed on the diamond image to find large intensity variations within the diamond (step 52 a). The diamond image may then be segmented into separate regions for analysis, with the detected boundaries as edges, to be combined with adjacent pixels of similar intensity (step 52 b). These neighboring pixels may all represent a particular inclusion or surface imperfection. A statistical determination of the regions may be performed to determine whether each individual region is an inclusion or a surface imperfection (step 52 c). The statistical measures for each individual region may include standard deviation, entropy, uniformity, and any other suitable statistical measure. The overall clarity grade of the diamond image may then be determined by comparing or correlating the identified inclusions with a diamond sample having a known clarity grade (step 52 d).

The known ratings database may then be normalized for color ratings and clarity ratings to obtain final color and clarity ratings.

Once the grade is obtained, the processor or computer may control the electromechanical system 140 to deposit the diamond in the collection container 183 or in a designated area corresponding to that particular grade.

The above image processing method is a preferred embodiment and the present invention does not exclude other image processing methods/algorithms for determining the quality of the diamond required for grading.

The above description of the invention includes preferred forms thereof. Modifications may be made to the invention without departing from its scope as defined in the accompanying claims.

Claims (27)

1. A diamond sorting system comprising:

a diamond source for supplying one or more diamonds to be graded,

a vision system configured to receive a diamond from the diamond source to grade the diamond, the vision system having:

one or more cameras arranged to acquire one or more images of the diamond, an

A processor arranged to receive data representing one or more images from the one or more cameras and to perform an algorithm on the data to grade the diamond,

a diamond collection unit arranged to receive graded diamonds from the vision system, an

An electromechanical diamond transporter arranged to transport diamonds to be graded from the diamond source to the vision system and further arranged to transport graded diamonds from the vision system to the diamond collection unit; and wherein the transporter comprises at least one robotic arm, each arm being movable to transport diamonds from the source to the vision system or from the vision system to the collection unit,

wherein the vision system is arranged to grade the diamond by both colour and clarity.

2. A diamond sorting system as claimed in claim 1 wherein the diamond source comprises a diamond feeder arranged to feed diamonds oriented for grading to the diamond transporter.

3. A diamond sorting system as claimed in claim 2 wherein the diamond feeder comprises: a container for holding one or more diamonds to be graded therein, and a vibratory platform extending from said container for transporting one or more diamonds along the platform to a location adjacent the diamond transporter.

4. A diamond sorting system as claimed in claim 1 wherein the robotic arm comprises a body rotatable between a pick-up position adjacent the diamond source and a delivery position adjacent the vision system.

5. A diamond sorting system as claimed in claim 4 further comprising an arm extending from the body portion and having a suction cup at an end thereof, the suction cup being arranged to: suction is applied to pick a diamond from the diamond source when the body portion is at the pick-up location, and at least partially removed when the body portion is at the delivery location to release the diamond onto the vision system for grading.

6. A diamond sorting system as claimed in claim 5 wherein the arm is pivotally coupled to the body portion to enable the suction cup to pivot towards or away from a diamond when the body portion is in the pick or drop position.

7. A diamond sorting system as claimed in claim 1 wherein the robotic arm comprises a first body portion rotatable between a pick-up position adjacent the vision system and a drop-in position adjacent the collection unit.

8. A diamond sorting system as claimed in claim 7 wherein an arm extends from the first body portion and includes a suction cup at its distal end, the suction cup being arranged to: applying suction to pick up a diamond from the vision system when the first body portion is at the pick-up location, and at least partially removing the suction to release a diamond at the collection unit when the body portion is at the delivery location.

9. A diamond sorting system as claimed in claim 8 wherein the arm is pivotally coupled to the first body portion such that the suction cup can pivot towards or away from a diamond when the body portion is in the pick or drop position.

10. A diamond sorting system as claimed in any one of claims 7 to 9 wherein the robot arm further comprises a second body portion, the first body portion being rotatably coupled thereto, the second body portion being rotatable about an axis substantially parallel to and spaced from the axis of rotation of the first body portion.

11. The diamond sorting system of any one of claims 1-9, wherein the diamond collection unit is partitioned into a plurality of zones, each zone corresponding to a particular diamond grade.

12. A diamond sorting system as claimed in claim 11 wherein the diamond collection unit comprises a zoned platform, each zone having a collection bin for storing a particular grade of diamond.

13. A diamond sorting system as claimed in any one of claims 1 to 9 wherein the system includes a computer arranged to drive the movement of the diamond transporter.

14. A diamond sorting system as claimed in claim 3 wherein the computer drives the diamond feeder into vibration.

15. A diamond sorting system as claimed in any one of claims 1 to 9 wherein the vision system comprises at least one camera and an imaging area for storing diamonds to be imaged and graded by the camera.

16. A diamond sorting system as claimed in claim 15 wherein the first camera comprises a lens arranged to capture an image suitable for colour grading of a diamond and the second camera comprises a lens arranged to capture an image suitable for clarity grading of a diamond.

17. A diamond sorting system as claimed in any one of claims 1 to 9 wherein the vision system comprises an integrating sphere arranged to receive a diamond and provide a substantially uniform distribution of light around the diamond to be imaged.

18. A diamond sorting system as claimed in claim 17 wherein the integrating sphere comprises a movable platform for transporting diamonds into the integrating sphere for imaging and, once graded, transporting diamonds out of the integrating sphere for transport to the collection unit.

19. A diamond sorting system as claimed in claim 18 wherein the platform is rotatable and passes through a slot in the integrating sphere to move a diamond on the platform into and out of the integrating sphere.

20. A diamond sorting system as claimed in claim 19 wherein the platform is a disc having at least one recessed step for storing diamonds.

21. A diamond sorting system as claimed in claim 20 wherein the disc comprises three radially spaced embedded steps such that during imaging one step is located within the integrating sphere, one step is adjacent the transport system to receive a diamond from the diamond source and one step is adjacent the transport system to provide a graded diamond to be delivered to the collection unit.

22. A diamond sorting system as claimed in any one of claims 1 to 9 wherein the vision system comprises a light source arranged to illuminate the diamond to be imaged.

23. The diamond sorting system of any one of claims 1 to 9, further comprising a closed enclosure for storing the diamond source, the vision system, the transportation system, and the data collection unit.

24. A diamond sorting system as claimed in claim 23 further comprising a dust ionizer in the enclosure for neutralizing electrostatic charges in the enclosure.

25. An automated method of sorting one or more diamonds comprising the steps of:

transporting the diamond from the diamond source to a vision system,

one or more images of the diamond are acquired,

processing data representing the image to grade the diamond, an

Transporting the diamond to a section of a diamond collection unit corresponding to the grade of the diamond, and wherein said step of transporting the diamond from the source to the vision system or said step of transporting the diamond to the collection unit, or both, utilizes at least one movable robotic arm to transport the diamond,

wherein the vision system is arranged to grade the diamond by both colour and clarity.

26. The method of claim 25, wherein a saturation value of the image of the diamond is extracted to grade the color of the diamond.

27. The method of claim 25, wherein large intensity variations in the image of the diamond are identified, thereby grading the clarity of the diamond.