HK1162286B - Apparatus and method for imaging the eye - Google Patents

Description

Apparatus and method for imaging an eye

Reference to related applications

This patent application claims priority from provisional patent application No. 61105901 filed on 16.10.2008 of the united states, the entire disclosure of which is incorporated herein by reference. Us non-provisional patent application 12580247 was filed on 10/15/2009.

A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright holder has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the patent and trademark office patent records or records, but otherwise reserves all other rights whatsoever.

Technical Field

The present invention relates to imaging the human eye, and more particularly to imaging the anterior and posterior halves of the human eye, the anterior half including the cornea, lens and aqueous humor of the eye, and the posterior half including the fundus in imaging form, such as color fundus, fluorescence angiography, blood-circulating green fundus angiography, defluorination, different wavelength autofluorescence of red, blue, red, near infrared, and functional imaging, such as flavoprotein autofluorescence and other fluorophores, including those in the retinoid cycle.

Background

Many clever ophthalmologists and optometrists do not make full use of ophthalmic imaging equipment (whether traditional fundus cameras or imaging at slit lamps) for a variety of reasons. These reasons are: today's devices are too expensive, do not have good image quality, do not easily align the device with the patient's eyes, are poorly trained by staff, are not easily accessible for images, and overall, do not have the capability to allow the clinician to feel the benefits and value of imaging. Physicians always prefer to have a wide range of mydriasis during retinal examinations, which is not always possible or convenient for the patient. The problem of managing duplicate images and other reflections during the examination, whether mydriatic or not, and the lack of patient cooperation are common conditions.

Retinal imaging devices (fundus cameras) have been widely adopted in the past in retinal specialties. In the retinal specialties, experienced technicians have been trained to operate complex instruments. Although there have been some market expansion to general ophthalmology and optometry with fundus cameras without pupil dilation, the cost, ease of use and complexity of operation of the equipment has prevented widespread adoption of today's equipment. These are typically separate, stand-alone devices that take up additional office space and inconvenience the examination lanes where the primary eye examination is being performed. Although many practice sites place existing equipment in the patient detection area, the usage rate is not high for the reasons mentioned above. Current slit-lamp imaging systems do not operate well and do not eliminate the reflection of the scope or other reflections from the image. Moreover, illumination is poorly controlled and suboptimal for retinal imaging over larger areas. The fundus camera utilizes an annulus to illuminate the retina and therefore requires a larger pupil size to obtain an image. Such devices may not align well with the patient's pupil.

In addition, some of the systems today use point sources of light for illumination, but their retinal field of view is severely limited, optical artifacts are common, difficult to eliminate, and image quality is often poor. Other systems use expensive laser scanning systems and such systems do not provide a color imaging mode. Some laser scanning systems also suffer from central artifacts and other reflections. Laser scanning systems have typically been targeted to retinal specials due to specialized diagnostic capabilities (fluorescence angiography, circulating green fundus angiography, and autofluorescence).

With the aging population and the widespread prevalence of eye diseases, there is a great unmet need for cost-effective retinal imaging in the mass market for ophthalmology and optometry with automated features. There is a need for a good quality image that can be imaged with a small pupil, is easy to operate, and provides an artifact free image.

Disclosure of Invention

In an exemplary embodiment of the invention, a slit-lamp mounted eye imaging apparatus is disclosed that is well suited for viewing a wide field of view and/or a magnified view of the retina or the anterior segment of the eye through a pupil that is not mydriatic or mydriatic. The device can image the focal plane between the posterior and anterior segments and portions of the eye. The apparatus includes a spotlight illumination system, a plurality of aperture stops, a controller, and a digital camera subsystem. The spotlight illumination system may consist of one or more light sources, or a single translating or rotating light source, such as an LED, may be delivered to the optical system on the optical axis or slightly off-axis from the center of the optical system and sent back from the retina into the imaging path. The device allows light to enter the eye and provides wide area retinal illumination and reduces glare, and removes artifacts and ghost reflections. The aperture stop, the position of the optics and/or the off-axis illumination block unwanted reflections or glare from the retinal image, however major artifacts are not avoided, but rather are removed from the image processing and two or more artifact-bearing images are obtained at truly different locations. Image processing consists of automatic detection of artifacts from one or more images, removal of the artifacts, and clipping two or more images together to remove the artifacts. If the aperture and illumination are sized and positioned according to the diameter of the non-mydriatic pupil, the device is well suited for achieving retinal imaging through a non-mydriatic pupil, a non-drug dilated pupil, or as small as 2 mm. The aperture adjustment may be fixed or user adjustable. It can also automatically sense pupil size and self-optimize aperture size and illumination, and also automatically sense optimal image capture trigger. Although the device can be mounted on a slit lamp, it can also be used on a device in which the chin rest is separate from the control rod. Moreover, the apparatus may utilize existing slit lamp optics, beam splitters, adapters and other optics, whereby the illumination and optics portions of the apparatus are contained in a separate housing and combined with the slit lamp to utilize the slit lamp imaging portion and subsystem.

The foregoing has outlined rather broadly the preferred features of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features of the invention will be described hereinafter that form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for designing or modifying other structures for carrying out the same purposes of the present invention without departing from the spirit and scope of the invention.

Drawings

Other aspects, features and advantages of the present invention will become more fully apparent from the following detailed description. In the appended claims and drawings, like elements are identified by like reference numerals.

FIG. 1 is an apparatus diagram of the principles of the present invention;

fig. 2 is a side view of an optical unit of the chin rest and control lever apparatus of the present invention;

FIG. 3 is a block diagram of a computer system for use with the present invention;

fig. 4 is a flow chart showing the steps of an image capture and image processing algorithm according to the principles of the present invention.

Detailed Description

Retinal imaging has traditionally been performed with a fundus camera that illuminates the retina with an annulus of light, returning in the return image path through the center of the illumination annulus. These devices often have complex illumination and imaging paths in order to make the annulus as small as possible to fit the small pupil, and also to eliminate optical artifacts and reflections, while leaving enough holes for the image to pass back through the center. Past optical designs have been used to achieve imaging over a wide area without reflection from the cornea or other surface. Conventional fundus inspection methods (direct, indirect, slit lamp based, or otherwise) based on illuminated point sources of light have provided limited fields of view if reflection-free images are desired. Retinal imaging systems based on point sources of light have historically reached a maximum of nearly thirty degrees in the field of view, eliminating reflections and other artifacts. Other systems, such as laser scanning ophthalmoscopes, provide a wider field of view than devices based on simple point sources (e.g. slit lamp retinal imaging) using a scanning mirror and a laser. Still other devices (Optos Optomap) achieve wide area imaging through a small pupil using a scanning system and large parabolic mirrors. These solutions are often expensive and require complex optical arrangements for controlling the scanning element and/or the image capturing element. The challenges faced in the past have been to image the retina cost effectively, large, and able to allow a small pupil, a wider field of view (from greater than forty degrees to an ultra wide field of view-200 degrees), and no artifacts and reflections. The design challenges faced are cost effective, can allow for these parameters, and can be slit lamp mounted for easy use by both the patient and the physician. The present invention solves each of the problems identified above by combining a novel optical design, a light source, and image processing techniques that address the problems listed above.

The disclosed devices can be used to image the eye, including but not limited to anterior segment imaging of the eye (cornea, lens and aqueous humor), posterior segment imaging of the eye including physiotherapy of colored fundus, fluorescence angiography, blood-based green fundus angiography, red, blue, red, near infrared, infrared autofluorescence of various wavelength spectra, and functional imaging (flavoprotein autofluorescence, fluorophores in the retinoid cycle, and others). Can operate in high magnification, wide field of view or magnification mode, and in a light field mode, combine different focal lengths into a composite image that can be divided into several parts or combined into a single image. The device may be comprised of one or more light sources and/or a varying optical distance (or elements thereof) to achieve one or more images containing artifacts or reflections at clearly different anatomical locations to combine into a reflection-free, artifact-free image. An angled, protruding eyecup is provided to hold the eyelid open to create a patient/device interface and a lightless environment suitable for operation without or with pupil dilation.

The disclosed device is a low cost slit lamp (or chin rest-lever separated device) eye imaging device well suited for viewing wide area and/or magnified fields of view and retinal images produced through pupils that are not mydriatic or mydriatic. It can also image the posterior segment of the eye, and the focal plane between/on the segment. The device includes one or more illumination sources, with LEDs, halogen, xenon or other lamps and filters, and an aperture stop to cleanly transfer energy from the one or more light sources. The spotlight illumination system may consist of one or more light sources, preferably using LEDs (of single and/or different wavelengths), and may be delivered to the optical system on the optical axis or slightly off-axis from the center of the optical system and sent back from the retina into the imaging path. The device directs light into the eye and provides wide area retinal illumination and reduced glare. The aperture stop, the position of the optics, and/or the off-axis illumination block unwanted reflections or glare from the retinal image. The device is well suited to achieve retinal imaging through a non-mydriatic pupil or a pupil as small as 2 mm, provided the aperture and spot light size are the diameter of the non-mydriatic pupil. The aperture may be fixed or adjustable by the user. It can also automatically sense the pupil size and self-optimize the aperture size. The device may turn on or off the LED or other light source in a sequential manner, possibly accompanied by a shift of the optics of one or more optical elements or components, to generate two (or more) images with mirror reflections and other artifacts at two different areas of the anatomy of each successively acquired image.

In another embodiment, one or more illumination sources are provided to shift the illumination and/or field of view with lateral movement or rotation of the optical element to illuminate and image a wider field of view on the retina. Also, when the images are combined, a final image with more uniform illumination and better image definition can be obtained, the image areas are analyzed from the different images, and the portions that provide the best focus, the least chromatic aberration, and the best overall image quality are used. An image processing algorithm may be used to automatically detect major reflection artifacts in the image and perform image reconstruction functions. The image reconstruction function is to utilize the effective image information from the corresponding image in which the artifact obscures the retina from the source image. Instead of flashing and combining the images, the device may simply clip the images together after a similar procedure of removing artifacts from one or a series of images has been performed. This can also be done with the patient changing the fixation in a random or a controlled or automatic manner. The optical design may include one or more light sources, and may incorporate a prism, such as a half-penta prism, Schmidt (Schmidt) prism, or a custom prism, that changes the direction of the illumination and imaging paths to slightly compensate for each other to produce overlapping illumination and images to an increased field of view that combine portions of the image into an optical artifact and a reflection-free image. These alternate illumination and imaging paths may enter the pupil of the eye at an angle compared to the central optical axis, or may enter slightly off axis but parallel to the center of the optical system. The angular separation and imaging paths of these different overlapping light sources may be variable, depending on the size of the pupil, and may be automatically adjusted based on the detection of pupil size.

Another embodiment of the apparatus is adapted for use with a slit lamp and captures images on the slit lamp using existing commercially available components, such as beam splitters, adapters, other optical instruments, video cameras, and digital cameras. With this arrangement illumination, the light source and additional optics are contained in a separate housing that can be coupled to the slit lamp in a variety of different ways, including a tonometer stem, a fundus optic (hruby) slide tray, or other mechanical coupling to the slit lamp. This embodiment distinguishes the illumination and optical portions of the device from the image capture portion of the device attached to the slit lamp, thereby taking advantage of the capture capabilities of existing slit lamps, yet still provides unique optical illumination and image processing of the device.

The device may have manual focusing and/or automatic focusing means. To optimize image quality, an auto-exposure algorithm and an algorithm for optimizing image brightness and contrast may be utilized. The alignment patterns in the visible, near infrared and infrared allow the user to align the retina or outer pupil. The device may include optical and image processing alignment aid systems to guide the user through the optimal alignment. The device may include automatic or manual alignment algorithms and mechanical controls to align the pupil of the eye with the pupil of the patient along an optical axis. The device may include a spatial light modulator to position and shape the illumination beam according to the sensed position and size of the pupil, and to measure and record the size of the pupil. The device may use an infrared or near infrared filter placed in alignment mode and flicked outward to pass wavelengths of other spectra and facilitate subsequent image capture.

In one embodiment, a shake-proof optical and/or other image stabilization software algorithm automatically aligns the device to the patient's eye and also facilitates alignment of the averaged image and other image processing and viewing functions.

The device may include a wireless SD card or other embedded wireless technology to automatically transfer images to a host or other storage device or software. The device may include a name tag scheme that allows the user to take an image of the patient's name, perform optical character recognition, detect the first name, last name and form code, know the date and time (and other data), and then automatically move these data to a database, all of which are transmitted to the host computer. These may be done with a processor or host embedded in the device.

The system described above can also be used with a flexible eyecup that can be affixed to the device, or with a consumable, in combination with the bottom of the device, for each patient. The eyecup may be made of a barrier flexible material, such as rubber, plastic or other soft material, and surrounds the patient's eyes to create a lighted environment. The eye cup may also be used to hold open the eyelid, perhaps by pressing on the eyelid with an angled internal spring arrangement. The barrier plate may be elastic to properly position the eye. One embodiment of the eyecup includes a solid rubber or plastic portion in an angularly protruding position in the approximately twelve and/or six o' clock direction for holding the upper and/or lower eyelids open during imaging. The other parts of the eyecup are overlaid on the eye to create a natural mydriatic environment without light. The Device may also include an infrared or near infrared LED or other light source connected to a detector, such as a CCD (Charge-Coupled Device), CMOS (Complementary metal oxide semiconductor) or other Device sensitive to light at this wavelength. This can be used for alignment, but off and the patient will be flashed by visible light, green light, blue light, de-reddened or any other imaging wavelength including fluorescence angiography, blood circulating green fundus angiography, fundus autofluorescence or other wavelengths used in other autofluorescence or functional imaging.

The device may have all the embodiments described above, with the addition of the function of generating a multi-focal optical field image, i.e. an image or video generated from images of multiple focal planes. The image may be formed by a camera system (which may include one or more cameras) having microlenses on a CCD or CMOS pixel arrangement and divided into two or more focal planes. The image can be calibrated and reconstructed into a multifocal light field image. Optical field multifocal images can also be produced by using a manual or automatic focusing device that finds the most ideal central focus and obtains additional images with minor focal length adjustments, equal to the periphery of the central focus. These images can then be combined into a single light field image or into an interactive video image, allowing the user to roll up or unwind the multi-focal plane like a scroll. The combined image algorithm automatically aligns the images while correcting for translation, rotation, curvature, and different magnification between the images. The software will detect high frequency information in each image plane corresponding to each optimal image plane.

The light domain algorithm can also be used to combine different forms of images. For example, details of the ocular choroid emphasized by the blood-circulating green fundus may be combined with details of the retina emphasized by the fluorescent angiography image. The optical domain algorithm may be used in any combination of retinal images or forms of retinal imaging, such as OCT (optical coherence tomography) and/or other forms from other retinal imaging devices. The algorithm may also be applied to images from a multifocal plane in the posterior segment of the eye. One embodiment achieves continuous image capture, from the front half to the back half of the entire eye, and applies the algorithm to combine into a single optical domain image or endless belt viewing function of the entire eye or portions thereof, including registration and other form of correction.

The device and all embodiments thereof may be constructed with components, light sources and filters that enable retinal imaging of all retinal species, including but not limited to color fundus imaging, de-reddening, blood-green fundus angiography, fluorescence angiography, infrared or near infrared imaging, all forms of fundus autofluorescence at different wavelengths and functional imaging.

In another embodiment of the device, the user programs an internal fixation target for the patient, tracks it, and then ties the images together as they are captured. This may also be applied to remove artifacts. The multiple images may be stored as a video file, multiple frames, or a single frame concatenated together.

In another embodiment of the device, interchangeable objectives are provided for different fields of view, as well as other form factors for posterior imaging by slit-shaped illumination and optimal posterior imaging.

In another embodiment of the present device, the lens, aperture and mask are optimized for posterior fluoroscopic imaging of the crystal and other eye structures.

Another embodiment of the present apparatus is incorporated into an optical coherence OCT system for the purpose of combining retinal imaging with OCT.

Another embodiment of the apparatus performs a dark correction algorithm whereby images of CCD or CMOS wafers are captured in the absence of light, and the miscellaneous information field images are processed, stored, and removed from the captured images as a means of reducing miscellaneous information and improving overall image quality.

Another embodiment of the device allows it to be operated in a transferable normal focal length or optical field mode, enabling capture of images from multiple focal planes.

Another embodiment of the apparatus has a stereoscopic optical system that gives a real-time or processed single image stereoscopic view. This is accomplished in a variety of different ways, including optical transfer, CCD multi-focal lens covers, and microlens covers from video scanning, movement, and/or focusing.

Another embodiment of the device is an alternative to the rapid alternating blinking of a single LED or multiple LEDs, rather than the optics rotating at a rate that is fast and synchronized with the image capture.

Another embodiment is a rotating or translating light source. This can be achieved with several optical elements in the system or even a fast rotating (simultaneous) optical instrument like a wedge prism. The artifact may be mapped to other images in pairs to remove the artifact. This can be achieved with image processing or even calibration and real-time memory mapping or single image capture. This may also be considered a means of increasing the field of view of the image and may be put together in the panorama with a single image of artifact removal.

Another embodiment of the apparatus instantly ties together panoramas from a video stream using any or all of the above elements.

The camera/digital camera 22 and the optics 29 form the optical subsystem of the apparatus 2 and are disposed in a common housing 30. Referring to fig. 1, the housing 30 is mounted on a slit lamp chin rest and control rod assembly 26.

Referring to fig. 1, slit-lamp chin rest and control rod assembly 26 is an interface between the patient's eye and the camera/digital camera 22 and light source optics 28. The slit-lamp chin rest and control rod apparatus 26 includes a head support 32, a movable base 34, a control rod 36, and a housing support 38. The head support 32 holds the chin and forehead of the patient in a known, fixed position. The head support 32 is provided with height adjustment means to provide a comfortable place for the patient to rest on. The position of the housing 30 relative to the head support 32 can be adjusted and fine tuned to a large extent by the control rod 36.

Fig. 2 is a bottom view of an optical unit of the chin rest and lever apparatus of the present invention. Fig. 2 shows the housing 30 in a schematic cross-sectional view. The housing 30 contains the camera/digital camera 22, the illumination optics 28, and approximately a sectioned eye 46, the eye 46 having a cornea 48 and a retina 52. The housing 30 may be cylindrical or other suitable shape.

It can be seen that the configuration of the housing 30, without the forwardly projecting portion, prevents any portion of the device from inadvertently coming into direct contact with the patient's cornea or five sense organs as the housing 30 is moved relative to the patient's eye. This feature of the invention is particularly advantageous in comparison with the background art. Many of the prior art methods of obtaining optical data require the optical instrument to be in close proximity to and/or in contact with the cornea to perform the inspection and image capture tasks. In contrast, the outer housing 30 and the optics contained therein of the present invention have been designed to be held at a distance from the cornea that is comfortable for the patient to detect. If desired, a fixed interface, such as a rubber cap, may be provided at the interface between the housing 30 and the patient's eye.

The inclusion of projection optics 28, viewing optics 29 and camera 22 in a single compact housing provides a high degree of accessibility. Placing all the elements of the system in one housing makes such a design relatively inexpensive. In addition, a shorter and more efficient optical path is provided for miniaturization of the design of observation and image capture, as compared to the fundus camera. The small design and the simplicity of the optical instrument reduce the production cost and greatly reduce the burden of the doctor on use. The present design enables imaging through a smaller pupil compared to the fundus camera.

The camera/digital camera 22 is preferably compact and incorporates a black and white CCD or CMOS image sensor. A manually controlled image focus button 44 is accessible from the back of housing 30, and image focus button 44 is connected to lens 40 of camera 22 to focus lens 40 with conventional optical actuators. The focusing of the lens 40 is to compensate the optics of the eye 46 with the image focus button 44. The lens 40 may be automatically focused or manually focused, and when the image focus button 44 is adjusted, by viewing the image displayed on the viewing video monitor, is adjusted to obtain a clear, focused picture on the viewing video monitor. The focal length of lens 40 may also be automatically adjusted by an electronic autofocus control system.

The camera/digital camera 22 may also include a black and white or color CCD or CMOS light sensing device.

Viewing optics 29 are connected to camera 22 and include lens 40, a viewing aperture 53, and a filter 55 as described above. Viewing aperture 53 and filter 55 transmit light reflected from retina 52 to lens 40, i.e., to camera 22. Filter 55 is an infrared blocking filter (or other filter for other imaging procedures) that improves the contrast of the image seen by camera 22.

If the device 2 is intended, additional filters may be used in due course for blood-borne green fundus angiography, color fundus photography, autofluorescence or fluorescence angiography. These filters are configured to be selectively rotated into and out of the viewing axis of camera 22, depending on the function being performed. The rotation may be achieved manually or by computer servo control.

With continued reference to fig. 2, projection optics 28 of the present invention project light onto retina 52 at an off-axis angle from central axis 57 of lens 40 of camera 22. Projection optics 28 includes a lamp 54, a lamp lens assembly 56, optics 64, a mirror 66, and a projection aperture 68. A control means (not shown) is provided to adjust the intensity of the light 54, either manually or under control of the personal computer 6, see fig. 1. The control device is also used to continuously control the plurality of lamps, transfer optics, such as 68, and image capture triggers.

Light from the lamp 54 passes through an aperture 58 and a series of two lens sets 56 of lamps. The lens of the lamp lens group 56 collects the output light of the lamp 54. Preferably, the lamp lens group 56 may be composed of two achromatic lenses. The light is then turned by mirror 66 and projection optics 29, mirror 66 being placed at a critical pitch angle with respect to camera 22. The light is passed by a mirror 66 through a projection aperture and a lens assembly 68 that concentrates the light. The light then passes through the cornea 48 and is projected onto the retina 52.

All of the holes utilized, such as holes 58 and 68, are suitably sized holes. Although the lamp 54 has been described as a broad LED lamp, it should be noted that the lamp 54 may be any source of radiant energy. In a preferred embodiment, lamp 54 is an infrared light source, and filter 55 is sized to pass the wavelength of lamp 54. Infrared illumination may be particularly desirable for alignment prior to image acquisition without the problems caused by the lack of a mydriatic pupil. The image can be captured in a relatively dark room with infrared illumination so the imaged eye will naturally enlarge. In another preferred embodiment, which illustrates the problem of lack of mydriasis during imaging, the light 54 may be a flash light, which may be full color, red-removed, near infrared, or some other preferred wavelength (depending on the desired imaging procedure) during image acquisition, without having to be continuously illuminated, thereby avoiding the energy of the light 54 from narrowing the pupil prior to image capture. Due to the unique design of the projection optics 28 and the performance of the image processing and the use of analysis software, useful image data can be collected from each image, with a minimum amount of mydriasis being obtained. In particular, the pupil of the imaged eye may be as small as 2 millimeters in diameter. The projection optics 28 of the device project light onto the retina 52, off the viewing path of the camera/digital camera 22.

Figure 1 generally shows the apparatus of the present invention. The personal computer 6 forms the center of the system, processes data and controls the operation of the other components of the system. The camera/digital camera 22 is connected to the personal computer 6. A viewing video monitor, which may be a personal computer screen, a slit lamp chin rest and control rod arrangement 26, projection optics 28 and viewing optics 29 are connected to an optical head 30.

Preferably, the personal computer 6 is a small computer, has relatively high processing power, uses a standard operating system, and has standard slots for peripheral devices such as video boards, printers, and screens. The personal computer 6 executes customization software, as will be described in more detail below.

The monitor or screen of the personal computer has the capability of ultra-high resolution color graphics suitable for displaying the image under analysis.

The digitizer tablet accepts a digital file or video input from the camera/digital camera 22, which functions as a frame grabber or display. That is, when a signal from the personal computer 6 is initiated, the digitizer collects recorded and/or digital data and images from the camera/digital camera 22 at that location and stores them as digital data. The generated digital data is stored in a memory and can be analyzed by the personal computer 6.

The present invention may be used in any properly installed general purpose computer system, such as the system shown in FIG. 3. Such a computer system 500 includes a processing unit (CPU)502 coupled by a bus to a Random Access Memory (RAM)504, a storage device 508, a keyboard 506, a display 510, and a mouse 512. Also, there is a means 514 for entering software and data, including software that embodies the invention to the system. Such a computer may be, for example, a Dell personal computer equipped with a Microsoft Windows operating system or Linux, Macintosh, etc. The invention can also be applied to notebook computers, mobile phones, PDAs and the like.

Various embodiments of the present invention are implemented as a computer executing a series of program instructions that direct a computer to perform the steps of the method, provided that the computer can retrieve all of the data needed for processing. The series of program instructions may be embodied in a computer program product that includes a medium on which the program instructions are stored. It will be appreciated by persons skilled in the art that the present invention may be implemented in hardware, software, or a combination of hardware and software. Any kind of computer/server system or other apparatus adapted for carrying out the methods described above is suited. A typical combination of hardware and software could be a general-purpose computer system with a computer program that, when being loaded and executed, carries out the methods. Variations of this method are described herein.

The present invention may be embodied as a system, method or computer program product. Accordingly, the present invention may take the form of a hardware embodiment, a software embodiment or an embodiment combining hardware and software. Moreover, the present invention may take the form of a computer program product on any tangible medium having computer-usable program code embodied in the medium.

Any combination of one or more computer usable or computer readable media may be utilized. Specifically, the computer readable medium may include: a hard disk, Random Access Memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM) or flash memory, a portable compact disc read-only memory (CD-ROM), and the like. In the context of this document, a computer-usable or computer-readable medium may be any medium that can be used by or in connection with the apparatus or the instruction execution system. Computer program code for carrying out operations of the present invention may be written in one programming language or in combination with multiple programming languages. The code may execute entirely on the user's computer, partly on the user's computer, in a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on a remote computer or server.

The above is a computer program according to an embodiment of the present invention. It will be understood that each block of the illustrations, and combinations of blocks in the illustrations, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable medium produce an article of manufacture including instruction means which implement the function specified in the block or blocks.

The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions specified.

The flowcharts in the figures illustrate the possible implementation, functionality, and operation of systems, methods and computer program products according to embodiments of the present invention. In this regard, each block in the flowchart illustrations may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should be noted that, in various implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the flowchart illustrations, and combinations of blocks in the flowchart illustrations, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

Fig. 4 is a flow chart showing the steps of an image capture and image processing algorithm according to the principles of the present invention. In describing these steps, reference will be made to the numbered elements in fig. 2 and 3. In a first step 80, the process begins and proceeds to block 82, which is a step at which patient demographics are entered at block 82. In block 84, image capture begins. The software waits for an indication that the patient is ready and the optics are focused. The patient places his head on the slit lamp chin rest and control rod assembly 26 such that the patient's head is substantially immovably supported. The physician uses the adjustment mechanism on slit-lamp chin rest and control rod assembly 26 to adjust the position of housing 30 and, in particular, control rod 36 until projection optics 28 and camera 22 are aligned with the cornea 48 of one or the other eye 46 of the patient. Next, in block 84, image capture begins. Image capture is triggered by the physician or automatically by the computer according to the optimal image alignment algorithm, by the physician pressing a button on the joystick, a bluetooth keypad, or triggering a foot pedal to signal the device that the image of the camera/digital camera 22 should be recorded. Next, an autofocus routine, block 86, and an autoexpose routine, block 88, are performed to obtain a clear image of the retina 52. In the next step, continuous illumination is initiated, block 90, and then optical transfer is initiated, block 92. Thereafter, image capture is terminated, block 94, and an artifact is identified, block 96. In response to the physician's (or via the controller) indication that the image should be recorded, the personal computer 6 will cause the image of the camera/digital camera 22 to store digital data representing the captured image.

In the examples the captured images contain artifacts in different areas-artifacts in different areas because the optical instrument is transferred, or they are multiple light sources at different locations in the optical design that produce artifacts at different locations in the image. These artifacts are detected and only combined with the better quality parts of the captured image.

While there have been shown and described and pointed out fundamental novel features of the invention as applied to preferred embodiments thereof, it will be understood that various changes, substitutions and omissions of the form and detail of the devices illustrated and described may be made by those skilled in the art without departing from the spirit of the invention.

Claims (33)

1. An apparatus for imaging anterior and posterior segments of a human eye, comprising:

a light source;

an optical system having a plurality of optical elements translatable to pass light from the light source onto the optical axis or slightly off-axis from the center of the optical system and back into the imaging path from the retina or other eye feature;

a control device connected to the light source and in each case continuously switching the light source on or off in synchronism with image capture to produce alternating illumination; and

a transfer means in the optical system for transferring at least one of the plurality of optical elements;

wherein two images having a reflection artifact of a scope in two different areas of the anatomy of each successively obtained image located at the anterior segment and the posterior segment of the eye are generated, and the reflection artifact passing through each image is detected by image processing;

wherein the image with the reflection artifact is combined with one or more images to produce a composite image or video stream without the reflection artifact;

wherein only clearly focused image portions are combined from one or more images to produce a composite image.

2. The apparatus of claim 1 wherein the light source is laterally displaced.

3. The apparatus of claim 1 wherein the light source is rotated.

4. The apparatus of claim 2 wherein the light source is translated and rotated.

5. The apparatus of claim 4 wherein the light source has at least two light sources that are sequentially activated.

6. The apparatus of claim 4, wherein the alternating illumination and imaging paths enter the pupil of the human eye at an angle to the optical axis but parallel to the center of the optical system.

7. The apparatus of claim 6, wherein the angle distinguishes between overlapping of at least two light sources that are sequentially activated, and the angle and imaging path are variable in size, position and shape, which depends on pupil size, and can be manually or automatically adjusted depending on pupil size.

8. The apparatus according to claim 7, wherein a spatial light modulator is further provided to position and shape an illumination beam according to the sensed position and the size of the pupil.

9. The apparatus for imaging anterior and posterior segments of a human eye of claim 7, wherein also for the alignment mode, an infrared or near infrared filter is provided and turned slightly outward to pass wavelengths of other spectra and facilitate subsequent image capture.

10. The apparatus for imaging the anterior and posterior segments of an eye of claim 7, wherein a flexible eyecup made of a flexible material is further provided to surround an eye of a person to create a lightless environment and to keep an eyelid of the person open while the eye is being imaged;

wherein the eye cup comprises a rigid portion positioned at a twelve o 'clock and/or six o' clock orientation and pressed upwardly and/or downwardly at a 45 degree angle to hold the eyelid open.

11. The apparatus of claim 7 wherein the focal length of the apparatus for imaging the anterior segment and the posterior segment of a human eye is variable and stepped to achieve capture of multifocal planes in the human eye and reconstruction into a single optical domain image and film.

12. The apparatus of claim 7, wherein the focal length of the apparatus is variable by a series of different focal length microlenses placed on an image sensor, and then the image is captured at multiple focal lengths.

13. The apparatus of claim 12, wherein the apparatus for imaging the anterior segment and the posterior segment of a human eye is combined with an existing slit lamp or fundus camera, and uses a portion of the optical elements and optical system for image capture and image processing.

14. The apparatus of claim 13, wherein the apparatus for imaging the anterior segment and the posterior segment of a human eye is provided with a plurality of light sources and a plurality of filters to achieve the following objectives: color fundus imaging, fluorescence angiography, de-reddening, bluish, circulating blood green fundus angiography, crystallography, cornea and other anterior segment imaging, tear film imaging, optical coherence tomography, and ultra-wide field imaging.

15. A method of imaging the anterior and posterior segments of a human eye, comprising the steps of: providing a light source;

providing an optical system having a plurality of optical elements translatable to pass light from the light source onto the optical axis or slightly off the optical axis to the center of the optical system and back into the imaging path from the retina or other ocular structure;

providing a control device connected to the light source and in each case continuously switching the light source on or off in synchronism with image capture to produce alternating illumination;

providing a transfer means in the optical system for transferring at least one of the plurality of optical elements;

wherein two images having a reflection artifact of a scope in two different areas of the anatomy of each successively obtained image located at the anterior and posterior segments of the eye are generated and the reflection artifact passing through each image is detected by image processing;

wherein the image with the reflection artifact is combined with one or more images to produce a composite image or video stream without the reflection artifact;

wherein only clearly focused image portions are combined from one or more images to produce a composite image.

16. The method of claim 15, wherein the light source is laterally displaced.

17. The method of claim 15, wherein the light source is rotated.

18. The method of claim 16, wherein the light source is translated and rotated.

19. The method of claim 18, wherein the light source has at least two light sources that are activated sequentially.

20. The method of claim 19, wherein the alternating illumination and imaging paths enter the pupil of the human eye at an angle to the optical axis but parallel to the center of the optical system.

21. The method of claim 20, wherein the angle distinguishes between overlapping of at least two light sources that are triggered sequentially, and the angle and imaging path are of variable size, position and shape, which depends on the size of the pupil, and can be adjusted manually or automatically depending on the pupil size.

22. The method of claim 21, further providing a spatial light modulator to position and shape an illumination beam based on the sensed position and the size of the pupil.

23. The method of claim 22, wherein also for the alignment mode, an infrared or near infrared filter is provided and turned slightly outward to pass other wavelengths of the spectrum and facilitate subsequent image capture.

24. The method of claim 23, wherein an elastic eyecup made of an elastic material is further provided to surround an eye of a person to create a lightless environment and to keep an eyelid of the person open while the eye is being imaged;

wherein the eye cup comprises a rigid portion positioned at a twelve o 'clock and/or six o' clock orientation and pressed upwardly and/or downwardly at a 45 degree angle to hold the eyelid open.

25. The method of claim 24, further comprising providing a one-to-one eye anterior and posterior imaging device, wherein the focal length of the one-to-one eye anterior and posterior imaging device is variable and stepped to achieve capture of multifocal planes in the eye and reconstruction into a single light field image and film.

26. The method of claim 25, wherein the focal length of the device for imaging the anterior and posterior segments of a human eye is variable by a series of microlenses of different focal lengths, which are placed on an image sensing device, and then the image is captured at multiple focal lengths.

27. The method of claim 26, wherein the means for imaging the anterior and posterior segments of a human eye is combined with an existing slit lamp or fundus camera and utilizes a portion of the optics and optical system for image capture and image processing.

28. The method of claim 27, wherein the means for imaging the anterior and posterior segments of a human eye is provided with a plurality of light sources and a plurality of filters to achieve the following: color fundus imaging, fluorescence angiography, de-reddening, bluish, circulating blood green fundus angiography, crystallography, cornea and other anterior segment imaging, tear film imaging, optical coherence tomography, and ultra-wide field imaging.

29. The method of claim 28, wherein a side comprising a plurality of optical elements is moved laterally to create a three-dimensional stereo pair.

30. The method of claim 29, comprising an anti-shake algorithm to remove eye movement and physician movement.

31. The method of claim 29, wherein an image stabilization algorithm is included to remove eye movement and physician movement.

32. The method of claim 30 or 31, wherein a wide-field panoramic image is automatically created at or at the end of image capture, on top of previously captured images, to create a large panorama of the retina or other eye anatomy and features.

33. The method of claim 32, including a means for controlling patient fixation, and thereby producing images with reflection artifacts at different anatomical locations, and thereby combining the images into a composite image without reflection artifacts.