CA2284299A1 - Method and apparatus for a high resolution eye scanner - Google Patents
Method and apparatus for a high resolution eye scanner Download PDFInfo
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- CA2284299A1 CA2284299A1 CA002284299A CA2284299A CA2284299A1 CA 2284299 A1 CA2284299 A1 CA 2284299A1 CA 002284299 A CA002284299 A CA 002284299A CA 2284299 A CA2284299 A CA 2284299A CA 2284299 A1 CA2284299 A1 CA 2284299A1
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- A61B3/10—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions
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Abstract
An apparatus and method are described which provide a unique way of creating a very high resolution image of the retina inside an eye.
In one aspect, the apparatus uses a very resolution linear CCD array coupled with structured light projectors (or low power eye safe lasers) to illuminate the retina to capture a very high resolution image segment of the retina.
In another aspect, a moving light pattern is used which is tracked by an observer whose eye is being scanned, and the image segments of the retina as the eye tracks the moving light pattern is integrated to form a very high resolution image segment of the retina.
In yet another aspect, the structured light projectors can be used to project a known pattern on the retina to reconstruct a 3D map of the retinal surface integrating 3D information computed as the eye tracks a moving light.
In yet another aspect, innovative methods are used to register the orientation of the eye being scanned with the very high resolution image segment captured at any point of time.
In one aspect, the apparatus uses a very resolution linear CCD array coupled with structured light projectors (or low power eye safe lasers) to illuminate the retina to capture a very high resolution image segment of the retina.
In another aspect, a moving light pattern is used which is tracked by an observer whose eye is being scanned, and the image segments of the retina as the eye tracks the moving light pattern is integrated to form a very high resolution image segment of the retina.
In yet another aspect, the structured light projectors can be used to project a known pattern on the retina to reconstruct a 3D map of the retinal surface integrating 3D information computed as the eye tracks a moving light.
In yet another aspect, innovative methods are used to register the orientation of the eye being scanned with the very high resolution image segment captured at any point of time.
Description
Method and apparatus for a high resolution eye scanner Field of the invention This invention relates to a device for creating very high resolution imagery of the retina inside a human eye. More specifically, the invention relates to combining image segments, captured with a high resolution linear CCD, as the eye moves to track a moving light pattern to create a very high resolution image of the retina. The invention also relates to a method and device for registering the image segments obtained as the eye moves, to track the moving light pattern, with the orientation of the eye.
Background of the invention Current devices for obtaining pictures of the retina suffer from lack of good detail, thereby making diagnosis of eye diseases difficult. This problem is especially relevant in the context of TeleHealth where images may be acquired for remote diagnosis by a doctor;
lack of high quality in the images captured means that tele-diagnosis is impossible.
This invention introduces a new method and apparatus which makes it possible to obtain images of the retina with quality surpassing what can be observed by a doctor with his or her naked eye.
There are several unique components in the device described in this invention compared to devices described heretofore. First, the method and apparatus for creating very high resolution retinal images is unique. Second, the method and device provides a means for integrating image segments over time to create a very high resolution retinal image. Third, the method and apparatus provides a means for illuminating the inside of the eye using limited amount of lighting, thereby not closing the iris while imaging. Forth, the method and apparatus provides a means of illuminating and imaging a wide field of view inside the eye.
Summary of the invention It is a primary object of this invention to provide a new and improved very high resolution imaging method and apparatus for scanning the retinal surface of human eyes.
It is a further object of this invention to provide a method and apparatus for accurately registering the image segment captured at an instant of time with the corresponding orientation of the eye.
According to the present invention, an eye scanning system is developed consisting of two or more structured light (or low power eye-safe laser line) projectors; a high resolution linear CCD based sensor and associated electronic components; an optional area CCD
based sensor and associated electronic components; an optional partial reflector (or partially silvered mirror) ; a device to place an eye for imaging; a moving light pattern; and a high speed standards based bi-directional communication device for transfernng digital image data to a computer or other storage device.
Background of the invention Current devices for obtaining pictures of the retina suffer from lack of good detail, thereby making diagnosis of eye diseases difficult. This problem is especially relevant in the context of TeleHealth where images may be acquired for remote diagnosis by a doctor;
lack of high quality in the images captured means that tele-diagnosis is impossible.
This invention introduces a new method and apparatus which makes it possible to obtain images of the retina with quality surpassing what can be observed by a doctor with his or her naked eye.
There are several unique components in the device described in this invention compared to devices described heretofore. First, the method and apparatus for creating very high resolution retinal images is unique. Second, the method and device provides a means for integrating image segments over time to create a very high resolution retinal image. Third, the method and apparatus provides a means for illuminating the inside of the eye using limited amount of lighting, thereby not closing the iris while imaging. Forth, the method and apparatus provides a means of illuminating and imaging a wide field of view inside the eye.
Summary of the invention It is a primary object of this invention to provide a new and improved very high resolution imaging method and apparatus for scanning the retinal surface of human eyes.
It is a further object of this invention to provide a method and apparatus for accurately registering the image segment captured at an instant of time with the corresponding orientation of the eye.
According to the present invention, an eye scanning system is developed consisting of two or more structured light (or low power eye-safe laser line) projectors; a high resolution linear CCD based sensor and associated electronic components; an optional area CCD
based sensor and associated electronic components; an optional partial reflector (or partially silvered mirror) ; a device to place an eye for imaging; a moving light pattern; and a high speed standards based bi-directional communication device for transfernng digital image data to a computer or other storage device.
Further, according to the present invention, a bi-directional communication system is provided, for real time modifications of the parameters of the imaging system in order to control the focussing of the light (laser) sources on the retina.
Brief description of the drawings The foregoing and other objects, features, benefits, and advantages of the invention will be described in the preferred embodiments of the system in conjunction with the accompanying drawings, in which:
Fig. 1 is a diagram of a preferred embodiment of the present invention.
Fig. 2 is a diagram showing the location of a tri-linear CCD within the camera 6 in Fig. 1.
Fig. 3 is a diagram showing the location of an optional partial reflector and the corresponding area CCD within the camera 6 in Fig. 1.
Fig. 4 is a diagram showing the projection of a narrow beam of light (or low power laser) on the retina from the lighting devices 7 in Fig. 1.
Fig. 5 is a diagram showing the configuration of a computer and communication with the eye scanning system.
Fig. 6 is a diagram showing another embodiment of the present invention.
Fig. 7 is a block diagram relating the operation of various hardware components.
Fig. 8 is a diagram showing the integration of image data over time to create a composite image of the retina.
Detailed description of the preferred embodiments Referring now to Figure 1, a curved surface 1 with an opening to allow an eye to look through is shown. A circular or elliptical or other appropriately shaped ring 3 holding a number of lights 4 that can be controlled to create a moving light pattern is also shown; a moving pattern on an LCD display can be used instead of a number of lights in 4. An eye placed at 2 can be imaged by a camera 6 with lens 5. The interior of the eye can be illuminated using two light sources (or low power eye-safe lasers) 7.
Refernng now to Figure 2, the inside of camera 6 is shown in greater detail.
In one form of operation only one tri-linear sensor 8, consisting of 3 sensor lines 9, 10, and 11 corresponding to red, green, and blue, is used to capture a vertical strip of image of part of the eye. In this form of operation the red sensor is tuned to capture the orientation of the eye with infra-red sensing, while the retina is illuminated with blue and green lighting which can be imaged by the blue and green sensors.
Referring now to Figure 3, the inside of the camera is shown in greater detail in another form of operation in which a partial reflector (or partially silvered mirror) 12 is used to reflect part of the image to be captured by an infrared CCD 13.
Referring now to Figure 4, the means of illuminating the inside of the eye using structured light (or low power laser) projectors 7 is shown in greater detail. Rays 14 from the top projector and rays 15 from the bottom projector in conjunction overlap to illuminate a large vertical field of view on the retina 16. Only thin vertical beams are projected inside the eyes, thereby the overall brightness perceived by the eye is low and does not cause the iris to close.
Referring now to Figure 5, the system is controlled by a computer 17 or similar electronic control device. The electronics in the camera 6 controls the lighting device 3 and synchronizes the image capture with movement of the light pattern in the lighting device 3.
The communication between the computer 17 and the camera 6 is bi-directional;
image segments inside the eye captured by the camera 6 are transferred to the computer 17 whereas operational commands issued by the computer 17 are transferred to the camera 6.
Referring now to Figure 6, another possible implementation of the system for eye scanning is shown. In this implementation several partially silvered mirrors or similar optical devices are used in conjunction with multiple lenses instead of the arrangement in Figure 1. In the implementation in Figure 6, the eye under observation 18 has a light pattern 19 projected on the retina which is imaged by an area CCD camera 22. The other components of the system in Figure 6 include: a half silvered mirror 20, a lens 21 for the area CCD
camera 22, another half silvered mirror 23 used to reflect part of the light to image a vertical segment of the retina using a lens 24 and a linear CCD 25, another half silvered mirror 26 used to guide a linear light source 28 with a lens 27 for focussing to project a linear beam on the retina, and a moving light source 29 (which may be created by a point source of light placed on a rotating unit) that when reflected by the half silvered mirror surface 20 appears as a moving light pattern similar to 3 in Figure 1.
Referring now to Figure 7, a block diagram relating the operation of and interactions among various electronic components of the system is shown. In this figure: A
is a Linear CCD Detector; B represents the Analog output of the Linear CCD Detector; C is an Analog to Digital converter; D represents the Digital output of A/D converter C; E is the Memory for storing the digital output of the Linear CCD Detector; F is the Linear CCD
Detector Memory output, 1 L( 1. . n) to NL( 1.. n); G is the Timing unit for CCD as well as address generator for Linear and area Detector Memories; H is an Area CCD
detector;
I is the Analog output of Area Detector; J is the Area Detector's Analog to Digital converter; K is the digital output of A/D J; L is the Memory for storing the Digital output of Area CCD Detector; M is Area CCD Detector Memory output, lA(x,y) to NA(x,y); N is a Microprocessor; O is the memory of the Microprocessor; P is the Memory Buffer for CCDs, linear and area; and Q is the Microprocessor Memory Bus.
Referring now to Figure 8, the image of a vertical strip 30 on the retina is obtained as an intensity map 32. The integration of the location of the strip with the intensity map produces an image strip 31 in the retina. The image strips 31 over time are accumulated to produce an image of a region 33 of the retinal surface.
In operation, an eye placed at location 2 tracks a continuously moving light pattern 4 contained inside a circular or elliptical or other relevant shape 3. Thin light beams (or eye-safe low power lasers) are projected on to the retina 16 from light (or laser) projectors 7.
The rays 14 and 15 from the light sources 7 in combination illuminate a large vertical segment of the retina 16. High resolution image segments are imaged by a camera 6 using a linear CCD 8 as the eye moves to track the light pattern 4. These image segments are integrated over time by registering the orientation of the eye with the image segment captured at an instant of time. Registering image segments captured at an instant of time with the orientation of an eye can be achieved in at least two different ways.
In one approach two linear sensors (say 9 and 10 representing blue and green) can be used to capture image segments inside the eye by illuminating the retina only with light in the blue and green spectrum, while 11 representing red can be tuned to capture an infrared segment of the surface of the eye, thereby making it possible to register retinal image segments with the corresponding orientation of the eye. In another approach, part of the light coming into the camera is reflected using a partial reflector (or partially silvered mirror) 12 to an infrared area CCD sensor which captures an outline of the outside surface of the eye, while the tri-linear sensor 8 can be concurrently used to capture a vertical strip of image inside the eye. Using the orientation of the eye as a reference, vertical image segments of the retina can be integrated over time to create a very high resolution image of the retinal surface.
In another mode of operation, the rays 14 and 15 from the light sources 7 can be used to project a known pattern on the retina, such as dot patterns, which can be imaged by the linear CCD 8 to obtain information that can be used to compute depth. In order to distinguish between the light sources 14 and 15 the two sources can project light in different wavelengths, e.g., blue and green, and these patterns can be aligned with the corresponding CCD line 9, 10 or 11 representing red , green and blue sensors.
Again, using the orientation of the eye as a reference, vertical image segments of the retina can be integrated over time to create a very high resolution image of the retinal surface.
In operation, a computer 17 controls the moving light pattern 4 while image segments of the retina are transferred to the computer storage along with an image (or image segment) recording the orientation of the eye. In one form of implementation, the computer has bi-directional communication over high-speed standard based communication links with a communication board in the imaging device. The communication board in the imaging device controls the operation of the moving light pattern as well as the structured light (or laser) projectors 7. However, various other arrangements of the communication system and protocol are possible without changing the essence of the overall apparatus.
There are various ways to achieve the basic setup in which a linear source of light is projected on the back retina while a patient follows a moving dot of light.
The projected line is located on the same vertical axis as a linear CCD which captures a line image of that part of retina illuminated by the linear light source. The patient follows the dot of light which causes the eye to scan left-right (yaw) up-down (pitch) whereby causing the line projection to sweep a connected region in the retina. The set up also monitors the iris and pupil with an area camera. The area camera or area CCD is used to register and record the orientation of the eye. The eye orientation can have Yaw, Pitch as well as some rotation (Roll) degrees of freedom. Another method of achieving the basic setup in shown in Figure 6. In this setup, the eye 18 tracks a moving light pattern created by the reflection of a moving point source of light 29 from a half silvered mirror 20. Note that 29 may consist of a single light source mounted on a rotating platform, rather than a collection of lights 3 creating a moving light pattern. The orientation of the eye is estimated by capturing the image of the iris and pupil using an infrared area CCD 22 camera with a lens 21. A linear segment of the retina on which a line beam is projected, by a line source 28 focussed using a lens 27 and reflected off half silvered mirrors 23 and 20, is imaged by a linear CCD 25 camera with a lens 24 for focussing; this arrangement is more compact than using two line light source projectors 7 in the arrangement in Figure 1. Again, the set up in Figure 6 can be used to obtain 3D data on the retinal surface by using the line beam projector 28 to projector a light pattern, such as a dot pattern, on the retina.
With reference to Figure 7, a method for integrating image segments over time is explained in greater detail using a block diagram showing the various hardware components and their inter-relationships. For correct registration the CCD
detectors are synchronized in time. Also for correct registration the address on each detector, Linear and Area, write into memory locations for the same address so that each area scan corresponds to a linear scan. In this way the three angles, elevation, azimuth and roll can be calculated by the microprocessor based on the area sensor mapping of the iris. Given the three angles calculated for each memory location the microprocessor then reads the linear scan memory and builds the map of the retina from the linear scans which represent small segments of the image. In this way the microprocessor reads all of the area memory and computes a compete table of locations for the linear scans to be filled in.
Step 1: Read area sensor at memory location 1 using 2D intensity map of area sensor for location one as first reference.
Step 2: Read area sensor at memory location 2 using area data calculate new eye location by differential mapping to location 1.
This calculation will yield eye pitch roll and tilt. Store these numbers in microprocessor memory at memory 1 A.
Step 3: Repeat step 2 sequentially reading area data and calculating and storing eye positions through complete set of area memory locations from lA to XA.
Raw Area Data Calculate Eye positions Calculated Mathematically NA(x,y) transforms to NP(pitch,roll,tilt) equals 1P(p,r,t);
Step 4:
Read calculated eye positions in memory lA. Given Pitch Roll and Tilt calculate the straight line projection of this on a series of memory locations 1 (x,y) to N(x,y) on a 2D
memory map corresponding to the projection of a straight line and the geometrical position of the eye. This can be done because of the prior knowledge of the line projection relationship to the area sensor.
Eye positions Calculated Calculate Line Projecrions Calculat Mathematically NP(pitch,roll,tilt) transforms to NP(x',y') 1P(p,r,t) gives the location of the line segment being imaged (30 in Figure 8).
Write into memory at 1P(x',y') to NP(x',y') the corresponding linear sensor memory location intensity readings IL(1...I~. At each line projection point calculated write the corresponding intensity value from the linear sensor memory.
Calculated Line Projectio Calculate Intensity Map projection Mathematically NP(x',y') transformers to 1VI(x',y') In other words, location of linear segment imaged 30 (Figure 7) combined with intensity map of linear CCD 32 gives image of a linear segment on the retina 31.
Step 5:
Repeat step 4 for each eye position calculated thereby filling the complete map of a region of the retina. In other words, linear image segments 31 (Figure 7) of the retina, captured as the eye moves to track a moving pattern, can be integrated over time to produce a high resolution image 33 of the retina.
The same set of steps can be repeated with a pattern light projected on the retina, instead of a simple vertical beam of light, to compute and obtain a 3D map of a region of the retina.
We hereby complete the map of the retina.
In the foregoing specifications, the invention has been described with respect to specific exemplary embodiments. However, various modifications may be made thereto without deviating from the broader spirit and scope of the invention as set forth in the appended claims.
1. A device for generating very high resolution retinal images, compris' an imaging device coupled with one or more linear light (or 1 projectors;
a moving light pattern;
at least one communication device for bi-dir nal communication between the said imaging device or the said laser pro' rs and a computer.
2. An arrangement o imaging device and the laser pattern projectors rding to claim 1 which in conjunction with a computer, or equivalent de ' , offer the following functionality:
Brief description of the drawings The foregoing and other objects, features, benefits, and advantages of the invention will be described in the preferred embodiments of the system in conjunction with the accompanying drawings, in which:
Fig. 1 is a diagram of a preferred embodiment of the present invention.
Fig. 2 is a diagram showing the location of a tri-linear CCD within the camera 6 in Fig. 1.
Fig. 3 is a diagram showing the location of an optional partial reflector and the corresponding area CCD within the camera 6 in Fig. 1.
Fig. 4 is a diagram showing the projection of a narrow beam of light (or low power laser) on the retina from the lighting devices 7 in Fig. 1.
Fig. 5 is a diagram showing the configuration of a computer and communication with the eye scanning system.
Fig. 6 is a diagram showing another embodiment of the present invention.
Fig. 7 is a block diagram relating the operation of various hardware components.
Fig. 8 is a diagram showing the integration of image data over time to create a composite image of the retina.
Detailed description of the preferred embodiments Referring now to Figure 1, a curved surface 1 with an opening to allow an eye to look through is shown. A circular or elliptical or other appropriately shaped ring 3 holding a number of lights 4 that can be controlled to create a moving light pattern is also shown; a moving pattern on an LCD display can be used instead of a number of lights in 4. An eye placed at 2 can be imaged by a camera 6 with lens 5. The interior of the eye can be illuminated using two light sources (or low power eye-safe lasers) 7.
Refernng now to Figure 2, the inside of camera 6 is shown in greater detail.
In one form of operation only one tri-linear sensor 8, consisting of 3 sensor lines 9, 10, and 11 corresponding to red, green, and blue, is used to capture a vertical strip of image of part of the eye. In this form of operation the red sensor is tuned to capture the orientation of the eye with infra-red sensing, while the retina is illuminated with blue and green lighting which can be imaged by the blue and green sensors.
Referring now to Figure 3, the inside of the camera is shown in greater detail in another form of operation in which a partial reflector (or partially silvered mirror) 12 is used to reflect part of the image to be captured by an infrared CCD 13.
Referring now to Figure 4, the means of illuminating the inside of the eye using structured light (or low power laser) projectors 7 is shown in greater detail. Rays 14 from the top projector and rays 15 from the bottom projector in conjunction overlap to illuminate a large vertical field of view on the retina 16. Only thin vertical beams are projected inside the eyes, thereby the overall brightness perceived by the eye is low and does not cause the iris to close.
Referring now to Figure 5, the system is controlled by a computer 17 or similar electronic control device. The electronics in the camera 6 controls the lighting device 3 and synchronizes the image capture with movement of the light pattern in the lighting device 3.
The communication between the computer 17 and the camera 6 is bi-directional;
image segments inside the eye captured by the camera 6 are transferred to the computer 17 whereas operational commands issued by the computer 17 are transferred to the camera 6.
Referring now to Figure 6, another possible implementation of the system for eye scanning is shown. In this implementation several partially silvered mirrors or similar optical devices are used in conjunction with multiple lenses instead of the arrangement in Figure 1. In the implementation in Figure 6, the eye under observation 18 has a light pattern 19 projected on the retina which is imaged by an area CCD camera 22. The other components of the system in Figure 6 include: a half silvered mirror 20, a lens 21 for the area CCD
camera 22, another half silvered mirror 23 used to reflect part of the light to image a vertical segment of the retina using a lens 24 and a linear CCD 25, another half silvered mirror 26 used to guide a linear light source 28 with a lens 27 for focussing to project a linear beam on the retina, and a moving light source 29 (which may be created by a point source of light placed on a rotating unit) that when reflected by the half silvered mirror surface 20 appears as a moving light pattern similar to 3 in Figure 1.
Referring now to Figure 7, a block diagram relating the operation of and interactions among various electronic components of the system is shown. In this figure: A
is a Linear CCD Detector; B represents the Analog output of the Linear CCD Detector; C is an Analog to Digital converter; D represents the Digital output of A/D converter C; E is the Memory for storing the digital output of the Linear CCD Detector; F is the Linear CCD
Detector Memory output, 1 L( 1. . n) to NL( 1.. n); G is the Timing unit for CCD as well as address generator for Linear and area Detector Memories; H is an Area CCD
detector;
I is the Analog output of Area Detector; J is the Area Detector's Analog to Digital converter; K is the digital output of A/D J; L is the Memory for storing the Digital output of Area CCD Detector; M is Area CCD Detector Memory output, lA(x,y) to NA(x,y); N is a Microprocessor; O is the memory of the Microprocessor; P is the Memory Buffer for CCDs, linear and area; and Q is the Microprocessor Memory Bus.
Referring now to Figure 8, the image of a vertical strip 30 on the retina is obtained as an intensity map 32. The integration of the location of the strip with the intensity map produces an image strip 31 in the retina. The image strips 31 over time are accumulated to produce an image of a region 33 of the retinal surface.
In operation, an eye placed at location 2 tracks a continuously moving light pattern 4 contained inside a circular or elliptical or other relevant shape 3. Thin light beams (or eye-safe low power lasers) are projected on to the retina 16 from light (or laser) projectors 7.
The rays 14 and 15 from the light sources 7 in combination illuminate a large vertical segment of the retina 16. High resolution image segments are imaged by a camera 6 using a linear CCD 8 as the eye moves to track the light pattern 4. These image segments are integrated over time by registering the orientation of the eye with the image segment captured at an instant of time. Registering image segments captured at an instant of time with the orientation of an eye can be achieved in at least two different ways.
In one approach two linear sensors (say 9 and 10 representing blue and green) can be used to capture image segments inside the eye by illuminating the retina only with light in the blue and green spectrum, while 11 representing red can be tuned to capture an infrared segment of the surface of the eye, thereby making it possible to register retinal image segments with the corresponding orientation of the eye. In another approach, part of the light coming into the camera is reflected using a partial reflector (or partially silvered mirror) 12 to an infrared area CCD sensor which captures an outline of the outside surface of the eye, while the tri-linear sensor 8 can be concurrently used to capture a vertical strip of image inside the eye. Using the orientation of the eye as a reference, vertical image segments of the retina can be integrated over time to create a very high resolution image of the retinal surface.
In another mode of operation, the rays 14 and 15 from the light sources 7 can be used to project a known pattern on the retina, such as dot patterns, which can be imaged by the linear CCD 8 to obtain information that can be used to compute depth. In order to distinguish between the light sources 14 and 15 the two sources can project light in different wavelengths, e.g., blue and green, and these patterns can be aligned with the corresponding CCD line 9, 10 or 11 representing red , green and blue sensors.
Again, using the orientation of the eye as a reference, vertical image segments of the retina can be integrated over time to create a very high resolution image of the retinal surface.
In operation, a computer 17 controls the moving light pattern 4 while image segments of the retina are transferred to the computer storage along with an image (or image segment) recording the orientation of the eye. In one form of implementation, the computer has bi-directional communication over high-speed standard based communication links with a communication board in the imaging device. The communication board in the imaging device controls the operation of the moving light pattern as well as the structured light (or laser) projectors 7. However, various other arrangements of the communication system and protocol are possible without changing the essence of the overall apparatus.
There are various ways to achieve the basic setup in which a linear source of light is projected on the back retina while a patient follows a moving dot of light.
The projected line is located on the same vertical axis as a linear CCD which captures a line image of that part of retina illuminated by the linear light source. The patient follows the dot of light which causes the eye to scan left-right (yaw) up-down (pitch) whereby causing the line projection to sweep a connected region in the retina. The set up also monitors the iris and pupil with an area camera. The area camera or area CCD is used to register and record the orientation of the eye. The eye orientation can have Yaw, Pitch as well as some rotation (Roll) degrees of freedom. Another method of achieving the basic setup in shown in Figure 6. In this setup, the eye 18 tracks a moving light pattern created by the reflection of a moving point source of light 29 from a half silvered mirror 20. Note that 29 may consist of a single light source mounted on a rotating platform, rather than a collection of lights 3 creating a moving light pattern. The orientation of the eye is estimated by capturing the image of the iris and pupil using an infrared area CCD 22 camera with a lens 21. A linear segment of the retina on which a line beam is projected, by a line source 28 focussed using a lens 27 and reflected off half silvered mirrors 23 and 20, is imaged by a linear CCD 25 camera with a lens 24 for focussing; this arrangement is more compact than using two line light source projectors 7 in the arrangement in Figure 1. Again, the set up in Figure 6 can be used to obtain 3D data on the retinal surface by using the line beam projector 28 to projector a light pattern, such as a dot pattern, on the retina.
With reference to Figure 7, a method for integrating image segments over time is explained in greater detail using a block diagram showing the various hardware components and their inter-relationships. For correct registration the CCD
detectors are synchronized in time. Also for correct registration the address on each detector, Linear and Area, write into memory locations for the same address so that each area scan corresponds to a linear scan. In this way the three angles, elevation, azimuth and roll can be calculated by the microprocessor based on the area sensor mapping of the iris. Given the three angles calculated for each memory location the microprocessor then reads the linear scan memory and builds the map of the retina from the linear scans which represent small segments of the image. In this way the microprocessor reads all of the area memory and computes a compete table of locations for the linear scans to be filled in.
Step 1: Read area sensor at memory location 1 using 2D intensity map of area sensor for location one as first reference.
Step 2: Read area sensor at memory location 2 using area data calculate new eye location by differential mapping to location 1.
This calculation will yield eye pitch roll and tilt. Store these numbers in microprocessor memory at memory 1 A.
Step 3: Repeat step 2 sequentially reading area data and calculating and storing eye positions through complete set of area memory locations from lA to XA.
Raw Area Data Calculate Eye positions Calculated Mathematically NA(x,y) transforms to NP(pitch,roll,tilt) equals 1P(p,r,t);
Step 4:
Read calculated eye positions in memory lA. Given Pitch Roll and Tilt calculate the straight line projection of this on a series of memory locations 1 (x,y) to N(x,y) on a 2D
memory map corresponding to the projection of a straight line and the geometrical position of the eye. This can be done because of the prior knowledge of the line projection relationship to the area sensor.
Eye positions Calculated Calculate Line Projecrions Calculat Mathematically NP(pitch,roll,tilt) transforms to NP(x',y') 1P(p,r,t) gives the location of the line segment being imaged (30 in Figure 8).
Write into memory at 1P(x',y') to NP(x',y') the corresponding linear sensor memory location intensity readings IL(1...I~. At each line projection point calculated write the corresponding intensity value from the linear sensor memory.
Calculated Line Projectio Calculate Intensity Map projection Mathematically NP(x',y') transformers to 1VI(x',y') In other words, location of linear segment imaged 30 (Figure 7) combined with intensity map of linear CCD 32 gives image of a linear segment on the retina 31.
Step 5:
Repeat step 4 for each eye position calculated thereby filling the complete map of a region of the retina. In other words, linear image segments 31 (Figure 7) of the retina, captured as the eye moves to track a moving pattern, can be integrated over time to produce a high resolution image 33 of the retina.
The same set of steps can be repeated with a pattern light projected on the retina, instead of a simple vertical beam of light, to compute and obtain a 3D map of a region of the retina.
We hereby complete the map of the retina.
In the foregoing specifications, the invention has been described with respect to specific exemplary embodiments. However, various modifications may be made thereto without deviating from the broader spirit and scope of the invention as set forth in the appended claims.
1. A device for generating very high resolution retinal images, compris' an imaging device coupled with one or more linear light (or 1 projectors;
a moving light pattern;
at least one communication device for bi-dir nal communication between the said imaging device or the said laser pro' rs and a computer.
2. An arrangement o imaging device and the laser pattern projectors rding to claim 1 which in conjunction with a computer, or equivalent de ' , offer the following functionality:
Claims (7)
1. A device for generating very high resolution retinal images, comprising:
an imaging device coupled with one or more linear light (or laser) projectors;
a moving light pattern;
at least one communication device for bi-directional communication between the said imaging device or the said laser projectors and a computer.
an imaging device coupled with one or more linear light (or laser) projectors;
a moving light pattern;
at least one communication device for bi-directional communication between the said imaging device or the said laser projectors and a computer.
2. An arrangement of the imaging device and the laser pattern projectors according to claim 1 which in conjunction with a computer, or equivalent device, offer the following functionality:
high speed digital communication of very high resolution image segments and corresponding infrared image representing eye orientation to a digital storage device;
ability to control the imaging device according to claim 1 in real time;
ability of control the light pattern projectors according to claim 1 in real time;
ability to obtain both retinal image and eye orientation on all parts of an eye being scanned, thereby allowing the integration of image segments of the retina to form a very high resolution image of the retina.
high speed digital communication of very high resolution image segments and corresponding infrared image representing eye orientation to a digital storage device;
ability to control the imaging device according to claim 1 in real time;
ability of control the light pattern projectors according to claim 1 in real time;
ability to obtain both retinal image and eye orientation on all parts of an eye being scanned, thereby allowing the integration of image segments of the retina to form a very high resolution image of the retina.
3. A configuration of lighting projectors, with two or more projectors, to illuminate a large vertical field of view of the retina.
4. A design of the lighting projection, as thin vertical beams, inside the eye according to claim1, whereby very high resolution image of the retina can be acquired without the need to expose the eye to high intensity of lighting.
5. A method and apparatus to create a moving light pattern using a single point source of light, a mirror surface, and a rotateable platform.
6. A method and apparatus for synchronizing the capture of eye orientation and registration of this information with a segment of retinal image.
7. A method and apparatus to create a 3D map of the retina, following the device in claim 1 replacing the linear light projectors with pattern (such as dots) light projector to allow the computation of depth on a retinal surface.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002284299A CA2284299A1 (en) | 1999-09-28 | 1999-09-28 | Method and apparatus for a high resolution eye scanner |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002284299A CA2284299A1 (en) | 1999-09-28 | 1999-09-28 | Method and apparatus for a high resolution eye scanner |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2284299A1 true CA2284299A1 (en) | 2001-03-28 |
Family
ID=4164258
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002284299A Abandoned CA2284299A1 (en) | 1999-09-28 | 1999-09-28 | Method and apparatus for a high resolution eye scanner |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2284299A1 (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1992276A1 (en) * | 2007-05-18 | 2008-11-19 | LINOS Photonics GmbH & Co. KG | Fundus camera |
| WO2009043475A1 (en) * | 2007-09-28 | 2009-04-09 | Carl Zeiss Meditec Ag | Device and method for examining the eye fundus, especially the photoreceptors |
| EP2171681A1 (en) * | 2007-06-27 | 2010-04-07 | i-Optics B.V. | Ophthalmic apparatus and method for increasing the resolution of aliased ophthalmic images |
| US8226232B2 (en) | 2008-12-17 | 2012-07-24 | Technion Research And Development Foundation, Ltd. | System and method for fast retinal imaging |
| CN102970917A (en) * | 2010-05-05 | 2013-03-13 | 梅勒妮·克龙比·威廉斯·坎贝尔 | Method and system for imaging amyloid beta in the retina of the eye in association with alzheimer's disease |
| EP2735264A4 (en) * | 2011-07-21 | 2015-05-06 | Shanghai Mediworks Prec Instr Co Ltd | System and method for eye imaging |
| CN111031894A (en) * | 2017-08-14 | 2020-04-17 | 威里利生命科学有限责任公司 | Dynamic illumination during continuous retinal imaging |
| US11666212B2 (en) | 2016-11-25 | 2023-06-06 | Nederlandse Organisatie voor toegepast-nataurwetenschappelijk onderzoek TNO | Quantitative retinal imaging |
-
1999
- 1999-09-28 CA CA002284299A patent/CA2284299A1/en not_active Abandoned
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1992276A1 (en) * | 2007-05-18 | 2008-11-19 | LINOS Photonics GmbH & Co. KG | Fundus camera |
| US7819526B2 (en) | 2007-05-18 | 2010-10-26 | Linos Photonics Gmbh & Co. Kg | Fundus camera |
| EP2171681A1 (en) * | 2007-06-27 | 2010-04-07 | i-Optics B.V. | Ophthalmic apparatus and method for increasing the resolution of aliased ophthalmic images |
| WO2009043475A1 (en) * | 2007-09-28 | 2009-04-09 | Carl Zeiss Meditec Ag | Device and method for examining the eye fundus, especially the photoreceptors |
| US8567948B2 (en) | 2007-09-28 | 2013-10-29 | Carl Zeiss Meditec Ag | Device and method for examining the eye fundus, especially the photoreceptors |
| US8226232B2 (en) | 2008-12-17 | 2012-07-24 | Technion Research And Development Foundation, Ltd. | System and method for fast retinal imaging |
| US8851671B2 (en) | 2008-12-17 | 2014-10-07 | Technion Research And Development Foundation Ltd | System and method for fast retinal imaging |
| CN102970917A (en) * | 2010-05-05 | 2013-03-13 | 梅勒妮·克龙比·威廉斯·坎贝尔 | Method and system for imaging amyloid beta in the retina of the eye in association with alzheimer's disease |
| CN102970917B (en) * | 2010-05-05 | 2016-11-23 | 梅勒妮·克龙比·威廉斯·坎贝尔 | The retina amyloid beta formation method relevant to stages alzheimer's disease, system |
| EP2735264A4 (en) * | 2011-07-21 | 2015-05-06 | Shanghai Mediworks Prec Instr Co Ltd | System and method for eye imaging |
| US11666212B2 (en) | 2016-11-25 | 2023-06-06 | Nederlandse Organisatie voor toegepast-nataurwetenschappelijk onderzoek TNO | Quantitative retinal imaging |
| CN111031894A (en) * | 2017-08-14 | 2020-04-17 | 威里利生命科学有限责任公司 | Dynamic illumination during continuous retinal imaging |
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