Nothing Special   »   [go: up one dir, main page]

US20140055567A1 - Video Infrared Retinal Image Scanner - Google Patents

Video Infrared Retinal Image Scanner Download PDF

Info

Publication number
US20140055567A1
US20140055567A1 US13/970,249 US201313970249A US2014055567A1 US 20140055567 A1 US20140055567 A1 US 20140055567A1 US 201313970249 A US201313970249 A US 201313970249A US 2014055567 A1 US2014055567 A1 US 2014055567A1
Authority
US
United States
Prior art keywords
retina
image
images
video
signal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US13/970,249
Inventor
David S. DYER
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dyer Holdings LLC
Original Assignee
Dyer Holdings LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dyer Holdings LLC filed Critical Dyer Holdings LLC
Priority to US13/970,249 priority Critical patent/US20140055567A1/en
Publication of US20140055567A1 publication Critical patent/US20140055567A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • G06K9/00617
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06VIMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V10/00Arrangements for image or video recognition or understanding
    • G06V10/40Extraction of image or video features
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06VIMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V40/00Recognition of biometric, human-related or animal-related patterns in image or video data
    • G06V40/10Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
    • G06V40/18Eye characteristics, e.g. of the iris
    • G06V40/197Matching; Classification
    • G06K9/00288
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06VIMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V40/00Recognition of biometric, human-related or animal-related patterns in image or video data
    • G06V40/10Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
    • G06V40/16Human faces, e.g. facial parts, sketches or expressions
    • G06V40/172Classification, e.g. identification
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06VIMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V40/00Recognition of biometric, human-related or animal-related patterns in image or video data
    • G06V40/10Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
    • G06V40/18Eye characteristics, e.g. of the iris
    • G06V40/19Sensors therefor
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/20Cameras or camera modules comprising electronic image sensors; Control thereof for generating image signals from infrared radiation only
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00Details of television systems
    • H04N5/30Transforming light or analogous information into electric information
    • H04N5/33Transforming infrared radiation

Definitions

  • a video infrared retinal image scanner uses an infrared light to illuminate an ocular system and a camera to capture and display an image.
  • the image may be analyzed and processed and rendered in 3-D.
  • Computer analysis of the retinal vessels is performed by looking at the branching pattern of the retinal vessels.
  • An overlay of the retinal vessels may be compared to previous scans to identify a person.
  • Biometric identification systems involve the use of finger prints, retinal blood vessel patterns, voice dynamics, hand geometry, facial recognition, and hand writing dynamics for identification of an individual.
  • These vessels can be recorded using a retinal scan of the retinal vessels.
  • the retinal scan can be used to overlay the vessels pattern over a preexisting image to match the images.
  • the retinal vessel branching pattern can also be analyzed by computer software to compare to the branching pattern of a previous image for identification. An accurate identification can be obtained by comparing this image to a database of retinal scans.
  • Biometric accuracy is measured in two ways, the rate of false acceptance (an impostor is accepted as a match—Type 1 error) and the rate of false rejects (a legitimate match is denied—Type 2 error).
  • Every biometric technique has a different method of assigning a “score” to the biometric match; a “threshold value” is defined which determines when a match is declared. Scores above the threshold value are designated as a “Hit” and scores below the threshold are designated as “No-Hit.”
  • a Type 2 error occurs if a true match does not generate a score above the threshold.
  • a Type 1 error is made when an impostor generates a match score above the threshold. If the Type 1 and Type 2 error rates are plotted as a function of threshold value, they will form curves which intersect at a given threshold value. The point of intersection (where Type 1 error equals Type 2 error) is called the crossover accuracy of the system. In general, as the value of the crossover accuracy increases the inherent accuracy of the biometric increases. The crossover accuracies of various means of identification are shown in Table I.
  • retinal scans are not without problems obtaining a good image.
  • the pupil size of the user A small pupil that is constricted to a further, smaller size because of a bright lighting environment can reduce the amount of light that reaches the retina via the pupil and vice versa. This can cause the system to have a higher rate of False Rejection.
  • a retinal image scanner includes an infrared light source, a beam splitter reflecting infrared radiation from the light source through one of a plurality of focusing lenses to a retina, a camera collecting radiation reflected by the retina through the beam splitter, an analog to digital convertor receiving a raw signal from the camera based on the collected radiation, the analog to digital convertor converting the raw signal to a digital signal, a streaming video converter processing the digital signal into a video signal, and a video monitor displaying an image of the retina based on the video signal, the retinal image scanner further comprising a video transmitter, the video transmitter transmitting the video signal to a computer over a network, the computer extracting a plurality of images from the video signal, a comparator comparing at least one of the plurality of images with at least one of a plurality of stored images, and a selector selecting one of the plurality of stored images that matches the one of the plurality of images.
  • a method of scanning a retinal image includes providing an infrared light source, emitting infrared radiation from the infrared light source toward a beam splitter, reflecting the infrared radiation with the beam splitter through a focusing lens, focusing the infrared radiation with the focusing lens on a retina, collecting radiation reflected by the retina through the beam splitter at a camera, producing an image signal representative of a plurality of images of the retina with the camera based on the collected radiation, selecting one of the plurality of images of the retina for display from the image signal, displaying the selected image of the retina on a display, comparing the selected image of the retina to at least one of a plurality of images of retinas stored in a database, selecting one of the plurality of images of retinas stored in the database that matches the selected image of the retina, and displaying the one of the matching image of the retina on the display along with the selected image of the retina.
  • FIG. 1 shows a wireless video infrared retinal image scanner according to an embodiment of the invention
  • FIG. 2 shows a wired video infrared retinal image scanner according to an embodiment of the invention
  • FIG. 3 shows a ray diagram for use with an infrared retinal image scanner
  • FIG. 4 shows a ray diagram for use with an infrared retinal image scanner
  • FIG. 5 shows a process of retinal scanning according to an embodiment of the invention.
  • infrared light could be used to perform a retinal scan to obtain an image of the retina.
  • a soft cuff stabilized the retinal scanner on the subject face, over the eye. It would be further advantageous if the soft cuff blocked any visible light from the eye so that the pupil would dilate naturally.
  • a retinal scanner employs an infrared light source to illuminate the retina instead of visible light.
  • the retinal scanner may be a video infrared retinal image scanner (VIRIS).
  • VIRIS video infrared retinal image scanner
  • the retinal scanner may have an inflatable cup shaped sleeve that rests on the forehead and cheek to completely cover the orbit surrounding the eye. This keeps the retinal scanner in a stable position close to the eye to limit any movement between the retinal scanner and the eye to be scanned.
  • the inflatable cup also blocks out substantially all of the visible light, allowing the pupil to dilate naturally to get a better view inside the eye.
  • the examination with the retinal scanner can be performed in a room with normal lighting.
  • the inflatable sleeve is disposable to prevent contamination between scans.
  • Infrared light is directed into the naturally dilated pupil and focused with the aid of lenses mounted on a wheel (“wheel of lenses”) that can be rotated in front of the camera lens to focus the image or focused automatically with an auto focus lens mounted in front of the CCD camera.
  • a camera such as a black and white CCD camera, a complementary metal oxide semiconductor-based camera, or a high-resolution camera, may be used to capture the image.
  • visible light may be used as a light source, and then a color CCD camera captures the image.
  • a plurality of images captured by the camera makes up a video signal.
  • the video signal is then sent to a liquid crystal display screen, such as a high-resolution LCD screen, that the observer can use to view the images of the retinal vessels. Depressing the “still image capture switch” then captures a still image.
  • a thumb wheel can be used to “scroll” up and down through sequential images near the “captured” image to isolate the best image for analysis.
  • the segments of video may comprise, for example, individual frames, or images.
  • the VIRIS is composed of multiple functions.
  • the first function is producing light to view into the eye. This may be done with an infrared light emitting diode (LED) (800-950 nm) that receives power from a direct power supply or from a Lithium Ion battery power supply.
  • LED infrared light emitting diode
  • the amperage is varied through a dimmer circuit using variable resistors to vary the light output of the LED.
  • the LED light is focused through an adjustable positive or negative diopter focusing lens to focus the light onto the retina inside the eye.
  • An auto focus lens can also be used.
  • a direct image is captured by a black-and-white (BW) charge coupled device (CCD) camera collecting infrared (IR) light.
  • BW black-and-white
  • CCD charge coupled device
  • IR infrared
  • the camera may be a complementary metal oxide semiconductor (CMOS)-based device.
  • the video image is converted from an analog signal to a digital signal by the Streaming Video Converter, which may be embodied in software. If a digital CCD camera is used no digital converter is needed.
  • the digital signal is then sent to a BW to Color Converter to convert the black/white image to color.
  • the conversion of a black/white image to a color image is done using a computer code imbedded on a high-speed computer processor in the unit.
  • a digital zoom is adjusted using a zoom in/out switch on the side of the VIRIS.
  • This image is then displayed on a high resolution liquid crystal display (LCD) screen, such as a high-resolution (Hi-Res) LCD screen on the back of the VIRIS to aid the examiner in obtaining a good scan.
  • LCD liquid crystal display
  • Hi-Res high-resolution LCD screen
  • the Video Transmitter sends the selected still image to a Laptop or computer.
  • Software on the laptop manipulates the raw image; adjusts the contrast, white balance, black balance, color saturation and brightness.
  • Software can also be used to digitally enhance the retinal vessels with an artificial color to enhance visualization. Images from the scan can be measured and compared on sequential examination visits. All of these images may be, for example, DICOM standard and/or MPEG4 standard images. Images and files produced will interface with the FBI database software system (SSL Certified) to allow downloads of the data. Connections to the network can be wireless (using WPA) or wired.
  • FIG. 1 a wireless video infrared retinal image scanner 100 according to an embodiment of the invention.
  • the video infrared retinal image scanner 100 may be used by an examiner to visualize and record the retina of the eye.
  • the video infrared retinal image scanner 100 is held in front of the examiner's eye by a handle, and then moved forward toward the subject's eye until the visible light is adjusted to visualize inside the subject's eye.
  • the video infrared retinal image scanner 100 has a light source 116 , which may be an infrared light source, such as a light emitting diode (LED). In another embodiment, the light source is a visible light source. In other embodiments, the light source 116 may be an electric lamp, a mercury vapor lamp, a halogen lamp, or a tungsten filament lamp. The light source 116 may be equipped with a filter to filter out visible wavelengths and pass infrared wavelengths of radiation. The light source 116 has a dimmer switch 112 . The light source 116 may be powered by a power supply 128 .
  • the power supply 128 may be a battery, such as a rechargeable lithium ion battery, a nickel cadmium battery, or an alkaline battery.
  • the light source 116 emits radiation in the range of 800-950 nm, and particularly, at about 945 nm.
  • the dimmer switch 112 controls the intensity of the infrared radiation emitted by the light source 116 , such as by a rheostat, or an amplifier.
  • the dimmer circuit may be controlled by a dimmer control knob 114 .
  • the examiner may manipulate the dimmer control knob 114 during the examination to increase or reduce the amount of infrared radiation shed on the patient's eye.
  • the light source 116 is a light emitting diode. Since light emitting diodes are current devices, the degree to which they illuminate is proportional to the amount of electric current flowing through the light emitting diode, rather than to the voltage drop across the light emitting diode. Consequently, a power supply that varies voltage across the light source 116 may not be efficient or linear when trying to control the intensity of radiation emitted from light source 116 .
  • the intensity of radiation produced by the light source 116 is controlled by supplying a pulsed width square wave to turn the light source 116 on and off very rapidly. Since a light emitting diode has a very fast turn on time, typically measured in nano-seconds, the intensity of radiation emitted from the light source 116 can be varied by varying the width of the pulses supplied to the light source 116 .
  • Radiation from the infrared light emitting diode 116 may be focused through a lens 106 toward the eye to be examined 110 .
  • the lens 106 may be an adjustable positive or negative diopter focusing lens.
  • the lens 106 may be one of a plurality of lens in a wheel of focusing lenses 146 of varying powers. The wheel of focusing lenses 146 may be rotated to select the proper lens for examination.
  • the video infrared retinal image scanner 100 may be equipped with a soft cuff 108 to encapsulate the eye to be examined 110 .
  • the soft cuff 108 may be disposable to prevent contamination between subjects.
  • the soft cuff 108 rests on the forehead and cheek to completely cover the orbit surrounding the eye, and keep ambient, or background light from interfering with the examination.
  • the radiation from the infrared light emitting diode 116 through the lens 106 also passes through the soft cuff 108 to reach the eye to be examined 110 .
  • the soft cuff 108 may be inflatable.
  • the soft cuff 108 keeps the video infrared retinal image scanner 100 in a stable position close to the eye to be examined 110 , and limits movement between the video infrared retinal image scanner 100 and the eye to be examined 110 , without the need for the observer to be close to the subject.
  • the soft cuff 108 also allows the pupil to dilate naturally, to afford a better view inside the eye, by blocking out substantially all of the surrounding light. Consequently, in one embodiment, an examination of the eye using the video infrared retinal image scanner 100 can be performed in a room with normal lighting.
  • the video infrared retinal image scanner 100 is held at a distance from the eye to be examined.
  • an examination of the eye using the video infrared retinal image scanner 100 may be performed in a darkened room. The darkened room may let the eye dilate naturally.
  • the video infrared retinal image scanner 100 is held at a distance of about 3 to 6 inches from the eye to be examined.
  • the video infrared retinal image scanner 100 is held at a distance of about 6 inches to 1 foot from the eye to be examined.
  • the video infrared retinal image scanner 100 is held at a distance of up to 3 feet from the eye to be examined.
  • Radiation reflected by the eye to be examined 110 returns through the lens 106 and through the beam splitter 104 and is collected by a camera 102 , such as a high-resolution camera 102 .
  • the radiation passes through the beam splitter 104 .
  • the beam splitter 104 may be fixed in place.
  • the radiation returns through an aperture in the soft cuff 108 .
  • the camera 102 is a charge coupled device. In another embodiment, the camera 102 is a complementary metal-oxide-semiconductor (CMOS) based device, or an array of light emitting diodes running in reverse, i.e., collecting light and converting it into an electrical signal.
  • CMOS complementary metal-oxide-semiconductor
  • the camera 102 may be a black-and-white camera.
  • the camera 102 is powered by the power supply 128 as well.
  • An autofocus lens may be mounted in front of the camera 102 to focus the light returning from the eye to be examined 110 .
  • visible light is used to examine the eye, and in that case, the image may be captured by a color camera.
  • the camera 102 captures an image of the retina to be examined 110 formed by the infrared radiation.
  • a video signal formed by the camera 102 of the image of the retina to be examined 110 is converted from an analog signal to a digital signal by a streaming video converter 122 .
  • the camera 102 is a digital camera, such as a digital charge coupled device, then no converter is needed.
  • the image of the retina may also be magnified in a magnifier 120 , such as a digital magnifier 120 after the image signal is converted to a digital signal.
  • the signal may be converted from black-and-white, or grayscale, to color in a black-and-white to color converter 124 .
  • the black-and-white to color converter 124 maps intensities of pixels of a charge coupled device to separate colors. Mapping the intensities of the pixels to colors may include interpolating pixel intensities between two (or more) pixels, or extrapolating pixel intensities around edges.
  • the black-and-white to color converter 124 creates a map of grey scale to color that is appropriate for the pattern of blood vessels in the retina.
  • the black-and-white to color converter 124 may normalize the black-and-white image of the eye.
  • the image of the eye may be normalized with a histogram normalizer. Normalizing the image of the eye produces a uniform intensity profile of the image.
  • the black-and-white to color converter 124 may also use edge detection image processing to identify the blood vessels and other structures of the eye. Finally, after the image of the eye has been mapped, direct spatial domain intensity transformations are applied to each structure of the eye, resulting in a colorized image of the eye.
  • the image signal is then sent to a screen 118 to display the image for the observer, so that the observer may view the images from inside the subject's eye.
  • the image is manipulated so that it is right side up and frontwards when it is presented to the examiner.
  • the screen 118 may be a high-resolution liquid crystal display screen.
  • the screen 118 may be an array of light emitting diodes or a plasma display screen.
  • a lens, such as a high of plus or positive diopter lens may be mounted over the screen 118 . Such a lens mounted over the screen 118 may magnify the image and limit the accommodation necessary to focus on the screen 118 .
  • the image signal from the streaming video converter 122 may also be sent to a video transmitter 126 , which transmits the image over a wireless connection to a laptop computer 134 for documentation and storage.
  • the video transmitter 126 transmits the image signal to a video receiver 162 coupled to the laptop computer 134 .
  • the video transmitter 126 transmits in the range of 800-1000 MHz, such as at 916 MHz.
  • the video transmitter 126 sends a raw digital video signal to a laptop computer 134 .
  • the laptop computer 134 has a separate black-and-white to color converter 136 , as well as a real-time video capture 138 .
  • the real-time video capture 138 captures the video signal in real time, and sends it to the black-and-white to color converter 136 .
  • Software 144 on the laptop may be used to manipulate the image signal by capturing the raw image, adjusting the contrast, white balance, black balance, color saturation, or brightness. Separate images of the eye can be “stitched” together to form a montage. A three-dimensional image can be developed from the images as well.
  • a three-dimensional image can be rotated or manipulated, such as translated in the X, Y, or Z axes.
  • Cross-sectional images can be produced from the separate images as well.
  • a three-dimensional effect is produced by displaying images taken closely together in time, but from slightly different points of view due to, for example, movement of the camera during examination.
  • Images of retinas can be measured and compared to images stored in a database.
  • the images conform to the XML, JPEG or DICOM standards.
  • the images conform to an MPEG-4 standard.
  • Images and files produced by the video infrared retinal image scanner 100 may be able to interface with any government or law enforcement record software system. Downloads of the images and associated data over a network to the government or law enforcement record system may be allowed. Connections to the network can be wireless or wired. Remote access to the images on the laptop may be allowed by software.
  • FIG. 2 a wired video infrared retinal image scanner 200 according to an embodiment of the invention.
  • the video infrared retinal image scanner 200 may be used by an examiner to visualize and record the retina of the eye.
  • the video infrared retinal image scanner 200 is placed in front of the examiner's eye, and then moved forward toward the subject's eye until the visible light is adjusted to visualize inside the subject's eye.
  • the video infrared retinal image scanner 200 has a light source 216 , which may be an infrared light source, such as a light emitting diode (LED). In another embodiment, the light source is a visible light source. In other embodiments, the light source 216 may be an electric lamp, a mercury vapor lamp, a halogen lamp, or a tungsten filament lamp. The light source 216 may be equipped with a filter to filter out visible wavelengths and pass infrared wavelengths of radiation. The light source 216 has a dimmer switch 212 . The light source 216 may be powered by a power supply 228 .
  • the power supply 228 may be a battery, such as a rechargeable lithium ion battery, a nickel cadmium battery, or an alkaline battery.
  • the light source 216 emits radiation in the range of 800-950 nm, and particularly, at about 945 nm.
  • the dimmer switch 212 controls the intensity of the infrared radiation emitted by the light source 216 , such as by a rheostat, or an amplifier.
  • the dimmer circuit may be controlled by a dimmer control knob 214 .
  • the examiner may manipulate the dimmer control knob 214 during the examination to increase or reduce the amount of infrared radiation shed on the patient's eye.
  • the light source 216 is a light emitting diode. Since light emitting diodes are current devices, the degree to which they illuminate is proportional to the amount of electric current flowing through the light emitting diode, rather than to the voltage drop across the light emitting diode. Consequently, a power supply that varies voltage across the light source 216 may not be efficient or linear when trying to control the intensity of radiation emitted from light source 216 .
  • the intensity of radiation produced by the light source 216 is controlled by supplying a pulsed width square wave to turn the light source 216 on and off very rapidly. Since a light emitting diode has a very fast turn on time, typically measured in nano-seconds, the intensity of radiation emitted from the light source 216 can be varied by varying the width of the pulses supplied to the light source 216 .
  • Radiation from the infrared light emitting diode 212 may be focused through a lens 206 toward the eye to be examined 210 .
  • the lens 206 may be an adjustable positive or negative diopter focusing lens.
  • the lens 206 may be one of a plurality of lens in a wheel of focusing lenses 246 of varying powers. The wheel of focusing lenses 246 may be rotated to select the proper lens for examination.
  • the video infrared retinal image scanner 200 may be equipped with a soft cuff 208 to encapsulate the eye to be examined 210 .
  • the soft cuff 208 may be disposable to prevent contamination between subjects.
  • the soft cuff 208 rests on the forehead and cheek to completely cover the orbit surrounding the eye, and keep ambient, or background light from interfering with the examination.
  • the radiation from the infrared light emitting diode 212 through the lens 206 also passes through the soft cuff 208 to reach the eye to be examined 210 .
  • the soft cuff 208 may be inflatable.
  • the soft cuff 208 keeps the video infrared retinal image scanner 200 in a stable position close to the eye to be examined 210 , and limits movement between the video infrared retinal image scanner 200 and the eye to be examined 210 , without the need for the observer to be close to the subject.
  • the soft cuff 208 also allows the pupil to dilate naturally, to afford a better view inside the eye, by blocking out substantially all of the surrounding light. Consequently, in one embodiment, an examination of the eye using the video infrared retinal image scanner 200 can be performed in a room with normal lighting.
  • the video infrared retinal image scanner 200 is held at a distance from the eye to be examined.
  • an examination of the eye using the video infrared retinal image scanner 200 may be performed in a darkened room. The darkened room may let the eye dilate naturally.
  • the video infrared retinal image scanner 200 is held at a distance of about 3 to 6 inches from the eye to be examined.
  • the video infrared retinal image scanner 200 is held at a distance of about 6 inches to 2 foot from the eye to be examined.
  • the video infrared retinal image scanner 200 is held at a distance of up to 3 feet from the eye to be examined.
  • Radiation reflected by the eye to be examined 210 returns through the lens 206 and through the beam splitter 204 and is collected by a camera 202 , such as a high-resolution camera 202 .
  • the radiation passes through the beam splitter 204 .
  • the beam splitter 204 may be fixed in place.
  • the radiation returns through an aperture in the soft cuff 208 .
  • the camera 202 is a charge coupled device. In another embodiment, the camera 202 is a complementary metal-oxide-semiconductor (CMOS) based device, or an array of light emitting diodes running in reverse, i.e., collecting light and converting it into an electrical signal.
  • CMOS complementary metal-oxide-semiconductor
  • the camera 202 may be a black-and-white camera.
  • the camera 202 is powered by the power supply 228 as well.
  • the camera 202 may be a black-and-white camera. In another embodiment, visible light is used to examine the eye, and in that case, the image may be captured by a color camera. An autofocus lens may be mounted in front of the camera 202 to focus the light returning from the eye to be examined 210 .
  • the camera 202 captures an image of the retina to be examined 210 formed by the infrared radiation.
  • a video signal formed by the camera 202 of the image of the retina to be examined 210 is converted from an analog signal to a digital signal by a streaming video converter 222 .
  • the camera 202 is a digital camera, such as a digital charge coupled device, then no converter is needed.
  • the image of the retina may also be magnified in a magnifier 220 , such as a digital magnifier 220 after the image signal is converted to a digital signal.
  • the image signal may be converted from black-and-white to color in a black-and-white to color converter 224 .
  • the black-and-white to color 224 may work in a manner similar to that of the black-and-white to color converter 104 shown in FIG. 1 . That is, wavelength components in the infrared range may be scaled by a predetermined amount so that wavelengths in the visible range are mapped instead.
  • the image signal is then sent to a screen 218 to display the image for the observer, so that the observer may view the images from inside the subject's eye.
  • the screen 218 may be a high-resolution liquid crystal display screen.
  • the screen 218 may be an array of light emitting diodes or a plasma display screen.
  • the image is manipulated so that it is right side up and frontwards when it is presented to the examiner.
  • a lens such as a high of plus or positive diopter lens may be mounted over the screen 218 . Such a lens mounted over the screen 218 may magnify the image and limit the accommodation necessary to focus on the screen 218 .
  • the image signal from the streaming video converter 222 may also be sent over a wired connection 232 to a lap top computer 234 for documentation and storage.
  • the connection 232 is a Universal Serial Bus.
  • a raw digital video signal is sent to the laptop computer 234 .
  • the laptop computer 234 has a separate black-and-white to color converter 236 , as well as a real-time video capture 238 .
  • the real-time video capture 238 captures the video signal in real time, and sends it to the black-and-white to color converter 236 .
  • Software 244 on the laptop may be used to manipulate the image signal by capturing the raw image, adjusting the contrast, white balance, black balance, color saturation, or brightness.
  • Separate images of the eye can be “stitched” together to form a montage.
  • a three-dimensional image can be developed from the images as well.
  • a three-dimensional image can be rotated or manipulated, such as translated in the X, Y, or Z axes.
  • Cross-sectional images can be produced from the separate images as well.
  • a three-dimensional effect is produced by displaying images taken closely together in time, but from slightly different points of view due to, for example, movement of the camera during examination.
  • Images of retinas can be measured and compared to images stored in a database.
  • the images conform to the JPEG or DICOM standards.
  • the images conform to an MPEG-4 standard.
  • Images and files produced by the video infrared retinal image scanner 200 may be able to interface with any government or law enforcement record software system. Downloads of the images and associated data over a network to the government or law enforcement record system may be allowed. Connections to the network can be wireless or wired. Remote access to the images on the laptop may be allowed by software.
  • images taken by the infrared retinal image scanner 200 may be stored on an internal memory chip, such as a SD card 226 .
  • the infrared retinal image scanner 200 may be rechargeable over a universal serial bus (USB) connection 230 , or over a network.
  • USB universal serial bus
  • FIG. 3 is shown a ray diagram for use with an infrared retinal image scanner.
  • infrared radiation emanating from an LED light source 310 is redirected by a beam splitter 318 toward an eye 308 .
  • the redirected beam is enumerated 314 .
  • the redirected beam of infrared radiation 314 reaches the eye 308 and is reflected off the eye 308 as beam 312 .
  • Beam 312 passes through the beam splitter 318 again as beam 316 , and also passes through a focusing lens 304 before reaching a camera 302 .
  • Some of the infrared radiation from LED light source 310 passes through the beam splitter 318 and reaches light sink 306 .
  • FIG. 4 a ray diagram for use with an infrared retinal image scanner.
  • infrared radiation emanating from of a light source 410 is redirected by a beam splitter 418 toward an eye 408 .
  • the redirected beam is enumerated 414 .
  • the redirected beam 414 may or may not pass through a handheld lens 424 held in front of the eyes 408 by the examiner.
  • the redirected beam 414 reaches the eye 408 and is reflected off of the eye 408 as beam 412 , toward the handheld lens 424 .
  • the handheld lens 424 is used by the examiner to focus the light on the eye 408 and eight in the examination.
  • Beam 412 passes through the handheld lens 424 as beam 416 and is focused on a camera lens 404 .
  • a virtual image of the retina 408 is formed between the handheld lens 424 and the camera lens 404 .
  • the beam 416 passes through the camera lens 404 and is collected by a camera 402 .
  • a signal from the camera 402 is distributed to two display screen 420 , in front of which may be placed lenses 422 . Images of the eye 408 are displayed on the screens 422 and viewed by the examiner.
  • FIG. 5 is shown a process of retinal scanning according to an embodiment of the invention.
  • a first operation 502 an infrared light source is provided.
  • the process moves to operation 504 , in which infrared radiation is emitted from the infrared light source toward a beam splitter.
  • the process moves to operation 506 , in which the infrared radiation is reflected by the beam splitter through a focusing lens.
  • the process moves to operation 508 , in which the infrared radiation is focused by the focusing lens on a retina.
  • the process moves to operation 510 , in which radiation reflected by the retina through the beam splitter is collected by a camera.
  • the process moves to operation 512 , in which an image signal representative of an image of the retina is produced by the camera based on the collected radiation.
  • the process moves to operation 514 , in which one of the plurality of images of the retina is selected from the image signal for display.
  • the process moves to operation 516 , in which the selected image of the retina is displayed on a display.
  • the process moves to operation 518 , in which the selected image of the retina is compared to at least one of a plurality of images of retinas stored in a database.
  • the process moves to operation 520 , in which one of the plurality of images of retinas stored in the database that matches the selected image of the retina is selected.
  • the process moves to operation 522 , in which the matching image of the retina is displayed on the display along with the selected image of the retina.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • General Health & Medical Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Human Computer Interaction (AREA)
  • Signal Processing (AREA)
  • Ophthalmology & Optometry (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Eye Examination Apparatus (AREA)
  • Image Input (AREA)

Abstract

A method of scanning a retinal image includes providing a light source, emitting radiation from the light source toward a beam splitter, focusing the radiation with a focusing lens on a retina, collecting radiation reflected by the retina with a camera, producing an image signal representative of a plurality of images of the retina based on the collected radiation, selecting one of the plurality of images of the retina for display from the image signal, displaying the selected image of the retina on a display, comparing the selected image of the retina to at least one of a plurality of images of retinas stored in the database that matches the selected image of the retina, and displaying the one of the matching image of the retina on the display along with the selected image of the retina.

Description

    CROSS-REFERENCE TO RELATED APPLICATIONS
  • This application is a continuation of U.S. patent application Ser. No. 12/612,547, filed on Nov. 4, 2009, which claims priority to U.S. Patent Application Ser. No. 61/111,506, filed Nov. 5, 2008, the disclosures of which are incorporated in its entirety by reference herein.
  • FIELD
  • A video infrared retinal image scanner uses an infrared light to illuminate an ocular system and a camera to capture and display an image. The image may be analyzed and processed and rendered in 3-D. Computer analysis of the retinal vessels is performed by looking at the branching pattern of the retinal vessels. An overlay of the retinal vessels may be compared to previous scans to identify a person.
  • DESCRIPTION OF THE RELATED ART
  • The patterns of branching of the retinal vessels in an eye are unique and can be used as a form of identification. Biometric identification systems involve the use of finger prints, retinal blood vessel patterns, voice dynamics, hand geometry, facial recognition, and hand writing dynamics for identification of an individual.
  • These vessels can be recorded using a retinal scan of the retinal vessels. The retinal scan can be used to overlay the vessels pattern over a preexisting image to match the images. The retinal vessel branching pattern can also be analyzed by computer software to compare to the branching pattern of a previous image for identification. An accurate identification can be obtained by comparing this image to a database of retinal scans.
  • Biometric accuracy is measured in two ways, the rate of false acceptance (an impostor is accepted as a match—Type 1 error) and the rate of false rejects (a legitimate match is denied—Type 2 error). Every biometric technique has a different method of assigning a “score” to the biometric match; a “threshold value” is defined which determines when a match is declared. Scores above the threshold value are designated as a “Hit” and scores below the threshold are designated as “No-Hit.”
  • A Type 2 error occurs if a true match does not generate a score above the threshold. A Type 1 error is made when an impostor generates a match score above the threshold. If the Type 1 and Type 2 error rates are plotted as a function of threshold value, they will form curves which intersect at a given threshold value. The point of intersection (where Type 1 error equals Type 2 error) is called the crossover accuracy of the system. In general, as the value of the crossover accuracy increases the inherent accuracy of the biometric increases. The crossover accuracies of various means of identification are shown in Table I.
  • TABLE I
    Biometric Crossover Accuracy
    Retinal Scan 1:10,000,000+
    Retina Scan 1:131,000
    Fingerprints 1:500
    Hand Geometry 1:500 (against a very
    small background database)
    Signature Dynamics 1:50
    Voice Dynamics 1:50
    Facial Recognition no data
    Vascular Patterns no data
  • Despite a high cross over accuracy, retinal scans are not without problems obtaining a good image.
  • There are sources of problems that could affect the performance of the retinal scanning device from obtaining an accurate scan (as is the case with any other biometric technology), thus impacting its ability to successfully verify or identify users. Among the problems are:
  • The lack of cooperation on part of the user. The user must remain very still in the entire process, especially in the image acquisition phase. Any movement can seriously affect the alignment of the lens in the retinal scanning device.
  • A dirty lens on the retinal scanning device. This will obviously interfere with the scanning process.
  • Other types of light interference from the external environment.
  • The pupil size of the user. A small pupil that is constricted to a further, smaller size because of a bright lighting environment can reduce the amount of light that reaches the retina via the pupil and vice versa. This can cause the system to have a higher rate of False Rejection.
  • SUMMARY
  • In one aspect, a retinal image scanner includes an infrared light source, a beam splitter reflecting infrared radiation from the light source through one of a plurality of focusing lenses to a retina, a camera collecting radiation reflected by the retina through the beam splitter, an analog to digital convertor receiving a raw signal from the camera based on the collected radiation, the analog to digital convertor converting the raw signal to a digital signal, a streaming video converter processing the digital signal into a video signal, and a video monitor displaying an image of the retina based on the video signal, the retinal image scanner further comprising a video transmitter, the video transmitter transmitting the video signal to a computer over a network, the computer extracting a plurality of images from the video signal, a comparator comparing at least one of the plurality of images with at least one of a plurality of stored images, and a selector selecting one of the plurality of stored images that matches the one of the plurality of images.
  • In another aspect, a method of scanning a retinal image includes providing an infrared light source, emitting infrared radiation from the infrared light source toward a beam splitter, reflecting the infrared radiation with the beam splitter through a focusing lens, focusing the infrared radiation with the focusing lens on a retina, collecting radiation reflected by the retina through the beam splitter at a camera, producing an image signal representative of a plurality of images of the retina with the camera based on the collected radiation, selecting one of the plurality of images of the retina for display from the image signal, displaying the selected image of the retina on a display, comparing the selected image of the retina to at least one of a plurality of images of retinas stored in a database, selecting one of the plurality of images of retinas stored in the database that matches the selected image of the retina, and displaying the one of the matching image of the retina on the display along with the selected image of the retina.
  • The above-described embodiments of the present invention are intended as examples, and all embodiments of the present invention are not limited to including the features described above.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1 shows a wireless video infrared retinal image scanner according to an embodiment of the invention;
  • FIG. 2 shows a wired video infrared retinal image scanner according to an embodiment of the invention;
  • FIG. 3 shows a ray diagram for use with an infrared retinal image scanner;
  • FIG. 4 shows a ray diagram for use with an infrared retinal image scanner; and
  • FIG. 5 shows a process of retinal scanning according to an embodiment of the invention.
  • DETAILED DESCRIPTION
  • Reference may now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.
  • It would be advantageous if infrared light could be used to perform a retinal scan to obtain an image of the retina.
  • It would be advantageous if an observer were allowed to see direct video images of the retina while performing an examination.
  • It would be advantageous if a retinal scan of the retina could be performed without dilation of the retina.
  • It would be advantageous if digital image enlargement (Zoom) were allowed during the active examination.
  • It would be advantageous if a specific tissue could be enhanced digitally for easier identification.
  • It would be advantageous if a soft cuff stabilized the retinal scanner on the subject face, over the eye. It would be further advantageous if the soft cuff blocked any visible light from the eye so that the pupil would dilate naturally.
  • It would be advantageous if the retinal scanner were connected to a government or law enforcement database, such as the FBI record system, for documentation of the examination.
  • If the proper eye distance is not maintained while the user attempts to look into the lens of the retinal scanning device, it may be difficult for a high quality scan to be captured. In order for a high quality scan to be captured, the user may need to focus his or her eye at an extremely close range to the lens. It would be advantageous if a good quality scan could be captured as far as three feet away from the lens of the scanning device to the retina of the user.
  • It would be advantageous if a wider image of the retinal vessels could be captured than with conventional retinal scanners. It would be further advantageous if the wider image contained more data points than a conventional retinal scan, reducing false positives and negatives.
  • In one embodiment, a retinal scanner employs an infrared light source to illuminate the retina instead of visible light. In one embodiment, the retinal scanner may be a video infrared retinal image scanner (VIRIS). The retinal scanner may have an inflatable cup shaped sleeve that rests on the forehead and cheek to completely cover the orbit surrounding the eye. This keeps the retinal scanner in a stable position close to the eye to limit any movement between the retinal scanner and the eye to be scanned. The inflatable cup also blocks out substantially all of the visible light, allowing the pupil to dilate naturally to get a better view inside the eye.
  • The examination with the retinal scanner can be performed in a room with normal lighting. The inflatable sleeve is disposable to prevent contamination between scans. Infrared light is directed into the naturally dilated pupil and focused with the aid of lenses mounted on a wheel (“wheel of lenses”) that can be rotated in front of the camera lens to focus the image or focused automatically with an auto focus lens mounted in front of the CCD camera.
  • A camera, such as a black and white CCD camera, a complementary metal oxide semiconductor-based camera, or a high-resolution camera, may be used to capture the image. In one embodiment, visible light may be used as a light source, and then a color CCD camera captures the image. A plurality of images captured by the camera makes up a video signal. The video signal is then sent to a liquid crystal display screen, such as a high-resolution LCD screen, that the observer can use to view the images of the retinal vessels. Depressing the “still image capture switch” then captures a still image.
  • Once a segment of video is captured, a thumb wheel can be used to “scroll” up and down through sequential images near the “captured” image to isolate the best image for analysis. The segments of video may comprise, for example, individual frames, or images. Once this image is identified it is sent to the laptop using a Video Transmitter. The image is processed in the laptop computer to establish the data points to be registered. This image can then be sent to the FBI database for comparison to previous scans or to initiate a new file specific to that person.
  • More specifically, the VIRIS is composed of multiple functions. The first function is producing light to view into the eye. This may be done with an infrared light emitting diode (LED) (800-950 nm) that receives power from a direct power supply or from a Lithium Ion battery power supply. The amperage is varied through a dimmer circuit using variable resistors to vary the light output of the LED. The LED light is focused through an adjustable positive or negative diopter focusing lens to focus the light onto the retina inside the eye. An auto focus lens can also be used.
  • In one embodiment, a direct image is captured by a black-and-white (BW) charge coupled device (CCD) camera collecting infrared (IR) light. In another embodiment the direct images captured by a color CCD camera collecting visible light. In another embodiment, the camera may be a complementary metal oxide semiconductor (CMOS)-based device. The video image is converted from an analog signal to a digital signal by the Streaming Video Converter, which may be embodied in software. If a digital CCD camera is used no digital converter is needed. The digital signal is then sent to a BW to Color Converter to convert the black/white image to color. In one embodiment, the conversion of a black/white image to a color image is done using a computer code imbedded on a high-speed computer processor in the unit.
  • In one embodiment, a digital zoom is adjusted using a zoom in/out switch on the side of the VIRIS. This image is then displayed on a high resolution liquid crystal display (LCD) screen, such as a high-resolution (Hi-Res) LCD screen on the back of the VIRIS to aid the examiner in obtaining a good scan. Once an image is selected (captured) the images sequential to the captured image can be viewed by scrolling through them on a time line using a thumb wheel and viewing them on the LCD screen. The best image is selected and then transmitted to the Laptop computer using a wired or wireless Video Transmitter.
  • Another aspect is image processing on a computer. The Video Transmitter sends the selected still image to a Laptop or computer. Software on the laptop then manipulates the raw image; adjusts the contrast, white balance, black balance, color saturation and brightness. Software can also be used to digitally enhance the retinal vessels with an artificial color to enhance visualization. Images from the scan can be measured and compared on sequential examination visits. All of these images may be, for example, DICOM standard and/or MPEG4 standard images. Images and files produced will interface with the FBI database software system (SSL Certified) to allow downloads of the data. Connections to the network can be wireless (using WPA) or wired.
  • In FIG. 1 is shown a wireless video infrared retinal image scanner 100 according to an embodiment of the invention. The video infrared retinal image scanner 100 may be used by an examiner to visualize and record the retina of the eye. The video infrared retinal image scanner 100 is held in front of the examiner's eye by a handle, and then moved forward toward the subject's eye until the visible light is adjusted to visualize inside the subject's eye.
  • The video infrared retinal image scanner 100 has a light source 116, which may be an infrared light source, such as a light emitting diode (LED). In another embodiment, the light source is a visible light source. In other embodiments, the light source 116 may be an electric lamp, a mercury vapor lamp, a halogen lamp, or a tungsten filament lamp. The light source 116 may be equipped with a filter to filter out visible wavelengths and pass infrared wavelengths of radiation. The light source 116 has a dimmer switch 112. The light source 116 may be powered by a power supply 128. The power supply 128 may be a battery, such as a rechargeable lithium ion battery, a nickel cadmium battery, or an alkaline battery.
  • The light source 116 emits radiation in the range of 800-950 nm, and particularly, at about 945 nm. The dimmer switch 112 controls the intensity of the infrared radiation emitted by the light source 116, such as by a rheostat, or an amplifier. The dimmer circuit may be controlled by a dimmer control knob 114. The examiner may manipulate the dimmer control knob 114 during the examination to increase or reduce the amount of infrared radiation shed on the patient's eye.
  • In one embodiment, the light source 116 is a light emitting diode. Since light emitting diodes are current devices, the degree to which they illuminate is proportional to the amount of electric current flowing through the light emitting diode, rather than to the voltage drop across the light emitting diode. Consequently, a power supply that varies voltage across the light source 116 may not be efficient or linear when trying to control the intensity of radiation emitted from light source 116. In one embodiment, the intensity of radiation produced by the light source 116 is controlled by supplying a pulsed width square wave to turn the light source 116 on and off very rapidly. Since a light emitting diode has a very fast turn on time, typically measured in nano-seconds, the intensity of radiation emitted from the light source 116 can be varied by varying the width of the pulses supplied to the light source 116.
  • Radiation from the infrared light emitting diode 116 may be focused through a lens 106 toward the eye to be examined 110. In one embodiment, the lens 106 may be an adjustable positive or negative diopter focusing lens. The lens 106 may be one of a plurality of lens in a wheel of focusing lenses 146 of varying powers. The wheel of focusing lenses 146 may be rotated to select the proper lens for examination.
  • The video infrared retinal image scanner 100 may be equipped with a soft cuff 108 to encapsulate the eye to be examined 110. The soft cuff 108 may be disposable to prevent contamination between subjects. In one embodiment, the soft cuff 108 rests on the forehead and cheek to completely cover the orbit surrounding the eye, and keep ambient, or background light from interfering with the examination. The radiation from the infrared light emitting diode 116 through the lens 106 also passes through the soft cuff 108 to reach the eye to be examined 110. In one embodiment, the soft cuff 108 may be inflatable. The soft cuff 108 keeps the video infrared retinal image scanner 100 in a stable position close to the eye to be examined 110, and limits movement between the video infrared retinal image scanner 100 and the eye to be examined 110, without the need for the observer to be close to the subject. The soft cuff 108 also allows the pupil to dilate naturally, to afford a better view inside the eye, by blocking out substantially all of the surrounding light. Consequently, in one embodiment, an examination of the eye using the video infrared retinal image scanner 100 can be performed in a room with normal lighting.
  • In another embodiment, the video infrared retinal image scanner 100 is held at a distance from the eye to be examined. In this embodiment, an examination of the eye using the video infrared retinal image scanner 100 may be performed in a darkened room. The darkened room may let the eye dilate naturally. In one embodiment, the video infrared retinal image scanner 100 is held at a distance of about 3 to 6 inches from the eye to be examined. In another embodiment, the video infrared retinal image scanner 100 is held at a distance of about 6 inches to 1 foot from the eye to be examined. In yet another embodiment, the video infrared retinal image scanner 100 is held at a distance of up to 3 feet from the eye to be examined.
  • Radiation reflected by the eye to be examined 110 returns through the lens 106 and through the beam splitter 104 and is collected by a camera 102, such as a high-resolution camera 102. In this embodiment, the radiation passes through the beam splitter 104. In one embodiment, the beam splitter 104 may be fixed in place. In one embodiment, the radiation returns through an aperture in the soft cuff 108.
  • In one embodiment, the camera 102 is a charge coupled device. In another embodiment, the camera 102 is a complementary metal-oxide-semiconductor (CMOS) based device, or an array of light emitting diodes running in reverse, i.e., collecting light and converting it into an electrical signal. The camera 102 may be a black-and-white camera. The camera 102 is powered by the power supply 128 as well.
  • An autofocus lens may be mounted in front of the camera 102 to focus the light returning from the eye to be examined 110. In another embodiment, visible light is used to examine the eye, and in that case, the image may be captured by a color camera.
  • The camera 102 captures an image of the retina to be examined 110 formed by the infrared radiation. A video signal formed by the camera 102 of the image of the retina to be examined 110 is converted from an analog signal to a digital signal by a streaming video converter 122. In the event that the camera 102 is a digital camera, such as a digital charge coupled device, then no converter is needed. The image of the retina may also be magnified in a magnifier 120, such as a digital magnifier 120 after the image signal is converted to a digital signal.
  • Next, the signal may be converted from black-and-white, or grayscale, to color in a black-and-white to color converter 124. In one embodiment, the black-and-white to color converter 124 maps intensities of pixels of a charge coupled device to separate colors. Mapping the intensities of the pixels to colors may include interpolating pixel intensities between two (or more) pixels, or extrapolating pixel intensities around edges.
  • In one embodiment, the black-and-white to color converter 124 creates a map of grey scale to color that is appropriate for the pattern of blood vessels in the retina. In this embodiment, the black-and-white to color converter 124 may normalize the black-and-white image of the eye. The image of the eye may be normalized with a histogram normalizer. Normalizing the image of the eye produces a uniform intensity profile of the image. The black-and-white to color converter 124 may also use edge detection image processing to identify the blood vessels and other structures of the eye. Finally, after the image of the eye has been mapped, direct spatial domain intensity transformations are applied to each structure of the eye, resulting in a colorized image of the eye.
  • The image signal is then sent to a screen 118 to display the image for the observer, so that the observer may view the images from inside the subject's eye. In one embodiment, the image is manipulated so that it is right side up and frontwards when it is presented to the examiner. In one embodiment, the screen 118 may be a high-resolution liquid crystal display screen. In another embodiment, the screen 118 may be an array of light emitting diodes or a plasma display screen. A lens, such as a high of plus or positive diopter lens may be mounted over the screen 118. Such a lens mounted over the screen 118 may magnify the image and limit the accommodation necessary to focus on the screen 118.
  • The image signal from the streaming video converter 122 may also be sent to a video transmitter 126, which transmits the image over a wireless connection to a laptop computer 134 for documentation and storage. In one embodiment, the video transmitter 126 transmits the image signal to a video receiver 162 coupled to the laptop computer 134. In one embodiment, the video transmitter 126 transmits in the range of 800-1000 MHz, such as at 916 MHz.
  • In one embodiment, the video transmitter 126 sends a raw digital video signal to a laptop computer 134. In this embodiment, the laptop computer 134 has a separate black-and-white to color converter 136, as well as a real-time video capture 138. The real-time video capture 138 captures the video signal in real time, and sends it to the black-and-white to color converter 136. Software 144 on the laptop may be used to manipulate the image signal by capturing the raw image, adjusting the contrast, white balance, black balance, color saturation, or brightness. Separate images of the eye can be “stitched” together to form a montage. A three-dimensional image can be developed from the images as well. A three-dimensional image can be rotated or manipulated, such as translated in the X, Y, or Z axes. Cross-sectional images can be produced from the separate images as well. In one embodiment, a three-dimensional effect is produced by displaying images taken closely together in time, but from slightly different points of view due to, for example, movement of the camera during examination.
  • Images of retinas can be measured and compared to images stored in a database. In one embodiment, the images conform to the XML, JPEG or DICOM standards. In another embodiment; the images conform to an MPEG-4 standard. Images and files produced by the video infrared retinal image scanner 100 may be able to interface with any government or law enforcement record software system. Downloads of the images and associated data over a network to the government or law enforcement record system may be allowed. Connections to the network can be wireless or wired. Remote access to the images on the laptop may be allowed by software.
  • In FIG. 2 is shown a wired video infrared retinal image scanner 200 according to an embodiment of the invention. The video infrared retinal image scanner 200 may be used by an examiner to visualize and record the retina of the eye. The video infrared retinal image scanner 200 is placed in front of the examiner's eye, and then moved forward toward the subject's eye until the visible light is adjusted to visualize inside the subject's eye.
  • The video infrared retinal image scanner 200 has a light source 216, which may be an infrared light source, such as a light emitting diode (LED). In another embodiment, the light source is a visible light source. In other embodiments, the light source 216 may be an electric lamp, a mercury vapor lamp, a halogen lamp, or a tungsten filament lamp. The light source 216 may be equipped with a filter to filter out visible wavelengths and pass infrared wavelengths of radiation. The light source 216 has a dimmer switch 212. The light source 216 may be powered by a power supply 228. The power supply 228 may be a battery, such as a rechargeable lithium ion battery, a nickel cadmium battery, or an alkaline battery.
  • The light source 216 emits radiation in the range of 800-950 nm, and particularly, at about 945 nm. The dimmer switch 212 controls the intensity of the infrared radiation emitted by the light source 216, such as by a rheostat, or an amplifier. The dimmer circuit may be controlled by a dimmer control knob 214. The examiner may manipulate the dimmer control knob 214 during the examination to increase or reduce the amount of infrared radiation shed on the patient's eye.
  • In one embodiment, the light source 216 is a light emitting diode. Since light emitting diodes are current devices, the degree to which they illuminate is proportional to the amount of electric current flowing through the light emitting diode, rather than to the voltage drop across the light emitting diode. Consequently, a power supply that varies voltage across the light source 216 may not be efficient or linear when trying to control the intensity of radiation emitted from light source 216. In one embodiment, the intensity of radiation produced by the light source 216 is controlled by supplying a pulsed width square wave to turn the light source 216 on and off very rapidly. Since a light emitting diode has a very fast turn on time, typically measured in nano-seconds, the intensity of radiation emitted from the light source 216 can be varied by varying the width of the pulses supplied to the light source 216.
  • Radiation from the infrared light emitting diode 212 may be focused through a lens 206 toward the eye to be examined 210. In one embodiment, the lens 206 may be an adjustable positive or negative diopter focusing lens. The lens 206 may be one of a plurality of lens in a wheel of focusing lenses 246 of varying powers. The wheel of focusing lenses 246 may be rotated to select the proper lens for examination.
  • The video infrared retinal image scanner 200 may be equipped with a soft cuff 208 to encapsulate the eye to be examined 210. The soft cuff 208 may be disposable to prevent contamination between subjects. The soft cuff 208 rests on the forehead and cheek to completely cover the orbit surrounding the eye, and keep ambient, or background light from interfering with the examination. The radiation from the infrared light emitting diode 212 through the lens 206 also passes through the soft cuff 208 to reach the eye to be examined 210. In one embodiment, the soft cuff 208 may be inflatable. The soft cuff 208 keeps the video infrared retinal image scanner 200 in a stable position close to the eye to be examined 210, and limits movement between the video infrared retinal image scanner 200 and the eye to be examined 210, without the need for the observer to be close to the subject. The soft cuff 208 also allows the pupil to dilate naturally, to afford a better view inside the eye, by blocking out substantially all of the surrounding light. Consequently, in one embodiment, an examination of the eye using the video infrared retinal image scanner 200 can be performed in a room with normal lighting.
  • In another embodiment, the video infrared retinal image scanner 200 is held at a distance from the eye to be examined. In this embodiment, an examination of the eye using the video infrared retinal image scanner 200 may be performed in a darkened room. The darkened room may let the eye dilate naturally. In one embodiment, the video infrared retinal image scanner 200 is held at a distance of about 3 to 6 inches from the eye to be examined. In another embodiment, the video infrared retinal image scanner 200 is held at a distance of about 6 inches to 2 foot from the eye to be examined. In yet another embodiment, the video infrared retinal image scanner 200 is held at a distance of up to 3 feet from the eye to be examined.
  • Radiation reflected by the eye to be examined 210 returns through the lens 206 and through the beam splitter 204 and is collected by a camera 202, such as a high-resolution camera 202. In this embodiment, the radiation passes through the beam splitter 204. In one embodiment, the beam splitter 204 may be fixed in place. In one embodiment, the radiation returns through an aperture in the soft cuff 208.
  • In one embodiment, the camera 202 is a charge coupled device. In another embodiment, the camera 202 is a complementary metal-oxide-semiconductor (CMOS) based device, or an array of light emitting diodes running in reverse, i.e., collecting light and converting it into an electrical signal. The camera 202 may be a black-and-white camera. The camera 202 is powered by the power supply 228 as well.
  • The camera 202 may be a black-and-white camera. In another embodiment, visible light is used to examine the eye, and in that case, the image may be captured by a color camera. An autofocus lens may be mounted in front of the camera 202 to focus the light returning from the eye to be examined 210.
  • The camera 202 captures an image of the retina to be examined 210 formed by the infrared radiation. A video signal formed by the camera 202 of the image of the retina to be examined 210 is converted from an analog signal to a digital signal by a streaming video converter 222. In the event that the camera 202 is a digital camera, such as a digital charge coupled device, then no converter is needed. The image of the retina may also be magnified in a magnifier 220, such as a digital magnifier 220 after the image signal is converted to a digital signal. Next, the image signal may be converted from black-and-white to color in a black-and-white to color converter 224. The black-and-white to color 224 may work in a manner similar to that of the black-and-white to color converter 104 shown in FIG. 1. That is, wavelength components in the infrared range may be scaled by a predetermined amount so that wavelengths in the visible range are mapped instead.
  • The image signal is then sent to a screen 218 to display the image for the observer, so that the observer may view the images from inside the subject's eye. In one embodiment, the screen 218 may be a high-resolution liquid crystal display screen. In another embodiment, the screen 218 may be an array of light emitting diodes or a plasma display screen. In one embodiment, the image is manipulated so that it is right side up and frontwards when it is presented to the examiner. A lens, such as a high of plus or positive diopter lens may be mounted over the screen 218. Such a lens mounted over the screen 218 may magnify the image and limit the accommodation necessary to focus on the screen 218.
  • The image signal from the streaming video converter 222 may also be sent over a wired connection 232 to a lap top computer 234 for documentation and storage. In one embodiment, the connection 232 is a Universal Serial Bus. In one embodiment, a raw digital video signal is sent to the laptop computer 234. In this embodiment, the laptop computer 234 has a separate black-and-white to color converter 236, as well as a real-time video capture 238. The real-time video capture 238 captures the video signal in real time, and sends it to the black-and-white to color converter 236. Software 244 on the laptop may be used to manipulate the image signal by capturing the raw image, adjusting the contrast, white balance, black balance, color saturation, or brightness. Separate images of the eye can be “stitched” together to form a montage. A three-dimensional image can be developed from the images as well. A three-dimensional image can be rotated or manipulated, such as translated in the X, Y, or Z axes. Cross-sectional images can be produced from the separate images as well. In one embodiment, a three-dimensional effect is produced by displaying images taken closely together in time, but from slightly different points of view due to, for example, movement of the camera during examination.
  • Images of retinas can be measured and compared to images stored in a database. In one embodiment, the images conform to the JPEG or DICOM standards. In another embodiment, the images conform to an MPEG-4 standard. Images and files produced by the video infrared retinal image scanner 200 may be able to interface with any government or law enforcement record software system. Downloads of the images and associated data over a network to the government or law enforcement record system may be allowed. Connections to the network can be wireless or wired. Remote access to the images on the laptop may be allowed by software.
  • In one embodiment, images taken by the infrared retinal image scanner 200 may be stored on an internal memory chip, such as a SD card 226. In one embodiment, the infrared retinal image scanner 200 may be rechargeable over a universal serial bus (USB) connection 230, or over a network.
  • In FIG. 3 is shown a ray diagram for use with an infrared retinal image scanner. As may be seen in FIG. 3, infrared radiation emanating from an LED light source 310 is redirected by a beam splitter 318 toward an eye 308. The redirected beam is enumerated 314. The redirected beam of infrared radiation 314 reaches the eye 308 and is reflected off the eye 308 as beam 312. Beam 312 passes through the beam splitter 318 again as beam 316, and also passes through a focusing lens 304 before reaching a camera 302. Some of the infrared radiation from LED light source 310 passes through the beam splitter 318 and reaches light sink 306.
  • In FIG. 4 is shown a ray diagram for use with an infrared retinal image scanner. As may be seen in FIG. 4, infrared radiation emanating from of a light source 410 is redirected by a beam splitter 418 toward an eye 408. The redirected beam is enumerated 414. The redirected beam 414 may or may not pass through a handheld lens 424 held in front of the eyes 408 by the examiner. The redirected beam 414 reaches the eye 408 and is reflected off of the eye 408 as beam 412, toward the handheld lens 424. The handheld lens 424 is used by the examiner to focus the light on the eye 408 and eight in the examination. Beam 412 passes through the handheld lens 424 as beam 416 and is focused on a camera lens 404. A virtual image of the retina 408 is formed between the handheld lens 424 and the camera lens 404. The beam 416 passes through the camera lens 404 and is collected by a camera 402. A signal from the camera 402 is distributed to two display screen 420, in front of which may be placed lenses 422. Images of the eye 408 are displayed on the screens 422 and viewed by the examiner.
  • In FIG. 5 is shown a process of retinal scanning according to an embodiment of the invention. In a first operation 502 an infrared light source is provided. After that, the process moves to operation 504, in which infrared radiation is emitted from the infrared light source toward a beam splitter. After that, the process moves to operation 506, in which the infrared radiation is reflected by the beam splitter through a focusing lens. After that, the process moves to operation 508, in which the infrared radiation is focused by the focusing lens on a retina. After that, the process moves to operation 510, in which radiation reflected by the retina through the beam splitter is collected by a camera. After that, the process moves to operation 512, in which an image signal representative of an image of the retina is produced by the camera based on the collected radiation. After that, the process moves to operation 514, in which one of the plurality of images of the retina is selected from the image signal for display. After that, the process moves to operation 516, in which the selected image of the retina is displayed on a display. After that, the process moves to operation 518, in which the selected image of the retina is compared to at least one of a plurality of images of retinas stored in a database. After that, the process moves to operation 520, in which one of the plurality of images of retinas stored in the database that matches the selected image of the retina is selected. After that, the process moves to operation 522, in which the matching image of the retina is displayed on the display along with the selected image of the retina.
  • Although a few preferred embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.

Claims (9)

We claim:
1. A retinal image scanner, comprising:
an infrared light source;
a beam splitter reflecting infrared radiation from the light source through one of a plurality of focusing lenses to a retina;
a camera collecting radiation reflected by the retina through the beam splitter;
an analog to digital convertor receiving a raw signal from the camera based on the collected radiation;
the analog to digital convertor converting the raw signal to a digital signal;
a streaming video converter processing the digital signal into a video signal; and
a video monitor displaying an image of the retina based on the video signal;
the retinal image scanner further comprising a video transmitter, the video transmitter transmitting the video signal to a computer over a network, the computer extracting a plurality of images from the video signal;
a comparator comparing at least one of the plurality of images with at least one of a plurality of stored images; and
a selector selecting one of the plurality of stored images that matches the one of the plurality of images.
2. The retinal image scanner of claim 1, wherein the video monitor comprises a high-resolution liquid crystal display screen.
3. The retinal image scanner of claim 1, wherein the light source further comprises a rheostat dimmer circuit, an infrared filter, and a focusing lens, the infrared filter substantially blocking visible and ultraviolet radiation, and the focusing lens focusing the infrared radiation from the light source on the beam splitter.
4. The retinal image scanner of claim 1, further comprising a lithium ion battery power supply power to the light source.
5. The retinal image scanner of claim 1, wherein the network is selected from the group consisting of a wired network, and a wireless network.
6. The retinal image scanner of claim 1, wherein the computer comprises: a real-time video capture capturing images from the video signal, a black-and-white to color converter for converting the images to color, 3D rendering software, and a messaging system.
7. The retinal image scanner of claim 1, further comprising a black and white to color converter scaling a plurality of wavelengths of the digital signal into a color signal, wherein the streaming video converter processes the color signal into the video signal.
8. A method of scanning a retinal image, comprising:
providing an infrared light source;
emitting infrared radiation from the infrared light source toward a beam splitter;
reflecting the infrared radiation with the beam splitter through a focusing lens;
focusing the infrared radiation with the focusing lens on a retina;
collecting radiation reflected by the retina through the beam splitter at a camera;
producing an image signal representative of a plurality of images of the retina with the camera based on the collected radiation;
selecting one of the plurality of images of the retina for display from the image signal;
displaying the selected image of the retina on display;
comparing the selected image of the retina to at least one of a plurality of images of retains stored in a database;
selecting one of the plurality of images of retinas stored in the database that matches the selected image of the retina; and
displaying the one of the matching image of the retina on the display along with the selected image of the retina.
9. The method of scanning a retinal image of claim 8, further comprising converting the image signal into a color signal; and displaying a plurality of color images of the retina on the display.
US13/970,249 2008-11-05 2013-08-19 Video Infrared Retinal Image Scanner Abandoned US20140055567A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US13/970,249 US20140055567A1 (en) 2008-11-05 2013-08-19 Video Infrared Retinal Image Scanner

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US11150608P 2008-11-05 2008-11-05
US12/612,547 US8514277B2 (en) 2008-11-05 2009-11-04 Video infrared retinal image scanner
US13/970,249 US20140055567A1 (en) 2008-11-05 2013-08-19 Video Infrared Retinal Image Scanner

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US12/612,547 Continuation US8514277B2 (en) 2008-11-05 2009-11-04 Video infrared retinal image scanner

Publications (1)

Publication Number Publication Date
US20140055567A1 true US20140055567A1 (en) 2014-02-27

Family

ID=42153239

Family Applications (2)

Application Number Title Priority Date Filing Date
US12/612,547 Expired - Fee Related US8514277B2 (en) 2008-11-05 2009-11-04 Video infrared retinal image scanner
US13/970,249 Abandoned US20140055567A1 (en) 2008-11-05 2013-08-19 Video Infrared Retinal Image Scanner

Family Applications Before (1)

Application Number Title Priority Date Filing Date
US12/612,547 Expired - Fee Related US8514277B2 (en) 2008-11-05 2009-11-04 Video infrared retinal image scanner

Country Status (11)

Country Link
US (2) US8514277B2 (en)
EP (1) EP2356613A1 (en)
JP (1) JP2012508423A (en)
KR (1) KR20110094037A (en)
CN (1) CN102272775A (en)
AU (1) AU2009313457A1 (en)
BR (1) BRPI0921121A2 (en)
CA (1) CA2742815A1 (en)
MX (1) MX2011004758A (en)
RU (1) RU2011122668A (en)
WO (1) WO2010054092A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016029032A1 (en) * 2014-08-20 2016-02-25 Matthew Rickard Systems and methods for monitoring eye health
WO2018111995A1 (en) * 2016-12-13 2018-06-21 Gentex Corporation Biometric identification system for gun
US11806078B1 (en) 2022-05-01 2023-11-07 Globe Biomedical, Inc. Tear meniscus detection and evaluation system

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8514277B2 (en) * 2008-11-05 2013-08-20 Dyer Holdings, Llc Video infrared retinal image scanner
JP5507376B2 (en) * 2010-07-28 2014-05-28 三洋電機株式会社 Imaging device
WO2012088424A1 (en) * 2010-12-23 2012-06-28 The Trustees Of Columbia University In The City Of New York Lensless retinal camera apparatus and method
SG11201407941UA (en) * 2012-06-01 2014-12-30 Agency Science Tech & Res Robust graph representation and matching of retina images
US8369595B1 (en) 2012-08-10 2013-02-05 EyeVerify LLC Texture features for biometric authentication
US8437513B1 (en) 2012-08-10 2013-05-07 EyeVerify LLC Spoof detection for biometric authentication
US8483450B1 (en) 2012-08-10 2013-07-09 EyeVerify LLC Quality metrics for biometric authentication
US9800866B2 (en) * 2015-04-08 2017-10-24 Algolux Inc. Method for providing an estimation of a point spread function indicative of intrinsic camera blur
RU2711050C2 (en) 2015-09-11 2020-01-14 Айверифай Инк. Image and attribute quality, image enhancement and identification of features for identification by vessels and faces and combining information on eye vessels with information on faces and / or parts of faces for biometric systems
US10708473B2 (en) 2017-12-22 2020-07-07 Verily Life Sciences Llc Ocular imaging with illumination in image path
CN111090020B (en) * 2020-03-24 2020-06-19 深圳市中科先见医疗科技有限公司 In-vivo and in-vitro joint regulation system for artificial retina and artificial retina testing method

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100245765A1 (en) * 2008-10-28 2010-09-30 Dyer Holdings, Llc Video infrared ophthalmoscope
US8514277B2 (en) * 2008-11-05 2013-08-20 Dyer Holdings, Llc Video infrared retinal image scanner

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3915564A (en) * 1974-09-12 1975-10-28 Zeiss Stiftung Retinal image-display system
US5224173A (en) 1991-10-29 1993-06-29 Kuhns Roger J Method of reducing fraud in connection with employment, public license applications, social security, food stamps, welfare or other government benefits
US5766016A (en) * 1994-11-14 1998-06-16 Georgia Tech Research Corporation Surgical simulator and method for simulating surgical procedure
US5838422A (en) 1996-01-03 1998-11-17 Caskey; Patrick J. Ophthalmological self-test unit for evaluating macular degeneration
US6305804B1 (en) 1999-03-25 2001-10-23 Fovioptics, Inc. Non-invasive measurement of blood component using retinal imaging
DE10047237A1 (en) 2000-09-23 2002-04-11 Physoptics Opto Electronic Gmb System for recording the retinal reflex image
US20040233038A1 (en) 2001-07-10 2004-11-25 American Express Travel Related Services Company, Inc. Method and system for retinal scan recognition biometrics on a fob
AU2003239135A1 (en) 2002-04-10 2003-10-27 Karl Storz Endoscopy-America, Inc. Apparatus and method for powering portable battery operated light sources
US7448753B1 (en) 2005-07-19 2008-11-11 Chinnock Randal B Portable Digital Medical Camera for Capturing Images of the Retina or the External Auditory Canal, and Methods of Use

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100245765A1 (en) * 2008-10-28 2010-09-30 Dyer Holdings, Llc Video infrared ophthalmoscope
US8514277B2 (en) * 2008-11-05 2013-08-20 Dyer Holdings, Llc Video infrared retinal image scanner

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016029032A1 (en) * 2014-08-20 2016-02-25 Matthew Rickard Systems and methods for monitoring eye health
CN107072528A (en) * 2014-08-20 2017-08-18 加州浸会大学 system and method for monitoring eye health
US9770169B2 (en) 2014-08-20 2017-09-26 California Baptist University Systems and methods for monitoring eye health
US10806341B2 (en) 2014-08-20 2020-10-20 California Baptist University Systems and methods for monitoring eye health
WO2018111995A1 (en) * 2016-12-13 2018-06-21 Gentex Corporation Biometric identification system for gun
US10139179B2 (en) 2016-12-13 2018-11-27 Gentex Corporation Biometric identification system for gun
US11806078B1 (en) 2022-05-01 2023-11-07 Globe Biomedical, Inc. Tear meniscus detection and evaluation system

Also Published As

Publication number Publication date
CA2742815A1 (en) 2010-05-14
JP2012508423A (en) 2012-04-05
CN102272775A (en) 2011-12-07
BRPI0921121A2 (en) 2016-02-16
AU2009313457A1 (en) 2010-05-14
WO2010054092A1 (en) 2010-05-14
US20100128117A1 (en) 2010-05-27
US8514277B2 (en) 2013-08-20
EP2356613A1 (en) 2011-08-17
MX2011004758A (en) 2011-10-05
KR20110094037A (en) 2011-08-19
RU2011122668A (en) 2012-12-20

Similar Documents

Publication Publication Date Title
US8514277B2 (en) Video infrared retinal image scanner
CN103106401B (en) Mobile terminal iris recognition device with human-computer interaction mechanism
US10643087B2 (en) Systems and methods of biometric analysis to determine a live subject
KR100939856B1 (en) Personal authentication method and device
CN103024338B (en) There is the display device of image capture and analysis module
WO2017132903A1 (en) Biometric composite imaging system and method reusable with visible light
US20120257163A1 (en) Video Infrared Ophthalmoscope
WO2005002441A1 (en) Organism eye judgment method and organism eye judgment device
JP2005004524A (en) Identifying system, and personal authenticating system
WO2014094173A1 (en) Handheld venipuncture-assisting device
JP2004030564A (en) Personal identification method, personal identification apparatus, and photographing device
US11506887B2 (en) Method and apparatus for gaze detection
US20210192205A1 (en) Binding of selfie face image to iris images for biometric identity enrollment
US8306609B2 (en) Vein imaging apparatus and thumbnail image creation method
JP2007219624A (en) Blood vessel image input device and personal identification system
RU97839U1 (en) DEVICE FOR PREPARING IMAGES OF IRIS OF THE EYES
US20210256103A1 (en) Handheld multi-sensor biometric imaging device and processing pipeline
CN109426762B (en) Biological recognition system, method and biological recognition terminal
KR20200107167A (en) Apparatus and Method for Making a Facial Image Suitable for Facial Recognition by Using Infraredat at Natural Lighting
CN110101363B (en) Collecting device for fundus images
CN217739940U (en) Identity recognition and authentication system based on multi-mode biological information
CN115131870A (en) Iris image acquisition method
Corcoran et al. Iris authentication in handheld devices-considerations for constraint-free acquisition

Legal Events

Date Code Title Description
STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION