Light field camera for fundus photography
Systems and methods for applying the concept of lightfield sensors to fundus photography are presented. In one embodiment, the ability to isolate specific regions of the collected lightfield are used to reduce the effects of glare in a fundus image. Additional embodiments in which aberrations can be characterized and removed, an image from a particular plane in the collected light field is used to aid in instrument alignment, and dynamic optimization of collection pupil diameter is accomplished are also presented.
1. An ophthalmic imaging system, said system comprising:
an illumination light source;
a detector for collecting both positional and directional information of the ray paths of illumination light reflected from the eye of a patient;
optics for directing the illumination light source to the eye of the patient and for directing light reflected from the eye of the patient to the detector;
a processor for processing the positional and directional information and for generating an image of the eye of the patient using the positional and directional information; and
a display for displaying the image.
2. A system as recited in claim 1 , wherein the detector is a light field sensor consisting of a two dimensional sensor array behind a microlens array.
3. A system as recited in claim 2 , wherein the distance between the microlens array and the sensor array is the focal length of the microlens array.
4. A system as recited in claim 2 , wherein the microlens array of the light field sensor is located approximately conjugate to the retina of the eye.
5. A system as recited in claim 1 , wherein the processor compensates for optical aberrations present in the imaging system.
6. A system as recited in claim 1 , wherein the imaging system is used to image the posterior section of the eye and the iris of the eye acts as an aperture.
7. A system as recited in claim 6 , wherein the processor generates a high resolution image of the retina of the eye of a patient.
8. A system as recited in claim 1 , wherein the processor reduces unwanted intensity information associated with reflections and scattering from portions of the eye other than the fundus to reduce glare in the image.
9. A system as recited in claim 1 , wherein the processor reduces intensity information associated with specular reflections from the cornea of the eye.
10. A system as recited in claim 1 , wherein the processor reduces intensity information associated with light scattered from the iris.
11. A system as recited in claim 1 , wherein the processor reduces intensity information associated with pathological media located in the anterior portion of the eye.
12. A system as recited in claim 1 , wherein the processor generates two images of the eye, each at a different depth in the eye.
13. A system as recited in claim 1 , wherein the processor calculates a synthetic aperture and applies the aperture to the signals to limit the image to a subset of light that is measured.
14. A system as recited in claim 1 , wherein the processor generates an image of the pupil plane of the instrument to aid in alignment of the instrument.
15. A system as recited in claim 1 , further comprising a light source that generates light of low numerical aperture for characterizing aberrations.
16. A method of obtaining images of the fundus of the eye of a patient comprising the steps of:
illuminating the eye with a light source;
capturing light rays reflected from the eye with a light field sensor, said sensor generating signals representative of both the position and direction of the captured light rays; and
processing the signals to generate an image of the fundus of the eye.
17. A method of obtaining images as recited in claim 16 , wherein said processing step operates to reduce unwanted intensity information associated with reflections and scattering from portions of the eye other than the fundus to reduce glare in the image.
18. A method of obtaining images as recited in claim 17 , wherein said processing step determines position and direction values from which unwanted reflections or scattering are occurring in order to reduce the unwanted intensity information from the image.
19. A method of obtaining images as recited in claim 17 , wherein the processing step reduces intensity information associated with specular reflections from the cornea of the eye.
20. A method of obtaining images as recited in claim 17 , wherein the processing step reduces intensity information associated with light scattered from the iris.
21. A method of obtaining images as recited in claim 17 , wherein the processing step reduces intensity information associated with pathological media located in the anterior portion of the eye.
22. A method of obtaining images as recited in claim 17 , wherein the processing step functions to reduce aberrations in the image.
23. A method of obtaining images as recited in claim 17 , wherein the processing step includes generating multiple images, each at a different depth in the retina.
24. A method of obtaining images as recited in claim 17 , wherein the processing step calculates a synthetic aperture and applies the aperture to the signals to limit the image to a subset of light that is measured.
25. A method on obtaining images as recited in claim 24 , wherein stereo images are generated.