Fundus imaging system

Patent metadata

Field	Value
Publication number	US-9918629-B2
Application number	US-201615297073-A
Country	US
Kind code	B2
Filing date	Oct 18, 2016
Priority date	Feb 11, 2014
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

A fundus imaging system includes: an image sensor array, where the image sensor array includes monochrome photodiodes and global shutter control, an illumination unit with one or more light-emitting diodes that have one or more dies, a computing system including a processor and memory, one or more lenses, one or more reflective mirrors, and a display. In an example method of use, a clinician positions a patient, initiates a focal adjustment, initiates a retinal imaging process, and the same or a different clinician views the image. In some embodiments, the imaging system is configured to analyze the image and identify detected physical attributes in the image relating to the diagnosis and treatment of diabetic retinopathy.

First claim

What is claimed is:

1. A non-mydriatic fundus imaging system, comprising:
an image sensor array capable of global reset operations wherein each pixel of a plurality of rows of pixels is exposed substantially simultaneously;
an illumination unit including a light emitting diode, the illumination unit capable of overdriving the light emitting diode;
a processor; and
memory storing instructions that, when executed by the processor, cause the fundus imaging system to:
capture a plurality of images in a first image capture mode;
process at least a portion of the plurality of images to determine a position of a pupil of a subject; and
capture an image in a second image capture mode when the position of the pupil is substantially aligned with an optical axis of the fundus imaging system, wherein the position of the pupil is substantially aligned with the optical axis of the fundus imaging system when an image sensor array angle formed between the optical axis and a vector formed between a lens of the fundus imaging system and the pupil is less than fifteen degrees, the second image capture mode including:
simultaneous exposure of each pixel of a plurality of rows of pixels of the image sensor array; and
overdrive of the light emitting diode during the simultaneous exposure.

2. The non-mydriatic fundus imaging system according to claim 1 , wherein the position of the pupil is substantially aligned with the optical axis of the fundus imaging system when an angle formed between the optical axis and a vector formed between a lens of the fundus imaging system and the pupil is less than two degrees.

3. The non-mydriatic fundus imaging system according to claim 1 , wherein the position of the pupil is substantially aligned with the optical axis of the fundus imaging system when the optical axis crosses the pupil.

4. The non-mydriatic fundus imaging system according to claim 1 , wherein the image sensor array includes a two-dimensional monochrome complementary metal-oxide-semiconductor.

5. The non-mydriatic fundus imaging system according to claim 4 , wherein:
the first image capture mode comprises a first resolution and a first illumination condition;
the second image capture mode comprises a second resolution and a second illumination condition;
the second resolution is greater than or equal to the first resolution; and
the second illumination condition is brighter than the first illumination condition.

6. The non-mydriatic fundus imaging system according to claim 4 , wherein the image sensor array has a resolution of 1280 by 1024 pixels.

7. The non-mydriatic fundus imaging system according to claim 6 , wherein each pixel in the image sensor array is about four microns by about four microns.

8. The non-mydriatic fundus imaging system according to claim 6 , wherein the light emitting diode is a multi-die LED.

9. The non-mydriatic fundus imaging system according to claim 8 , wherein the illumination unit is configured to cause the multi-die LED to, consecutively, illuminate red only, illuminate green only, and illuminate blue only.

10. The non-mydriatic fundus imaging system according to claim 9 , further comprising illuminating red, green and blue simultaneously.

11. The non-mydriatic fundus imaging system according to claim 1 , wherein the illumination unit is configured to emit monochrome light for 1 millisecond during the second image capture mode.

12. The non-mydriatic fundus imaging system according to claim 1 , wherein a duration of the second image capture mode is no greater than 2 milliseconds.

13. A method for imaging a fundus, comprising:
capturing a plurality of images in a first image capture mode, by a fundus imaging system, of a pupil of a subject;
processing at least a portion of the plurality of images to determine a position of the pupil;
when the position of the pupil is in a desired position, capturing a fundus image of the subject in a second image capture mode, the desired position being substantial alignment of the pupil with an optical axis of the fundus imaging system, wherein the substantial alignment occurs when an angle formed between the optical axis and a vector formed between a lens of the fundus imaging system and the pupil is less than fifteen degrees, the second image capture mode including:
exposing simultaneously each pixel of a plurality of rows of pixels of an image sensor array of the fundus imaging system; and
during exposing each pixel, overdriving a light emitting diode.

14. The method for imaging a fundus according to claim 13 , wherein capturing the plurality of images in the first image capture mode occurs at a first resolution and a first illumination condition;
wherein capturing the fundus image in the second image capture mode occurs at a second resolution and a second illumination condition, the second resolution being greater than or equal to the first resolution and the second illumination condition being brighter than the first illumination condition.

15. An imaging system for imaging an ocular fundus, comprising:
an image sensor array including a plurality of photodiodes arranged as a plurality of rows of pixels, the image sensor array being capable of global reset wherein each pixel of a plurality of rows of pixels is exposed substantially simultaneously;
a lens;
an aperture;
an illumination unit including a light emitting diode, the illumination unit capable of overdriving the light emitting diode;
a processor; and
memory storing instructions that, when executed by the processor, cause the imaging system to:
capture a plurality of images in a first image capture mode, the first image capture mode including a first resolution and a first illumination condition;
process at least a portion of the plurality of images to determine a position of a pupil of a subject; and
capture an image in a second image capture mode when the position of the pupil is substantially aligned with an optical axis of the imaging system, the second image capture mode including a second resolution and a second illumination condition, the second resolution being greater than or equal to the first resolution and the second illumination condition being brighter than the first illumination condition, wherein the second image capture mode includes:
simultaneous exposure of each pixel of a plurality of rows of pixels of the image sensor array; and
overdrive of the light emitting diode during the simultaneous exposure.

16. The imaging system according to claim 15 , further comprising a housing supporting the image sensor array, the lens, the aperture, the processor, the memory, and the illumination unit; and
wherein the position of the pupil is substantially aligned with the optical axis of the imaging system when an angle formed between the optical axis and a vector formed between the lens of the imaging system and the pupil is less than fifteen degrees.

17. The imaging system according to claim 16 , wherein the light emitting diode is a multi-die LED; and
wherein the illumination unit is configured to emit monochrome light for 1 millisecond during the second image capture mode.

18. The imaging system according to claim 17 , wherein the image sensor array is additionally capable of global transfer and sequential readout, the global reset being simultaneous reset of the plurality of photodiodes.

Assignees

• Welch Allyn Inc

Inventors

• Wang Ynjiun Paul

Classifications

• A61B3/0025

  characterised by electronic signal processing, e.g. eye models · CPC title

• A61B3/152

  for aligning · CPC title

• A61B3/0008

  provided with illuminating means (A61B3/117, A61B3/14 take precedence) · CPC title

• A61B3/12 Primary

  for looking at the eye fundus, e.g. ophthalmoscopes (A61B3/13 takes precedence) · CPC title

• A61B3/14

  Arrangements specially adapted for eye photography · CPC title