Calculating conjunctival redness

Patent metadata

Field	Value
Publication number	US-11298018-B2
Application number	US-201916719321-A
Country	US
Kind code	B2
Filing date	Dec 18, 2019
Priority date	Feb 21, 2012
Publication date	Apr 12, 2022
Grant date	Apr 12, 2022

Abstract

The present application includes methods, systems and computer readable storage devices for determining a color score for at least a portion of a biological tissue. The subject matter of the application is embodied in a method that includes obtaining a digital image of the biological tissue, and receiving a selection of a portion of the image as an evaluation area. The method also includes determining for each of a plurality of pixels within the evaluation area, a plurality of color components that are based on a Cartesian color space, and determining, from the color components, a hue value in a polar coordinate based color space. The method further includes determining a color value based on the hue value for each of the plurality of pixels, and assigning a color score to the evaluation area based on an average of the color values of the plurality of pixels.

First claim

What is claimed is:

1. A computer-implemented method for evaluating a condition of an ocular surface, the method comprising:
obtaining a digital signal representing at least a portion of the ocular surface, the digital signal indicative of a plurality of Cartesian space-based color components for a portion of the digital signal;
determining, from the plurality of Cartesian space-based color components, a value of a first component in a polar coordinate-based color space, the polar coordinate-based color space consisting of first, second, and third components;
determining, in response to the first component being within a range in the polar coordinate-based color space representing a color range associated with the condition, a color value as a function of the value of the first component of the polar coordinate-based color space and at least one of the first component or the second component of the polar coordinate-based color space, the function being based on the condition being evaluated; and
generating, based on the color value, a color score of the ocular surface representing a quantitative evaluation of the condition of the ocular surface.

2. The method of claim 1 , further comprising applying an average gain to a first portion of the digital signal, the average gain being associated with a second portion of the digital signal.

3. The method of claim 1 , wherein the color range associated with the condition represents a degree of redness of the ocular surface.

4. The method of claim 1 , wherein the ocular surface comprises conjunctiva.

5. The method of claim 1 , wherein the plurality of Cartesian space-based color components are a plurality of color components of a red-green-blue (RGB) color space.

6. The method of claim 1 , wherein the polar coordinate-based color space is a hue-saturation-value color space, the first, second, and third components in the polar coordinate-based color space being selected from the group consisting of a hue, a saturation, and a value.

7. The method of claim 6 , wherein the first component in the polar coordinate-based color space is a hue.

8. The method of claim 1 , further comprising storing the color score and an association of the color score with the digital signal.

9. The method of claim 1 , wherein the digital signal is a digital representation of a stained portion of the ocular surface.

10. The method of claim 9 , wherein the stained portion of the ocular surface comprises a stained portion of a conjunctiva.

11. The method of claim 1 , wherein generating, based on the color value, the color score comprises generating, based on a plurality of color values comprising the color value, the color score.

12. The method of claim 11 , wherein generating, based on the plurality of color values, the color score comprises computing a linear combination of the color values.

13. The method of claim 1 , further comprising identifying a progression of the condition of the ocular surface by comparing the color score to a previously-generated color score.

14. A system for evaluating a condition of an ocular surface, the system comprising:
an imaging system configured to obtain one or more digital images of the ocular surface; and
a controller in communication with the imaging system, the controller configured to execute instructions to perform operations comprising:
determining, from a plurality of Cartesian space-based color components represented in a portion of the one or more digital images, a value of a first component in a polar coordinate-based color space, the polar coordinate-based color space consisting of first, second, and third components;
determining, in response to the first component being within a range in the polar coordinate-based color space representing a color range associated with the condition, a color value as a function of the value of the first component of the polar coordinate-based color space and at least one of the first component or the second component of the polar coordinate-based color space, the function being based on the condition being evaluated; and
generating, based on the color value, a color score of the ocular surface representing a quantitative evaluation of the condition of the ocular surface.

15. The system of claim 14 , wherein the operations further comprise applying an average gain to a first portion of the one or more digital images, the average gain being associated with a second portion of the one or more digital images.

16. The system of claim 14 , wherein the ocular surface comprises conjunctiva.

17. The system of claim 14 , wherein the plurality of Cartesian space-based color components are a plurality of color components of a red-green-blue (RGB) color space.

18. The system of claim 14 , wherein the polar coordinate-based color space is a hue-saturation-value color space, the first, second, and third components in the polar coordinate-based color space being selected from the group consisting of a hue, a saturation, and a value.

19. The system of claim 14 , wherein the one or more digital images are digital representation of a stained portion of the ocular surface.

20. The system of claim 14 , wherein generating, based on the color value, the color score comprises generating, based on a plurality of color values comprising the color value, the color score.

21. The system of claim 20 , wherein generating, based on the plurality of color values, the color score comprises computing a linear combination of the color values.

22. The system of claim 14 , wherein the operations further comprise identifying a progression of the condition of the ocular surface by comparing the color score to a previously-generated color score.

Assignees

• Massachusetts Eye & Ear Infirmary

Inventors

• Dana Reza
• Amparo Pulido Francisco L
• Wang Haobing

Classifications

• H04N1/628 Primary

  Memory colours, e.g. skin or sky · CPC title

• G06T7/90

  Determination of colour characteristics · CPC title

• A61B5/103

  Measuring devices for testing the shape, pattern, {colour,} size or movement of the body or parts thereof, for diagnostic purposes (measuring instruments specially adapted for dentistry A61C19/04) · CPC title

• G06T2207/30041

  Eye; Retina; Ophthalmic · CPC title

• G06T7/0012

  Biomedical image inspection · CPC title