Calculating conjunctival redness

Patent metadata

Field	Value
Publication number	US-10548474-B2
Application number	US-201715856134-A
Country	US
Kind code	B2
Filing date	Dec 28, 2017
Priority date	Feb 21, 2012
Publication date	Feb 4, 2020
Grant date	Feb 4, 2020

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 based on a color of the ocular surface, the method comprising:
obtaining a digital signal representing at least a portion of the ocular surface;
determining, from a portion of the digital signal, a plurality of color components that are based on a Cartesian color space;
determining, from the color components, a hue value in a polar coordinate based color space;
selecting an angle range in the polar coordinate based color space in accordance with a color associated with the condition being evaluated;
determining that the hue value lies within the angle range that represents the color associated with the condition being evaluated in a hue circle representation of the polar coordinate based color space;
mapping the hue value to a scalar value within a predetermined range in response to determining that the hue value lies within the angle range;
selecting a function of one or both of two other components of the polar coordinate based color space, wherein the function is selected based on the condition being evaluated;
determining a color value as a product of the scalar value and the function of one or both of the two other components of the polar coordinate based color space; and
generating a color score as a function of the color value, wherein the color score of the ocular surface relates to a quantitative evaluation of the condition of the ocular surface.

2. The method of claim 1 , further comprising
receiving a selection of at least a first portion of the digital signal;
determining an average gain associated with the first portion of the digital signal; and
applying the average gain to a second portion of the digital signal.

3. The method of claim 1 , wherein mapping the hue value to the scalar value comprises using a parabolic curve to map the hue value to the scalar value within the predetermined range.

4. The method of claim 1 , further comprising receiving a selection of a portion of the digital signal through a graphical user interface,
wherein assigning the color score comprises assigning the color score to the portion of the digital signal.

5. The method of claim 1 , wherein the color score indicates a degree of redness of the ocular surface.

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

7. The method of claim 1 , wherein the Cartesian color space is an RGB color space.

8. The method of claim 1 , wherein the polar coordinate based color space is an HSV color space.

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

10. The method of claim 1 , wherein the digital signal is related to one or more of corneal neovascularization, fluorescein stained epithelial punctate keratitis and epithelial defects, eyelid and skin telangiectasia, and conjunctival/scleral pigmented lesions.

11. A computer readable storage device having encoded thereon computer readable instructions, which when executed by a processor, cause a processor to perform operations comprising:
obtaining a digital signal representing at least a portion of an ocular surface;
determining, from a portion of the digital signal, a plurality of color components that are based on a Cartesian color space;
determining, from the color components, a hue value in a polar coordinate based color space;
selecting an angle range in the polar coordinate based color space in accordance with a color associated with a condition of the ocular surface;
determining that the hue value lies within the angle range that represents the color associated with the condition being evaluated in a hue circle representation of the polar coordinate based color space;
mapping the hue value to a scalar value within a predetermined range in response to determining that the hue value lies within the angle range;
selecting a function of one or both of two other components of the polar coordinate based color space, wherein the function is selected based on the condition being evaluated;
determining a color value as a product of the scalar value and the function of one or both of the two other components of the polar coordinate based color space; and
generating a color score as a function of the color value, wherein the color score of the ocular surface relates to a quantitative evaluation of the condition of the ocular surface.

12. The computer readable storage device of claim 11 , further comprising
receiving a selection of at least a first portion of the digital signal;
determining an average gain associated with the first portion of the digital signal; and
applying the average gain to a second portion of the digital signal.

13. The computer readable storage device of claim 11 , wherein mapping the hue value to the scalar value comprises using a parabolic curve to map the hue value to the scalar value within the predetermined range.

14. The computer readable storage device of claim 11 , wherein the operations further comprise receiving a selection of a portion of the digital signal through a graphical user interface,
wherein assigning the color score comprises assigning the color score to the portion of the digital signal.

15. The computer readable storage device of claim 11 , wherein the color score indicates a degree of redness of the ocular surface.

16. The computer readable storage device of claim 11 , wherein the ocular surface comprises conjunctiva.

17. The computer readable storage device of claim 11 , wherein the Cartesian color space is an RGB color space.

18. The computer readable storage device of claim 11 , wherein the polar coordinate based color space is an HSV color space.

19. The computer readable storage device of claim 11 , wherein the operations further comprise storing the color score and an association of the color score with the digital signal.

20. The computer readable storage device of claim 11 , wherein the digital signal is related to one or more of corneal neovascularization, fluorescein stained epithelial punctate keratitis and epithelial defects, eyelid and skin telangiectasia, and conjunctival/scleral pigmented lesions.

Assignees

• Massachusetts Eye & Ear Infirmary

Inventors

• Dana Reza
• Amparo Pulido Francisco L
• Wang Haobing

Classifications

• G06T7/90

  Determination of colour characteristics · CPC title

• H04N1/628 Primary

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

• G06T2207/30041

  Eye; Retina; Ophthalmic · CPC title

• G06T7/0012

  Biomedical image inspection · CPC title

• A61B3/14 Primary

  Arrangements specially adapted for eye photography · CPC title