Calculating conjunctival redness
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.
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.