# US 11,298,018 B2 · Calculating conjunctival redness > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,298,018 B2 - Document ID: US11298018B2 - Status: Granted - Kind: B2 - Application number: 16/719,321 - Filed: 2019-12-18 - Published: 2020-07-23 - Granted: 2022-04-12 - Earliest claimed: 2012-02-21 - Assignees: Massachusetts Eye and Ear Infirmary - Applicants: Massachusetts Eye and Ear Infirmary - Inventors: Reza Dana; Francisco L. Amparo Pulido; Haobing Wang - Web page: https://patentgrep.com/patent/US11298018B2 ## CPC - A61B 3/14: Arrangements specially adapted for eye photography - A61B 3/0016: {Operational features thereof} - G06T 7/0012: {Biomedical image inspection} - G06T 7/90: Determination of colour characteristics - H04N 1/628: {Memory colours, e.g. skin or sky} - A61B 5/103: 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) - A61B 5/1032: {Determining colour of tissue for diagnostic purposes} - G06T 2207/30041: Eye; Retina; Ophthalmic - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## 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. ## Claims ### Claim 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. ### Claim 2 (depends on 1) 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. ### Claim 3 (depends on 1) The method of claim 1, wherein the color range associated with the condition represents a degree of redness of the ocular surface. ### Claim 4 (depends on 1) The method of claim 1, wherein the ocular surface comprises conjunctiva. ### Claim 5 (depends on 1) 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. ### Claim 6 (depends on 1) 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. ### Claim 7 (depends on 6) The method of claim 6, wherein the first component in the polar coordinate-based color space is a hue. ### Claim 8 (depends on 1) The method of claim 1, further comprising storing the color score and an association of the color score with the digital signal. ### Claim 9 (depends on 1) The method of claim 1, wherein the digital signal is a digital representation of a stained portion of the ocular surface. ### Claim 10 (depends on 9) The method of claim 9, wherein the stained portion of the ocular surface comprises a stained portion of a conjunctiva. ### Claim 11 (depends on 1) 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. ### Claim 12 (depends on 11) 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. ### Claim 13 (depends on 1) 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. ### Claim 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. ### Claim 15 (depends on 14) 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. ### Claim 16 (depends on 14) The system of claim 14, wherein the ocular surface comprises conjunctiva. ### Claim 17 (depends on 14) 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. ### Claim 18 (depends on 14) 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. ### Claim 19 (depends on 14) The system of claim 14, wherein the one or more digital images are digital representation of a stained portion of the ocular surface. ### Claim 20 (depends on 14) 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. ### Claim 21 (depends on 20) 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. ### Claim 22 (depends on 14) 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.