Patent WO-2021249895-A1 (WO)
Inventor: BERG MAX
IPC: G01N21/27
Filed: 2021-06-07
Abstract: A method of determining the concentration of at least one analyte in a sample of a bodily fluid by using a mobile device (112) having at least one camera (120), the method comprising: i) capturing, by using the camera (120), at least one image of at least a part of a color reference card (118) and of at least a part of at least one reagent test field (116) of at least one optical test strip (114) having the sample applied thereto, - wherein, in the image, the test field (116) is in a defined position with respect to the color reference card (118), - wherein the color reference card (118) comprises a plurality of different gray reference fields (126) locally assigned to the test field (116), wherein the plurality of gray reference fields (126) and the test field (116) are locally assigned to each other by being placed in neighboring positions or wherein the plurality of gray reference fields (126) locally assigned to the test field (116) are arranged on the color reference card (118) such that the plurality of gray reference fields (126) surrounds the test field (116), and - wherein the color reference card (118) comprises a plurality of different color reference fields (128) having known reference color values and a plurality of different gray reference fields (126) locally assigned to the color reference fields (128), wherein the plurality of gray reference fields (126) and the color reference fields (128) are locally assigned to each other by being placed in neighboring positions or wherein the plurality of gray reference fields (126) locally assigned to the color reference fields (128) are arranged on the color reference card (118) such that the plurality of gray reference fields (126) surrounds the color reference fields (128), ii) applying at least one predetermined pixel-based mean tone map correction to the image obtained in step i), thereby obtaining at least one first intensity-corrected image, wherein the predetermined pixel-based mean tone map correction comprises an assignment of a second brightness value to a first brightness value, wherein the first brightness value is recorded by the camera (120), wherein each pixel of the recorded image is corrected individually by the predetermined A method of determining the concentration of at least one analyte in a sample of a bodily fluid by using a mobile device (112) having at least one camera (120), the method comprising: i) capturing, by using the camera (120), at least one image of at least a part of a color reference card (118) and of at least a part of at least one reagent test field (116) of at least one optical test strip (114) having the sample applied thereto, - wherein, in the image, the test field (116) is in a defined position with respect to the color reference card (118), - wherein the color reference card (118) comprises a plurality of different gray reference fields (126) locally assigned to the test field (116), wherein the plurality of gray reference fields (126) and the test field (116) are locally assigned to each other by being placed in neighboring positions or wherein the plurality of gray reference fields (126) locally assigned to the test field (116) are arranged on the color reference card (118) such that the plurality of gray reference fields (126) surrounds the test field (116), and - wherein the color reference card (118) comprises a plurality of different color reference fields (128) having known reference color values and a plurality of different gray reference fields (126) locally assigned to the color reference fields (128), wherein the plurality of gray reference fields (126) and the color reference fields (128) are locally assigned to each other by being placed in neighboring positions or wherein the plurality of gray reference fields (126) locally assigned to the color reference fields (128) are arranged on the color reference card (118) such that the plurality of gray reference fields (126) surrounds the color reference fields (128), ii) applying at least one predetermined pixel-based mean tone map correction to the image obtained in step i), thereby obtaining at least one first intensity-corrected image, wherein the predetermined pixel-based mean tone map correction comprises an assignment of a second brightness value to a first brightness value, wherein the first brightness value is recorded by the camera (120), wherein each pixel of the recorded image is corrected individually by the predetermined pixel- based mean tone map correction, wherein the mean tone map correction is derived by combining a plurality of tone map corrections for different types of mobile devices; iii) deriving, from the first intensity-corrected image, local brightness information (174) for at least some of the color reference fields (128) and for the test field (116), by using the gray reference fields (126) locally assigned to the color reference fields (128) and the test field (116), respectively, wherein the local brightness information (174) comprises a numerical indication describing the local intensity of at least one RGB color of the color reference fields (128) and the test field (116), respectively; iv) applying at least one mobile device-specific tone map correction to the first intensity-corrected image, the mobile device-specific tone map correction taking into account the local brightness information (174), thereby obtaining at least one second intensity-corrected image; and v) determining the analyte concentration based on a color formation reaction of the test field (116) by using the second intensity-corrected image.