Multi-factor urine test system that adjusts for lighting and timing

Abstract

System that enables urine testing in a home environment. A user may apply a urine sample to a card containing multiple tests, and capture an image of the card using a phone; an analysis system executing on the phone or in the cloud may analyze the image and determine test results. The test card and analysis system may compensate for variability in lighting conditions and time of exposure to the urine sample, which are difficult to control in a home environment. The test card may contain fiducial markers of known colors; the analysis system may adjust colors in the captured image based on appearance of these markers. Color adjustments may also compensate for nonuniform lighting across the card. The card may also contain time indicators that change appearance over time after urine is applied, and the analysis system may use these indicators to calculate the time of exposure.

What is claimed is: 
     
         1 . A multi-factor urine test system that adjusts for lighting and timing, comprising:
 a test card comprising
 a plurality of test regions,
 wherein said plurality of test regions comprise either lateral flow assay regions or colorimetric test regions or both; 
 wherein each test region comprises one or more reagents configured to
 react with one or more substances that may be present in a urine sample to which each test region is exposed; and 
 change appearance based on a presence of or a quantity of the one or more substances in the urine sample; 
 
 
 a plurality of fiducial markers, each fiducial marker of the plurality of fiducial markers comprising a reference color that is measured under a reference lighting condition, and wherein the plurality of fiducial markers comprises
 corner fiducial markers located at a boundary of an area of the test card within which the plurality of test regions are contained; 
 
   a test analyzer comprising a stored program configured to execute on one or more processors, wherein the stored program is configured to
 receive an image of the test card captured after the test card is exposed to the urine sample; 
 analyze the image of the test card to extract
 an appearance of each fiducial marker of said plurality of fiducial markers in the image; and 
 an appearance of each test region in the image; 
 
 analyze the appearance of each fiducial marker of said plurality of fiducial markers in the image to generate a color adjustment that transforms colors in the image to adjusted colors under the reference lighting condition; 
 apply the color adjustment to the appearance of each test region in the image to generate an adjusted appearance of each test region; 
 for each test region, calculate the presence of or the quantity of the one or more substances in the urine sample based on
 the adjusted appearance of each test region. 
 
   
     
     
         2 . The system of  claim 1 , wherein
 the color adjustment comprises a function of the colors in the image of a region and of a position in the test card of the region.   
     
     
         3 . The system of  claim 2 , wherein
 the function comprises a linear function.   
     
     
         4 . The system of  claim 3 , wherein the linear function comprises a sum of
 a first matrix multiplied by a first vector comprising the colors in the image of the region;   a second matrix multiplied by a second vector comprising the position in the test card of the region; and,   a third vector comprising an offset.   
     
     
         5 . The system of  claim 1 , wherein reference colors associated with the corner fiducial markers are identical. 
     
     
         6 . The system of  claim 1 , further comprising
 a plurality of color fiducial markers,
 wherein said plurality of color fiducial markers comprise said colors and wherein said plurality of color fiducial markers differ from said corner fiducial markers wherein said corner fiducial markers comprise said reference color and 
 wherein the colors of each of said plurality of color fiducial markers do not deviate beyond a threshold from a reference color standard measured under said reference lighting condition of each respective color fiducial marker of said plurality of color fiducial markers; 
 wherein the plurality of color fiducial markers comprises at least 3 color fiducial markers of at least 3 different reference colors. 
   
     
     
         7 . The system of  claim 6 , wherein the plurality of color fiducial markers comprises at least 9 color fiducial markers of at least 9 different reference colors. 
     
     
         8 . The system of  claim 6 , wherein the plurality of color fiducial markers comprises at least 12 color fiducial markers of at least 12 different reference colors. 
     
     
         9 . The system of  claim 6 , wherein
 the color adjustment comprises a function of the colors in the image of a region and of a position in the test card of the region;   the stored program is further configured to calculate the color adjustment as a linear regression with
 inputs comprising positions and the appearance in the image of the corner fiducial markers and of the plurality of color fiducial markers; and, 
 outputs comprising reference colors of the corner fiducial markers and of the plurality of color fiducial markers. 
   
     
     
         10 . The system of  claim 1 , wherein the stored program is further configured to analyze the image of the test card to determine whether the image includes excessive glare;
 when the image includes the excessive glare, generate an indication that the image is not usable.   
     
     
         11 . The system of  claim 10 , wherein analyze the image of the test card to determine whether the image includes the excessive glare comprises
 calculate a color value of an area of the image;   calculate a reference color value of the area of the image under the reference lighting condition;   determine whether a difference between the color value of the area and the reference color value of the area exceeds a threshold value.   
     
     
         12 . The system of  claim 10 , wherein the analyze the image of the test card to determine whether the image includes the excessive glare comprises
 calculate a first color value of a first area of the image;   calculate a second color value of a second area of the image proximal to the first area; wherein a first reference color value of the first area under the reference lighting condition is similar to a second reference color value of the second area under the reference lighting condition;   determine whether a difference between the first color value and the second color area exceeds a threshold value.   
     
     
         13 . The system of  claim 1 , wherein the stored program is further configured to
 analyze the image of the test card to determine whether the image includes shadows;   when the image includes the shadows, generate an indication that the image is not usable.   
     
     
         14 . The system of  claim 13 , wherein
 said analyze the image of the test card to determine whether the image includes the shadows comprises
 calculate color values of the corner fiducial markers; and, 
 determine whether differences among the color values of the corner fiducial markers exceed a threshold value. 
   
     
     
         15 . The system of  claim 14 , wherein the differences among the color values of the corner fiducial markers comprise a maximum color value of the corner fiducial markers minus a minimum color value of the corner fiducial markers. 
     
     
         16 . The system of  claim 1  further comprising:
 at least one time indicator configured to change appearance based on a duration of time that the at least one time indicator is exposed to the urine sample; and, 
 wherein said stored program is further configured to
 analyze the image of the test card to extract the appearance of the at least one time indicator in the image; 
 analyze the appearance of the at least one time indicator to determine an elapsed time between exposure of the test card to the urine sample and capture of the image; and, 
 for each test region, calculate the presence of or the quantity of the one or more substances in the urine sample further based on the elapsed time between the exposure of the test card to the urine sample and the capture of the image. 
 
 
     
     
         17 . The system of  claim 16 , wherein
 the at least one time indicator comprises two or more time indicators;   the stored program is further configured to
 apply the color adjustment to the appearance of the at least one time indicator in the image to generate the adjusted appearance of the at least one time indicator; 
 analyze the adjusted appearance of each time indicator of the two or more time indicators to determine the elapsed time associated with each time indicator between the exposure of each time indicator to the urine sample and the capture of the image; 
 when the elapsed time associated with each time indicator differs from the elapsed time associated with a different time indicator by more than a threshold amount, generate an indication that test results are not valid. 
   
     
     
         18 . The system of  claim 17 , wherein determine the elapsed time associated with each time indicator comprises
 compare the adjusted appearance of each time indicator to a time indicator calibration sequence comprising a reference appearance of a reference time indicator after the exposure of the reference time indicator to a reference urine sample for a sequence of known times.   
     
     
         19 . The system of  claim 16 , wherein each time indicator of the at least one time indicator comprises a lateral flow assay comprising non-human antibodies and not comprising human antibodies. 
     
     
         20 . The system of  claim 1 , wherein the stored program is further configured to
 obtain a calibration curve for each test region, wherein
 the calibration curve is captured under the reference lighting condition; 
 the calibration curve is captured by exposing the one or more reagents of each test region to different quantities of corresponding one or more substances for a period of time corresponding to or proximal to an elapsed time between exposure of the test card to the urine sample and capture of the image; 
 the calibration curve relates the appearance of each test region to the quantity of the corresponding one or more substances; and, 
   calculate the presence of or the quantity of the one or more substances in the urine sample based on a closest point on the calibration curve for each test region to the adjusted appearance of each test region.   
     
     
         21 . The system of  claim 1 , wherein the test card further comprises a code that identifies the plurality of test regions, wherein said code is a readable code. 
     
     
         22 . The system of  claim 21 , wherein the code further identifies a manufacturing batch of the test card. 
     
     
         23 . The system of  claim 1 , wherein
 said lateral flow assay regions comprise at least two lateral flow assays; and,   said colorimetric tests regions comprise at least two colorimetric tests.   
     
     
         24 . The system of  claim 1 , wherein the plurality of fiducial markers are located in specific positions and orientations on the test card, such that the plurality of fiducial markers are used to correct a geometry of the image based on said positions and the orientations on the test card. 
     
     
         25 . The system of  claim 1 , wherein said test card further comprises a cover and pads. 
     
     
         26 . The system of  claim 25 , wherein
 the colorimetric test regions are configured to be exposed directly to the urine sample;   the lateral flow assay regions are configured to receive the urine sample from said pads;   each pad of the pads comprise a portion that is exposed through the cover of the test card, and a remainder of the each pad routes the urine sample to a corresponding lateral flow assay region of the lateral flow assay regions.