Quantifying color changes in chemical test pads induced by different concentrations of analytes under different lighting conditions

Inventors

Burg, Bernard • Zizi, Martin • Rowe, Aaron Alexander • Smart, Anthony • De Brouwer, Walter

Assignees

HealthyIo Ltd

Abstract

Color quantification of chemical test pads and titration of analytes can be performed under different lighting conditions. In one embodiment, the lighting condition is estimated under which a digital image is captured and utilized to select a set of reference colors from which the quantified color is compared to determine the titration. In another embodiment, a plurality of comparisons are made with different lighting conditions with the result having the highest confidence level being selected to determine the titration.

Core Innovation

The disclosed invention quantifies color change of at least one test medium on a diagnostic instrument by obtaining a digital image of at least a portion of the diagnostic instrument exposed to a biological sample. The diagnostic instrument includes at least one color reference comprising a plurality of reference samples of different colors, and at least one test medium containing a reagent that changes color in response to a concentration of a particular analyte. Reference samples and test media are identified in the digital image, and dominant camera-captured colors of the reference sample and the test medium are determined.

Lighting conditions under which the digital image is obtained are estimated, and the dominant camera-captured color of the at least one test medium is corrected in response to a color correction factor derived at least in part from the dominant camera-captured color of the reference sample. The correction yields a corrected test medium color, and a test result including an analyte concentration of the biological sample is determined based on the corrected test medium color.

The approach further grounds correction and quantification in calibration and modeled color trajectories, including mapping captured colors into a MICC/ACC color space and determining confidence/titration based on distance to polynomial or interpolated color trajectories. Measurements are accepted or rejected based on distance relative to modeled confidence tubes or confidence ribbons, with reject criteria based on predetermined values. Instrument condition and identity may be validated using a security table for unused instruments, and images may be rejected if expected color change exceeds maximum allowable.

Claims Coverage

The document provides two independent claims. Each independent claim shares a common inventive sequence: capture a digital image of a diagnostic instrument, determine dominant camera-captured colors from reference samples and test media, estimate lighting conditions, correct test-medium color using a color correction factor derived from the reference sample color, and determine a test result including analyte concentration from the corrected test-medium color.

Across both independent claims, the core coverage centers on obtaining a digital image of a diagnostic instrument, extracting dominant camera-captured colors for both reference samples and test media, estimating lighting conditions, applying a reference-derived color correction factor to obtain a corrected test medium color, and then determining an analyte-concentration-based test result from the corrected color.

Stated Advantages

Documented Applications