Camera Test Strip Analysis With Tone Map Correction
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Solution Overview
Problem
The use of mobile devices to determine analyte concentrations in bodily fluids using optical test strips is challenging due to variations in brightness and device-specific image processing, which complicates accurate determination of color changes on the test strips.
Innovation Solution
A method utilizing a mobile device with a camera to capture images of a color reference card and a reagent test field, applying pixel-based mean tone map and local tone map corrections to account for local brightness variations, enabling accurate determination of analyte concentration through color formation reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mobile devices with cameras are used to capture images of test strips, then ease of operation and accessibility are improved, but measurement precision deteriorates due to variations in brightness and device-specific image processing
Solution Approach 1:
The patent applies tone map corrections to transform image parameters, specifically correcting brightness and color values to account for local illumination variations and device-specific processing characteristics. This involves adjusting the parametric description of the image data to normalize measurements across different mobile devices and lighting conditions
Solution Approach 2:
The patent introduces a color reference card with known color values as an intermediary standard. This reference card serves as a mediator between the variable mobile device camera and the test strip, providing a stable reference for calibration and correction of device-specific image processing variations
2Measurement precision
If tone map corrections are applied to account for local brightness variations, then measurement precision is improved, but device complexity increases due to additional image processing steps
Solution Approach 1:
The system performs self-calibration by automatically capturing images of the color reference card and using those images to determine correction parameters. The mobile device itself generates the calibration data needed to correct its own image processing variations, eliminating the need for external calibration equipment or complex manual setup
Solution Approach 2:
The patent applies preliminary tone map corrections to the captured image before performing the actual analyte concentration measurement. By pre-correcting for local brightness variations and device-specific characteristics, the system simplifies subsequent measurement steps while improving overall precision
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides user-friendly, high-accuracy, and reliable analyte concentration measurements in bodily fluids, accounting for local illumination and device-specific factors.
Implementation Method 1
determining the concentration of an analyte in a sample of a bodily fluid... based on a color formation reaction of the test field
Data Source
AI summary
A method of determining the concentration of an analyte in a sample of a body fluid with a mobile device having a camera is disclosed. The camera captures an image of a color reference card and of a reagent test field of an optical test strip having a sample applied to it. A predetermined pixel-based mean tone map correction is applied to the image obtained, which results in a first intensity-corrected image. Local brightness information is derived from the first intensity-corrected image. A mobile device-specific tone map correction is applied to the first intensity-corrected image, taking into account the local brightness information. A second intensity-corrected image is thereby obtained. Analyte concentration is determined based on a color formation reaction of the test field by using the second intensity-corrected image. Optionally, a color correction may be derived and applied to the second intensity-corrected image to obtain an intensity-corrected and color-corrected image.