Test Strip Imaging for Ambient-Light-Compensated Analyte Detection
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Solution Overview
Problem
The reliability and accuracy of analytical measurements using mobile devices are compromised by ambient light, which affects the evaluation of color changes on test strips, leading to inconsistent results in detecting analytes in bodily fluids.
Innovation Solution
A detection method involving a mobile device with a camera and illumination source, capturing images with and without ambient light, and using camera-specific transmission functions to determine analyte concentration by comparing light intensities before and after sample application, thereby accounting for ambient light interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If ambient light is present during measurement, then the measurement process can be performed in normal lighting conditions, but the reliability and accuracy of analyte detection deteriorates due to interference with color change evaluation
Solution Approach 1:
The measurement process is segmented into multiple phases: pre-illumination baseline capture, illumination phase capture, and post-illumination capture. By dividing the measurement into distinct temporal segments with different illumination states, the system can separate ambient light effects from analyte-specific color changes, enabling reliable detection in normal lighting conditions.
Solution Approach 2:
The system changes the illumination parameter by switching the illumination source on and off during the measurement sequence. This parameter change creates distinguishable signal states that allow the evaluation unit to calculate differential values representing ambient light contribution, which are then subtracted from the analyte detection signal to improve reliability.
2Device complexity
If ambient light is present during measurement, then no additional illumination control is needed, but the accuracy of color change evaluation deteriorates leading to inconsistent results
Solution Approach 1:
The system performs preliminary actions by capturing a baseline image of the test strip in ambient light before applying the sample, and capturing additional images during illumination. These preliminary measurements establish reference values that are used to compensate for ambient light effects during the actual analyte detection, improving measurement precision without significantly increasing user burden.
Solution Approach 2:
The evaluation unit uses feedback from multiple image captures (pre-illumination, illumination, and post-illumination) to calculate ambient light contribution and subtract it from the final measurement. This feedback mechanism continuously refines the analyte detection accuracy by using actual measured ambient light conditions rather than assuming constant lighting.
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 method enhances the reliability and accuracy of analyte detection by minimizing the impact of ambient light, providing robust and user-friendly results in varying imaging conditions.
Implementation Method 1
the test field comprising at least one test chemical for performing an optical detection reaction in the presence of the analyte
Implementation Method 2
providing at least one mobile device having at least one camera and at least one illumination source
Implementation Method 3
capturing a plurality of images of at least one region of the test strip
Data Source
AI summary
A method for detecting an analyte in a sample is disclosed. The method includes providing a mobile device having a camera and an illumination source. A test strip having a test field with at least one test chemical for performing an optical detection reaction in the presence of the analyte is provided. The sample is applied to the test field. Several images of a region of the test strip are captured. The region includes at least part of the test field to which sample is applied. The images are captured before and after the sample is applied and with the illumination source turned on and off. The images captured are compared and differences in light intensities are determined. Analyte concentration is determined using the images captured and the determined light intensities.