Optical Sensor Drift Compensation via Dual-Time Concentration Measurement
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Solution Overview
Problem
Existing sensor technologies face challenges in accurately determining component concentrations in fluids due to drift errors over time, which are not effectively compensated for by current calibration methods.
Innovation Solution
A method and optical sensor arrangement that measure light intensities at two different points in time using two optical sensors with distinct concentration functions, providing correlation information to derive accurate component concentrations, thereby compensating for drift without the need for maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standard calibration methods (ABC method, dual sources, dual detectors) are used to compensate for drift errors, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The sensor performs self-calibration by utilizing its own measurements at different operating points. The control unit automatically determines calibration parameters by measuring light intensities at two different concentrations of the target component, eliminating the need for external calibration equipment or complex hardware modifications.
Solution Approach 2:
The method changes the operating parameters of the sensor by measuring at two different concentrations of the target component. By varying the concentration parameter and measuring the corresponding light intensities, the system derives calibration parameters that compensate for drift errors without requiring additional hardware.
2Reliability
If dual detectors with reference wavelengths or different path lengths are used, then drift compensation is improved, but manufacturing complexity increases
Solution Approach 1:
A single detector is used to perform multiple functions: measuring light intensity at different concentrations and deriving calibration parameters. The same detector that measures the target component concentration also performs the calibration function, eliminating the need for separate reference detectors or additional measurement paths.
Solution Approach 2:
The calibration function is extracted from complex hardware configurations (dual detectors, reference wavelengths) and implemented through a software-based method that uses the existing sensor's measurements at different operating points to determine calibration parameters.
3Measurement precision
If frequent calibration is performed to maintain accuracy, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The sensor performs preliminary calibration by automatically determining calibration parameters during normal operation when it encounters two different concentrations of the target component. This preliminary calibration action prepares the sensor for accurate measurements without requiring separate calibration sessions, reducing time loss.
Solution Approach 2:
The calibration process is integrated into the continuous measurement operation. The sensor continuously measures light intensities and can determine calibration parameters whenever it encounters appropriate concentration variations, maintaining continuous useful action without interrupting the measurement process for separate calibration.
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 allows for accurate compensation of drift errors by measuring at different concentrations and times, ensuring reliable measurements even as gas concentrations vary, reducing sensitivity to sensor noise and improving long-term accuracy.
Implementation Method 1
providing from a first optical sensor, configured to measure an intensity of light which has interacted with the fluid, a first light intensity
Data Source
AI summary
A method and a device for determining a concentration of a component in a fluid is described. The method comprises the steps of providing from a first optical sensor (1) a first light intensity (IR1A) for light which has interacted with the fluid at a first point in time (A), and a second light intensity (IR1B) for light which has interacted with the fluid at a second point in time (B), wherein the first light intensity (IR1A) is different from the second light intensity (IR1B), and providing from a second optical sensor (2) a third light intensity (IR2A) for light which has interacted with the fluid at the first point in time (A), and a fourth light intensity (IR2B) for light which has interacted with the fluid at the second point in time (B). The method also comprises determining the concentration of the component in the fluid, measured by the first optical sensor (1), at the first point in time (A) and/or at the second point in time (B), based on the first light intensity (IR1A), the second light intensity (IR1B), the third light intensity (IR2A), the fourth light intensity (IR2B), a first concentration function (func1), a second concentration function (func2), and correlation information (Corr).