Multi-spectral OGI Camera Gas Quantification
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Solution Overview
Problem
Current infrared optical gas imaging (IR OGI) systems face challenges in accurately quantifying gas concentration-length and differentiating between target gases and contaminants, leading to potential false alarms and inefficient gas leak detection.
Innovation Solution
A multi-spectral IR OGI camera configuration with a reference band outside the absorption window of the target gas and an active band within it, combined with a processing unit that estimates background radiance using a calibration model, allows for precise gas concentration-length quantification and differentiation between target and contaminant gases by analyzing radiance ratios and triggering alerts when thresholds are exceeded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional single-band IR OGI cameras are used for gas leak detection, then the system is simple and cost-effective, but the accuracy of gas concentration-length quantification is insufficient and false alarms occur due to inability to differentiate target gases from contaminants
Solution Approach 1:
The infrared spectrum is segmented into multiple spectral bands (active bands within absorption windows and reference bands outside absorption windows). The multi-spectral OGI camera divides the detection task across these segmented bands, with active bands capturing gas absorption signals and reference bands providing background radiance information, thereby improving quantification accuracy while managing system complexity through functional division
Solution Approach 2:
The system transitions from single-band detection to multi-spectral detection by adding the spectral dimension. Instead of relying on a single radiance measurement, the camera captures radiance across multiple wavelength bands, creating a spectral fingerprint that enables both accurate quantification and differentiation of gases, effectively moving the problem from one-dimensional to multi-dimensional space
2Reliability
If multi-spectral OGI camera with multiple bands is used, then gas quantification accuracy and differentiation capability are improved, but the device complexity and calibration requirements increase
Solution Approach 1:
Reference bands act as intermediaries that provide background radiance information without being affected by gas absorption. These reference bands mediate between the active detection bands and the environment, enabling the system to separate target gas signals from background interference and contaminant gases, thereby improving reliability while managing complexity through the intermediary reference measurements
Solution Approach 2:
The system changes the detection parameter from single radiance value to multi-spectral radiance ratios. By measuring radiance across multiple bands and computing ratios between active and reference bands, the system transforms the detection approach to be more robust against environmental variations and instrument drift, improving reliability while the ratio-based processing helps manage analytical complexity
3Measurement precision
If background radiance is not accurately estimated, then the gas concentration-length calculation becomes inaccurate, but developing complex calibration models increases system complexity
Solution Approach 1:
The calibration model is developed and stored in advance during the preliminary setup phase. The model establishes the relationship between reference band radiance and background radiance in active bands before actual gas detection begins. This preliminary action allows the system to use pre-computed calibration data during operation, improving background estimation accuracy while avoiding the need for complex real-time calculations during detection
Solution Approach 2:
The reference bands create a copy or proxy measurement of the background radiance that would otherwise be present in the active bands. Instead of directly measuring background radiance in the presence of gas absorption, the system uses reference bands to create an indirect copy of the background signal, which is then used to estimate and subtract the background component from active band measurements, improving accuracy while simplifying the measurement approach
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 enhances the accuracy of gas concentration-length quantification, reduces false alarms, and improves the reliability of gas leak detection by effectively differentiating between target and contaminant gases, enabling more precise monitoring and alert triggering.
Implementation Method 1
A multi-spectral configuration of the multi-spectral OGI camera may include a reference band that is outside an absorption window of a target gas and an active band that includes at least a portion of the absorption window of the target gas
Implementation Method 2
acquiring a multi-spectral image of detected radiance comprising a plurality of pixels using a multi-spectral optical gas imaging (OGI) camera
Data Source
AI summary
A gas concentration-length quantification method may include: acquiring a multi-spectral image of detected radiance including a plurality of pixels using a multi-spectral optical gas imaging camera; estimating a background radiance for at least one of the pixels; calculating a gas concentration-length for the at least one of the pixels based on the detected radiance and the estimated background radiance; and triggering an alert when each alert condition in a list of alert conditions is satisfied. A multi-spectral configuration of the camera may include a reference band that is outside an absorption window of a target gas and an active band that includes at least a portion of the absorption window. Estimating the background radiance may include determining a model relating a detected radiance of the active band to a detected radiance of the reference band and using the model to estimate the background radiance for the active band.