Optical Sensor Test Gas Detection Through Image Comparison
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Solution Overview
Problem
Existing methods for detecting test gas leaks in large test specimens are inefficient due to varying concentrations of test gas in air flows and require human intervention for image evaluation.
Innovation Solution
An automated method using an optical sensor to capture and compare digital images before and after disturbing a test gas cloud, evaluating signal amplitudes to detect leaks based on absorption spectrum differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a hand-held sniffer probe is used to detect test gas leaks, then the detection can be performed on large test specimens without a test chamber, but the test gas concentration in the drawn-in air flow varies and requires human intervention for evaluation
Solution Approach 1:
The patent replaces the manual mechanical sniffer probe operation with an automated optical imaging system. Instead of using a hand-held probe that requires human movement and evaluation, the system uses an infrared camera to automatically detect and image test gas leaks, eliminating the need for human intervention in the detection process.
Solution Approach 2:
The system enables self-service detection by capturing images that automatically display the spatial distribution and concentration of test gas. The infrared camera self-evaluates the leak locations and concentrations through image analysis, without requiring human operators to manually assess the gas presence.
2Extent of automation
If thermographic infrared camera is used to detect gas clouds, then the detection is automated, but the method requires subtracting individual pixel amplitudes of successive images which complicates the evaluation process
Solution Approach 1:
The patent applies preliminary action by introducing a gas shock before image capture to actively move the test gas cloud into a detectable position. This preparatory step ensures the gas is properly positioned for imaging, eliminating the need for complex post-processing subtraction methods and simplifying the evaluation process.
Solution Approach 2:
The system utilizes the infrared absorption characteristics of the test gas to create visual contrast in the captured images. The test gas appears as darkened areas in the infrared image due to its absorption spectrum, providing direct visual indication of leak locations without requiring complex image processing or pixel amplitude subtraction.
3Extent of automation
If optical radiation is received at two different points in time, then automated leak detection is enabled, but the method requires comparing signal amplitudes of image points which increases processing complexity
Solution Approach 1:
The patent extracts the essential leak detection information by focusing on specific image regions where leaks are suspected. Instead of comparing all image points, the system identifies and analyzes only the relevant areas containing test gas, simplifying the comparison process while maintaining automated detection capability.
Solution Approach 2:
The patent uses a gas shock as an intermediary element to facilitate the detection process. The gas shock actively moves the test gas cloud, making it easier to detect and compare between images. This intermediary action simplifies the image comparison by creating distinct, movable gas patterns that are easier to differentiate from background variations.
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
Enables automated leak detection independent of user and distance, improving efficiency and accuracy by analyzing image amplitude differences exceeding a threshold value.
Implementation Method 1
The sensor is configured to sense at least one wavelength of the optical absorption spectrum of the test gas
Implementation Method 2
The sensor can be designed by suitable optics that detect the at least one wavelength of the absorption spectrum, for example by using a suitable optical filter in the beam path between test specimen and sensor to block out wavelengths outside the absorption spectrum
Implementation Method 3
If the camera is now pointed at a corresponding gas cloud, the radiation components transmitted through the gas cloud appear darker in the range of the infrared absorption spectrum than the radiation reflected from the background
Data Source
AI summary
A method for detecting a test gas escaping from a leak in a test specimen that uses an optical sensor to measure optical radiation reflected or emitted from the test specimen or its background at different points in time and comparing the measured optical radiation at the different points in time to determine whether a leak exists.