Alternating Filter Infrared Sensor Array for Gas Detection
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Solution Overview
Problem
Current thermal imaging techniques for gas detection face challenges in accurately capturing and quantifying gases due to background radiation interference, alignment issues, and high complexity, cost, and power consumption, particularly in filter-based approaches.
Innovation Solution
Implementing a single focal plane array with alternating sets of filters for adjacent infrared sensors, allowing simultaneous capture of spatially and time-aligned images filtered for gas and background radiation, enabling accurate gas detection with reduced noise and improved contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a beam splitter is used to pass thermal radiation to separate sensor arrays for filtering, then independent filtering and calibration of sensor arrays is enabled, but precise alignment (optical, mechanical, and temporal) is required which increases system complexity, cost, and size
Solution Approach 1:
The patent merges the filtering function directly into the sensor array by placing filters in registration with the infrared sensors, eliminating the need for a beam splitter. This integration allows different sensors to be filtered differently while capturing images simultaneously without requiring complex optical alignment between separate arrays.
Solution Approach 2:
The patent introduces a filter array as an intermediary component positioned between the lens and the sensor array. This filter array serves as a mediator that distributes different filtered views to different sensors, enabling independent filtering without requiring separate sensor arrays and their associated complex alignment.
2Device complexity
If separate detector arrays receive thermal radiation independently without a beam splitter, then some complexity is reduced, but the captured images exhibit parallax which reduces detection accuracy
Solution Approach 1:
The patent combines multiple filtered views into a single sensor array rather than using separate arrays. By placing different filters in registration with different sensors within the same array, all sensors capture images from the same viewpoint simultaneously, eliminating parallax while maintaining structural simplicity.
3Object-affected harmful factors
If image subtraction is used to detect gas presence, then background radiation can be removed, but a disproportionally large portion of the gas signal is also removed which prevents quantification
Solution Approach 1:
The patent segments the thermal radiation spectrum by using multiple filters with different transmission characteristics. Instead of removing background through subtraction, each filter captures a different spectral portion, allowing the gas signal to be preserved in at least one filtered image while background is suppressed, enabling accurate quantification.
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 enables reliable and accurate gas detection with high confidence by eliminating parallax and allowing same-integration-period calibration, resulting in high-quality images for precise quantification and visualization.
Implementation Method 1
Different infrared sensors (e.g., detectors) of a single focal plane array (FPA) may be separately filtered by at least two types of filters that are interleaved with each other and distributed over the entirety of the FPA's infrared sensors
Implementation Method 2
specific gases may emit and/or absorb thermal radiation in characteristic ways at particular wavelengths
Implementation Method 3
When a scene is thermally imaged in accordance with such techniques
Implementation Method 4
specific gases may emit and/or absorb thermal radiation in characteristic ways at particular wavelengths
Data Source
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AI summary
Improved techniques for thermal imaging and gas detection are provided. In one example, a system (100) includes a first set of filters (131) configured to pass first filtered infrared radiation comprising a first range of thermal wavelengths associated with a background portion of a scene (170). The system (100) also includes a second set of filters (131) configured to pass second filtered infrared radiation comprising a second range of thermal wavelengths associated with a gas present in the scene. The first and second ranges are independent of each other. The system (100) also includes a sensor array (130) comprising adjacent infrared sensors configured to separately receive the first and second filtered infrared radiation to capture first and second thermal images respectively corresponding to the background portion and the gas. Additional systems and methods are also provided.