Single-Pixel Thermal Imaging for Low-Cost Material Defect Detection
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Solution Overview
Problem
Existing thermal imaging technologies are expensive due to the high cost of infrared cameras with high temperature measurement accuracy and resolution, and there is a lack of spatial light modulators that can operate in the far-infrared band, limiting the application of single-pixel imaging for thermal detection of material defects.
Innovation Solution
A method combining encoded structured light projection with radiation heating active thermal imaging using Bernoulli random matrices and an inverse discrete cosine matrix to reconstruct thermal images, employing a laser module, spatial light modulation, and a thermal infrared single-pixel detector to detect surface and internal defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an infrared camera with high temperature measurement accuracy and high resolution is used, then the detection precision is improved, but the cost increases
Solution Approach 1:
The patent divides the imaging function into two separate components: a low-cost single-pixel detector for temperature measurement and a spatial light modulator for encoding. This segmentation allows each component to be optimized independently, using affordable technologies while achieving high-resolution thermal imaging through computational reconstruction
Solution Approach 2:
The patent introduces a spatial light modulator as an intermediary component that encodes spatial information into the thermal radiation detected by the single-pixel detector. This intermediary enables the system to capture spatially-resolved thermal data without requiring a costly infrared camera array
2Ease of manufacture
If a single-pixel imaging architecture is used, then the cost is reduced, but the ability to perform active thermal imaging is lost
Solution Approach 1:
The patent makes the single-pixel detection system multi-functional by integrating it with a spatial light modulator and coded excitation source. This combination enables the system to perform both passive thermal observation and active thermal imaging, allowing the same low-cost architecture to serve multiple detection purposes
3Adaptability or versatility
If a far-infrared spatial light modulator is used, then thermal imaging capability is improved, but device complexity increases due to non-existence of such modulators
Solution Approach 1:
The patent uses a near-infrared spatial light modulator as a functional copy or substitute for the unavailable far-infrared version. By operating in the near-infrared band where成熟 technology exists, the system achieves spatial light modulation capability without requiring complex far-infrared modulator development
Solution Approach 2:
The patent changes the operating wavelength parameter from far-infrared to near-infrared, enabling the use of commercially available spatial light modulators. This parameter change maintains the essential functionality of spatial encoding while avoiding the complexity of developing far-infrared modulation technology
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
Achieves effective thermal imaging of material defects using a single pixel, reducing costs by integrating active radiation excitation with computational imaging, enabling detection of both surface and internal defects.
Implementation Method 1
a laser module, a spatial light modulation module, a projection lens module, an optical convergence coupling module, a thermal infrared single-pixel detector
Implementation Method 2
generating laser light in a near-infrared band; spatially encoding the laser light; projecting the spatially encoded laser light to a projection heating area on the surface of the object under detection, and heating the surface of the object under detection by using the spatially encoded laser light
Implementation Method 3
an optical convergence coupling module, a thermal infrared single-pixel detector; measuring a temperature field of the projected heating area on the surface of the object under detection
Data Source
AI summary
Provided are a method and apparatus for single-pixel thermal imaging detection of surface and internal defects of a material. The laser module is configured to generate uniform laser light. The spatial light modulation module is configured to spatially encode and modulate received uniform laser light. The projection lens module is configured to project and amplify an encoded light field, and project the encoded light field onto a surface of an object under detection. The optical convergence coupling module is configured to capture and image thermal radiation of the object under detection, and integrate and sum thermal radiation intensities of a projection heating area to obtain a thermal radiation temperature. The thermal infrared single-pixel detector is configured to measure the thermal radiation temperature. The image reconstruction module is configured to sparsely reconstruct data, and finally reconstruct a defect detection result of the projection heating area.