Terahertz Imaging System with Cryogenic Receiver and Confocal Optics
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Solution Overview
Problem
Existing terahertz imaging systems face challenges in generating high-quality images in urban environments due to noise and the need to cope with high through-flows of objects, such as people and vehicles.
Innovation Solution
The development of a terrestrial terahertz imaging system that includes an imaging assembly and a receiver assembly, utilizing reflective optical components in a confocal configuration to image at finite conjugates, and employing a cryostat with re-imaging optics and a detector to generate high-quality images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing terahertz imaging systems are used in urban environments, then security scanning capability is provided, but image quality deteriorates due to noise and background interference
Solution Approach 1:
The system divides the imaging process into two distinct stages: a calibration stage where a thermal source is imaged to capture background noise characteristics, and an actual imaging stage where the target is captured. This segmentation allows the system to separate and subsequently remove background interference from the final image, improving image quality in noisy urban environments while maintaining security scanning capability
Solution Approach 2:
The system performs a preliminary calibration imaging action before the actual security scanning. During this preliminary stage, the thermal source is imaged to establish baseline noise and background characteristics. This preliminary action enables the system to pre-characterize environmental interference, which is then used to enhance the quality of subsequent security scanning images by removing identified noise patterns
2Productivity
If existing terahertz imaging systems operate in high through-flow environments, then coverage of moving objects is achieved, but image quality deteriorates due to motion and environmental challenges
Solution Approach 1:
The system segments the imaging operation into rapid sequential frames that capture moving objects at different positions in the through-flow. By processing each frame individually with noise removal and then combining them, the system maintains the ability to handle high throughput while improving the quality of images of moving objects through subsequent noise elimination
Solution Approach 2:
The system maintains continuous imaging operation to handle high through-flows of objects without interruption. The calibration and imaging processes operate in rapid succession, ensuring continuous coverage of moving objects while the noise removal processing continues seamlessly, maintaining both productivity and image quality
3Measurement precision
If terahertz detectors are made highly sensitive to detect weak signals, then detection capability is improved, but the system becomes more susceptible to noise and local interference
Solution Approach 1:
The system converts the harmful effect of noise into a beneficial calibration reference. By intentionally imaging a thermal source that produces known noise and background signals, the system creates a noise profile that can be subtracted from subsequent images. This transforms the previously harmful noise into a useful reference for enhancing detection capability while reducing noise susceptibility
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
The system achieves improved image quality and spatial resolution, capable of handling high through-flows of objects, while reducing noise and background interference, making it suitable for security scanning applications in urban environments.
Implementation Method 1
The imaging assembly comprises reflective optical components arranged in a confocal configuration that is arranged to image at finite conjugates
Implementation Method 2
The receiver assembly comprises a cryostat that maintains a detector within the receiver assembly at temperatures below freezing point
Data Source
AI summary
Certain examples relate to a terrestrial terahertz imaging system. In one example, the terrestrial terahertz imaging system has an imaging assembly to form a first image of at least a portion of an object using electromagnetic radiation in a terahertz band of frequencies and a receiver assembly comprising a cryostat. The cryostat contains a detector and reflective cold re-imaging optical components to receive the electromagnetic radiation from the imaging assembly. The reflective cold re-imaging optical components form a second image of at least a portion of the object on the detector. The imaging assembly has reflective optical components arranged in a confocal configuration that is arranged to image at finite conjugates. The reflective cold re-imaging optical components implement a reflective, confocal optical relay. Other examples relate to body and vehicle scanning devices that may be used in security applications.