THz Camera Time-Division Imaging for Concealed Article Detection
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Solution Overview
Problem
Terahertz wave cameras struggle to detect features of inspection targets like human bodies or clothes due to specular reflection, making it difficult to acquire information about concealed articles.
Innovation Solution
A camera system that radiates and detects terahertz waves at different timings to generate images from the difference between these signals, allowing simultaneous detection of concealed articles and features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If terahertz waves are used for inspection, then concealed articles can be detected, but features of contours and inspection targets cannot be acquired
Solution Approach 1:
The terahertz wave imaging is segmented into two distinct modes: a first image generated from signals acquired when the terahertz wave is radiated (detecting concealed articles), and a second image generated from signals acquired when the terahertz wave is not radiated (detecting contours and features). This segmentation allows each image to optimize for its specific detection purpose without interference from the other mode.
Solution Approach 2:
The system employs periodic action by alternately radiating and not radiating the terahertz wave in time-division manner. The radiation unit radiates the terahertz wave in periodic intervals, allowing the camera unit to acquire different types of signals at different time periods. This periodic switching enables the acquisition of both first signals (for concealed article detection) and second signals (for contour detection) using the same hardware configuration.
2Reliability
If terahertz waves with longer wavelengths are used, then specular reflection occurs without scattering, but scattering of terahertz waves on the subject surface is reduced
Solution Approach 1:
The system uses periodic action by switching between two operational states: radiating the terahertz wave to exploit specular reflection for concealed article detection, and not radiating the terahertz wave to capture scattered components for contour detection. This time-division multiplexing allows the same hardware to achieve both detection goals that would otherwise require different wave characteristics.
Solution Approach 2:
The invention extracts and separates the two types of information (concealed articles and surface features) by taking out the signals corresponding to each type at different time points. The first signal containing concealed article information is extracted during radiation periods, while the second signal containing surface feature information is extracted during non-radiation periods, allowing independent processing and optimization of each detection objective.
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 the detection of concealed articles while capturing the contours and features of inspection targets by selectively acquiring and processing terahertz wave signals.
Implementation Method 1
a radiation unit that radiates terahertz waves
Implementation Method 2
the terahertz waves are subject to specular reflection without being scattered on the surface of the subject
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A camera system (100) is capable of simultaneously acquiring a feature of a subject (150) while detecting a concealed article and includes a radiation unit (110) configured to radiate terahertz waves, a camera unit (120) configured to acquire a first signal at a timing at which the terahertz waves are radiated by the radiation unit (110) and acquire a second signal different from the first signal at a timing at which the terahertz waves are not radiated by the radiation unit (110), and a signal processing unit (160) configured to generate an image from the first and second signals acquired by the camera unit (110). The camera unit (120) or the signal processing unit (160) acquires a difference between the first and second signals. The signal processing unit (160) generates a first image from the difference between the first and second signals and generates a second image different from the first image from the second signal.