Millimeter-Wave ISAR Imaging for Personnel Safety Inspection
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Solution Overview
Problem
Millimeter wave imaging systems used in safety inspections suffer from low imaging speed and small field of view, limiting their effectiveness in personnel safety inspections.
Innovation Solution
A millimeter wave real-time imaging system utilizing a conveying device, a millimeter wave transceiver module, an antenna array, a switch array, and a quadrature demodulation and data acquisition module, which employs the inverse synthetic aperture radar (ISAR) imaging principle to generate and display three-dimensional images of moving targets, enhancing imaging speed and field of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-channel mechanical scanning system is used for millimeter wave imaging, then the structure is simple, but the scanning time is long
Solution Approach 1:
The patent divides the single scanning channel into multiple parallel scanning channels, each equipped with its own transmitter and receiver. This segmentation allows simultaneous scanning of multiple areas, dramatically reducing total scanning time while maintaining manageable complexity through modular architecture
Solution Approach 2:
The patent combines multiple scanning channels into a unified imaging system with centralized control and integrated signal processing. This merging approach enables parallel operation of multiple channels while consolidating control functions, achieving fast scanning without proportionally increasing system complexity
2Productivity
If an 8×8 array receiving mechanism is used to shorten scanning time, then the scanning speed improves, but the field of view becomes less than 50 cm
Solution Approach 1:
The patent transitions from a two-dimensional 8×8 array to a three-dimensional phased array configuration with multiple elements distributed in space. This dimensional expansion allows the system to achieve both fast scanning through parallel channels and large field of view through spatial diversity, overcoming the limitation of small coverage area
3Measurement precision
If the PMC-2 imaging system with 3 mm phased array antenna is used, then the imaging resolution improves, but the cost becomes relatively high
Solution Approach 1:
The patent changes the antenna element spacing and array configuration parameters to achieve effective imaging resolution without requiring the expensive 3 mm phased array. By optimizing the wavelength-to-element-spacing ratio and using appropriate signal processing, the system maintains good resolution at lower cost through larger element spacing and moderate frequency
4Volume of moving object
If focal plane imaging array or passive millimeter wave imaging system is used, then the system size is reduced, but the field of view becomes less than 50 cm
Solution Approach 1:
The patent employs dynamic beam steering through phased array technology, allowing the imaging system to electronically scan across a large field of view without physically moving the entire system. This dynamic capability enables a compact system design with small physical footprint while achieving large effective field of view through electronic scanning
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 real-time imaging with improved speed and a significantly enlarged field of view, reducing the need for back-and-forth movement of inspection devices and decreasing costs by using fewer signal transceiver modules.
Implementation Method 1
Millimeter wave imaging technology uses millimeter wave radar. The millimeter wave radar refers to a radar transmitting a signal with the frequency in the millimeter wave band
Implementation Method 2
a radar transmitting a signal with the frequency in the millimeter wave band, and the frequency of the millimeter wave is from 30 GHz to 300 GHz
Implementation Method 3
employs the inverse synthetic aperture radar (ISAR) imaging principle to generate and display three-dimensional images of moving targets
Implementation Method 4
a quadrature demodulation and data acquisition module, wherein an input end of the quadrature demodulation and data acquisition module is connected to the millimeter wave transceiver module
Data Source
AI summary
A millimeter-wave real-time imaging based safety inspection system and safety inspection method. The safety inspection system includes a conveying device (10), a millimeter wave transceiver module (11), an antenna array (17, 18), a switch array (16a, 16b), a switch control unit (15a, 15b), a quadrature demodulation and data acquisition module (12), and an image display unit (13). By using an Inverse Synthetic Aperture Radar (ISAR) imaging principle, the millimeter-wave real-time imaging based safety inspection system performs real-time imaging on an object to be inspected when the object moves, so that not only the imaging speed is improved, but also the field of view is enlarged. A safety inspector can determine whether an inspected person carries dangerous goods by observing a three-dimensional diagram of the inspected person, thereby eliminating the inconvenience caused by back-and-forth movement of a safety inspection device used by the safety inspector around the inspected person.