Multi-band passive detection and imaging system for concealed weapon with dual assessment method

Abstract

Technological advancements in the millimeter-wave (MMW) and terahertz (THz) frequency bands have seen rapid progress, especially in the field of concealed weapon detection. The capability to detect concealed objects under clothing without causing harm to individuals is of utmost importance. Because of this reason, the concept of the variable target ranges in a passive MMW/THz imaging system with the infrared band has been studied in detail. An imaging system, called multi-band passive detection and imaging system (MIS) in this study, with variable target ranges, was designed and tested. A passive MMW/THz imaging system is developed specifically for concealed weapon detection, with a primary focus on variable target ranges. In addition to this, an infrared imaging system has been incorporated into the concept of concealed weapon detection. To integrate these two imaging systems, image fusion techniques have been employed as a conjunction between them. Detailed analyses have been conducted to assess the concealed weapon detection capabilities of this integrated system. The image fusion results, combining infrared and passive MMW/THz bands, have been tested at variable target ranges, and the fused images have been compared in terms of structural similarity index (SSIM) and contrast levels (CL). The SSIM alone is an inadequate method in the concept of concealed weapon detection. The CL method, used with SSIM, eliminates the shortcoming of the SSIM alone. The outcomes of these tests demonstrate that MIS enhances the detectability of concealed weapons with the use of SSIM and CL together. As a result, this study lays a solid foundation for the future detection of concealed objects beneath clothing. The dual assessment method proposed in this study will enable the development of new methods that will increase the detection of specific objects under the clothes in the future.