Passive millimeter-wave imaging system with variable focal length optical configuration


Ünal A.

Journal of Optics (India), vol.52, no.4, pp.1826-1836, 2023 (ESCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 52 Issue: 4
  • Publication Date: 2023
  • Doi Number: 10.1007/s12596-023-01198-7
  • Journal Name: Journal of Optics (India)
  • Journal Indexes: Emerging Sources Citation Index (ESCI), Scopus
  • Page Numbers: pp.1826-1836
  • Keywords: Concealed weapon detection, Optical design, Passive millimeter-wave imaging, Variable focal length
  • Middle East Technical University Affiliated: Yes

Abstract

Passive millimeter-wave (PMMW) imaging systems are widely used in concealed weapon detection due to their passive nature. Improving imaging resolution according to target distance is an essential technique in these systems, and it plays a vital role in detecting concealed weapons. Hence, a variable focal length optical configuration has been applied to a PMMW imaging system to enhance imaging resolution depending on the target distance. In this way, it is possible to set the system for variable target distances. The system parameters, aside from the effective focal length and the target distances, were kept constant throughout the tests. Experiments were carried out taking into account the detection of concealed weapons up to 45 m in indoor environments, and the results were presented. The experiments validate that it is possible to improve the resolution of PMMW images using the optical setup with a variable focal length. As a consequence, this research will contribute to the development of PMMW imaging systems against suicide bombers in the near future to detect concealed weapons at long target ranges.