Research On Passive Millimeter-wave Penetration Characteristics And Image Processing Of Buried Metals

Millimeter wave can penetrate objects such as sand and soil to detect buried targets,especially metal targets,and millimeter wave passive detection system has the advantage of good concealment,small size,low power consumption,can work around the clock,so the application prospects are huge.Driven by high technology both millimeter-wave passive detection and passive imaging technologies are rapidly developing.At this stage,there is still a lot of research space for the implementation of covert detection of metallic targets and penetrating imaging,based on these issues,the research work in this paper is as follows:(1)The millimeter wave radiation model of planar and three-dimensional metal targets was established,and the relationship between the radiation temperature of planar metal plates and the detection angle was simulated,and the relevant conclusions were obtained by comparative analysis;a radiometer was used to image metal planar targets buried shallowly in sand and soil,and the resolution effect of millimeter wave imaging technology was explored.(2)Compared with the optical image,the resolution of millimeter wave image is not high because of its long wavelength,this paper adopts the classical filtering and image enhancement algorithm to filter the millimeter wave image for noise reduction and enhancement,and analyzes and compares it with the traditional edge detection operator.The features of the target region are analyzed,and the relative positions and sizes of the imaging results and the actual targets are compared and the causes of the errors are analyzed.(3)Aiming at the problem that the database of millimeter-wave dual-polarized radiation characteristics of typical feature targets is still not perfect,the field experiment is carried out using a dual-channel radiometer to obtain dual-polarized radiation characteristics to enrich the database of millimeter-wave radiation characteristics of features;the relationship between the thickness of tiles and sandy soil and the emissivity is analyzed.Radiometer ground detection penetration thickness is limited,while the air detection can be used to get a larger penetration thickness of the "cold air",the passive detection system can be buried in the ground to achieve covert detection.Theoretical and data support is provided for further practical ground-space application studies.