Research On Millimeter Wave Radiation Characteristics And Imaging Of Shallow Buried Metal Targets

The millimeter wave(MMW)can penetrate and millimeter wave radiometer can work all-weather and all-day.The passive millimeter wave(PMMW)detection system has good performance for the detection of metal targets,which makes it attract much attention.Just as radar technology can be used in many fields to detect through common concealment,PMMW technology has certain application potential in the detection and imaging of concealed targets.There is still much room for the research of radiation characteristics of metal targets and PMMW imaging.Focusing on the radiation characteristics and the application scenarios of shallow-buried metal detection and imaging,the main research is as follows:(1)With the passive radiation characteristics and antenna temperature contrast theory of metal target analyzed,we simulated and measured the related sky brightness temperature.The experiment with metal plane of different sizes and the analysis of the data is also performed.Furthermore,considering that the target is static and imaging with sufficient integration time is important for the stage,the point-by-point sampling method is used for the imaging of the bare and shallow-buried metal under the sand.(2)For the PMMW image of the shallow-buried metal target,different enhancement methods and related improved algorithms are practised.Considering both the subjective and objective fidelity,the effects and characteristics of different methods are analyzed.For the blurring characteristics of image,taking the related improved algorithms as a reference,we practised the fuzzy enhancement method to explore its effect on our PMMW image.(3)The target segmentation and feature analysis of the MMW image are carried out,also improvement and adaptive solutions are attempted.For images with multiple single connected objects,considering the unsatisfactory performance of threshold method and the need of single target in research,the region growing method is first used to extract single objects preliminarily and then pertinent treatment and error estimation are performed.This paper explores the effect of different edge extraction operators,contour feature is analyzed to study the target radiation and imaging characteristics.For the interested single object,its center and geometric parameters are calculated which lays a foundation for further research.The related experimental attempts and data,solutions for improvement and existing problems lay the foundation for further research.