| Contracted with Light, Infrared, Millimeter wave is not almost affected by bad weather environment, it can image all-weather, round-the-clock; Contracted with Microwave, the wavelengths of Millimeter wave is shorter, so the Millimeter wave imaging has a higher resolution, at the same time, Millimeter wave radiometer is passive system, which is no radiation damage to the human body. Based on these advantage, the Millimeter wave passive imaging technology has been widely applied in the fields of remote sensing, guidance, security check and pollution monitoring in recent years. The basis of Millimeter wave imaging technology is the difference of radiation characteristics between objects in Millimeter wave band, but the calculation of objects’radiation characteristics in Millimeter wave band is lack of relevant theoretical support in present stage, at the same time the database of the objects’electromagnetic characteristics is uncompleted in Millimeter wave band, therefore in this paper, we focused pn the building model of the objects’radiation characteristics in Millimeter wave band, and studied on the correlation between the radiation characteristics of the object with the thickness and moisture content of the object. At the same time, this paper also studied on the image processing technique related Millimeter wave radiometric image feature extraction, this paper mainly contains the following three parts:(1)Introduced the related domestic and abroad development status of Millimeter wave imaging and remote sensing application; introduced the objects’radiation characteristics in Millimeter wave band; introduced the composition and principle of Millimeter wave radiometer; deduced the relationship between radiation characteristics of the object and the complex dielectric constant based on the boundary conditions of electromagnetic field; deduced the calculation formula of radiation characteristics of multilayer media based on the coherent method and incoherent method.(2) Introduced the calibration method of radiometer, and through the experiment verified the calibration method; through the experiment verified the radiation characteristics of the sky; modelled and simulated the radiation characteristics of surface of the water and metal targets, and through the experiment verified the result; modelled and simulated the relationship between objects’radiation characteristics and objects’moisture content, and through the sand experiment verified the result; modelled and simulated the relationship between objects’radiation characteristics and objects’thickness and through the experiment of oil-film on water surface and the experiment of metal sheet coated sand verified the result.(3) Because of the long wavelength, the Millimeter image has low resolution, so we need to enhance the image of millimeter radio by image process technology. In this paper we had some try to image noise reduction, image segmentation, image edge extraction and image center position. We had proposed a way which combined the genetic algorithm and maximum between-cluster variance to analysis the image segmentation threshold. Through this way we can realize the segmentation of the image threshold very quickly; improved the image’s edge shape by morphology processing; extracted image edge information by arithmetic operators, and realization the location of the target’s center by the extraction method to the target center which designed by own.In this paper we firstly deduced the relationship between radiation characteristics of the material and the complex dielectric constant,deduced the calculation formula of radiation characteristics of multilayer media based on the coherent method and incoherent method; then through the simulation and experiment verified the correlation between the objects’ radiation characteristics with the objects’ thickness and water content, The obtained results provide a certain reference for Millimeter wave imaging and Millimeter wave radiation remote sensing, and have a certain scientific significance; Finally put forward the related image processing algorithms, and provided a method for Millimeter wave radiation image feature extraction. |
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