Physically Based Object Contour Edge Display Using Adjustable Linear Polarization Ratio for Passive Millimeter-Wave Security Imaging

Passive millimeter-wave (PMMW) imaging has been used for several close-range applications such as personal security checks, scene monitoring, and so on. PMMW images contain a variety of types of image edges which represent intensity discontinuities. As a special edge, an object contour edge is an important feature for object detection and recognition, which denotes the external shape of the object. In this article, a physically based contour edge display method using adjustable linear polarization ratio (ALPR) by multipolarization imaging is proposed. Polarization brightness temperature (TB) models of the object and radiometer observation are built. According to the physical principle of edge generation, the ALPR properties of the contour edge are investigated. By fusing multipolarization information, the simple feature parameter ALPR is sensitive to the object contour edge. Then, the specific operation process of the proposed method based on multipolarization images is presented. Simulations and measurements of polarimetric imaging for personal security inspection scenes were conducted to verify the contour edge display performance. Finally, the applicability of the method is discussed and summarized.