Critical Area Identification of Sea Target Using Passive Millimeter-Wave Imaging

Passive millimeter-wave (PMMW) imaging has effective maritime monitoring capabilities under adverse weather conditions. The existing research mainly focuses on the detection of the whole target. However, when the detector is close to the target, we need to identify the critical areas of the target. There is no work to address this problem. In this paper, we propose a physical-based identification method that identifies critical areas of ships. The method first adjusts the brightness temperature threshold to differentiate between the sea surface and the ship's body and enhances the continuity of target areas through morphological operations after analyzing the brightness temperature distribution at close range. Subsequently, critical areas are calibrated by identifying the active jamming area and the area of the ship's fuel tanks are located. Edge detection techniques are further employed to optimize the recognition of these critical areas, ensuring accurate focus on critical areas of ships. Through simulation and experimental verifications, our study ensures the accuracy of critical area identification in complex marine environments and provides adequate methodological support for developing ship automatic identification and tracking systems. The application of this method strengthens monitoring capabilities under adverse visual conditions and demonstrates the potential of PMMW imaging technology in maritime security domains.