Research On IR-UWM Confocal Imaging Based On FDTD

IR-UWB imaging technique refers to a nanosecond narrow pulse signal as a carrierfor the unknown target detection and image reconstruction. IR-UWB is one of the mostwidely used as a detecting signal for its advantages such as penetrating ability, highresolution, low energy of the electromagnetic radiation signal, target recognitioncapability, carrying a large quantity of information, resolving multipath capability,making it have a unique advantage for through the wall detection, medical imaging andother fields. The imaging algorithm is a key fundation of IR-UWB imaging systemtheory. Imaging system performance is closely dependent on the imaging algorithms. Inpractical applications, people constantly improve present IR-UWB imaging algorithmsto meet the different performance requirements of imaging system.In this paper, The traditional frequency-domain imaging algorithms have someweaknesses, such as large computational load, high algorithm complexity, unclearperformance indicators. Taking the confocal imaging as the cut-in point, based on finitedifference time domain, taking full advantage of IR-UWB signal with high resolution inthe time domain, some potential applications of IR-UWB detection and imaging aremade explorations and excavations. The IR-UWB confocal imaging system frameworkis builded, and a kind of improved confocal imaging algorithm is expounded, which isto meet requirements of many different applications. The following research work isdone:Firstly, The basic theory of finite difference time domain method and its role ofimaging system are presented. Taking the interaction of IR-UWB signal and a givenmedium target as the background, the simulation of IR-UWB signal propagation intwo-dimensional space is made and used as a method to generate excitation signal of theconfocal imaging algorithm. Then, Research on IR-UWB point targets imaging basedon the real aperture antenna array is carried out. According to the scattering centermodel theory, detection manner and imaging algorithm in the IR-UWB imaging systemare explored in detail. Ideal point targets are taken as objects of interest, IR-UWB signaland the real aperture antenna array are used as the detection manner, the confocalimaging is choose as the imaging method, imaging results of two-dimensional pointtargets in free space are realized. Based on FDTD, the simulation results are given, andthe main performance evaluation indicators of IR-UWB imaging system are analyzed.Finally, Research on IR-UWB targets outline image based on the synthetic apertureantenna array is carried out. The deficiencies of the conventional confocal imagingalgorithm for the target outline image are analyzed, and then the target surface detectionalgorithm is presented, combining with the synthetic antenna array to make themechanism research on outline image. Compared with the traditional confocal imaging in outline creation, the performance of the target surface detection algorithm is verifiedvia FDTD, the simulation results show that the improved algorithm is more feasible andpredominant in identification of the target boundary.