Sub-Image Extraction Based On SAR Image And 3D Reconstruction Of Buildings

Nowadays,as the improvement of information technology,more and more new Synthetic Aperture Radar(SAR)systems spring up,such as Terra SARX.The latest SAR technology can achieve meter or sub-meter resolution.So there emerged a lot of high revolution SAR images,human can get the geometrical parameters of scattering characteristics from SAR images,which makes detecting building targets or reconstructing building targets based on a single SAR image come true.In the processing of large scene SAR images,the first step is to split them into tiles in order to reduce the load of computer's computation effort and memory,which is crucial in the follow-up procedures of building radar footprints detection or reconstruction.Compared to the traditional cockamamie gridding method,we propose an automatic sub-images extraction approach based on the density and distance-based(DD)clustering algorithm and the connected-component labeling(CCL)algorithm of the graph theory which can avoid a mass of unnecessary least error finding works.According to our method,the original image can be split without introducing excessive subjective operations,which can remain the primary information of buildings' images efficiently.Meanwhile,automatic area searching reduces manpower effectively.In the area of three-dimensional reconstruction of buildings based on SAR images,the robustness of reconstruction based on one SAR image is unsatisfactory.On the one hand,because of speckle noise,many false alarms are identified as targets.On the other hand,in the scattering characteristics of building targets,there are minor differences between shadow pixels and background pixels.So that the manual pretreatment is necessary for subsequent processing,which greatly reduces the efficiency of radar image processing.In order to solve these problems,according to the characteristics of scattering features and speckle noise in the SAR image,some new algorithms of image feature extracting are used to get the preliminary information of scattering feature.With those information,the simulated annealing genetic algorithm is used to obtain parameters accurately.Finally,based on the geometric relations between the building and its scattering feature,the 3D reconstruction of buildings is completed.In this paper,all parts are interdependent.From the preprocessing of radar images to the acquisition of geometric parameters of scattering features,this paper introduces the 3D reconstruction of buildings in detail.The segmentation of SAR images is based on clustering algorithm,its robustness can be improved according to self-adaption.The scattering features of SAR images are extracted by the thought of primitive,the universality of this algorithm can be improved by extending more primitives.