Research about a method of enhancing SAR (Synthetic Aperture Radar) image spatial resolution-based on the theory of interleaved sampling CCD image reconstruction

摘要

SAR (Synthetic Aperture Radar) image has characteristics of all weather,all-day,intensive penetrability etc.,which can play an important role in many research fields.However,the recognition capability of spatial information is restricted because of large quantity noise in SAR image.Based on the theory of interleaved sampling CCD image reconstruction,we processed four multi-temporal ERS LR (Low Resolution)SAR images of same place to reduce noise and enhance resolution in this paper,and then acquired a HR(High Resolution) image.The method used indicates the spatial resolution can be enhanced by use of time frames.The process changing time resolution into spatial resolution comes true.The obtaining course of SPOT5 2.5m panchromatic band makes full use of the theory above.The paper applied the theory into the anaphase process of seasoned image,and didn't modify the imaging process.We acquire the HR image by man-induced resampling and reconstructing image.The detailed process includes 3 main parts: image preprocessing,interleaved sampling and interpolating,and resolution improving.In the image preprocessing part,the four multi-temporal LR SAR images are intercorrected to high-accuracy,and the histogram stretching of them is completed to reduce the contrast of DN;in the interleaved sampling and interpolating part,the average DN value of four images are imparted into the overlap region,which preserves the information of four images and can reduce noise partly;in the resolution improving part,many calculations are applied to the images which interpolated and reconstructed.We choose a better calculation to decrease fuzziness and reduce noises and enhance resolution.Compared to the original LR image,the HR image processed is clearer and some ground targets are identified easily in it where noises are smoothed.Then,the LR image,intermediate image,and HR image are fused with TM image and the fusion images are analyzed.Both the single HR images and the fusion images prove that the method is preferable and feasible.Besides the SAR images,it can be used in many other RS images,which makes RS images widespread availability.The way can be popularized and enhanced for further.