The Algorithm Of Image And Seismic Signals Interpolation Based On The Nonsampled Contourlet Transform

The nonsampled contourlet transform(NSCT) as a kind of complete shift invariance form of the contourlet transform.This method is based on the iterative nonsampled filter banks,which is more sparse to obtain a directional multiscales image.Low-resolution images often have the phenomenons of vague,unclear details and so on,which bring a lot of inconvenience in the application of image field.In contrast, high-resolution image has the important theoretical significance and application value because of the more broad application prospect.At the same time,the lack of seismic data can lead to the prediction error of multiple wave,affecting the fidelity of seismic data,causing distress for post-processing of seismic data,so interpolation in image and seismic data both have an important significance.Firstly,this thesis analyse the research significance as well as the present situation both at home and abroad in image interpolation and seismic data interpolation.and gives the theory analysis and simulation experiment of the nonsampled contourlet transform.at the same time,this thesis gives the evaluation standard for image quality.Then,in this thesis,an advanced bilinear interpolation method is improved based on the traditional bilinear arithmetic, aiming at the’block effect’and the image degradation phenomnon of the traditional image interpolation algorithm. At first,the interpolation method compute six directions of horizontal,vertical,45°and135°with inverse distance square approaches in the neighborhood of the interpolation point.and then multipled by the weight of the interpolation points to the direction of the interpolation distance.in order to certain this weight,we consider the six direction of gray gradient at the same time.And then reconstruct the low-resolution image to high-resolution image combined by the nonsampled contourlet transform(NSCT) and the advanced bilinear.The experiment results show that this method can get better result of keeping image’s edges and details,compared with other methods,the results have improved both in subjective evaluation and PSNR value.Finally,due to the phenomenon of seismic data loss and bad sectors because of the geographical envirment and the sensitivity of the sensor in seismic acquisition.Adaptive threshold of interpolation method for seismic data based on nonsubsampled contourlet transform(NSCT) is proposed in order to improve the seismic data reconstruction effect. This algorithm transforn the missing seismic data,and calculation the corresponding threshold of N times iteration using NSCT transform coefficients. At each iteration,multidirectional and multiscale NSCT coefficients are processed using the adaptive threshold. And the missing seismic data can be reconstructed by filing the reserved seismic data in the missing area with inverse transformation.The experiment results show that this method can get better interpolation reconstruction effects in uniform loss and random loss.when takes full use of translation invariant of NSCT and adaptive threshold...