对Lena图先进行jpeg压缩，再对压缩后的图像分别进行小波软阈值去噪和非抽样硬阈值去噪，比较两种去噪方案，非抽样硬阈值有更好的效果。这是根据一篇外文文献来进行编程的，最后有图像对比结果。-According to the paper of OPTIMAL WAVELET THRESHOLDING FOR VARIOUS CODING SCHEMES ,I firstly compresse the Lena picture using the jpeg method ,then respect