对cameraman.tif图像进行DCT变换，分别选取最大的1/4、1/8、1/16个变换系数(其余置为0)，进行反DCT得到重构图像，显示原图像和各重构图像并分别计算重构图像的峰值信噪比。-Cameraman.tif DCT transform of the image, were selected maximum 1/4,1/8,1/16 transform coefficients (the remainder is set to 0), inverse DCT to obtain the reconstructed image, the original image in a reconstructed image and various and calculate the peak signal to noise ratio of the reconstructed image.