Introduction - If you have any usage issues, please Google them yourself
Using discrete cosine transform function (dct2 and idct2) analog JPEG compression process. On " lena.bmp" do compression, the compression effect was observed. (JPEG compression process: First, the original image is divided into 88 sub-image, and then use dct2 of each sub-image, respectively, discrete cosine transform, the upper left corner of the transform coefficients to retain only 15 values, then use the 15 coefficients discrete cosine transform regain each sub-image, and then sub-images together into a complete picture)