利用DCT进行图像压缩（首先将图像分割成8×8的图像，对每个子图像进行DCT，这样每个子图像有64个系数，舍去50％小的变换系数，进行2：1的压缩。）-Using DCT for image compression (first image into 8 × 8 image, for each sub-image DCT, so that each sub-image by a factor of 64, rounding 50　of the small transform coefficients, the 2:1 compression.)