1.实现对lena.bmp灰度图像的快速傅立叶变换,并求其变换后的系数（幅度）分布；

2.实现对lena.bmp图像做离散余弦变换,选择适当的DCT系数阈值对其进行DCT反变换 ；-1 to achieve the fast Fourier transform on lena.bmp grayscale image, and to find the transformed coefficients (amplitude) distribution　2. To achieve lena.bmp images do discrete cosine transform, select the appropriate DCT coefficient threshold to the DCT inverse transform