说明：  选取一个.gif格式文件，在MATLAB中显示原图像，进行二维傅立叶变换，然后取傅立叶变换的实部和虚部，计算频谱幅值。
(A.Gif format file is selected, the original image is displayed in MATLAB, the two-dimensional Fu Liye transform is carried out, then the real and virtual parts of the Fu Liye transform are taken to calculate the amplitude of the spectrum.)