一、　　计算图象的频谱函数
设计图象120*30/256*256；选用Matlab函数直接调用实现。

二、根据计算证明傅立叶变换的性质
1，　　共轭对称性:
F(u,v)=F*(-u,-v) ;
　
三、图象的频域滤波
1，　　设计一个指数低通滤波器，对两图象（f1(x,y)为30*30/256*256的图象；f2(x,y)=p3-02图象）进行低通滤波，观察分析空域图象和频谱分布的变化。

四、图象变换比较
　　利用现有的离散傅立叶变换、离散余弦变换、Walsh-Hadamard变换对同一图象实施变换，比较三种变换所得到的频谱。(1. The spectral function of the computed image
Design image: 120*30/256* 256; Use Matlab function to call the implementation directly.

The properties of Fourier transform are proved by calculation
1. Conjugate symmetry:
F (u, v) = F * (- u, v);

3. Frequency domain filtering of images
1. Design an exponential low-pass filter with two images (f1 (x,y) as 30*30/256* 256. F2 (x,y)=p3-02 image) to conduct low pass filtering to observe the change of spatial image and spectral distribution.

4. Comparison of image transformation
Using the existing discrete Fourier transform, discrete cosine transform and Walsh-Hadamard transform to transform the same image, compare the spectrum obtained by three kinds of transformations.)