说明：  对图像进行傅里叶变换，其频谱图能量集中在一点，通过对其对比度进行扩展，则图像的频谱图更加清晰，本程序实现了此过程。
(Fourier transform of the image, and its energy concentrated in the frequency spectrum that the expansion of its contrast, the frequency spectrum of the image more clearly, the procedures for the realization of this process.)