该程序包含了二维傅里叶变换、低通滤波器、高通滤波器-The program includes two-dimensional Fourier transform, low pass filters, high pass filter

快速无损的傅里叶变换，效率最高的FFT之一，包含一维fft，二维fft（FK变换），以及三维fft（FKK变换）。-One of the most efficient FFT, contains one-dimensional fft transform two-dimensional fft (FK transform), and three-dimensional fft (FKK transform), a rapid non-destructive Fourier transform.

C语言实现FFT，实测效果极好，可经过修改实现二维FFT，以及FFT反变换。(C language to achieve FFT, measured results are excellent, can be modified to achieve two-dimensional FFT, and FFT inverse transform.)