比较复杂的频域处理，它首先把图像通过傅立叶变换等等转换为频域的数据，然后用各种滤波器对图像进行处理。后来通过google在codeproject上找到这种基于频域的缩放算法-More complex frequency domain processing, it first through the Fourier transform, and so the image is converted to frequency domain data, and then use a variety of filters for image processing. Later, through google to find this in the codeproject scaling algorithm based on frequency domain