要求做一个实验，对一副M*N大小的图像重复使用截频为D0的高斯低通滤波器进行滤波。假设K为滤波次数。当K足够大时，滤波结果是什么样-Asked to do an experiment, a M* N-size image re-use the cutoff frequency for the D0 Gaussian low-pass filter for filtering. Assuming K is filtering times. When K is sufficiently large, the filter result is what