函数paddedsize可计算P和Q的最小偶数值，PQ则是避免折叠误差的串扰所采用的补零方法。

函数dftfilt是用于频率域滤波的M函数

在house中进行空域滤波与频域滤波的比较

函数dftuv创建用于实现频率域滤波器的网格数组

在number中进行低通滤波

还可基于lpfilter生成高通滤波器。

函数D=hypot(U,V)<=>D=sqrt(U.^2+V.^2)替代

函数f=tofloat(f)<=>f=im2double(f)替代-Paddedsize calculate P and Q function minimum even value, PQ is zero-padded to avoid aliasing errors Crosstalk being used.

Dftfilt function is used for frequency domain filtering function M

Comparing spatial filtering and frequency domain filtering in the house in

Function dftuv create a grid array is used to implement frequency domain filter

Low-pass filtering in number of

It can also generate a high-pass filter based on lpfilter.

Function D = hypot (U, V) <=> D = sqrt (U. ^ 2+ V. ^ 2) substitute

Function f = tofloat (f) <=> f = im2double (f) Alternate