如何在基于移动窗口的操作中减少for循环？

Question

如何在基于移动窗口的操作中减少for循环？我在两个图像上使用15x15窗口并执行乘法以获得每个像素的平均值。

    [ma,na]=size(g);
z= (win1 -1)/2;%centre of window
ini=z+1;
 for i= ini :(ma-z)
     for j= ini:(na-z)
          for a= (i-z):(i+z)    
              for b=(j-z):(j+z)
                  W(pp,qq)= g(a, b);%window on image
                  Es(pp,qq)=edg(a,b);%window on edge
                  qq=qq+1;
              end
              qq=1;
              pp=pp+1;
          end 
          pp=1;
   E(i,j)=sum(sum(W.*Es))/sum(sum(Es));
     end
  end

Answer 1

我可能已经迷失在你的循环中，我无法完全阅读公式（它有点模糊）但我认为这就是你想要的：

g = rand(5); %sample img1
edg = rand(5); %sample img2
windowsize = 3; %set this to 15 for real images

A = g.*edg; % multiply each element beforehand, corresponds to mu*sigma in formula
B = movsum(movsum(A,windowsize,2),windowsize,1); % get moving window sum of A, corresponds to numerator in formula
C = movsum(movsum(edg,windowsize,2),windowsize,1); % get moving window sum of edg, corresponds to denominator in formula
E = B./C; %hopefully what you wanted

Ps：你需要2016a或更新版本才能运行