cm.m

图像对齐（inage registration）工具箱

function [M]=cm(img,r)

% M is a matrix of central moments up to the r-th order of the image img
% img - image matrix
% \mu{pq} = M(p+1,q+1)

 [n1,n2]=size(img);
 m00 =sum(sum(img));

 w=linspace(1,n2,n2);
 v=linspace(1,n1,n1);
 
 tx=(sum(img*w'))/m00; 
 ty=(sum(v*img))/m00;

 a=w-tx;
 c=v-ty;

for i=1:r+1;
for j=1:r+2-i;
	p=i-1;
	q=j-1;

	A=a.^p;
	C=c.^q;

	M(i,j)=C*img*A';
end;
end;

if r>0
	M(1,2)=0;
	M(2,1)=0;
end;