Tim Moores wrote:I have done a fair amount of image processing work, and have no idea what you mean by "curl of an image"; where did you see that? In the computing domain, "curl" is a command line tool to access a particular URL.
I am sorry I do not express it clearly. the curl from the wiki
http://en.wikipedia.org/wiki/Curl_(mathematics)
here is the code I use to count the "curl" in MATLAB
%count the gradient of an image
I = imread('a.jpg');
[rows cols dim]=size(I);
%sobel operator used to calculate gradient image
Grd=[ -1 -2 -1;
0 0 0;
1 2 1];
Emean=zeros(rows,cols);
for i=1:dim
Ev(:,:,i)=conv2(x(:,:,i),Grd,'same');
Eh(:,:,i)=conv2(x(:,:,i),Grd.','same');
E(:,:,i)=abs(Eh(:,:,i))+abs(Ev(:,:,i));
% E(:,:,i)=conv2(X(:,:,i),Grd1,'same');
end
Emean=1/dim*sum(E,3); %finds average gradient image
%count the "curl"
Ecurl = zeros(rows, cols);%creat a 0 rows * cols matrix
for i = 1:dim
Ecurl(:,:,i) = conv2(Iy(:,:,i), Grd.', 'same') - conv2(Ix(:,:,i), Grd, 'same');
end
theCurl = 1/dim*sum(Ecurl,3);
looking forward to your reply .thanks