v = directiona​lVariogram​(img, xoffset, yoffset); in which version of matlab this function is suported? also in which toolbox?

 v = directionalVariogram(img, xoffset, yoffset);
in which version of matlab this function is suported?
also in which toolbox?

Answer 1

[Wayne King]

This is not a MathWorks' function. It was a function written and posted by Daniel Young as far as I can tell

function v = directionalVariogram(img, xoffset, yoffset)
%directionalVariogram computes empirical direction variogram
%   v = directionalVariogram(img, xoffset, yoffset) takes a 2D image array
%   and offsets in the x and y directions. It returns the mean of the
%   squared differences between pairs of pixels in the image such that the
%   spatial offsets between the pixels are as specified.

if xoffset < 0  % difference is symmetric so can force xoffset positive
    xoffset = -xoffset;
    yoffset = -yoffset;
end

% make offset and trimmed copies of image
if yoffset > 0
    imga = img(1+yoffset:end, 1+xoffset:end);
    imgb = img(1:end-yoffset, 1:end-xoffset);
else
    imga = img(1:end+yoffset, 1+xoffset:end);
    imgb = img(1-yoffset:end, 1:end-xoffset);
end

d = imga - imgb;
v = mean(d(:).^2);

end

To see Daniel's original answer:

http://www.mathworks.com/matlabcentral/answers/4587

[vipul utsav]

is it variogram(img) also a written function?

[Wayne King]

That is also not a MathWorks' function, but perhaps you are talking about this?

http://www.mathworks.com/matlabcentral/fileexchange/20355-experimental-semi-variogram/content/variogram.m

[vipul utsav]

it is right