function dilated_image = dilate2( source_image, neighborhood );
% DILATE2 dilate a greyscale image.
%   dilated_image = dilate2( source_image, neighborhood );
% dilates the image to make white objects larger, black cracks smaller.
% (The MatLab function "dilate.m"
% does the same thing, but only accepts binary black-and-white image).
% Assumes source_image is a array 0 = black, max(source_image)=white pixels;
% Assumes neighborhood is a array of
% 1 = neighbor pixels, 0 = non-neighbor pixels.
% See also ERODE2, OPEN2, CLOSE2, DILATE.

% Change log:
% 1998-03-26:DAV: updated to grayscale version.
% 1998-02-04:DAV: David Cary wrote binary version

elements = nnz(neighborhood);
% rotate structuring element halfway around
% to make it consistent with MatLab's "dilate" command.
% (this helps "open2" and "close2" do the Right Thing
% when the neighborhood is not symmetrical around "the" center pixel,
% and when the neighborhood has even size -- for example, circle(10).).
dilated_image = ordfilt2(source_image, elements, rot90(neighborhood,2));
% end dilate2.m