Calculating the distance between patches

Is there a way in MATLAB to calculate the distance between patches of two images?

Thanks.

[Image Analyst]

Which distance? The Hausdrof distance, distance between closest vertices, or distance between centroids?

[med-sweng]

@Image Analyst. Thanks for your reply. Say that we have patches of size `3x3`, how would the "Hausdorff distance" or the "Euclidean distance" be applied on that? That is, patches instead of pixel points?

Answer 1

[Image Analyst]

If you know the vertices, you can calculate centroid and the Hausdorf distance from formulas you can find on the web. For a 3x3 rectangular array, the centroid is obviously at the middle element. For arbitrary polygons, it seems not so straightforward: https://en.wikipedia.org/wiki/Centroid#Locating_the_centroid but you can use regionprops() to compute the centroid, if you want to create an image out of the vertices with poly2mask().

[med-sweng]

@Image Analyst. Say I use `pdist` to find the distance, how can I combine the `centroid` (patches) with that?

[Image Analyst]

I don't have pdist(). See my image segmentation tutorial for how you can get centroids: http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862 Once you have the centroid, you can plug into norm(), hypot(), or pdist(), or the Pythagorean theorem to get the Euclidean distance.