How to find the Alpha Hull of 2-D image

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ganesh s 2015-12-1

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评论： Sean de Wolski 2015-12-3

i would like to know how to find the alpha hull of the image like convex hull for 2-D image

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Sean de Wolski 2015-12-1

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编辑：Sean de Wolski 2015-12-1

在 MATLAB Online 中打开

You will need to binarize the image (however, you need to do that), find the points on the perimeter ( find/bwperim , or bwboundaries) and then call alphaShape on those points.

Simple example:

I = imread('onion.png');
BW = I(:,:,2)>100 & I(:,:,1)<150;
[r,c] = find(bwperim(BW));
ah = alphaShape(c,r);
plot(ah)

This is about as simple of an example as it gets. You might want to do more advanced things like calling regionprops with 'SubarrayIdx' so that you find the alpha hull of each object in the image, etc.