Measuring indentation in an object

Dear Researchers,

How can I we measure how many indentation or foldings are present in the three objects presented below

http://s20.postimage.org/s1zoc1r8t/indent.png

Subrajeet

Answer 1

[Image Analyst]

Use the convex hull, bwconvhull(). Subtract the original image from the convex hull and call bwlabel

indentsBinaryImage = bwconvhull(binaryImage) - binaryImage;
[labeledImage, numberOfIndents] = bwlabel(indentsBinaryImage);

Answer 2

[Amith Kamath]

http://blogs.mathworks.com/steve/2011/10/04/binary-image-convex-hull-algorithm-notes/ and the convex hull concept would help. I suppose you need to isolate each blob using http://www.mathworks.com/help/images/ref/bwconncomp.html and then find it's convex hull, and then the number of black blobs inside the convex hull will give you the number of folds. Hope this helps!