inner surface of an object

Dear all,

Does anybody know how can I extract the inner surface of a volume with hollow (for example a cup!)

Answer 1

[Image Analyst]

I'd probably try this:

1. Do a hole fill.
2. Subtract the original, to get the solid hole.
3. Do a dilation, to expand back into the inner surface of the original.
4. Subtract the "second" original (the solid hole image).

Answer 2

[Violet P]

Dear "Image Analyst",

Thank you for your prompt response. I used your suggestion it worked :)