How to calculate chain code and how to get the boundary as an np-by-2 array (it's required for the chain code)?

I am trying to determine chain code for an image. I have tried Freeman chain code ( http://www.mathworks.com/matlabcentral/fileexchange/29518-freeman-chain-code) and also a code from Gonzalez book. I have two problems.

1. For the chain code, how do i get the boundary as np-by-2 array from my image?

2. In the code grom Gonzalez book, i see this error, "the input curve is broken... ... ..."

Any help would be appreciated. Thanx

Answer 1

[Image Analyst]

Why not use bwboundaries() to get an ordered list of the boundary coordinates. If you really need the chain code, you could get it from the list of x,y boundary coordinates.