How to calculate the chain code of an image?

I am trying to calculate the chain code of an image. Actually I am working on character recognition. I tried to implement the code from the Gonzalez book. But it shows error. I cant move on without the chain codes. So any help would be appreciated.

Answer 1

[Walter Roberson]

http://www.mathworks.com/matlabcentral/fileexchange/29518-freeman-chain-code

Note: "it shows error" is not enough information for us to debug the problem.