How to update the value of next pixel in chain code?

I am getting first non zero pixel and its chain code but then i need to go to next pixel depending upon that direction.How I can proceed further? Thanks in advance.

[Walter Roberson]

There is code for Freeman chain in the File Exchange

[Ekta Sharma]

Yes Sir...You are right.Code is available but I am unable to understand it.How to provide input to the function?

Answer 1

[Walter Roberson]

Use bwboundaries to extract boundaries. The first output of it will be a cell array, one entry for each region found. Pass the contents of each entry in the cell array to the chaincode routine at http://www.mathworks.com/matlabcentral/fileexchange/29518-freeman-chain-code

B = bwboundaries(YourImage);
numregions = length(B);
chains = cell(numregions,1);
for blobnum = 1 : numregions
   chains{blobnum} = chaincode(B{blobnum});
end