See my Image Segmentation Tutorial: http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862
You probably don't need chain codes. If you still have questions after running my tutorial, post your image then come back and tell us where you posted it and what you want to measure in the image. Give the "big picture" not some low level thing like I need to measure boundary coordinates or chain codes.
