I thought I gave you a really good answer in your prior, duplicate question http://www.mathworks.com/matlabcentral/answers/111131#answer_119804. Perhaps I'll respond to this follow up question if you'll
- respond to my answer there, where I thought I gave you a pretty good solution for that question, and
- post your original gray scale image so we can see what image you're trying to find edges of , and we can see if edge detection is even the best approach.
