close lines after edge detection

Hi all, After edge detection and adding some circular object, I like to close the lines and fill each area. this is an example : http://i48.tinypic.com/35hq0cg.jpg

is there a way to close the lines without dilation or morfological operations? those would modify the accuracy of the detection.

[Stephen]

what was the original image?

[Elad]

Its fungi on a leaf , but this image is after a few manipulations allready.

Answer 1

[Image Analyst]

You can try edge linking: http://www.csse.uwa.edu.au/~pk/Research/MatlabFns/#edgelink

Other options would be convex hull or restricted convex hull, or Sean's shrink wrap: http://www.mathworks.com/matlabcentral/fileexchange/29175-shrinkwrap

[Elad]

Thanks, I'll try it.

[Stelios Fanourakis]

Hi.

Did you manage to solve your issue? Image Analyst, is there a way to apply the convex hull to pixels?

[Image Analyst]

Using a convex hull may not always be a good choice - it won't give the right shape in some situations. For a banana shape, it convex hull would give a D-shape. One must really look at the image and not just make blanket generalizations.

[Stelios Fanourakis]

Image Analyst. I want to apply convex hull to a closed contour shape. Thus, the convex hull shape is more or less defined when applied to a closed contour. Isn't it?

Answer 2

[Walter Roberson]

imfill( YourBWArray, 'holes' )

[Elad]

Thanks but not all lines are closed, that's the problem.

[Walter Roberson]

The example where the line leaves a gap: where should it attach to the main body? If the "accuracy of the detection" is an issue, every choice is wrong, unless there is external information available.

[Elad]

Yes, you are right , I guess I would like to complete the closing in a circular way.

I found this answer that works sometimes, if the gap is small:

http://www.mathworks.com/matlabcentral/answers/23467-filling-the-objects-found-by-canny-edge