Thinning lines preserving 4-connectivity

Hi

I have bw 4-connectivity images where some lines are too thick and I am looking for a method to thinning them but preserving 4-connectivity.

So far I only find the bwmorph 'skel' option but it converts to 8 connectivity.

This is part of the original image. Please notice the bottom double thick segments.

Result after bwmorph(BW,'skel');

Is there any similar function for thinning the lines but preserving 4-connectivity?

Thanks

Answer 1

[Image Analyst]

There does not seem to be an option to skeletonize with bwskel or bwmorph to create a skeleton with 4-connectivity. It looks like 8-connectivity is the only option. Why do you need an option to have it be 4-connected?

[Luis Rosety]

Thanks for the information!

But this image needs 4-connectivity for futher processing being limited so far to this connectivity.

[Image Analyst]

When I asked "Why?", you basically said "because it does", which is not an explanation.

You can just scan the image and if you find certain patterns, like a diagonal pattern, to fill in a pixel. There should be just a handful of possible patterns that are not 4-connected.