Detect the corroded pit areas using ROIs

Hello guys,
I need to detect the corroded pit areas of the following pics. I have tried many methods but i can’t exactly detect the corroded pits areas and mean RGB values of the rois beacuse there are thousands of regions appear when applying the thresholding and i want to reduce these ROIs to 100 or nearby value. If you can suggest any method or idea it would be greatful.

You may want to try a two step process where you first threshold the large central object first, and then threshold the pits after that. Even so, be careful with the shading from the corners of however you are taking the images. Without even illumination, pretty much any form of analysis will be impacted.

The writing on object FT-13 probably won’t help either.

I guess Weka is one of the tools you have already tried? That is generally the go-to for situations like this in FIJI. You might also try Ilastik or other pixel classifier programs as well.

Try to make the images using a good desktop photo scanner with a high resolution instead of taking pictures with a camera. That will guarantee even lighting conditions and no reflections. The thicker the scanner, the better the depth of focus.

I think the current images are of too low quality to have any reasonable hope of getting any reliable measurements out of them.