Find area of black parts in this porous material

Hello, i need to find the area of these black "lumps" in the image. I diddn't have much luck with all the image segmentation operations, as the porositiy of the material makes it rather difficult for me. Do you have any ideas how this can be solved? Thanks in advance.

Answer 1

[Image Analyst]

Try the Color Thresholder app on the Apps tab of the tool ribbon. It's going to be a judgment call since this image has a continuous 3-D color gamut, not a nice bimodal one (see figure below). So where white, and green/gold, and black are separated is not a well defined boundary.

[Nimos Sereth]

Thanks, I tried it to presumably find out, that I am not getting nice seperation of the blackish spots from the rest, no matter how much I change the sliders.

Would converting to grayscale help?

[Image Analyst]

Converting to grayscale would definitely not help - that would be just like thresholding on the V or L channel in colorspace. You may have to combine color segmentation with a second technique based on spatial things like shape or whatever.

[Nimos Sereth]

So would you recommend K-means clustering or something different?

[Image Analyst]

What would the features be with kmeans()? I can't imagine what features, so please inform me.

Have you tried using different illumination? Is there a spectral range where they look drastically different, like in the infrared, or ultraviolet, or even with a narrow visible filter? Please post the spectra of the two materials so we can determine that.

Otherwise you might have to just look at bulk statistical measures like mean color or something, if you're not happy with the judgment call way of doing color segmentation.

[Nimos Sereth]

I am currently working with different lighting and some new lense filters. Thanks for your help so far!