image processing detect artifacts and removing it

Hi,

I want to compare pixel based DICOM with approximated geometry. However, I have some artifact showing other pixels in my samples. What is the most efficient way to remove those artifacts which are discontinuous and shown in Blue rectangles?

So far I used rgb to visualize both samples to seperate the pixels and geometry.

</matlabcentral/answers/uploaded_files/89174/Cross1012_G.png> </matlabcentral/answers/uploaded_files/89175/Cross1012_R.png>

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