MG can produce blank output when eroding non-binary WM mask

[bathomas]

The erosion of the WM using itk::BinaryErodeImageFilter can fail. Changing to itk::GrayscaleErodeImageFilter appears to fix the problem.

[bilgelm]

I'm encountering blank outputs with MG for multiple scans. The masks contain 0's and 1's only, but the data type stored in the nifti format mask file is uint8. I will try what you suggested - is it simply changing itk::BinaryErodeImageFilter to itk::GrayscaleErodeImageFilter in petpvcMullerGartnerImageFilter.h (and using the corresponding #include)?