Pyradiomics feature extraction for bin-width 255


I was extracting radiomics features from a CT dataset using PyRadiomics at various bin-widths for a comparison study (25, 32, 255 etc).

I was comparing individual gray level features between bin-width 25 and 255. My CT images are normalized to intensity levels (0 to 255). So, for bin-width 255, I just have 1 gray level.

While comparing GLCM between bin-width 25 and 255 , I noticed that GLCM for bin-width 255 is almost non-existing which makes sense since I have only one gray level. However, while comparing GLRLM between bin-width 25 and 255, I see a similar pattern between bin-width 25 and 255. I have attached three slides describing what is happening.

My question is for bin-width 255, both GLCM and GLRLM should behave in a similar way since we are dealing with only one gray level. But why, GLRLM feature pattern at bin-width 255 are similar to bin-width 25?

Could you please help me figure it out?

Version (please complete the following information):

  • OS: [iOS]
  • Python version: [3.8.1]
  • PyRadiomics version [v3.0.1.post3+g0c53d1d]

Thank you,