ENH: remove repetitive monochorme1 warning

[blowekamp]

I have seen this warning message 100s of thousands of time while working with large chest X-ray data sets.

These is not problem to "warn" about the image loads as expected.

PR Checklist

• No API changes were made (or the changes have been approved)
• No major design changes were made (or the changes have been approved)
• Added test (or behavior not changed)
• Updated API documentation (or API not changed)
• Added license to new files (if any)
• Added Python wrapping to new files (if any) as described in ITK Software Guide Section 9.5
• Added ITK examples for all new major features (if any)

Refer to the ITK Software Guide for
further development details if necessary.

[N-Dekker]

Do I understand correctly that GDCMImageIO threats MONOCHROME1 just like MONOCHROME2, and produces a bright (inverted) image when the original image was dark?

[blowekamp]

I am not sure you clearly articulated that.

Generally, images can be store ( disk or memory) in a different way that is different than their photometric meaning. For example an image can be stored as an index into a pallet, where the pallet contains the RGB photometric meaning.

The photometric meaning of a MONOCHROME1 is that "min is black", which is opposite of ITK's conventional Gray scale.

ITK's meta data does not contain definitions for photometric meaning e.g RGB color space, XYZ color space, min-is-black or min-is-white. In lieu of this ITK has conventions, and the ImageIO's generally convert from the representation to these common conventions.

This conversion is little different than applying the slope intercept to get a float from the integer values in the DICOM file.

[N-Dekker]

I'm OK with removing the itkWarningMacro call, just wondering if the read "PhotometricInterpretation" tag is still of interest to anyone.

[blowekamp]

The tag is still in the metadata dictionary, it has just been applied similarly to the slope intercept.

[N-Dekker]

👍