why to Dataset preprocessing?

[SniperM99]

I can't understand why to Dataset preprocessing，and what is RAI ？can you explain for me? TK u

[christianpayer]

The dataset preprocessing is performed to bring every image to the same orientation, i.e., RAI, for easier subsequent processing within the framework. RAI is the orientation, where the direction matrix is the eye matrix. If you need more information on volumetric image orientation and how to interpret spacing, direction, and origin, I would recommend you to look more into the topic of coordinate systems for medical images (e.g., https://www.aliza-dicom-viewer.com/manual/orientation, https://www.slicer.org/wiki/Coordinate_systems).