Assignment of the source series UIDs to the segmentation frames

[fedorov]

Currently, communication of the source series DICOM files serves multiple purposes:

• initialize patient/study/FoR for the segmentation to be created
• list all of the instances passed as input in the ReferencedInstanceSequence
• UIDs of the instances that match the spatial positions of the slices corresponding to the segmentation slices are listed in the PerFrameFunctionalGroupsSequence > DerivationImageSequence

It will be more flexible (but also more complicated) if these different purposes are separated.

A related use case is segmentation of the time series data, where multiple source series slices will map to the same segmentation series frame.