TOF segment bug fix, extra members and update visualisation to add TOF

[KrisThielemans]

• fixes ProjData::get_segment_by_*(const SegmentIndices&)
• adds some more members to Segment classes that use *Indices
• update @robbietuk 's visualisation tool to add a TOF slider etc

[KrisThielemans]

@NicoleJurjew this might come in handy for showing your TOF data

[robbietuk]

Am I right in thinking the summation over TOF bins collapses into a non-TOF view/sinogram? If so, we should add a checkbox to do this.

[KrisThielemans]

We could do, but it's another feature. There are many other desirable features here, including having 2 projection datasets, displaying over tof dimension etc etc.

If you're happy with the current implementation, I'll merge this

[robbietuk]

I assume this is tested? Currently the demo uses examples/recon_demo/smalllong.hs, which is not TOF data.

Otherwise, merge.

[robbietuk]

There is a bug, segment_number argument is not used.

STIR/examples/python/projdata_visualisation/BackendTools/STIRInterface.py

Lines 102 to 117 in c0c4c5b

	def get_limits(self, dimension: ProjDataDims, segment_number: int) -> tuple:
	"""
	Returns the limits of the projection data in the indicated dimension.
	:param dimension: The dimension to get the limits for, type SinogramDimensions.
	:param segment_number: The segment number to get the limits for. Only _truly_ required for axial position.
	:return: A tuple containing the minimum and maximum value of the dimension (min, max).
	"""
	if self.projdata is None:
	return 0, 0
	if dimension == ProjDataDims.SEGMENT_NUM:
	return self.projdata.get_min_segment_num(), \
	self.projdata.get_max_segment_num()
	elif dimension == ProjDataDims.AXIAL_POS:
	return self.projdata.get_min_axial_pos_num(self.get_current_segment_num()), \
	self.projdata.get_max_axial_pos_num(self.get_current_segment_num())

return self.projdata.get_min_axial_pos_num(self.get_current_segment_num()), \ 
    self.projdata.get_max_axial_pos_num(self.get_current_segment_num()) 

Should read

return self.projdata.get_min_axial_pos_num(segment_num), \ 
    self.projdata.get_max_axial_pos_num(segment_num) 

Edit: I can't edit your branch or make a suggested change.

[KrisThielemans]

ok, but that was an existing bug then, so should have created problems in non-TOF as well. Can you check?

I assume this is tested?

yes, on some local TOF data. It looked fine, but I probably didn't try to switch segments

[robbietuk]

ok, but that was an existing bug then, so should have created problems in non-TOF as well. Can you check?

Yes. It is actually a latent bug so no need to fix here. c0c4c5b drew my attention to it.

yes, on some local TOF data. It looked fine, but I probably didn't try to switch segments

I think you can still merge this and I'll add an issue and PR some fixes.