Allow tilted rotation axis with parallel beam geometry for tigre projectors

[hrobarts]

Description

Calculate Euler angles for tilted parallel geometry

If geometry is parallel and advanced

• Calculate roll, pitch and yaw as before
• Calculate Euler angles based on roll, pitch and yaw
• Reset tigre rotDetector to 0
• Return Euler angles to be used with projection operator

Still needs:

• Unit tests

Example Usage

TomographicImaging/CIL-Demos#281

Contribution Notes

• The content of this Pull Request (the Contribution) is intentionally submitted for inclusion in CIL (the Work) under the terms and conditions of the Apache-2.0 License
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❤️ Thanks for your contribution!

[gfardell]

This seems to be tilting the object, not the rotation axis. The cuboid example shows the same so potentially something has dropped from the original code. It'll need a bit more thought so marking as draft for now.

#%%
from cil.utilities import dataexample
from cil.utilities.display import show2D
from cil.plugins.astra import ProjectionOperator as ProjectionOperator_A
from cil.plugins.tigre import ProjectionOperator as ProjectionOperator_T
from cil.framework import AcquisitionGeometry
from cil.utilities.display import show_geometry

import numpy as np
#%%
phantom = dataexample.SIMULATED_SPHERE_VOLUME.get()
data_orig = dataexample.SIMULATED_PARALLEL_BEAM_DATA.get()


plantom_thin = phantom.geometry.allocate(0)
plantom_thin.array[128//2-10:128//2+10,:,:] = phantom.array[128//2-10:128//2+10,:,:]

show2D(plantom_thin, slice_list=[(0,64),(1,64),(2,64)])

# %%
ag_tilt = AcquisitionGeometry.create_Parallel3D(rotation_axis_direction=[0,-np.sin(np.radians(20)),np.cos(np.radians(20))])\
                        .set_panel([128,128],[16.,16.])\
                        .set_angles(np.linspace(0,360,300,False))

show_geometry(ag_tilt)

#%%
#astra fp
ag_tilt.set_labels(['vertical', 'angle','horizontal'])
PO = ProjectionOperator_A(plantom_thin.geometry, ag_tilt)
fp_tilt_A = PO.direct(plantom_thin)

#tigre fp
ag_tilt.set_labels(['angle','vertical','horizontal'])
PO = ProjectionOperator_T(plantom_thin.geometry, ag_tilt)
fp_tilt_T = PO.direct(plantom_thin)

#%%
show2D([fp_tilt_A, fp_tilt_T],slice_list=('angle',0))
show2D([fp_tilt_A, fp_tilt_T],slice_list=('angle',75))
show2D([fp_tilt_A, fp_tilt_T],slice_list=('angle',150))
show2D([fp_tilt_A, fp_tilt_T],slice_list=('angle',225))

[gfardell]

Updated and it appears to work as expected for the interpolated direct method, but not for Siddon.