Add JAX 3D X-ray CT projector (#529)

Co-authored-by: Brendt Wohlberg <brendt@ieee.org>

.gitignore

@@ -123,6 +123,9 @@ venv.bak/
 # Rope project settings
 .ropeproject
 
+# VS Code settings
+.vscode/
+
 # mkdocs documentation
 /site
 

CHANGES.rst

@@ -7,6 +7,7 @@ Version 0.0.6   (unreleased)
 ----------------------------
 
 • Significant changes to ``linop.xray.astra`` API.
+• New integrated 3D X-ray transform via ``linop.xray.XRayTransform3D``.
 • New functional ``functional.IsotropicTVNorm`` and faster implementation
   of ``functional.AnisotropicTVNorm``.
 • New linear operators ``linop.ProjectedGradient``, ``linop.PolarGradient``,

docs/source/examples.rst

@@ -37,7 +37,9 @@ Computed Tomography
    examples/ct_astra_modl_train_foam2
    examples/ct_astra_odp_train_foam2
    examples/ct_astra_unet_train_foam2
-   examples/ct_projector_comparison
+   examples/ct_projector_comparison_2d
+   examples/ct_projector_comparison_3d
+   examples/ct_multi_cs_tv_admm
    examples/ct_multi_tv_admm
 
 Deconvolution

examples/scriptcheck.sh

@@ -90,6 +90,10 @@ for f in $SCRIPTPATH/scripts/*.py; do
         printf "%s\n" skipped
         continue
     fi
+    if [ $SKIP_GPU -eq 1 ] && grep -q 'ct_projector_comparison_3d' <<< $f; then
+        printf "%s\n" skipped
+        continue
+    fi
 
     # Create temporary copy of script with all algorithm maxiter values set
     # to small number and final input statements commented out.

examples/scripts/README.rst

@@ -39,8 +39,10 @@ Computed Tomography
       CT Training and Reconstructions with ODP
    `ct_astra_unet_train_foam2.py <ct_astra_unet_train_foam2.py>`_
       CT Training and Reconstructions with UNet
-   `ct_projector_comparison.py <ct_projector_comparison.py>`_
-      X-ray Transform Comparison
+   `ct_projector_comparison_2d.py <ct_projector_comparison_2d.py>`_
+      2D X-ray Transform Comparison
+   `ct_projector_comparison_3d.py <ct_projector_comparison_3d.py>`_
+      3D X-ray Transform Comparison
    `ct_multi_tv_admm.py <ct_multi_tv_admm.py>`_
       TV-Regularized Sparse-View CT Reconstruction (Multiple Projectors)
 

examples/scripts/ct_multi_tv_admm.py

@@ -27,7 +27,7 @@
 
 import scico.numpy as snp
 from scico import functional, linop, loss, metric, plot
-from scico.linop.xray import Parallel2dProjector, XRayTransform, astra, svmbir
+from scico.linop.xray import XRayTransform2D, astra, svmbir
 from scico.optimize.admm import ADMM, LinearSubproblemSolver
 from scico.util import device_info
 
@@ -54,9 +54,7 @@
     "svmbir": svmbir.XRayTransform(
         x_gt.shape, 2 * np.pi - angles, det_count, delta_pixel=1.0, delta_channel=det_spacing
     ),  # svmbir
-    "scico": XRayTransform(
-        Parallel2dProjector((N, N), angles, det_count=det_count, dx=1 / det_spacing)
-    ),  # scico
+    "scico": XRayTransform2D((N, N), angles, det_count=det_count, dx=1 / det_spacing),  # scico
 }
 
 

examples/scripts/ct_projector_comparison.py → examples/scripts/ct_projector_comparison_2d.py

@@ -6,10 +6,10 @@
 
 
 r"""
-X-ray Transform Comparison
-==========================
+2D X-ray Transform Comparison
+=============================
 
-This example compares SCICO's native X-ray transform algorithm
+This example compares SCICO's native 2D X-ray transform algorithm
 to that of the ASTRA toolbox.
 """
 
@@ -22,7 +22,7 @@
 
 import scico.linop.xray.astra as astra
 from scico import plot
-from scico.linop import Parallel2dProjector, XRayTransform
+from scico.linop.xray import XRayTransform2D
 from scico.util import Timer
 
 """
@@ -46,7 +46,7 @@
 
 projectors = {}
 timer.start("scico_init")
-projectors["scico"] = XRayTransform(Parallel2dProjector((N, N), angles))
+projectors["scico"] = XRayTransform2D((N, N), angles)
 timer.stop("scico_init")
 
 timer.start("astra_init")

examples/scripts/ct_projector_comparison_3d.py

@@ -0,0 +1,200 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+# This file is part of the SCICO package. Details of the copyright
+# and user license can be found in the 'LICENSE.txt' file distributed
+# with the package.
+
+
+r"""
+3D X-ray Transform Comparison
+=============================
+
+This example shows how to define a SCICO native 3D X-ray transform using
+ASTRA toolbox conventions and vice versa.
+"""
+
+import numpy as np
+
+import jax
+import jax.numpy as jnp
+
+import scico.linop.xray.astra as astra
+from scico import plot
+from scico.examples import create_block_phantom
+from scico.linop.xray import XRayTransform3D
+from scico.util import ContextTimer, Timer
+
+"""
+Create a ground truth image and set detector dimensions.
+"""
+N = 64
+# use rectangular volume to check whether axes are handled correctly
+in_shape = (N + 1, N + 2, N + 3)
+x = create_block_phantom(in_shape)
+x = jnp.array(x)
+
+# use rectangular detector to check whether axes are handled correctly
+out_shape = (N, N + 1)
+
+
+"""
+Set up SCICO projection.
+"""
+num_angles = 3
+
+
+rot_X = 90.0 - 16.0
+rot_Y = np.linspace(0, 180, num_angles, endpoint=False)
+angles = np.stack(np.broadcast_arrays(rot_X, rot_Y), axis=-1)
+matrices = XRayTransform3D.matrices_from_euler_angles(
+    in_shape, out_shape, "XY", angles, degrees=True
+)
+
+"""
+Specify geometry using SCICO conventions and project.
+"""
+num_repeats = 3
+
+timer_scico = Timer()
+with ContextTimer(timer_scico, "init"):
+    H_scico = XRayTransform3D(in_shape, matrices, out_shape)
+
+with ContextTimer(timer_scico, "first_fwd"):
+    y_scico = H_scico @ x
+    jax.block_until_ready(y_scico)
+
+with ContextTimer(timer_scico, "avg_fwd"):
+    for _ in range(num_repeats):
+        y_scico = H_scico @ x
+        jax.block_until_ready(y_scico)
+timer_scico.td["avg_fwd"] /= num_repeats
+
+with ContextTimer(timer_scico, "first_back"):
+    HTy_scico = H_scico.T @ y_scico
+
+with ContextTimer(timer_scico, "avg_back"):
+    for _ in range(num_repeats):
+        HTy_scico = H_scico.T @ y_scico
+        jax.block_until_ready(HTy_scico)
+timer_scico.td["avg_back"] /= num_repeats
+
+
+"""
+Convert SCICO geometry to ASTRA and project.
+"""
+
+vectors_from_scico = astra.convert_from_scico_geometry(in_shape, matrices, out_shape)
+
+timer_astra = Timer()
+with ContextTimer(timer_astra, "init"):
+    H_astra_from_scico = astra.XRayTransform3D(
+        input_shape=in_shape, det_count=out_shape, vectors=vectors_from_scico
+    )
+
+with ContextTimer(timer_astra, "first_fwd"):
+    y_astra_from_scico = H_astra_from_scico @ x
+    jax.block_until_ready(y_astra_from_scico)
+
+with ContextTimer(timer_astra, "avg_fwd"):
+    for _ in range(num_repeats):
+        y_astra_from_scico = H_astra_from_scico @ x
+        jax.block_until_ready(y_astra_from_scico)
+timer_astra.td["avg_fwd"] /= num_repeats
+
+with ContextTimer(timer_astra, "first_back"):
+    HTy_astra_from_scico = H_astra_from_scico.T @ y_astra_from_scico
+
+with ContextTimer(timer_astra, "avg_back"):
+    for _ in range(num_repeats):
+        HTy_astra_from_scico = H_astra_from_scico.T @ y_astra_from_scico
+        jax.block_until_ready(HTy_astra_from_scico)
+timer_astra.td["avg_back"] /= num_repeats
+
+
+"""
+Specify geometry with ASTRA conventions and project.
+"""
+
+angles = np.random.rand(num_angles) * 180  # random projection angles
+det_spacing = [1.0, 1.0]
+vectors = astra.angle_to_vector(det_spacing, angles)
+
+H_astra = astra.XRayTransform3D(input_shape=in_shape, det_count=out_shape, vectors=vectors)
+
+y_astra = H_astra @ x
+HTy_astra = H_astra.T @ y_astra
+
+
+"""
+Convert ASTRA geometry to SCICO and project.
+"""
+
+P_from_astra = astra._astra_to_scico_geometry(H_astra.vol_geom, H_astra.proj_geom)
+H_scico_from_astra = XRayTransform3D(in_shape, P_from_astra, out_shape)
+
+y_scico_from_astra = H_scico_from_astra @ x
+HTy_scico_from_astra = H_scico_from_astra.T @ y_scico_from_astra
+
+
+"""
+Print timing results.
+"""
+print(f"init         astra    {timer_astra.td['init']:.2e} s")
+print(f"init         scico    {timer_scico.td['init']:.2e} s")
+print("")
+for tstr in ("first", "avg"):
+    for dstr in ("fwd", "back"):
+        for timer, pstr in zip((timer_astra, timer_scico), ("astra", "scico")):
+            print(f"{tstr:5s}  {dstr:4s}  {pstr}    {timer.td[tstr + '_' + dstr]:.2e} s")
+        print()
+
+
+"""
+Show projections.
+"""
+fig, ax = plot.subplots(nrows=3, ncols=2, figsize=(8, 10))
+plot.imview(y_scico[0], title="SCICO projections", cbar=None, fig=fig, ax=ax[0, 0])
+plot.imview(y_scico[1], cbar=None, fig=fig, ax=ax[1, 0])
+plot.imview(y_scico[2], cbar=None, fig=fig, ax=ax[2, 0])
+plot.imview(y_astra_from_scico[:, 0], title="ASTRA projections", cbar=None, fig=fig, ax=ax[0, 1])
+plot.imview(y_astra_from_scico[:, 1], cbar=None, fig=fig, ax=ax[1, 1])
+plot.imview(y_astra_from_scico[:, 2], cbar=None, fig=fig, ax=ax[2, 1])
+fig.suptitle("Using SCICO conventions")
+fig.tight_layout()
+fig.show()
+
+fig, ax = plot.subplots(nrows=3, ncols=2, figsize=(8, 10))
+plot.imview(y_scico_from_astra[0], title="SCICO projections", cbar=None, fig=fig, ax=ax[0, 0])
+plot.imview(y_scico_from_astra[1], cbar=None, fig=fig, ax=ax[1, 0])
+plot.imview(y_scico_from_astra[2], cbar=None, fig=fig, ax=ax[2, 0])
+plot.imview(y_astra[:, 0], title="ASTRA projections", cbar=None, fig=fig, ax=ax[0, 1])
+plot.imview(y_astra[:, 1], cbar=None, fig=fig, ax=ax[1, 1])
+plot.imview(y_astra[:, 2], cbar=None, fig=fig, ax=ax[2, 1])
+fig.suptitle("Using ASTRA conventions")
+fig.tight_layout()
+fig.show()
+
+
+"""
+Show back projections.
+"""
+fig, ax = plot.subplots(nrows=1, ncols=2, figsize=(8, 5))
+plot.imview(HTy_scico[N // 2], title="SCICO back projection", cbar=None, fig=fig, ax=ax[0])
+plot.imview(
+    HTy_astra_from_scico[N // 2], title="ASTRA back projection", cbar=None, fig=fig, ax=ax[1]
+)
+fig.suptitle("Using SCICO conventions")
+fig.tight_layout()
+fig.show()
+
+fig, ax = plot.subplots(nrows=1, ncols=2, figsize=(8, 5))
+plot.imview(
+    HTy_scico_from_astra[N // 2], title="SCICO back projection", cbar=None, fig=fig, ax=ax[0]
+)
+plot.imview(HTy_astra[N // 2], title="ASTRA back projection", cbar=None, fig=fig, ax=ax[1])
+fig.suptitle("Using ASTRA conventions")
+fig.tight_layout()
+fig.show()
+
+
+input("\nWaiting for input to close figures and exit")

examples/scripts/ct_tv_admm.py

@@ -29,7 +29,7 @@
 
 import scico.numpy as snp
 from scico import functional, linop, loss, metric, plot
-from scico.linop.xray import Parallel2dProjector, XRayTransform
+from scico.linop.xray import XRayTransform2D
 from scico.optimize.admm import ADMM, LinearSubproblemSolver
 from scico.util import device_info
 
@@ -46,7 +46,7 @@
 """
 n_projection = 45  # number of projections
 angles = np.linspace(0, np.pi, n_projection) + np.pi / 2.0  # evenly spaced projection angles
-A = XRayTransform(Parallel2dProjector((N, N), angles))  # CT projection operator
+A = XRayTransform2D((N, N), angles)  # CT projection operator
 y = A @ x_gt  # sinogram
 
 

examples/scripts/index.rst

@@ -24,7 +24,8 @@ Computed Tomography
    - ct_astra_modl_train_foam2.py
    - ct_astra_odp_train_foam2.py
    - ct_astra_unet_train_foam2.py
-   - ct_projector_comparison.py
+   - ct_projector_comparison_2d.py
+   - ct_projector_comparison_3d.py
    - ct_multi_tv_admm.py
 
 Deconvolution