FP_CUDA
This is a GPU implementation of a simple forward projection algorithm for 2D data sets. It takes a volume as input, and returns the projection data.
Supported geometries: parallel, parallel_vec, fanflat, fanflat_vec.
Configuration options
Name |
Description |
|---|---|
ProjectionDataId |
Data object ID to store the result. The computed forward projection is added to this data. |
VolumeDataId |
|
option.DetectorSuperSampling |
Each detector element will be subdivided by this factor along each dimension. This should only be used if detector elements are larger than the pixels in the volume (default: 1). |
option.GPUindex |
The index of the GPU to use (default: 0). |
Example
import astra
import matplotlib.pyplot as plt
import numpy as np
# Create geometries
N = 256
N_ANGLES = 180
det_spacing = 1.0
angles = np.linspace(0, np.pi, N_ANGLES)
proj_geom = astra.create_proj_geom('parallel', det_spacing, N, angles)
vol_geom = astra.create_vol_geom(N, N)
# Generate phantom image
phantom_id, phantom = astra.data2d.shepp_logan(vol_geom)
# Calculate forward projection
projection_id = astra.data2d.create('-sino', proj_geom)
cfg = astra.astra_dict('FP_CUDA')
cfg['ProjectionDataId'] = projection_id
cfg['VolumeDataId'] = phantom_id
algorithm_id = astra.algorithm.create(cfg)
astra.algorithm.run(algorithm_id)
projection = astra.data2d.get(projection_id)
plt.imshow(projection, cmap='gray')
# Clean up
astra.data2d.delete([projection_id, phantom_id])
astra.algorithm.delete(algorithm_id)
%% Create phantom
N = 256;
phantom = phantom(N);
%% Create geometries
det_spacing = 1.0;
N_ANGLES = 180;
angles = linspace(0, pi, N_ANGLES);
proj_geom = astra_create_proj_geom('parallel', det_spacing, N, angles);
vol_geom = astra_create_vol_geom(N, N);
%% Calculate forward projection
phantom_id = astra_mex_data2d('create', '-vol', vol_geom, phantom);
projection_id = astra_mex_data2d('create', '-sino', proj_geom);
cfg = astra_struct('FP_CUDA');
cfg.ProjectionDataId = projection_id;
cfg.VolumeDataId = phantom_id;
algorithm_id = astra_mex_algorithm('create', cfg);
astra_mex_algorithm('run', algorithm_id);
projection = astra_mex_data2d('get', projection_id);
imshow(projection, []);
%% Clean up
astra_mex_data2d('delete', phantom_id, projection_id);
astra_mex_algorithm('delete', algorithm_id);