diff options
Diffstat (limited to 'samples/matlab')
-rw-r--r-- | samples/matlab/s010_supersampling.m | 28 | ||||
-rw-r--r-- | samples/matlab/s017_opTomo.m | 62 |
2 files changed, 72 insertions, 18 deletions
diff --git a/samples/matlab/s010_supersampling.m b/samples/matlab/s010_supersampling.m index 80f6f56..148f6ad 100644 --- a/samples/matlab/s010_supersampling.m +++ b/samples/matlab/s010_supersampling.m @@ -12,23 +12,15 @@ vol_geom = astra_create_vol_geom(256, 256); proj_geom = astra_create_proj_geom('parallel', 3.0, 128, linspace2(0,pi,180)); P = phantom(256); -% Because the astra_create_sino_gpu wrapper does not have support for -% all possible algorithm options, we manually create a sinogram -phantom_id = astra_mex_data2d('create', '-vol', vol_geom, P); -sinogram_id = astra_mex_data2d('create', '-sino', proj_geom); -cfg = astra_struct('FP_CUDA'); -cfg.VolumeDataId = phantom_id; -cfg.ProjectionDataId = sinogram_id; +% We create a projector set up to use 3 rays per detector element +cfg_proj = astra_struct('cuda'); +cfg_proj.option.DetectorSuperSampling = 3; +cfg_proj.ProjectionGeometry = proj_geom; +cfg_proj.VolumeGeometry = vol_geom; +proj_id = astra_mex_projector('create', cfg_proj); -% Set up 3 rays per detector element -cfg.option.DetectorSuperSampling = 3; -alg_id = astra_mex_algorithm('create', cfg); -astra_mex_algorithm('run', alg_id); -astra_mex_algorithm('delete', alg_id); -astra_mex_data2d('delete', phantom_id); - -sinogram3 = astra_mex_data2d('get', sinogram_id); +[sinogram3 sinogram_id] = astra_create_sino(P, proj_id); figure(1); imshow(P, []); figure(2); imshow(sinogram3, []); @@ -39,14 +31,14 @@ rec_id = astra_mex_data2d('create', '-vol', vol_geom); cfg = astra_struct('SIRT_CUDA'); cfg.ReconstructionDataId = rec_id; cfg.ProjectionDataId = sinogram_id; -% Set up 3 rays per detector element -cfg.option.DetectorSuperSampling = 3; +cfg.ProjectorId = proj_id; + % There is also an option for supersampling during the backprojection step. % This should be used if your detector pixels are smaller than the voxels. % Set up 2 rays per image pixel dimension, for 4 rays total per image pixel. -% cfg.option.PixelSuperSampling = 2; +% cfg_proj.option.PixelSuperSampling = 2; alg_id = astra_mex_algorithm('create', cfg); diff --git a/samples/matlab/s017_opTomo.m b/samples/matlab/s017_opTomo.m new file mode 100644 index 0000000..891a93d --- /dev/null +++ b/samples/matlab/s017_opTomo.m @@ -0,0 +1,62 @@ +% ----------------------------------------------------------------------- +% This file is part of the ASTRA Toolbox +% +% Copyright: 2010-2015, iMinds-Vision Lab, University of Antwerp +% 2014-2015, CWI, Amsterdam +% License: Open Source under GPLv3 +% Contact: astra@uantwerpen.be +% Website: http://sf.net/projects/astra-toolbox +% ----------------------------------------------------------------------- + +% This sample illustrates the use of opTomo. +% +% opTomo is a wrapper around the FP and BP operations of the ASTRA Toolbox, +% to allow you to use them as you would a matrix. +% +% This class requires the Spot Linear-Operator Toolbox to be installed. +% You can download this at http://www.cs.ubc.ca/labs/scl/spot/ + +% load a phantom image +im = phantom(256); +% and flatten it to a vector +x = im(:); + +%% Setting up the geometry +% projection geometry +proj_geom = astra_create_proj_geom('parallel', 1, 256, linspace2(0,pi,180)); +% object dimensions +vol_geom = astra_create_vol_geom(256,256); + +%% Generate projection data +% Create the Spot operator for ASTRA using the GPU. +W = opTomo('cuda', proj_geom, vol_geom); + +p = W*x; + +% reshape the vector into a sinogram +sinogram = reshape(p, W.proj_size); +imshow(sinogram, []); + + +%% Reconstruction +% We use a least squares solver lsqr from Matlab to solve the +% equation W*x = p. +% Max number of iterations is 100, convergence tolerance of 1e-6. +y = lsqr(W, p, 1e-6, 100); + +% the output is a vector, so we reshape it into an image +reconstruction = reshape(y, W.vol_size); + +subplot(1,3,1); +imshow(reconstruction, []); +title('Reconstruction'); + +subplot(1,3,2); +imshow(im, []); +title('Ground truth'); + +% The transpose of the operator corresponds to the backprojection. +backProjection = W'*p; +subplot(1,3,3); +imshow(reshape(backProjection, W.vol_size), []); +title('Backprojection'); |