%------------------------------------------------------------------------ % This file is part of the % All Scale Tomographic Reconstruction Antwerp Toolbox ("ASTRA-Toolbox") % % Copyright: iMinds-Vision Lab, University of Antwerp % License: Open Source under GPLv3 % Contact: mailto:astra@ua.ac.be % Website: http://astra.ua.ac.be %------------------------------------------------------------------------ % In this example we will create a reconstruction in a circular region, % instead of the usual rectangle. % This is done by placing a circular mask on the square reconstruction volume: c = -127.5:127.5; [x y] = meshgrid(-127.5:127.5,-127.5:127.5); mask = (x.^2 + y.^2 < 127.5^2); figure(1); imshow(mask, []); vol_geom = astra_create_vol_geom(256, 256); proj_geom = astra_create_proj_geom('parallel', 1.0, 384, linspace2(0,pi,50)); % As before, create a sinogram from a phantom P = phantom(256); [sinogram_id, sinogram] = astra_create_sino_gpu(P, proj_geom, vol_geom); figure(2); imshow(P, []); figure(3); imshow(sinogram, []); % Create a data object for the reconstruction rec_id = astra_mex_data2d('create', '-vol', vol_geom); % Create a data object for the mask mask_id = astra_mex_data2d('create', '-vol', vol_geom, mask); % Set up the parameters for a reconstruction algorithm using the GPU cfg = astra_struct('SIRT_CUDA'); cfg.ReconstructionDataId = rec_id; cfg.ProjectionDataId = sinogram_id; cfg.option.ReconstructionMaskId = mask_id; % Create the algorithm object from the configuration structure alg_id = astra_mex_algorithm('create', cfg); % Run 150 iterations of the algorithm astra_mex_algorithm('iterate', alg_id, 150); % Get the result rec = astra_mex_data2d('get', rec_id); figure(4); imshow(rec, []); % Clean up. Note that GPU memory is tied up in the algorithm object, % and main RAM in the data objects. astra_mex_algorithm('delete', alg_id); astra_mex_data2d('delete', mask_id); astra_mex_data2d('delete', rec_id); astra_mex_data2d('delete', sinogram_id);