CGLS ==== This is a CPU implementation of the Conjugate Gradient Least Squares (CGLS) algorithm for 2D data sets. It takes projection data and an initial reconstruction as input, and returns the reconstruction after a specified number of CGLS iterations. The internal state of the CGLS algorithm is **NOT** reset between astra_mex_algorithm('iterate') calls. Updating the contents of the projection data and reconstruction data astra_mex_data2d objects between astra_mex_algorithm('iterate') calls will produce undefined behaviour. Supported geometries: parallel, fanflat, fanflat_vec, matrix. Configuration options --------------------- =============================== ======== ======================================= name type description =============================== ======== ======================================= cfg.ProjectorId required The astra_mex_projector ID of the projector. cfg.ProjectionDataId required The astra_mex_data2d ID of the projection data cfg.ReconstructionDataId required The astra_mex_data2d ID of the reconstruction data. The content of this when starting CGLS is used as the initial reconstruction. cfg.option.SinogramMaskId optional If specified, the astra_mex_data2d ID of a projection-data-sized volume to be used as a mask. cfg.option.ReconstructionMaskId optional If specified, the astra_mex_data2d ID of a volume-data-sized volume to be used as a mask. =============================== ======== ======================================= Example ------- .. code-block:: matlab %% create phantom V_exact = phantom(256); %% create geometries and projector proj_geom = astra_create_proj_geom('parallel', 1.0, 256, linspace2(0,pi,180)); vol_geom = astra_create_vol_geom(256,256); proj_id = astra_create_projector('linear', proj_geom, vol_geom); %% create forward projection [sinogram_id, sinogram] = astra_create_sino(V_exact, proj_id); %% reconstruct recon_id = astra_mex_data2d('create', '-vol', vol_geom, 0); cfg = astra_struct('CGLS'); cfg.ProjectorId = proj_id; cfg.ProjectionDataId = sinogram_id; cfg.ReconstructionDataId = recon_id; cgls_id = astra_mex_algorithm('create', cfg); astra_mex_algorithm('iterate', cgls_id, 100); V = astra_mex_data2d('get', recon_id); imshow(V, []); %% garbage disposal astra_mex_data2d('delete', sinogram_id, recon_id); astra_mex_projector('delete', proj_id); astra_mex_algorithm('delete', cgls_id);