--- /dev/null
+/*****************************************************************************
+** FILE IDENTIFICATION
+**
+** Name: rec_t.c Image Reconstruction Procedures
+** Programmer: Kevin Rosenberg
+** Date Started: Aug 84
+**
+** GLOBAL FUNCTIONS
+** proj_reconst() Reconstruct Image from Projections
+**
+** This is part of the CTSim program
+** Copyright (C) 1983-2000 Kevin Rosenberg
+**
+** $Id: reconstr.cpp,v 1.1 2000/06/19 02:59:34 kevin Exp $
+**
+** This program is free software; you can redistribute it and/or modify
+** it under the terms of the GNU General Public License (version 2) as
+** published by the Free Software Foundation.
+**
+** This program is distributed in the hope that it will be useful,
+** but WITHOUT ANY WARRANTY; without even the implied warranty of
+** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+** GNU General Public License for more details.
+**
+** You should have received a copy of the GNU General Public License
+** along with this program; if not, write to the Free Software
+** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+******************************************************************************/
+
+#include "ct.h"
+
+
+/* NAME
+ * proj_reconst Reconstruct Image from Projections
+ *
+ * SYNOPSIS
+ * im = proj_reconst (im, proj, filt_type, filt_param, interp_type)
+ * IMAGE *im Output image
+ * RAYSUM *proj Raysum data if in memory
+ * int filt_type Type of convolution filter to use
+ * double filt_param Filter specific parameter
+ * Currently, used only with Hamming filters
+ * int interp_type Type of interpolation method to use
+ *
+ * ALGORITHM
+ *
+ * Calculate one-dimensional filter in spatial domain
+ * Allocate & clear (zero) the 2d output image array
+ * For each projection view
+ * Convolve raysum array with filter
+ * Backproject raysums and add (summate) to image array
+ * end
+ */
+
+ImageFile&
+proj_reconst (ImageFile& im, Projections& proj, const FilterType filt_type, double filt_param, InterpolationType interp_type, int interp_param, const BackprojType backproj_type, const int trace)
+{
+ int ndet = proj.nDet();
+ int nview = proj.nView();
+ double det_inc = proj.detInc();
+ double detlen = (ndet - 1) * det_inc;
+ double *vec_proj = new double [ndet]; // projection data
+ int n_filtered_proj = ndet;
+ double* filtered_proj = new double [n_filtered_proj]; // convolved result
+
+#ifdef HAVE_BSPLINE_INTERP
+ int spline_order = 0, zoom_factor = 0;
+ if (interp_type == I_BSPLINE) {
+ zoom_factor = interp_param;
+ spline_order = 3;
+ zoom_factor = 3;
+ n_filtered_proj = (ndet - 1) * (zoom_factor + 1) + 1;
+ }
+#endif
+
+ int n_vec_filter = 2 * ndet - 1;
+ double filterBW = 1. / det_inc;
+ double filterMin = -detlen;
+ double filterMax = detlen;
+ double* vec_filter = filter_generate (filt_type, filterBW, filterMin, filterMax, n_vec_filter, filt_param, D_SPATIAL, 0);
+
+#if HAVE_SGP
+ double *plot_xaxis = NULL; /* array for plotting */
+ SGP_ID gid;
+ plot_xaxis = new double [n_vec_filter];
+
+ if (trace > TRACE_TEXT) {
+ int i;
+ double f;
+ double filterInc = (filterMax - filterMin) / (n_vec_filter - 1);
+ for (i = 0, f = filterMin; i < n_vec_filter; i++, f += filterInc)
+ plot_xaxis[i] = f;
+
+ gid = ezplot (plot_xaxis, vec_filter, n_vec_filter);
+ cio_put_str ("Press any key to continue");
+ cio_kb_getc ();
+ sgp2_close (gid);
+ }
+ if (trace >= TRACE_TEXT) {
+ printf ("nview=%d, ndet=%d, det_start=%.4f, det_inc=%.4f\n", proj.nView(), proj.nDet(), proj.detStart(), proj.detInc());
+ }
+#endif //HAVE_SGP
+
+ Backproject* bj = selectBackprojector (backproj_type, proj, im, interp_type);
+
+ for (int iview = 0; iview < nview; iview++) {
+ if (trace >= TRACE_TEXT)
+ printf ("Reconstructing view %d (last = %d)\n", iview, nview - 1);
+
+ DetectorArray& darray = proj.getDetectorArray (iview);
+ DetectorValue* detval = darray.detValues();
+
+ for (int j = 0; j < ndet; j++)
+ vec_proj[j] = detval[j];
+
+ for (int j = 0; j < ndet; j++)
+ filtered_proj[j] = convolve (vec_proj, vec_filter, det_inc, j, ndet, FUNC_BOTH);
+
+#ifdef HAVE_SGP
+ if (trace >= TRACE_PLOT) {
+ ezset ("clear.");
+ ezset ("xticks major 5.");
+ ezset ("xlabel ");
+ ezset ("ylabel ");
+ ezset ("xlength .5.");
+ ezset ("box.");
+ ezset ("grid.");
+ ezset ("ufinish yes.");
+ ezplot (vec_proj, plot_xaxis, proj.nDet());
+ ezset ("clear.");
+ ezset ("xticks major 5.");
+ ezset ("xlabel ");
+ ezset ("ylabel ");
+ ezset ("ustart yes.");
+ ezset ("xporigin .5.");
+ ezset ("xlength .5.");
+ ezset ("box");
+ ezset ("grid");
+ gid = ezplot (filtered_proj, plot_xaxis, proj.nDet());
+ }
+#endif //HAVE_SGP
+
+#ifdef HAVE_BSPLINE_INTERP
+ if (interp_type == I_BSPLINE)
+ bspline (proj.nDet(), zoom_factor, spline_order, filtered_proj, filtered_proj);
+
+#ifdef HAVE_SGP
+ if (trace >= TRACE_PLOT && interp_type == I_BSPLINE) {
+ bspline (proj.nDet(), zoom_factor, spline_order, filtered_proj, filtered_proj);
+ ezplot_1d (filtered_proj, n_filtered_proj);
+ }
+#endif
+#endif
+
+ bj->BackprojectView (filtered_proj, darray.viewAngle());
+
+#ifdef HAVE_SGP
+ if (trace >= TRACE_PLOT) {
+ char str[256];
+ printf ("Do you want to exit with current pic (y/n) -- ");
+ fgets(str, sizeof(str), stdin);
+ sgp2_close (sgp2_get_active_win());
+ if (tolower(str[0]) == 'y') {
+ break;
+ }
+ }
+#endif //HAVE_SGP
+ }
+
+ delete bj;
+ delete vec_proj;
+ delete filtered_proj;
+ delete vec_filter;
+
+#ifdef HAVE_SGP
+ delete plot_xaxis;
+#endif
+
+ return (im);
+}
+
projects / ctsim.git / blobdiff