+
+/* NAME
+ * Projections::reconstruct Reconstruct Image from Projections
+ *
+ * SYNOPSIS
+ * im = proj.reconstruct (im, filt_type, filt_param, interp_type)
+ * IMAGE *im Output image
+ * 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
+ */
+
+bool
+Projections::reconstruct (ImageFile& im, const char* const filterName, double filt_param, const char* const interpName, int interp_param, const char* const backprojectName, const int trace)
+{
+ int nview = m_nView;
+ double det_inc = m_detInc;
+ double detlen = (m_nDet - 1) * det_inc;
+ int n_filtered_proj = m_nDet;
+ double filtered_proj [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 = (m_nDet - 1) * (zoom_factor + 1) + 1;
+ }
+#endif
+
+ int n_vec_filter = 2 * m_nDet - 1;
+ double filterBW = 1. / det_inc;
+ double filterMin = -detlen;
+ double filterMax = detlen;
+
+ SignalFilter filter (filterName, filterBW, filterMin, filterMax, n_vec_filter, filt_param, "spatial", 0);
+ if (filter.fail()) {
+ sys_error (ERR_SEVERE, "%s [Projections::reconstruct]", filter.failMessage().c_str());
+ return false;
+ }
+
+ if (trace)
+ cout << "Reconstruct: filter="<<filterName<< ", interp="<<interpName<<", backproject="<<backprojectName<<endl;
+
+#if HAVE_SGP
+ SGP_ID gid;
+ double plot_xaxis [n_vec_filter]; // array for plotting
+
+ 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, filter.getFilter(), 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", m_nView, m_nDet, m_detStart, m_detInc);
+ }
+#endif //HAVE_SGP
+
+ Backprojector bj (*this, im, backprojectName, interpName);
+ if (bj.fail()) {
+ sys_error (ERR_SEVERE, "%s [Projections::reconstruct]", bj.failMessage().c_str());
+ return false;
+ }
+
+ for (int iview = 0; iview < m_nView; iview++) {
+ if (trace >= TRACE_TEXT)
+ printf ("Reconstructing view %d (last = %d)\n", iview, m_nView - 1);
+
+ DetectorArray& darray = getDetectorArray (iview);
+ DetectorValue* detval = darray.detValues();
+
+ for (int j = 0; j < m_nDet; j++)
+ filtered_proj[j] = filter.convolve (detval, det_inc, j, m_nDet);
+
+#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 (detval, plot_xaxis, m_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, m_nDet);
+ }
+#endif //HAVE_SGP
+
+#ifdef HAVE_BSPLINE_INTERP
+ if (interp_type == I_BSPLINE)
+ bspline (m_nDet, zoom_factor, spline_order, filtered_proj, filtered_proj);
+
+#ifdef HAVE_SGP
+ if (trace >= TRACE_PLOT && interp_type == I_BSPLINE) {
+ bspline (m_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
+ }
+
+ return true;
+}
+