+
+/* 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 filterMethodName, const int zeropad, const char* const interpName, int interpFactor, const char* const backprojectName, const int trace) const
+{
+ double detInc = m_detInc;
+ int n_filteredProj = m_nDet * interpFactor;
+ double filteredProj [n_filteredProj]; // filtered projections
+
+#ifdef HAVE_BSPLINE_INTERP
+ int spline_order = 0, zoom_factor = 0;
+ if (interp_type == I_BSPLINE) {
+ zoom_factor = interpFactor;
+ spline_order = 3;
+ zoom_factor = 3;
+ n_filteredProj = (m_nDet - 1) * (zoom_factor + 1) + 1;
+ }
+#endif
+
+ double filterBW = 1. / detInc;
+ SignalFilter filter (filterName, filterMethodName, filterBW, m_detInc, m_nDet, filt_param, "spatial", zeropad, interpFactor);
+ filter.setTraceLevel(trace);
+
+ 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
+ int nVecFilter = filter.getNFilterPoints();
+ double plot_xaxis [nVecFilter]; // array for plotting
+
+ if (trace > TRACE_TEXT && nVecFilter > 0) {
+ int i;
+ double f;
+ double filterInc = filter.getFilterIncrement();
+ for (i = 0, f = filter.getFilterMin(); i < nVecFilter; i++, f += filterInc)
+ plot_xaxis[i] = f;
+
+ if (filter.getFilter()) {
+ SGPDriver sgpDriver ("Filter Function");
+ SGP sgp (sgpDriver);
+ EZPlot ezplot (sgp);
+
+ ezplot.ezset ("title Filter Response");
+ ezplot.addCurve (plot_xaxis, filter.getFilter(), nVecFilter);
+ ezplot.plot();
+ cio_put_str ("Press any key to continue");
+ cio_kb_getc ();
+ }
+ }
+ if (trace >= TRACE_TEXT) {
+ printf ("nview=%d, ndet=%d, det_start=%.4f, detInc=%.4f\n", m_nView, m_nDet, m_detStart, m_detInc);
+ }
+#endif //HAVE_SGP
+
+ Backprojector bj (*this, im, backprojectName, interpName, interpFactor);
+ 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);
+
+ const DetectorArray& darray = getDetectorArray (iview);
+ const DetectorValue* detval = darray.detValues();
+
+ filter.filterSignal (detval, filteredProj);
+
+
+
+#ifdef HAVE_BSPLINE_INTERP
+ if (interp_type == I_BSPLINE)
+ bspline (m_nDet, zoom_factor, spline_order, filteredProj, filteredProj);
+
+#ifdef HAVE_SGP
+ if (trace >= TRACE_PLOT && interp_type == I_BSPLINE) {
+ bspline (m_nDet, zoom_factor, spline_order, filteredProj, filteredProj);
+ ezplot_1d (filteredProj, n_filteredProj);
+ }
+#endif
+#endif
+
+ bj.BackprojectView (filteredProj, darray.viewAngle());
+
+#ifdef HAVE_SGP
+ if (trace >= TRACE_PLOT) {
+ SGPDriver sgpDriverProj ("Projection");
+ SGP sgpProj (sgpDriverProj);
+ EZPlot ezplotProj (sgpProj);
+
+ ezplotProj.ezset ("clear");
+ ezplotProj.ezset ("title Filtered Projection");
+ ezplotProj.ezset ("xticks major 5.");
+ ezplotProj.ezset ("xlabel ");
+ ezplotProj.ezset ("ylabel ");
+ ezplotProj.ezset ("yporigin .5.");
+ ezplotProj.ezset ("ylength .5.");
+ ezplotProj.ezset ("box.");
+ ezplotProj.ezset ("grid.");
+ ezplotProj.addCurve (plot_xaxis, detval, m_nDet);
+ ezplotProj.plot();
+ ezplotProj.ezset ("clear");
+ ezplotProj.ezset ("xticks major 5.");
+ ezplotProj.ezset ("xlabel ");
+ ezplotProj.ezset ("ylabel ");
+ ezplotProj.ezset ("ylength .5.");
+ ezplotProj.ezset ("box");
+ ezplotProj.ezset ("grid");
+ ezplotProj.addCurve (plot_xaxis, filteredProj, n_filteredProj);
+ ezplotProj.plot();
+
+ cout << "Do you want to exit with current pic (y/n)? " << flush;
+ char str[256];
+ fgets(str, sizeof(str), stdin);
+ if (tolower(str[0]) == 'y') {
+ break;
+ }
+ }
+#endif //HAVE_SGP
+ }
+
+ return true;
+}
+