+const char Backprojector::BPROJ_TRIG_STR[]= "trig";
+const char Backprojector::BPROJ_TABLE_STR[]= "table";
+const char Backprojector::BPROJ_DIFF_STR[]= "diff";
+const char Backprojector::BPROJ_DIFF2_STR[]= "diff2";
+const char Backprojector::BPROJ_IDIFF2_STR[]= "idiff2";
+const char Backprojector::BPROJ_IDIFF3_STR[]= "idiff3";
+
+const char Backprojector::BPROJ_TRIG_TITLE_STR[]= "Direc Trigometric";
+const char Backprojector::BPROJ_TABLE_TITLE_STR[]= "Trig Table";
+const char Backprojector::BPROJ_DIFF_TITLE_STR[]= "Diff";
+const char Backprojector::BPROJ_DIFF2_TITLE_STR[]= "Diff2";
+const char Backprojector::BPROJ_IDIFF2_TITLE_STR[]= "Integer Diff2";
+const char Backprojector::BPROJ_IDIFF3_TITLE_STR[]= "Integer Diff3";
+
+const char Backprojector::INTERP_NEAREST_STR[]= "nearest";
+const char Backprojector::INTERP_LINEAR_STR[]= "linear";
+const char Backprojector::INTERP_BSPLINE_STR[]= "bspline";
+const char Backprojector::INTERP_FREQ_PREINTERPOLATION_STR[]= "freq_preinterpolation";
+
+const char Backprojector::INTERP_NEAREST_TITLE_STR[]= "Nearest";
+const char Backprojector::INTERP_LINEAR_TITLE_STR[]= "Linear";
+const char Backprojector::INTERP_BSPLINE_TITLE_STR[]= "B-Spline";
+const char Backprojector::INTERP_FREQ_PREINTERPOLATION_TITLE_STR[]= "Frequency Preinterpolation";
+
+
+Backprojector::Backprojector (const Projections& proj, ImageFile& im, const char* const backprojName, const char* const interpName, const int interpFactor)