my $pj_if_cmd = "$::bindir/pj2if $pj_fname $pj_if_fname";
my $ir_cmd = "$ctrec_ver $pj_fname $ir_fname $IR_Nx $IR_Ny --filter $IR_Filter --filter-param $IR_Filter_Param --interp $IR_Interp --backproj $IR_Backproj";
my $diff_cmd = "$diff_ver $phantom_fname $ir_fname $diff_fname --comp";
my $pj_if_cmd = "$::bindir/pj2if $pj_fname $pj_if_fname";
my $ir_cmd = "$ctrec_ver $pj_fname $ir_fname $IR_Nx $IR_Ny --filter $IR_Filter --filter-param $IR_Filter_Param --interp $IR_Interp --backproj $IR_Backproj";
my $diff_cmd = "$diff_ver $phantom_fname $ir_fname $diff_fname --comp";