2 ***********************************************************
3 $SNARK_Header: S N A R K 1 4 - A PICTURE RECONSTRUCTION PROGRAM $
4 $HeadURL: svn://dig.cs.gc.cuny.edu/snark/trunk/src/snark/art_artbck.cpp $
5 $LastChangedRevision: 85 $
6 $Date: 2014-07-02 16:07:08 -0400 (Wed, 02 Jul 2014) $
8 ***********************************************************
10 CALCULATE BACKPROJECTIONS (THE SAME AS BCKRAY)
11 WITH OPTION "HALF" IN ART
21 void art_class::artbck(
42 for(nb = 0; nb < numb; nb++) {
45 pictk += amt * weight[nb];
49 pictk = clip(pictk, thrlo, thrup, relax);
53 if(Modefl.lofl && (pict[k] <= thrlo) && (pictk >= halfwy)) {
54 pictk = halfwy - thtol;
57 if(Modefl.upfl && (pict[k] >= thrup) && (pictk <= halfwy)) {
58 pictk = halfwy + thtol;