Merge pull request #146 from Bookaflok/bugfix20220120

Fix bug with improper cluster threshold set for variable threshold situations

src/extract.c

@@ -58,6 +58,7 @@ int sortit(infostruct *info, objliststruct *objlist, int minarea,
 	   deblendctx *deblendctx);
 void plistinit(int hasconv, int hasvar);
 void clean(objliststruct *objlist, double clean_param, int *survives);
+PIXTYPE get_mean_thresh(infostruct *info, pliststruct *pixel);
 int convert_to_catalog(objliststruct *objlist, const int *survives,
                        sep_catalog *cat, int w, int include_pixels);
 
@@ -626,7 +627,10 @@ int sep_extract(const sep_image *image, float thresh, int thresh_type,
 			  if ((int)info[co].pixnb >= minarea)
 			    {
 			      /* update threshold before object is processed */
-			      objlist.thresh = thresh;
+			      if (PLISTEXIST(thresh))
+			    objlist.thresh = get_mean_thresh(&info[co], objlist.plist);
+			      else
+			    objlist.thresh = thresh;
 
 			      status = sortit(&info[co], &objlist, minarea,
 					      finalobjlist,
@@ -993,6 +997,25 @@ void clean(objliststruct *objlist, double clean_param, int *survives)
     } /* outer loop of objlist (obj1) */
 }
 
+/************************** get_mean_thresh **********************************/
+/*
+Compute an average threshold from all pixels in the cluster
+*/
+PIXTYPE get_mean_thresh(infostruct *info, pliststruct *pixel)
+{
+  pliststruct   *pixt;
+  int           pix_accum=0;
+  PIXTYPE       thresh_accum=0;
+
+  for (pixt=pixel+info->firstpix; pixt>=pixel;
+       pixt=pixel+PLIST(pixt,nextpix))
+    {
+      thresh_accum += PLISTPIX(pixt,thresh);
+      pix_accum++;
+    }
+
+  return thresh_accum / pix_accum;
+}
 
 /*****************************************************************************/
 /* sep_catalog manipulations */