fixed wrong call for preprocessing 3D image channels

semseg/SemSegObliqueTree.cpp

@@ -79,9 +79,9 @@ void SemSegObliqueTree::preprocessChannels (
                     {
                         double h,s,v;
                         ColorConversion::ccRGBtoHSV(r, g, b, &h, &s, &v);
-                        imgD->set( x, y, h, 0);
-                        imgD->set( x, y, s, 1);
-                        imgD->set( x, y, v, 2);
+                        imgD->set( x, y, z, h, 0);
+                        imgD->set( x, y, z, s, 1);
+                        imgD->set( x, y, z, v, 2);
                     }
                     else if ( colorMode == 2 )
                     {