6D-Reconstruction: fixed another bug in the volume downscaling

Signed-off-by: Nicola Vigano <nicola.vigano@esrf.fr>

zUtil_Maths/gtMathsUpsampleVolume.m

@@ -23,7 +23,15 @@ end
 
 function vol = upsample_interp_interleaving(vol, scale)
 % Faster than the custom made, bu still way slower than the simple one
-    vol = interpn(vol, scale-1, 'linear', 0);
+    num_size_4 = size(vol, 4);
+    if (num_size_4 == 1)
+        vol = interpn(vol, scale-1, 'linear', 0);
+    else
+        for ii4 = num_size_4:-1:1
+            new_vol(:, :, :, ii4) = interp3(vol(:, :, :, ii4), scale-1, 'linear', 0);
+        end
+        vol = new_vol;
+    end
 end
 
 function vol = upsample_interp(vol, scale)