Index: /trunk/psLib/src/imageops/psImageConvolve.c
===================================================================
--- /trunk/psLib/src/imageops/psImageConvolve.c	(revision 34723)
+++ /trunk/psLib/src/imageops/psImageConvolve.c	(revision 34724)
@@ -605,6 +605,16 @@
     PS_ASSERT_IMAGE_NON_NULL(image, false);
 
+    if (sigma < 0.25) {
+        psTrace("psLib.imageops", 5, "sigma: %f < 0.25 skipping smoothing", sigma);
+        return true;
+    }
+
     // relevant terms
     int Nrange = sigma*Nsigma + 0.5;    // Number of pixels either side for convolution kernel
+    if (Nrange < 1) {
+        // using zero will cause an arithmetic exception in the loop
+        psTrace("psLib.imageops", 5, "Nrange %d for smoothing too small skipping smoothing", Nrange);
+        return true;
+    }
     int Nx = image->numCols;            // Number of columns
     int Ny = image->numRows;            // Number of rows