Index: trunk/ppImage/src/ppImageMeasureCrosstalk.c
===================================================================
--- trunk/ppImage/src/ppImageMeasureCrosstalk.c	(revision 23871)
+++ trunk/ppImage/src/ppImageMeasureCrosstalk.c	(revision 23903)
@@ -87,4 +87,5 @@
 	    if (!cell) continue;
 	    psImage *image = imageRow->data[col];
+	    if (!image) continue; // XXX assert on this?
 
 	    psStatsInit (stats);
@@ -100,4 +101,5 @@
 	for (int col = 0; col < cellRow->n; col++) {
 	    psImage *image = imageRow->data[col];
+	    if (!image) continue;
 
 	    // initialize the storage vectors
@@ -144,4 +146,5 @@
 
 		pmCell *cell = cellRow->data[i];
+		if (!cell) continue; // XXX assert on this?
 
 		psStatsInit (stats);