Index: opencv/modules/features2d/src/detectors.cpp
===================================================================
--- opencv/modules/features2d/src/detectors.cpp	(revision 3295)
+++ opencv/modules/features2d/src/detectors.cpp	(working copy)
@@ -50,15 +50,14 @@
 */
 struct MaskPredicate
 {
-    MaskPredicate( const Mat& _mask ) : mask(_mask)
+    MaskPredicate( const Mat& _mask ) : mask(&_mask)
     {}
-    MaskPredicate& operator=(const MaskPredicate&) {}
     bool operator() (const KeyPoint& key_pt) const
     {
-      return mask.at<uchar>( (int)(key_pt.pt.y + 0.5f), (int)(key_pt.pt.x + 0.5f) ) == 0;
+      return mask->at<uchar>( (int)(key_pt.pt.y + 0.5f), (int)(key_pt.pt.x + 0.5f) ) == 0;
     }
 
-    const Mat& mask;
+    const Mat* mask;
 };
 
 void FeatureDetector::removeInvalidPoints( const Mat& mask, vector<KeyPoint>& keypoints )