diff --git a/core/src/com/google/zxing/qrcode/QRCodeReader.java b/core/src/com/google/zxing/qrcode/QRCodeReader.java
index eb394df61..a073b2612 100644
--- a/core/src/com/google/zxing/qrcode/QRCodeReader.java
+++ b/core/src/com/google/zxing/qrcode/QRCodeReader.java
@@ -118,6 +118,11 @@ public class QRCodeReader implements Reader {
     int bottom = rightBottomBlack[1];
     int left = leftTopBlack[0];
     int right = rightBottomBlack[0];
+    
+    // Sanity check!
+    if (left >= right || top >= bottom) {
+      throw NotFoundException.getNotFoundInstance();
+    }
 
     if (bottom - top != right - left) {
       // Special case, where bottom-right module wasn't black so we found something else in the last row