From 6c3137a8b5e71785a86e40cc78e0e5748e30ce8f Mon Sep 17 00:00:00 2001
From: Andrey Kamaev <no@email>
Date: Wed, 27 Jun 2012 15:15:32 +0000
Subject: [PATCH] Fixed divide by zero problem in cvStereoRectify (thanks to
 Philip Van Valkenberg) #2099

---
 modules/calib3d/src/calibration.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/modules/calib3d/src/calibration.cpp b/modules/calib3d/src/calibration.cpp
index f211c5db8..ffe1c5855 100644
--- a/modules/calib3d/src/calibration.cpp
+++ b/modules/calib3d/src/calibration.cpp
@@ -2366,7 +2366,8 @@ void cvStereoRectify( const CvMat* _cameraMatrix1, const CvMat* _cameraMatrix2,
     // calculate global Z rotation
     cvCrossProduct(&t,&uu,&ww);
     double nw = cvNorm(&ww, 0, CV_L2);
-    cvConvertScale(&ww, &ww, acos(fabs(c)/nt)/nw);
+    if (nw > 0.0)
+        cvConvertScale(&ww, &ww, acos(fabs(c)/nt)/nw);
     cvRodrigues2(&ww, &wR);
 
     // apply to both views