Copied errorCovPre to errorCovPost. This allows the correct behaviour of the uncertainty to grow when there is missing data for each predict step.

modules/video/src/kalman.cpp

@@ -266,6 +266,7 @@ const Mat& KalmanFilter::predict(const Mat& control)
 
     // handle the case when there will be measurement before the next predict.
     statePre.copyTo(statePost);
+    errorCovPre.copyTo(errorCovPost);
 
     return statePre;
 }