opencv backgroundsubtractor not updating

Question

I'm using python 2.7.9 and opencv version 2.4.8.

I'm trying to detect moving cars from a movie. First frame in the movie already has a car and once the car leaves, the contour stays there. I tried playing with BackgroundSubtractorMOG params but they seemed to be ignored. Setting history to 10 does nothing and 200 frames into the movie I still have the original contour.

Thanks for reading

Answer 1

In reading opencv tickets I found that Sebastian Ramirez found the problem source and a solution.

The problem is that method "apply" has learningRate set to zero by default. Solve the problem by calling it like this:

history = 10 # or whatever is appropriate for you

fgmask = fgbg.apply(frame, learningRate = 1.0/history)