Flickering depth map OpenCV

Question

after some attempts I managed to get a pretty accurate disparity map of the scene I am filming with my stereo camera, using OpenCV's StereoSGBM function after rectification and calibration of the camera, and computing the disparity. I have also applied the Weighted Least Squares (WLS) filter on the final result which made me obtain something way more homogenous and nicely looking:

However, there is still a depth map "flickering" that needs to be fixed, meaning that stable objects change their depth grey value from frame to frame making the information non reliable. I read it is a common problem but have not found a way to solve it. The depth map is recalculating depths for each frame while something time consistent is needed. Any idea on how to solve this?

Answer 1

I don't know if you found a solution for this but I'm experiencing a similar problem. What I understood so far is that this "flickering" can be mainly because the normalization operation of the depth values.

In my case I noticed that when there are blobs, the upper and lower values for the depth is inside a big range and this lead to a different values normalization. How do you use to normalize the depth map? This can be relevant!

Another thing that I suggest you to investigate are the parameters of the stereo algorithm. For StereoSGBM you have a lot of parameters to play with, try using a different combination of them.

P.S. = If you found a solution for this, I would be more than happy to know how you figured it out, if you can share the solution I will appreciate it. Mine are just some ideas and starting point that are in my opinion the major causes.