Hello everyone, I'm also new here. :-)
@shuzhiyu I'm also interested in getting optical flow data. I don't think it can be generated by unrealcv at this point, but hopefully others will correct me if I'm wrong.
In the MPI Sintel dataset the authors "modified
Blender’s internal motion blur pipeline to give us accurate motion vectors at
each pixel" [http://files.is.tue.mpg.de/black/papers/ButlerECCV2012-corrected.pdf]
Doing something similar might be possible in UE4 as well.
@qiuwch Thanks for your answer. Indeed, it's not trivial to combine it with the static scene renderings and the way the camera is moved now. I was thinking about implementing a vehicle model, which is responsible for moving the camera instead of the jumps with location/moveto/rotation commands. In a bit similar way how AirSim does, but with a lot simpler model. However, then view synchronization might get tricky (it is not solved in AirSim at this point)... So not necessarily a good direction.
On top of this, optical flow is not necessarily the same as motion blur, if you decide to capture frames with a lower rate than the frame rate of your camera.
Anyway, I'll keep thinking on this. I'm trying to use UnrealCV for an RL project, so it would be nice to have both motion blur on the captured images and optical flow accessible. But for now I'm just getting started with UE4 and UnrealCV. :-)