This is somewhat a follow-up to my earlier question asking how can I get optical flow out of a Blender scene
I have successfully achieved that goal by enabling vector output in the render layers, and saving the output as OpenEXR files.
However, I see that blender takes the liberty of thresholding the motion values so as to make "stationary" pixels 0. The problem is that blender's threshold is too high, and it also zeroes pixels with little motion.
The graph is the motion along a rotating plane turning in one direction.As the graph shoes, anything that's below 0.10 are assigned to 0, whereas in reality the values should form a continuous line starting from 0 (i.e. rotation axis), going to higher motion values (i.e. the edge of the plane). That means blender simply ignores smaller motion.
I understand the computational necessity behind this. But is there a way to adjust this threshold (preferably using python interface)? I'm just losing too much information and I'm just not happy cropping everything below an arbitrary number that blender imposes.