Thanks for the Optical Flow module!
from United States  [214 posts]
12 years
Hi STeven,

The new Optical Flow module rocks!  Congratulations on getting it
out--it is truly amazing.

I have one question on how to use it.  Suppose I want my robot to detect a moving person even though the robot and its camera are moving.  I see you have a checkbox called "Eliminate Global Flow".  When I check this box and move the camera slowly and smoothly, I see how the length of the red needles is greatly reduced and the green average movement vector is roughly zero.  I'm guessing that under perfect conditions, the red needles would disappear altogether so that any left over needles would belong to a moving object--is that correct?  If so, would it be possible to have a threshold for "needle length" so that all needles smaller than the threshold are not displayed?  The the left over needles--corresponding to the moving object--could then be fed into the COG module for tracking.

Or is there a better way to do this?


Anonymous 12 years

Thanks for the feedback. Appreciate it!

Yes, you could probably disable the needles and add in the "block" color. Then use a threshold module to eliminate the low light blocks which are the shorter needles that you mention. This allows you to eliminate slow movement and allow the COG to focus on the larger (or in the case of the blocks the "lighter" areas). It should work and the reason for the Block color. Be sure to uncheck the display as annotation and remove the vector color too otherwise the COG will pick up on those graphics too!

from United States  [214 posts] 12 years
Thanks STeven--don't know how I missed that!  Yes, that is exactly what I was looking for.  So I'll play with some threshold strategies and see how well I can separate out object movement from global movement of the camera.


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