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optical flow in opencv_apps #67
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@k-okada created that package: it is an adaptation of the OpenCV samples for ROS. |
My initial motivation for this package is to used in 'proper' applications , so thanks you for your advice. As for your Renaming from |
Thanks for the response. I was not sure whether you can rely on no message drops, but now I realized that you can detect message drops by checking Another suggestion is that there should be a difference between dense and sparse optical flow in the messages. Dense optical flow is in opencv an Image of type |
Issue got moved to ros-perception/opencv_apps#2 |
remove warnings
Hi! First of all I'm quite new to ROS so I'm not sure whether this is a silly question.
What role do the
opencv_apps
play in this repository? Are those meant just as code examples and not meant to be used within 'proper' applications?In short: is it advisable to use
opencv_apps/Flow.msg
andfback_flow_nodelet
in my application or should I roll my own? The fact thatfback_flow_nodelet
unconditionally draws the flow visualization suggests that it's really meant more as an example application, rather than a general nodelet for optical flow.If
opencv_apps
are meant to be useful apart from serving as a code example I would suggest a few changes (and gladly provide pull requests) to the optical flow part.In particular I think that the definition of the flow messages should be different. In
Flow.msg
the flow vector is calledvelocity
, but whatfback_flow_nodelet
andlk_flow_nodelet
really compute are the motions between two frames in pixels irrespective of the time passed between the two frames. So either the nodelets need to scale the movement by the time between the frames, so that thevelocity
field inFlow.msg
get a proper unit (px/s e.g.), orvelocity
needs to be renamed todisplacement
and atime
field needs to be added toFlow.msg
.PS: great repo! 👍 😄
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