How to track a marked point from this video?

asked 2016-07-11 05:24:00 -0600

Frederic Faure gravatar image

Hi, I am preparing some lectures about "chaotic dynamics" and for this i would like to study the motion of this object: https://goo.gl/photos/TNoUum1inhhFCZ259

I know C++ but not opencv. What is the best way to extract a list of positions x(t), y(t) (where t is time or image number) of one of the yellow marked points from one of these videos please?

Thanks!

Frederic Faure.

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Comments

In my opinion:

You will have to finely tune the parameters I think.

Eduardo gravatar imageEduardo ( 2016-07-11 07:22:14 -0600 )edit

For the segmenting the yellow, you also need the inRange function.

Secondly, make sure you use Mophological operations to close any small holes in the segmentation.

Personally, I suggest using the connectedComponents function instead of contours as it's simpler to understand.

And last, remember that the yellow spots don't move very far, so just grab the closest blob centroid to the previous one and you should have a good list of points.

Tetragramm gravatar imageTetragramm ( 2016-07-11 17:58:10 -0600 )edit

Previous comment are the way even if it looks you are looking for 4 markers right ? My hints:

  • For accurate positions you have to calibrate your camera and apply reverse perspective transform (To understand the point look at the lines in the wood)
  • Play with the environment to enhance markers detectability. For example
    • Avoid frontal light because reflection saturates the image
    • If you can, paint or use a mask on disks so that will be similar to the background.
    • As markers use 4 small sticks with complementary colors like green,magenta, red, cyan and avoid the black dot inside.
pklab gravatar imagepklab ( 2016-07-12 02:10:17 -0600 )edit
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