Tracking a Laser pointer with Python and OpenCV

Published on Jan. 24, 2008, 7:13 a.m.

opencv python

A recent thread on the OpenCV mailing list (entitled: "Tracking laser dots") discussed techniques that could be used to track the dot from a laser pointer. This sounded like something fun, so I finally got around to trying it out. Essentially this could be done acheived by the following algorithm:

  1. Grab the video frame.
  2. Convert the video frame to the HSV color space.
  3. Split the frame into individual components (separate images for H, S, and V).
  4. Apply a threshold to each compenent (hopefully keeping just the dot from the laser). It was originally suggested that just the Hue component be used to search for the laser's dot, but I actually got several false positives doing this. Therefore, using Value in addition to Hue gave me a more reliable result. I can see where finding good threshold values for all 3 components would be a good approach in some situations.
  5. Finally, perform an AND operation on the 3 images (which "should" cut down on false positives)

I should note that my testing was performed using a red laser pointer and a large white sheet of paper in an well-lit office. Since I was only tracking the dot on the paper, this turned out to be a fairly easy task to accomplish. Finding good threshold values in other situations would be much more difficult.

Update: This code is now on Github: https://github.com/bradmontgomery/python-laser-tracker

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