Rhett Allain is an Associate Professor of Physics at Southeastern Louisiana University. He
enjoys teaching and talking about physics. Sometimes he takes things apart and can't
put them back together.I have previously compared Tracker Video Analysis and Logger Pro - check that out here. Really, the only advantage Logger Pro has over Tracker is that maybe it is easier to use for simple things and maybe students are already familiar with it from other analysis.
There are other video analysis programs out there. There is VideoPoint - but this is not free and I don't think it has been updated in quite some time. Also, don't forget Video Graph. A great program for it's time, but that time was 1997.
So, this post is really about Tracker and its feature of calibration point pairs. What is that? Ok. Suppose you have a movie and the darn camera keeps moving around. Each frame you have to move the origin, change the angle and rescale it. Crazy tedious. Tracker has a feature that allows you to pick two points in the video to take care of origin, angle, and scaling. Instead of describing how to use these points, I will just show you.
Hope that helps.
Comments
There is one more bonus LoggerPro has over Tracker. LoggerPro is a lot more stable. I don't know that LoggerPro has ever crashed on me while doing video analysis. Tracker does crash a bit on some computers. I had my students using it and some thought it was the greatest and some were very frustrated by the crashing. The bottom line for me is Tracker has a lot more power and I also like it better, but SAVE OFTEN!
Posted by: Steve Dickie | August 8, 2009 7:18 AM
Hi Rhett,
I've not used either, but I'm curious as to the statement that "the calibration points should be in the same plane." When are two distinct points not in a plane? Do you mean that the line connecting the points should be parallel to the plane of the camera?
Rob
Posted by: Rob | August 9, 2009 12:07 PM
@Rob,
Yes, same plane in the video but not same plane in real life. If the camera is moving, then 2 points at a different distance would have different motions due to parallax.
Ideally, you should be able to choose points that are in a plane that the object of interest is moving in.
Posted by: Rhett | August 10, 2009 4:39 PM
You mentioned a previous article about Tracker and LoggerPro, however, the link goes to Vernier. I tried looking for that article, but couldn't find it. Could you edit the above so that I can read what looks to be a promising article.
Thanks,
M Magnuson
Posted by: M Magnuson | November 7, 2010 5:02 PM