Tracking Objects in Physics Experiment Videos

Via the Twitterz, @voiceofrally linked to a blog post on sub-zero effects on rally cars relating to the upcoming Arctic Rally. Poking around the blog — — I came across a fascinating post on periodicity in wake turbulence, as seen in WRC rally car dust trails (Dust flow visualization images from Rally Portugal).

Hmmm.. I don’t need any more side projects, particularly related to things I know nothing about, like video image analysis, but I wondered if there are any tools out that that could do point tracking in video feeds of such noisy points…

I’m not sure if you can or not because I got sidetracked from my search almost immediately by Tracker, a seemingly longlived (i.e. several years old and still apparently maintained) Java application for video analysis and physics modeling.

In its basic form, you can import a video a and step through the frames, manually marking tracked points along the way. A coordinate system frame of reference can be defined, and data points grabbed accordingly. A range of data analysis tools let you analyse and chart the data you have collected as required.

So far, so brilliant. This allows learners to engage in the measurement and analysis part of the experimental process in a "digital humanities" style workflow. (Apps to support the coding of observational / behaviour data from video have been around for ages; for a recent example, see something like BORIS (Behavioral Observation Research Interactive Software).)

But manual coding can be time consuming after a while, and once you’ve started to develop a tacit / visceral feel for the process, what it involves, what sorts of mistakes / errors you can make, and what those mistakes look like in the data, then you can move on to automating parts of the data collection, perhaps in otehr situations, and spend more time on the analysis part of the experimental process.

And it seems like Tracker can help there too…

If I was in a position of having to be a home educator, I think this tool might be a good one to have in the physics toolbox…

…along with some videos from the maestro of physics education at all educational levels, Richard Feynman…

(Shorter clips from the Feynman video can also be found on Youtube, but I fail to see how anyone with even the shortest attention span can’t help but remain engaged by Feynman’s even faster flitting beween curiousity driven "and then I wondered…" observations…)

Author: Tony Hirst

I'm a Senior Lecturer at The Open University, with an interest in #opendata policy and practice, as well as general web tinkering...

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