- Joaquim Rocha
- Principal Software Engineering Manager at Microsoft
The first release of Skeltrack in 2013 is out!
This is also the first version I release without being associated with Igalia but the company agreed that I keep maintaining the project. That’s one of the good aspects of working in Free Software as your daily job: you can continue working on them even if you’re no longer in the company where it was first developed.
This new version is not bloated with new features so “why such a wait?” you might ask. Well, the reason is that there have been a few changes in my life since last year and, more importantly, after I left Igalia, I didn’t have a Kinect and thus, working on Skeltrack was a bit difficult… But finally a few weeks ago I bought one so now I am able to keep hacking.
The greatest thing in this release is a big improvement in the performance of Skeltrack when tracking joints. You see, when I originally developed it, I was more concerned with getting it to actually track the skeleton joints than doing it quickly 🙂 Luckily, Iago López (kudos to him) did a neat work in fixing some misuses of GList but more importantly, re-implementing Dijkstra using a priority queue. If you remember your algorithms courses well, with this change you can make Dijkstra go from quadratic to linearithmic time and that’s a BIG improvement. Here is the difference between the old code and the new expressed in a plot:
The values used to generate the plot were the time it took skeltrack_skeleton_track_joints_sync to execute. For each of the versions, this function was called 25 times for each of the 550 depth frames and the final values in the plot are the arithmetic average of the results per frame. They were executed in my i5 2.40 GHz laptop without any applications or the desktop running (besides system’s services). As you can see, there’s a great difference between the speed of the old code and the new. I can’t wait to try Skeltrack on weaker hardware now 😀
(BTW, why 0.1.14 and not 0.1.12? Because of the “release curse” which made me aware of a simple but important bug fix right after pushing 0.1.12…)
Besides some small bug fixing in the library, the Skeltrack Kinect example was ported to Clutter 1.12 to keep up with the work done upstream.
Another new thing is that now Skeltrack has a webpage. I recently found out about GitHub’s automatically generated web pages and I thought this would be better than having people visit GitHub’s repo page so there you go: http://joaquimrocha.github.io/Skeltrack/ The page is a bit ugly and minimalist but we’ll improve it.