- Joaquim Rocha
- Principal Software Engineering Manager at Microsoft
That’s right, a new version of the world’s first Free Software skeleton tracking library is out. In every version we try to make Skeltrack more robust and this one is no exception.
We have changed the way the shoulders are inferred. This heuristic now uses a circumference around the user’s head and an arc with which it searches for the shoulders. Since we like to keep giving developers the ability to tweak the algorithm’s parameters, we had to change the properties related to the shoulders. We should probably improve the documentation with a visual explanation of how those properties work but meanwhile you can check the properties’ documentation.
Another issue we had was that the extremas we initially calculate result in e.g. the point at tip of the a finger (for a hand joint) or the top of the head. This was not an issue specifically but it might result in more unstable joints. For example, the Kinect device in particular might give blind spots in very bushy hair which would result in the head joint jittering more than usual. To fix this, we calculate the average of points around an extrema and assign it with that value. The radius of the sphere surrounding an extrema that is used to calculate this average can be controlled by using the extrema-sphere-radius property. Thus, if this behavior is not desired, this feature can be turned off just by simply assigning a 0 to this property.
Here is a couple of pictures describing this issue:
Due to a project that Igalia Interactivity has been working on, we had to use the Kinect in a vertical stance. By doing this we discovered a small bug that prevented Skeltrack to be used with a vertical depth image. This is corrected in this 0.1.10 version and while fixing it, we found out that it seems the other skeleton tracking alternatives also do not support the Kinect in a vertical stance; this might mean that if you want to use skeleton tracking with the Kinect vertically, your only choice is either to use Skeltrack or to convince Microsoft or PrimeSense to fix their solutions for you 🙂
Last but not least, the function skeltrack_skeleton_new was returning a GObject instance by mistake. We have corrected that and it now returns a pointer to SkeltrackSkeleton as expected.