Category Archives: igalia

Django Workshop at Free Software Master 2012

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Last weekend I gave my annual Django workshop for this year’s students of the Free Software Master that Igalia organizes.

When I started with Django it was 2007 and I was happy with its version 0.96 :)
Currently with its version 1.4, the path that it took and the improvements it has got are incredible and it is used by many interesting companies and organizations.

My presentation for this year’s workshop covers more things and is based on Django 1.4.
You can check it out below, the license is Creative Commons as usual:


(direct link to presentation in SpeakerDeck)

Skeltrack 0.1.4 “smoothie skeleton”

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Here is the new version of Skeltrack, the Free Software library for human skeleton tracking from depth buffers.

Since the last release, I have presented Skeltrack at two events and built a cool demo of what can be done with this library.

What’s new

Apart from some bug fixes, this 0.1.4 version also introduces unit tests for making our development easier.
Yet, the big feature introduced in this version is the joints’ smoothing. If you have tried Skeltrack or watched the videos, you might have noticed that the skeleton is all jittery as if the joints were doing some caribbean dance. This is due to noise and other small changes in the depth buffer that happen in devices like the Kinect (and if you are wondering, it happens to the proprietary alternatives as well), so I implemented a way to smooth the joints’ jitters.

Smooth and quiet

This improvement was implemented using Holt’s Double Exponential Smoothing (which, for example, is what Microsoft’s Kinect SDK uses).
There are two properties that control this feature. The self-explanatory “enable-smoothing” property will turn the smoothing on or off and the “smoothing-factor” determines how much it should be smoothed. This value ranges from 0 to 1 and works as described in the mentioned Holt’s algorithm: values closer to 0 will give more weight to previous values of the joints as opposed to values closer to 1 that will consider the latest and current joints’ values more important. This means that values closer to 0 will offer a better smoothing but a bit of lag might be noticed so users should really choose this value themselves, as there’s no “good for all” factor. The smoothing is enabled by default with a factor of 0.5.

To show how well this might improve your Skeltrack-powered application, here is a video showing Skeltrack with the smoothing disabled and then enabled with a factor of 0.25.


(direct link to video in Vimeo)

The application shown in the video is the Kinect example we ship with Skeltrack which was also updated to allow controlling the smoothing feature.

Contribute

There are still a good number of tasks to be done that will improve Skeltrack. You can contribute too by forking the project at GitHub and sending us patches or you can of course hire Igalia to boost its development and make it rock even harder.

Let me know of any applications you’re developing with Skeltrack and how we can make it better. Check out the documentation and file some bugs if you run into trouble.

Stay smooth.

New SeriesFinale Harmattan and Fremantle releases

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That’s right, a couple of weeks ago new versions of SeriesFinale were released.
There was a long absence between these and the previous releases. The truth is that it has become more and more difficult for me to find the motivation (and time) to do work on an application for platforms I am not currently using. Still, I have had some emails from people showing their appreciation and Juan has also helped a lot (he is the reason there is also a new N900 release).

If you’re following the development of SeriesFinale, I have recently moved the repository over to GitHub (like I did for most of my projects). GitHub is so much faster than Gitorious and has nice features such as an issue tracker. Before you say it, although GitHub is not Open Source software, we’re talking about a hosted solution for Git repositories from a very cool company and I had no intentions of hosting Gitorious on my own anyway.

So what’s new in SeriesFinale? I need to differentiate between the platforms’ versions first.
Harmattan (N9) is on the 0.6.9 version and many bugs were solved like:
* Marking all episodes from the episodes’ list menu (nd#1)
* Episodes’ overview height (nd#9)
* Updating the shows season list
* Add a close button to show info dialog
* Add mark none action to the episodes’ list menu

There are still some issues when scrolling the lists which I’ve looked into and could not find any solution, I am convinced it actually has to do with the Python bindings of QML…

Fremantle (N900) is on version 0.6.10 and has less visible changes but the threads, languages and sorting functions were improved.

Adding the the new Harmattan version to the Nokia Store was also a challenge (it kept being rejected due to tiny details) but it eventually went through.

Be sure to test and vote for SF on Fremantle, or, in case you have an N9, get the new version from the Nokia Store:

Get SeriesFinale from Ovi Store

Attending LinuxTag 2012

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I will be travelling to wonderful Berlin next Wednesday to attend LinuxTag 2012.

I really liked the event last year and got good feedback from the people that attended my OCRFeeder‘s presentation.

This year I am presenting Skeltrack, a Free Software skeleton tracking library I created in Igalia. If you haven’t heard about it, take a look at these videos to see what it is about. My presentation will be on Saturday, at 10:30, in Europa II room.

I’m looking forward to meet people in there so let’s have a beer together and talk about Free Software.