OpenKinect Maturity

Question

I'm interested in writing some homebrew code for the Microsoft Kinect console. I have a few applications which I think would translate well to the platform. I've been toying with the idea of giving it a shot using the OpenKinect drivers and libraries. Obviously this would be a lot of work, but I am wondering just how much. Does anyone have experience with OpenKinect? Do you get only the raw video/audio data from the device, or has anyone written higher level abstractions to make common tasks easier?

Answer 1

The OpenKinect library is basically a driver — at least for now — so don't expect much high functions from it. You will more or less get the raw data from both the depth and the video cameras.
This is basically an array received in a callback function each time a frame arrives.

You can give it a try by following the instructions provided on the OpenKinect website, it's really quick to install and try it, and you can play a bit with the glview application provided to get a feeling of what's possible. I've set up a few demos using opencv, and got pretty cool results even though I didn't have much background in computer vision so I can only encourage you to try it yourself!

 
Alternately, if you're looking for more advanced functions, the OpenNI framework was just released this week and provides some impressive high level algorithms such as skeleton tracking and some gesture recognition. Part of the framework is proprietary algorithms from PrimeSense (like the powerful skeleton tracking module...). I haven't tried it yet and don't know how well it integrates with the kinect and the different OS, but since a bunch of guys from different groups (OpenKinect, Willow Garage...) are working hard on it that shouldn't be an issue within a week.

Answer 2

Elaborating further on what Jules Olleon wrote, i've worked with OpenNI (http://www.openni.org) and the algorithms above it (NITE), and I highly recommend using these frameworks. Both frameworks are well-documented, and come with numerous samples from which you can start out.

Basically, OpenNI abstracts the lower-level details of working with the sensor and its driver for you, and gives you a convenient way to get what you want from a "generator" (e.g. xn::DepthGenerator for getting the raw depth data). OpenNI is open-source and free to use in any application. OpenNI also handles the platform-abstraction for you. As of today, OpenNI is supported and works fine for Windows 32/64 and linux, and is in the process of being ported to OSX. Bindings are available for use in multiple programming languages (C, C++, .NET, Python, and a few others I believe).

NITE has additional interfaces built above OpenNI, which give you higher-level results (e.g. track a hand-point, skeletons, scene analysis etc). You'll want to check the subtleties of NITE's license regarding when/where you can use it, but it's still probably the easiest and fastest way to get analysis (e.g. skeleton) for now. NITE is closed-source, so PrimeSense need to supply a binary version for you to use. Currently windows and linux versions are available.

Answer 3

I haven't worked with with OpenKinect but I've been working with OpenNI and SensorKinect for a few months now for my research. If you are planning to work with raw data from Kinect, they work great in giving you depth and video (they don't support motor control). I've used it with C++ and OpenGL in both Windows 64bit and Ubuntu 32bit with almost no modifications to the code. It's very easy to learn if you know basic c++. Installing it might be a little headache.

For more advanced features such as skeleton detection, gesture recognition, etc., I highly recommend using the middlewares such as NITE with OpenNI or the ones provided in here: Middlewares developed around OpenNI rather than re-inventing the wheel. Nite is also very easy to use once you have OpenNI working; e.g. joint recognition is something around 10-20 extra lines of code.

Something that I would recommend to my younger self would be to learn and work with a basic game engine (e.g. Unity) rather than directly with OpenGL. It would give you a lot better and more enjoyable graphics, less hassle and would also enable you to easily integrate your program with other tools such as PhysX. I haven't tried any, but I know there are some plugins for using Kinect drivers in Unity.