Two weeks ago, when I first wrote about Microsoft's upcoming Kinect for Windows, I wondered how substantially it'd differ from the Xbox 360-intended model, and whether the changes would reflect evolution in software, hardware or both. Shortly-thereafter coverage in Wired indicated:
The Kinect for Windows unit also offers a modified USB connector and better protection against noise and interference. Both tweaks are designed to better incorporate the Kinect hardware to the PC environment — even if the basic hardware looks identical to the original.
Still, my fundamental question remained unanswered…were Kinect for Windows' "eyes", infrared transmitter and other vision hardware identical to those in its Xbox 360 precursor? Via a tweet sent Friday night, a follow-up blog post from Craig Eisler, Microsoft's General Manager, Kinect for Windows, seems to suggest that the answer is 'yes'.
The lenses on the Kinect for Windows sensor are the same as the Kinect for Xbox 360 sensor, so near mode does not change the field of view as some people have been speculating. As some have observed, the Kinect for Xbox 360 sensor was already technically capable of seeing down 50 centimeters – but with the caveat “as long as the light is right”. That caveat turned out to be a pretty big caveat. The Kinect for Windows team spent many months developing a way to overcome this so the sensor would properly detect close up objects in more general lighting conditions.
This resulted not only in the need for new firmware, but changes to the way the devices are tested on the manufacturing line. In addition to allowing the sensor to see objects as close as 40 centimeters, these changes make the sensor less sensitive to more distant objects: when the sensor is in near mode, it has full accuracy and precision for objects 2 meters away, with graceful degradation out to 3 meters. Here is a handy chart one of our engineers made that shows the types of depth values returned by the runtime [editor note: see above graphic]
Check out Eisler's complete writeup for more details, including depth-reporting variances between the current beta runtime code and the planned v1.0 'gold' release, and Microsoft's plans for incremental supporting skeletal tracking over time.
In closing, I'll ask the same question I did two weeks ago; particularly considering that refurb'd units are currently available for well under $100, is it just me or does anyone else also wonder how quickly the hacker community will figure out how to add "near mode" firmware support to Kinect for the Xbox 360?