Mirror Image

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Technology behind project Natal

Latest info is here.


23, January, 2010 - Posted by | Uncategorized


  1. Have you ever tried looking at an infra-red remote control through a cellphone camera? It seems to detect the blinking pattern flashed by the remote once a button is pressed (and show it in visible light). I don’t know if that amounts to anything, just an observation.

    Anyway, infrared stereo cameras equipped cellphones can also be used to read invisible IR markers which can serve many interesting uses.

    Comment by rouli | 23, January, 2010

  2. Cant find out, is it related to the ToF[1] cameras? Right now I’m working with the PMD[2] Cam-driven SLAM and interested to play with markerless AR. ToF cameras looks like nice playground for AR apps (64×48 3D points, 25fps), but is not yet too compact and cheap. Here is how the data output looks: http://twitpic.com/zdi9d (yellow is PMD-captured points).

    [1] http://en.wikipedia.org/wiki/Time-of-flight_camera
    [2] http://www.pmdtec.com/products-services/pmdvisionr-cameras/pmdvisionr-o3/

    Comment by cfr | 23, January, 2010

  3. @cfr
    Absolutely not (that is if I’m correct in how it works). TOF is something a lot more technically complex, based on the capture of the phase, as I understand. Here is a simple application of computer vision technics.

    Comment by mirror2image | 23, January, 2010

  4. The explanation in the article isn’t correct.
    First of all PN have only 1 IR camera, not 2 (as you can see in the scheme posted).
    The technology used by PN to determine the depth value isn’t triangulation. PN uses a pulsed IR light and a camera with an IR filter and a shutter to generate a b&W image in wich the gray level indicate the depth value. The technology is called fly time and is the same technology of the aircraft radars, submarine sonar.

    Comment by rigelpd | 23, January, 2010

  5. Project Natal tecnology IS time of fight, i’m absolutely confident. The scheme you posted is very clear. Look: where you see the 2 IR cameras?? I see only an IR light and an IR camera.

    Comment by rigelpd | 23, January, 2010

  6. I’m an optical engineer and I work in metrology, you may be confident that I’m right.

    Comment by rigelpd | 23, January, 2010

  7. Thanks for clearing that rigelpd. In that case this tech is of no interest to me. Not applicable for mobiles it seems.

    Comment by mirror2image | 23, January, 2010

  8. IMO, stereoscopic cameras would be nice, but in terms of affordability, the IR/camera concept makes practical sense. Besides, there could be future IR applications that would only need software, rather than a hardware upgrade.

    BTW, I’m really lookinng forward to PN!

    Comment by Joey1058 | 1, February, 2010

  9. Anyway it is possible that Project Natal technology isn’t Time of Flight…In this case I think that the technology used by PN to determine the depth value may be reflectometry. If PN uses reflectometry the IR light isn’t pulsed and the player will need to scansionate his body every time he begin to play. This because reflectometry need to mapping the reflectivity to work well.

    Comment by rigelpd | 4, February, 2010

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