Skeleton tracking in front of wall (or lying on table) RRS feed

  • General discussion

  • Hi all,

    in my work I have problems with skeleton tracking when lying on a table with the Kinect mounted on the ceiling.

    The problem is that the method NuiSkeletonGetNextFrame internally does two steps.

    1. User segmentation

    2. Fitting of a skeleton into the body

    The user segmentation fails while standing directly in front of a wall (or lying on a table) however I am able to do a user segmentation myself. Does anybody know if it is possible that in one of the future versions it is possible to calculate a skeleton on a presegmented scene? It could also be that I missed something.


    The Skeletal Viewer Walktrough states:

    "If skeleton tracking is enabled, the low-order 3 bits of the value contain the skeleton (player) ID; otherwise, these 3 bits are 0. The remaining bits contain the depth value in millimeters."

    So it would be possible to set all pixels belonging to a user. But not to calculate a skeleton.






    Wednesday, July 6, 2011 2:08 PM

All replies

  • Hi Lukas, 

    I'm also trying to achieve the similar objective, but for the current release it's impossible to send any input to the skeleton tracker. So we cannot do skeleton tracking after doing the foreground extraction by ourselves. 

    However, I tried put the kinect facing the ground, and it was able to get the skeleton when I was lying on the floor. So I would assume it would work for lying on the table as well. Please let me know if you have some progress in this issue. Thanks!


    Wednesday, July 6, 2011 4:47 PM
  • Hi,

    2 questions:

    - what color and material is the floor you lie on?

    - is your skeleton tracked before you lie down or are you recognized already lying on the floor.

    I let you know if I am able to do this.





    Friday, July 8, 2011 12:17 PM
  • 1. The color is gray and it's covered the carpet. Though I don't think the color and material of the floor matters too much, since only the depth image is used for skeleton tracking. 

    2. Skeleton is tracked after I lay down on the floor. 

    When you try this, make sure that the kinect is rotated 90 degrees than its usual pose. In that way, you can trick the kinect such that it will consider a lying person as a standing person.


    Friday, July 8, 2011 1:59 PM
  • The team does not discuss on the forums which features might be available in future versions of the SDK, so we can't give a firm answer to your original question about skeleton tracking on presegmented images, Lukas.

    Keep in mind that the Kinect was originally made as a gaming peripheral, and the algorithms are tightly integrated and optimized to work at high frame rates. They weren't designed for the kind of extensibility that many of the forum participants have asked about. But we hear that you're interested in that.

    Many members of the team are reading these forums and other discussions about the SDK, and those discussions are part of the planning for future versions. The team are listening, and it's worth your time to make these suggestions. Please continue!

    Friday, July 8, 2011 6:17 PM
  • According to one of our internal white papers: "The depth sensor depends on reflected light to read depth information. Therefore, objects that are highly reflective (mirrors, shiny metal) or highly absorptive (fluffy or dark materials) may not be registered by the depth sensor."

    So the carpeting might be affecting the depth image accuracy because it's absorptive. You could try putting paper on the floor, and then lie on the paper.


    (I'm working on getting this white paper, and some of our other internal white papers revised so they can be posted on the Kinect for Windows site. This will probably take some time.)

    Friday, July 8, 2011 6:32 PM
  • Hi.

    Now (in 2013) I have got same problem. I want to track skeleton of person in fron of wall, or person lying on the table.

    Is there something new about this issue? How did you reach that goal?

    Thnx. Ontolo.

    Saturday, September 28, 2013 9:08 AM
  • HI,
    I tried to do the same, but it dint worked, so can you give me a better idea how you come up with the skeleton tracking of a person lying on bed using kinect.."???
    Thanx in advance

    I look forward to hear from you..

    Friday, January 31, 2014 6:44 AM