how can i smoothing the depth image from kinect ( use openni and opencv)

[peter_wwj]

   hi,i want to smoothing the depth image from kinect ( use openni and opencv),because the depth image have too mush noise , anybody can help me? my english is poor ,sorry about that, thanks .....

[Gideon Adhirianto]

Hello,

If it is the depth image that you would like to smooth then you can use opencv's GaussianBlur or MedianBlur ( if you use opencv 2.3 or newer) or cvSmooth ( if you use older opencv).

MedianBlur is usually used in stereovision depth map to enhance disparity ( if i'm not mistaken). Therefore it is suitable to smooth depth image and will even clear the difference between dark and bright pixels more.

I dont really understand about Gaussian because there's some math inside. What I know is it is convolving with something that is called Gaussian kernel. Ive tried using GaussianBlur in my application of finger detection to do smoothing and it works very well. Although dont use a window more than 7x7.

Thats what I can say about depth image smoothing. Hope this helps.

Best regards / Mit freundlichen Grüßen,

Gideon Adhirianto
Mechatronics Dept
Swiss German University

Sent from my Sony Xperia S

On Jul 26, 2012 2:17 PM, "peter_wwj" <w.wj....@gmail.com> wrote:

   hi,i want to smoothing the depth image from kinect ( use openni and opencv),because the depth image have too mush noise , anybody can help me? my english is poor ,sorry about that, thanks .....

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[Paul Doliotis]

here is an interesting approach for what you need

http://www.radfordparker.com/papers/kinectinpainting.pdf 

Paul

[Lorne Covington]

Using any kind of filter that smooths the image by generating intermediate levels of gray may make the depth image look better, but what it will actually do is generate artifacts that appear as slopes between objects.  So if you are standing in front of a wall, the point cloud will have points sloping out of the wall to your position, looking like you were pressed out from the wall.  Interesting effect maybe, but probably not what you want.

Search this list's archives, and maybe libfreenect's.  I know I've seen methods posted here that did not do depth smearing and filled in missing holes.

Good luck!

- Lorne