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OpenNI camera parameters gives faulty marker detection

asked 2011-04-15 23:30:08 -0500

Aslund gravatar image

updated 2016-10-24 09:01:57 -0500

ngrennan gravatar image

Hey everyone

Following my problem with getting the camera parameters from the OpenNi driver which is now solved, then I have set up ArToolKitPlus to detect markers using the RGB camera with the parameters from "rgb/camera_info". I have previously used the ArToolKitPlus in another project where it worked fine, but this time I experienced some problems with the distance in the z-axis. I have used rviz to compare the frame of the marker with the RGB point cloud, the marker frame has "openni_rgb_optical_frame". Screenshots of this is can be seen here and here, there square marker might be a bit hard to see, but it looks like the found marker fits regarding the x- and y-position, but the depth is totally off. The question is why the depth is failing using ArToolKitPlus, I am have also tried to do manual calibration of the camera and getting more or less the same parameters, so the problem must be something internal in the Kinect camera. Maybe something originating from the depth sensing?

I hope someone has an idea to solve this problem as marker detection is crucial for two of my projects.

Regards

Sebastian Aslund

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I have done some further testing, it seems that the further the marker is away from the camera, the higher is the error in the depth. 16cm away from the camera is the error 7cm, 40cm away is the error 15cm and 80cm away the error is 28cm.
Aslund gravatar image Aslund  ( 2011-04-16 03:55:37 -0500 )edit

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answered 2011-06-17 10:39:35 -0500

tfoote gravatar image

This would suggest that your intrinsic calibration for the rbg camera is incorrect.

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Asked: 2011-04-15 23:30:08 -0500

Seen: 695 times

Last updated: Jun 17 '11