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Filtering modelVeiw Matrix

November 30, 2010 - 2:42am #1

Hi have an "issue" I'd like to smooth.

The tracking of the target is working fine and when I draw a mesh just on top of it it's "stable" (i mean it doesn't "shake")
But when I'm drawing a mesh just close to the camera ( floating just in front of it away from the target), the mesh is "shaking".
This behavior is more important as the camera is far from the target.

So my guess is that QCAR is having issue to accurately track the target and compute its modelview matrix, and this jitter is amplified by the distances of the objects from the target and the distance of the camera from the target.

Question: is there a way to filter this; for example by keeping the previous value of the modelview matrix and to compute a median with the current?


Re: Filtering modelVeiw Matrix

June 16, 2011 - 10:55pm #3

I am also experiencing massive jitter with the teapot demo (Image Targets demo). I am using a google Nexus S. Focusing the camera, changing light conditions, etc. does not make a difference. Only if the camera is moved really close to the tracker, the jitter is acceptable.

It seems that String AR doesn't have as much jitter so I am sure it is possible to optimize the tracking engine to get rid of it.

As a side note, would it be possible to add an option to make the tracked features visible? Like small colored dots on the tracker, just as with the PTAM software.

Re: Filtering modelVeiw Matrix

December 1, 2010 - 3:37pm #2

I am also seeing this behavior, and I believe you are correct, it is a matter of small errors being magnified at a distance. We'll see if there is anything that can be done, but I'm afraid it might just be the nature of the tracker. I'm not sure that smoothing the modelview matrices by averaging them will help, but it might be worth a try!

- Kim

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