Great idea, nice job guys!  That is a much more elegant solution than our
calibration target -- we used some aluminum squares sitting up on blocks
(they're actually coasters I had sitting around, see attached).  We should
probably decide on a standardized calibration target (glass with circles?)
so we can all build one.

We also calibrated our rig today, and although our initial calibration still
has a fair amount of error, we're starting to be able to get some reasonable
looking XYZRGB point clouds: http://www.youtube.com/watch?v=YZ9bHf1CT2o .
 With a more accurate calibration technique, it seems like the Kinect will
be able to produce very nice data!

Cheers,
Alex


On Tue, Nov 16, 2010 at 9:35 PM, Radu Bogdan Rusu <rusu@willowgarage.com>wrote:

> Hi Bill,
>
> Great work! A few suggestions:
>
>  * use a larger calibration pattern that covers more of the image
>
>  * use a calibration pattern with more squares
>
>  * if the estimates of the corners (after subpixel refinement) are still
> bad, an iterative fitting process (or LMedS or
> RANSAC) could help
>
>
> Alternatively, a calibration plate with circles would be better. We already
> have code ready that we need to commit for
> finding out centers of circles/ellipses and using those for calibration
> plates a la
>
> http://www.mvtec.com/halcon/applications/imgs/3d-vision-example-3d-calibration01.png,
> so this might improve things.
>
>
> Cheers,
> Radu.
>
>
> On 11/16/2010 05:44 PM, Bill Morris wrote:
> > Ivan had a great idea for using stereo calibration to calibrate between
> > the depth image and the RGB by taking advantage of the optical
> > properties of glass.
> >
> > So after a busy day of arts and crafts we would like to present the
> > attached image of black squares rubber cemented to a sheet of glass.
> >
> > We should have more detailed results tomorrow.
> >
> > William Morris
> > Ivan Dryanovski
> > CCNY Robotics Lab
> >
> >
> >
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