Yes, I am using the correct checkerboard. I am doing everything
correctly. I am knee deep in the calibrator.py source, and everything
looks good after the StereoCalibrate() command -- the rotation and
translation between the two cameras seems reasonable (rotation close to
I, translation on the right scale). It seems to be after the
set_alpha() call where the final projection matrices end up with HUGE
numbers for focal length (tens of thousands), and the rotation matrices
have unexpected off diagonal components.
Vijay Pradeep wrote:
> Hi Patrick,
>
> Is the checkerboard 8x6 corners? If so, make sure that you always keep
> the target in a 'landscape' orientation. If the checkerboard gets close
> to a 'portrait' orientation, the OpenCV detector may mess up the
> correspondence between both cameras (thus, making the calibration
> routine want to rotate one of the cameras 180 degrees).
>
> This rotational ambiguity can also be solved by using a checkerboard
> with [odd]x[even] corners.
>
> Vijay
>
> On Tue, Apr 6, 2010 at 2:01 PM, Patrick Beeson <beeson.p@gmail.com
> <mailto:beeson.p@gmail.com>> wrote:
>
> Sorry, I just checked and I am actually using the trunk, not latest.
> The problem is that I'm getting large rotational values, and I'm only
> ever seeing a horizontal offset in T (top right value in projection
> matrix) as non-zero, even though the cameras are at slightly different
> heights. I can send the saved tar.gz file that contains the images used
> and the ost.txt created if it helps.
>
> Patrick Beeson wrote:
> > I checked out latest and had to do a small bit of changes to sync the
> > timestamps of the two cameras whenever frames have very close
> > timestamps. So they aren't EXACTLY synced, but VERY closely
> synced. I
> > can try to send you a screen shot of the output. Note, I am testing
> > this with a quite small checkerboard (your checkerboard, but with
> 26mm
> > squares). Maybe that's the problem? Maybe I'm sampling a space too
> > close to the cameras?
> >
> > Eric Perko wrote:
> >> Patrick,
> >>
> >> What version of camera_calibration are you using? Boxturtle?
> >>
> >> - Eric
> >>
> >> On Tue, Apr 6, 2010 at 4:31 PM, Patrick Beeson
> <beeson.p@gmail.com <mailto:beeson.p@gmail.com>>
> >> wrote:
> >>> I'm trying to calibrate two identical 1394 cameras that are
> sitting next
> >>> to each other. The stereo calibration from camera_calibration
> converges
> >>> to VERY bad R and T matrices, rotating the frames and
> >>> the warping the images drastically. I've tried several times, with
> >>> no luck.
> >>>
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