[ros-users] camera_calibration

[Eric Perko]

Hmm... dunno... I'll try it out on my cameras tonight and get back you
with the results. What type of 1394 cameras are you using?

On Tue, Apr 6, 2010 at 5:15 PM, Patrick Beeson <beeson.p at gmail.com> wrote:
>
>
> Eric Perko wrote:
>> Have you tried different baselines to see if that affects the
>> calibration results at all? And I'm pretty sure my checkerboard has
>> 28.58 mm squares, so yours is not that much smaller. Can you try a
>> larger checkerboard?
>>
>
> I'd have to print one.  I've tried this multiple times and at a variety
> of distances.
>
>> I'd assume that, if your cameras are not moving and you can hold the
>> checkerboard still until both cameras have taken a pair, syncing
>> shouldn't be a huge problem for calibration. What happens if you
>> calibrate each camera separately and view rectified images? Do they
>> come out okay or are there issues with monocular calibration as well?
>> Specifically, does that checkerboard work for monocular calibration?
>>
>
> Yes.  Monocular works fine.
>
>> Also, some other students working on stereovision using OpenCV
>> directly have found that you have to be careful while watching the
>> calibration to make sure that the corner detection is working
>> properly. For example, if it begins by marking corners in red on top
>> in both cameras, it has to always mark the top corners in red - if
>> they ever flip or otherwise change orientation, it will make things go
>> quite funky. I've seen it happen with my monocular calibrations if the
>> person with the checkerboard isn't careful and accidentally lets the
>> checkerboard rotate along the axis from the camera to the
>> checkerboard.
>>
>
> Didn't happen.
>
> Problem is that R and T are retuning VERY high values.  I just went from
> trunk to latest, added a small fix to the node source to only accept two
> images if there timestamps are within 0.05 seconds of each other, and
> tried again.  With latest, I get even larger crazy values in R.  Again,
> I can send the output tar file, which I assume you can run through in an
> offline manner, and you can see that the checkerboard is proerly found
> on all used frames.
>
>
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