[ros-users] [Pr2-users] How to calibrate camera_synchronizer_node?

[Lorenz Mösenlechner]

Hi Blaise,

are you guys at Willow maybe running a newer kernel version? On our
PR2, we have version 2.6.29.6-rt24 and top shows that processes like
sirq-net-rx/6 eat up quite some cpu (up to 10%) on an idle
robot.

Lorenz

> Hi Ulrich,
> 
> I just did some tests on one of our robots, and it is rock solid, except for:
> 1. glitches every few multiples of 10 seconds because of the trigger
> controller refresh I got you to try taking out.
> 2. glitches that coincide with ethercat dropping packets (you can see
> this in the diagnostics for eth Ethercat Master, in the Motors
> section.
> 
> From the data you sent me, you are getting glitches that are not
> related to case 1. Can you have a look to see if dropped packets are
> being reported by the ethercat master diagnostics?
> 
> Do these glitches occur even when the computers are under light load?
> (Nothing running except robot.launch and the image viewers.)
> 
> If you are dropping packets every few seconds under light load, then
> there may be a problem with your robot, and I would recommend opening
> a support ticket.
> 
> Thanks,
> Blaise
> 
> On Thu, Sep 23, 2010 at 11:21 AM, Blaise Gassend
> <blaise at willowgarage.com> wrote:
> > Hi Ulrich,
> >
> > I had a look at your bags, and I am noticing that there is a lot of
> > oscillation in the image intensity. Auto-gain/exposure don't work well
> > with alternating mode, and I would recommend switching them off.
> >
> >> Thomas Rühr could help me out -i could not be in the lab today - and
> >> recorded two bags with a synchronization node including the code changes you
> >> proposed.
> >
> > Thanks for the bags. I see in the textured an interval of 3 seconds
> > between flashes. Is that interval always the same, or is it different
> > each time?
> >
> > Can you confirm that both cameras have problems at the same time?
> >
> > From the times at which the images are being sent, it looks like there
> > may be an extra or missing trigger pulse. I'm going to try to
> > reproduce this on one of our robots...
> >
> > I wonder if you could send me a bag of the following topics:
> > /head_camera_trigger/waveform, /projector_trigger/waveform,
> > /head_camera_trigger/trigger_narrow_stereo_both,
> > /projector_trigger/on_time, /projector_trigger/off_time,
> > /narrow_stereo/left/camera_info,
> > /narrow_stereo_textured/left/camera_info,
> > /narrow_stereo/right/camera_info,
> > /narrow_stereo_textured/right/camera_info. You can make this one
> > pretty long, say a minute, as it is a lot less data.
> >
> >> Do you think, that is solvable at all?
> >
> > Hard to know until we know what the problem is.
> >
> >> Can the projector be switched on and
> >> off instead of being modulated?
> >
> > The projector cannot be turned on continuously because it would
> > overheat. It is limited to 2 ms pulses (I forget the exact duty
> > cycle). You can of course turn it off all the time, but I don't see
> > how that would help you if you need alternating mode.
> >
> > One last thing: if you want to be able to filter out the images that
> > are having trouble, I believe that you can use the image timestamp.
> > The timestamps should be totally periodic when things are working
> > well. When you get the bad images, the interval between two images
> > will be different from what it usually is.
> >
> > Cheers,
> > Blaise
> >
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-- 
Lorenz Mösenlechner            | moesenle at in.tum.de
Technische Universität München | Boltzmannstr. 3
85748 Garching bei München     | Germany
http://ias.cs.tum.edu/         | Tel: +49 (89) 289-26910