[ros-users] Sync problem with stereo_image_proc
Sacha Aury
sacha at shadowrobot.com
Mon May 24 14:42:08 UTC 2010
Dear Radu,
I am trying to calibrate my cameras right now. I didn't do it before,
because I didn't find the way to do it on the step-by-step tutorial. It
could be good to add a link somewhere in
http://www.ros.org/wiki/stereo_image_proc to tell it has to be done.
I try to do the calibration using 320*340 resolution and 30 fps.
Everything is fine until I click on "calibrate", then the python script
fails :
epipolar error: 0.857935751957
OpenCV Error: Assertion failed (src.type() == dst.type() && dst.size()
== mapx.size()) in cvRemap,
file /opt/ros/boxturtle/stacks/vision_opencv/opencv2/build/opencv-svn/src/cv/cvimgwarp.cpp, line 3083
Exception in thread Thread-9:
Traceback (most recent call last):
File "/usr/lib/python2.6/threading.py", line 532, in __bootstrap_inner
self.run()
File
"/opt/ros/boxturtle/stacks/image_pipeline_copy/camera_calibration/nodes/cameracalibrator.py", line 59, in run
self.function(m)
File
"/opt/ros/boxturtle/stacks/image_pipeline_copy/camera_calibration/nodes/cameracalibrator.py", line 233, in handle_stereo
lscrib = self.c.lremap(lrgb)
File
"/opt/ros/boxturtle/stacks/image_pipeline_copy/camera_calibration/src/camera_calibration/calibrator.py", line 407, in lremap
cv.Remap(src, r, self.lmapx, self.lmapy)
error: src.type() == dst.type() && dst.size() == mapx.size()
I tried to do it using 15fps/640*480, but the cams are not very usable
at this rate. The calibration seems to work (at least, not crashing)
like this, but the params K and P are still infinite...
Cheers,
Sacha
Le vendredi 21 mai 2010 à 09:20 -0700, Radu Bogdan Rusu a écrit :
> Dear Sacha,
>
> Thanks for the uploading the data. I had a look at the bag file that you recorded, and as far as I can tell, it looks
> like the camera_info is screwed up:
>
> header:
> seq: 2145
> stamp: 2144000000000
> frame_id: fixed_frame
> height: 240
> width: 320
> roi:
> x_offset: 100
> y_offset: 0
> height: 240
> width: 320
> D: [0.0, 0.0, 0.0, 0.0, 0.0]
> K: [inf, 0.0, 159.5, 0.0, inf, 119.5, 0.0, 0.0, 1.0]
> R: [1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0]
> P: [inf, 0.0, 159.5, 0.0, 0.0, inf, 119.5, 0.0, 0.0, 0.0, 1.0, 0.0]
>
> Did you calibrate the cameras using the instructions on the wiki? Having inf values in K and P is bad :)
>
> Cheers,
> Radu.
>
> On 05/21/2010 09:15 AM, Sacha Aury wrote:
> > Dear Radu
> >
> > Thanks for your help. Since my connection at work is not really fast, I
> > will send the bag on http://fly.yozora-irc.net/shadow tonight. You can
> > already see my disparity map and both left / right images at this place.
> >
> > Cheers,
> > Sacha
> >
> > Le vendredi 21 mai 2010 à 08:55 -0700, Radu Bogdan Rusu a écrit :
> >> Dear Sacha,
> >>
> >> Can you assemble a bag file with the following topics? Please replace "mystereo" with the name of your stereo camera:
> >> /mystereo/left/image_raw
> >> /mystereo/left/camera_info
> >> /mystereo/right/image_raw
> >> /mystereo/right/camera_info
> >>
> >> and upload it somewhere where I can access it?
> >>
> >> In the meantime, can you make a screenshot of the disparity image? Just visualize it using image_view, and save it to a
> >> jpg/png.
> >>
> >> Thanks,
> >> Radu.
> >>
> >> On 05/21/2010 02:41 AM, Sacha Aury wrote:
> >>> Dear Radu,
> >>>
> >>> Even if I understand that having some not valid disparity values is
> >>> possible, I actually do not have any good ones. Moreover, all my points
> >>> are quite the same (0.0, 0.0, nan) which is a bit strange I think. What
> >>> could I do to fix this ? I already tried to change parameters with
> >>> dynamic_reconfigure, but it did not change anything.
> >>>
> >>> Cheers,
> >>> Sacha
> >>>
> >>> Le jeudi 20 mai 2010 à 10:45 -0700, Radu Bogdan Rusu a écrit :
> >>>> Dear Sacha,
> >>>>
> >>>> What you're seeing makes sense. Though your disparity "looks good", I am sure you don't have valid disparity values at
> >>>> each pixel in the disparity image. None of us do :). What you are seeing as the output of rostopic echo is the list of
> >>>> 3D points that do not have valid disparity values (we mark those with nan).
> >>>>
> >>>> Cheers,
> >>>> Radu.
> >>>>
> >>>> On 05/20/2010 09:37 AM, Sacha Aury wrote:
> >>>>> I do not really understand why, but I looked to the TF tutorial, added a
> >>>>> few things to my program and rviz do not complain anymore. To recap, I
> >>>>> now have a disparity map, rviz do not complain about a fixed_frame, but
> >>>>> my goal is to get the points cloud. Rviz warns :
> >>>>> [ WARN] 1274372115.122808000: TF_OLD_DATA ignoring data from the past
> >>>>> for frame /test at time 16566 according to authority /camera_sync
> >>>>> Possible reasons are listed at
> >>>>>
> >>>>>
> >>>>>
> >>>>> $rostopic echo /stereo/points | less :
> >>>>> header:
> >>>>> seq: 937
> >>>>> stamp: 18596000000000
> >>>>> frame_id: fixed_frame
> >>>>> points: [
> >>>>> x: 0.0
> >>>>> y: 0.0
> >>>>> z: nan,
> >>>>> x: 0.0
> >>>>> y: 0.0
> >>>>> z: nan,
> >>>>> x: 0.0
> >>>>> y: 0.0
> >>>>> z: nan,
> >>>>> x: 0.0
> >>>>> y: 0.0
> >>>>> z: nan,
> >>>>> x: 0.0
> >>>>> y: 0.0
> >>>>> z: nan,
> >>>>> x: 0.0
> >>>>>
> >>>>> I don't get it, since my disparity map looks good. I can send you a
> >>>>> screenshot of the map if you need it.
> >>>>> So, why is the processing not sending the good coords ? I did not
> >>>>> calibrate my cameras since I did not find a way to do it for stereo
> >>>>> vision, is there a problem with that ?
> >>>>>
> >>>>> Thanks.
> >>>>>
> >>>>> Le mercredi 19 mai 2010 à 10:38 -0700, Josh Faust a écrit :
> >>>>>> If you don't have a TF transform tree (http://ros.org/wiki/tf), the
> >>>>>> fixed frame needs to match the frame you've set. You also need to set
> >>>>>> the timestamp in the header.
> >>>>>>
> >>>>>> msg.header.stamp = ros::Time::now();
> >>>>>>
> >>>>>> Josh
> >>>>>>
> >>>>>> On Wed, May 19, 2010 at 7:53 AM, Sacha Aury<sacha at shadowrobot.com>
> >>>>>> wrote:
> >>>>>> Thanks for your help. I now have a single node synchronizing
> >>>>>> my two
> >>>>>> cameras (image and infos). It works with the stereo_view and I
> >>>>>> get the
> >>>>>> disparity map, which I am configuring. My question is now
> >>>>>> about rviz,
> >>>>>> which I've never used. It seems to need a fixed frame to
> >>>>>> display my 3D
> >>>>>> cloud points. I tried to set a frame_id in my synchronization
> >>>>>> node
> >>>>>> (before broadcasting it to stereo_image_proc), but it does not
> >>>>>> work,
> >>>>>> rviz still can't get any fixed frame.
> >>>>>>
> >>>>>> How can I do that ? I think I am close to the result, but I
> >>>>>> can't see
> >>>>>> it !
> >>>>>>
> >>>>>> Le mardi 18 mai 2010 à 09:07 -0700, Blaise Gassend a écrit :
> >>>>>>
> >>>>>> > Hi Sacha,
> >>>>>> >
> >>>>>> > stereo_image_proc doesn't care about when your message was
> >>>>>> published, it
> >>>>>> > just cares about the timestamp in the message. So your
> >>>>>> republishing node
> >>>>>> > needs to set the timestamp, both in the image topic and in
> >>>>>> the
> >>>>>> > camera_info topic.
> >>>>>> >
> >>>>>> > Blaise
> >>>>>> >
> >>>>>> > On Tue, 2010-05-18 at 16:29 +0100, Sacha Aury wrote:
> >>>>>> > > I think that having a hardware solution is a bit overkill
> >>>>>> for my
> >>>>>> > > problem. So I tried to write a node which collected image
> >>>>>> messages from
> >>>>>> > > my two cameras and which published both message every x
> >>>>>> seconds,
> >>>>>> > > typically 1/2. And when I am using
> >>>>>> image_pipeline/stereo_image_proc, I
> >>>>>> > > got messages of that kind :
> >>>>>> > >
> >>>>>> > > [ WARN] 1274196325.866264000: [stereo_image_proc] Low
> >>>>>> number of
> >>>>>> > > synchronized left/right image pairs received.
> >>>>>> > > Left images received: 831
> >>>>>> > > Right images received: 831
> >>>>>> > > Synchronized pairs: 0
> >>>>>> > > Possible issues:
> >>>>>> > > * The cameras are not synchronized.
> >>>>>> > > * The network is too slow. For each synchronized image
> >>>>>> pair, at most 1
> >>>>>> > > is getting through.
> >>>>>> > >
> >>>>>> > > I don't know what I could do more, since the
> >>>>>> synchronisation should be
> >>>>>> > > done by a TimeSynchronizer in the stereo_image_proc class.
> >>>>>> Could it be
> >>>>>> > > posible to cheat on the timestamps in any way ?
> >>>>>> > >
> >>>>>> > > Thanks, and sorry for the double post, I made a mistake at
> >>>>>> first.
> >>>>>> > >
> >>>>>> > > Le lundi 17 mai 2010 à 07:53 -0700, Gary Bradski a écrit :
> >>>>>> > > > What level do you want synchronization on? Within
> >>>>>> framerate (both
> >>>>>> > > > frames happen randomly but within 1/30 of a second of
> >>>>>> each other) or
> >>>>>> > > > exact frame synchronization? The first is achievable,
> >>>>>> the second needs
> >>>>>> > > > extra hardware.
> >>>>>> > > >
> >>>>>> > > > At most, ROS can get you timestamps to align to, but to
> >>>>>> get actual
> >>>>>> > > > simultaneous frames, you'll need a triggering signal in
> >>>>>> hardware such
> >>>>>> > > > as a wire between 2 cameras (that allow for this). Some
> >>>>>> 1394 cameras
> >>>>>> > > > may allow triggering over the 1394 bus and then you'll
> >>>>>> only have the
> >>>>>> > > > problem of getting both buses to trigger at the same
> >>>>>> time ... which
> >>>>>> > > > may be approximately possible, most of the time ... on
> >>>>>> average.
> >>>>>> > > > Depends on the driver and the 1394 port.
> >>>>>> > > >
> >>>>>> > > > I've seen an automotive 1394 article (not ROS related)
> >>>>>> where they have
> >>>>>> > > > about 10 cameras. The cameras run the cameras at very
> >>>>>> high framerates
> >>>>>> > > > and then they do timestamp synchronization which allows
> >>>>>> fairly
> >>>>>> > > > synchronous alignment of multiple with no extra
> >>>>>> hardware.
> >>>>>> > > >
> >>>>>> > > > Gary
> >>>>>> > > >
> >>>>>> > > > On Mon, May 17, 2010 at 5:23 AM, Sacha Aury
> >>>>>> <sacha at shadowrobot.com>
> >>>>>> > > > wrote:
> >>>>>> > > > Hi,
> >>>>>> > > >
> >>>>>> > > > I am trying to make a stereo camera acquisition
> >>>>>> using ROS with
> >>>>>> > > > the
> >>>>>> > > > cameradc1394 driver and the stereo_proc package.
> >>>>>> I've got a
> >>>>>> > > > separate
> >>>>>> > > > computer to stream the image_raw from my two
> >>>>>> cameras. The
> >>>>>> > > > stream works,
> >>>>>> > > > but when I launch stereo_image_proc, it seems
> >>>>>> that my two
> >>>>>> > > > cameras are
> >>>>>> > > > not synchronized :
> >>>>>> > > >
> >>>>>> > > > [ WARN] 1274098675.074074000:
> >>>>>> [stereo_image_proc] Low number
> >>>>>> > > > of
> >>>>>> > > > synchronized left/right image pairs received.
> >>>>>> > > > Left images received: 3079
> >>>>>> > > > Right images received: 3076
> >>>>>> > > > Synchronized pairs: 0
> >>>>>> > > > Possible issues:
> >>>>>> > > > * The cameras are not synchronized.
> >>>>>> > > > * The network is too slow. For each
> >>>>>> synchronized image
> >>>>>> > > > pair, at most 1
> >>>>>> > > > is getting through.
> >>>>>> > > >
> >>>>>> > > > Here is my launch file :
> >>>>>> > > >
> >>>>>> > > > <!-- startstream.launch -->
> >>>>>> > > > <launch>
> >>>>>> > > > <param name="display" type="int"
> >>>>>> value="0"/>
> >>>>>> > > > <param name="framerate" type="double"
> >>>>>> value="15"/>
> >>>>>> > > > <param name="mode"
> >>>>>> value="MODE_320x240_YUV422"/>
> >>>>>> > > >
> >>>>>> > > > <node name="camera_left" pkg="cameradc1394"
> >>>>>> > > > type="cameradc1394"
> >>>>>> > > > respawn="true">
> >>>>>> > > > <param name="prefix" type="string"
> >>>>>> > > > value="/stereo/left/"/>
> >>>>>> > > > <param name="cameraindex" type="int"
> >>>>>> value="0"/>
> >>>>>> > > > </node>
> >>>>>> > > >
> >>>>>> > > >
> >>>>>> > > > <node name="camera_right" pkg="cameradc1394"
> >>>>>> > > > type="cameradc1394"
> >>>>>> > > > respawn="true">
> >>>>>> > > > <param name="prefix" type="string"
> >>>>>> > > > value="/stereo/right/"/>
> >>>>>> > > > <param name="cameraindex" type="int"
> >>>>>> value="1"/>
> >>>>>> > > > </node>
> >>>>>> > > >
> >>>>>> > > > </launch>
> >>>>>> > > >
> >>>>>> > > > Is there any specific way to make the two
> >>>>>> cameras
> >>>>>> > > > synchronize ?
> >>>>>> > > >
> >>>>>> > > > I am following that tutorial :
> >>>>>> > > >
> >>>>>> > > > http://www.ros.org/wiki/stereo_image_proc
> >>>>>> > > >
> >>>>>> > > > Thank you for any help.
> >>>>>> > > >
> >>>>>> > > > Sacha
> >>>>>> > > >
> >>>>>> > > >
> >>>>>> > > > _______________________________________________
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> >>>>>> > > >
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