Hi Asghari, As Jack points out, I think that rostopic hz is giving you an update once per second. If the exposure time is 5 seconds, then four out of five updates of rostopic hz will not have any new messages. Blaise On Tue, Feb 15, 2011 at 12:45 PM, Asghari Oskoei, Mohammadreza wrote: > > Blaise, > > The output to both > > rostopic hz /stereo/left/image_rect_color   (image_view_proc) > rostopic hz /stereo/left/image_raw          (image_raw) > > in exposure 5, is something as below > > Rate: x.xxx > max: xxx min: xxx .... > no new message > no new message > no new message > no new message > Rate: x.xxx > max: xxx min: xxx .... > no new message > no new message > no new message > no new message > > in exposure 0.5, is something as below > > Rate: x.xxx > max: xxx min: xxx .... > Rate: x.xxx > max: xxx min: xxx .... > > 1 PC run just roscore + 1 PC run just camera drivers and image_proc + 2 net prosilical cameras (640x480) + 1 desktop to run rostopics all connected through a network with two hubs is hardly to say limitation in hardware, > > Could it be a problem in configuration? > > Reza, > > > > > > -----Original Message----- > From: ros-users-bounces@code.ros.org [mailto:ros-users-bounces@code.ros.org] On Behalf Of Blaise Gassend > Sent: 15 February 2011 17:40 > To: User discussions > Subject: Re: [ros-users] stereo image sync > > What do you mean that you get one message out of 5? Do you mean that > you see messages on the image_raw topic but not on the output of > stereo_image_proc, or does it mean that the images aren't even > arriving on the image_raw topic? > > In any case, resource limitations of various types can cause a lower > than expected frame rate: > - CPU overload can cause frames to be dropped. > - Insufficient lighting can cause the exposure time to be long, and > the frame rate to be lower than requested. > - Insufficient network bandwidth can limit how many frames get over > the network (seems unlikely in your case). > > Hard to say more without knowing more about your system. > > On Tue, Feb 15, 2011 at 2:47 AM, Asghari Oskoei, Mohammadreza > wrote: >> >> >> Hi, >> >> I setup a pair of prosilica camera, in mode 640x480 in two exposure rates 5 >> and 0.5 , >> >> When I subscribe to their topics by either "rostopic hz >> /stereo/left/image_rect_color" or "rostopic hz /stereo/left/image_raw" >> >> >> >> In exposure rate 0.5, receive all messages without missing any  and then it >> repeats again >> >> In exposure rate 5, receive just 1 message and miss other 4 messages then it >> repeats again >> >> >> >> I tried this in different rates and found out that I just can receive two >> messages (one left and one right) per second (or per ROS refresh rate), and >> any more messages would be missed by ROS. >> >> >> >> The other point is that when I run stereo_image_proc  it crashes as soon as >> starting to subscribe to it by either stereo_view or face_detector. >> >> >> >> Anyone can help, please? >> >> Reza, >> >> _______________________________________________ >> ros-users mailing list >> ros-users@code.ros.org >> https://code.ros.org/mailman/listinfo/ros-users >> >> > _______________________________________________ > ros-users mailing list > ros-users@code.ros.org > https://code.ros.org/mailman/listinfo/ros-users > _______________________________________________ > ros-users mailing list > ros-users@code.ros.org > https://code.ros.org/mailman/listinfo/ros-users >