rick187's profile - activity

Thanks a lot for the answer. I was aware of that package (I should have mentioned it in the question) but I am not sure that it actually skips the serialization/deserialization phase and (more importantly) that it is still supported. It also seem to require quite some changes in the code.

Hello, I know that one can easily obtain zero-copy transfers between nodelets within a single node but I was wondering if there is a way to avoid copy (and most importantly serialization/deserialization) between two nodes running on the same machine. I want the vrep simulator to send image messages to matlab and I am using the vrep_ros_bridge and matlab_ros_bridge (I am one of the authors) for this. However the message passing is quite slow due to the multiple copies and serializations. On the other hand I cannot use nodelets because vrep and matlab each have their own executables. The only thing I could think of is to have two nodelets running in a single node and each one sharing a shared_memory portion with vrep and matlab respectively but this seems quite cumbersome. Any other idea? Thank you. Riccardo

I have accepted the last answer because it is more complete, but the one from ASeyfi points in the right direction too. I don't know the rules in these cases.

Anyway I finally solved with this command:

rosrun image_view video_recorder image:="/usb_cam/image_raw" _filename:="/tmp/video.avi" _max_depth_range:="0" _fps:="30" _codec:="I420"

I can open the file in VLC and it works perfectly. The last option (the codec) can be removed and the video still plays fine (but it is compressed in this case).

Thank you all.

Riccardo

No, I am afraid I didn't

Hello,

I am trying to directly record a video from an image topic using video_recorder from image_view. I am testing it with my laptop camera running

roslaunch usb_cam usb_cam-test.launch

When I launch the recording with

rosrun image_view video_recorder image:="/usb_cam/image_raw" _filename:="/home/user/video.avi"

I get the following error "Unable to convert rgb8 image to bgr8". I have also tryed using

rosrun image_view video_recorder image:="/usb_cam/image_raw" _filename:="/home/user/video.avi" _encoding:="rgb8"

but this produces "Unable to convert rgb8 image to rgb8".

The exact same happens for images published by the V-REP simulator (which is what I actually need to record in the end).

Any help would be very much appreciated. Thanks.

Riccardo

Hi everybody,

I am trying to run ros on an Android device using rosjava. I have first tried downloading the android_sensors_driver app from the Market and everything works fine: I can start a roscore on my laptop and connect to it from the app and I can log all imu/gps data.

However if I try the same with the latest version of the app from the git repo https://github.com/ros-android/androi... it does not work.

I had no problems compiling. When I run the app, I set the master uri with the ip of my laptop and the app says it successfully connected to the master. However when I run rosnode list, I cannot see the app and neither I can see the topics it publishes.

I also tried with the other tutorial apps in https://github.com/rosjava/android_core but they all do the same: they seem to connect to the master, but no node/topic shows up.

I found other people having similar issues and I did these checks/tests: - both the smartphone and the laptop are connected to the same wifi network - both can ping each other - there should be no special firewall in the router and I also tried connecting both devices to a third android device working as a hot spot - I tried different phones

I am using ros indigo and Android kitkat.

Thank you very much for any help. Cheers.

Riccardo

I don't know how to retrieve the version. Sorry but It wasn't me who installed ros on this machine and I don't have dpkg on mi Fedora distribution. Do you know any other way? BTW in the package.xml of rqt_plot it says 0.2.10.

hallo,

as soon as I launch rqt_plot using

rqt_plot "topic name"

or

rosrun rqt_plot rqt_plot "topic name"

I get the following errors

rqt_plot.plot: importing PyQtGraphDataPlot
rqt_plot.plot: import of PyQtGraphDataPlot failed
rqt_plot.plot: importing MatDataPlot
rqt_plot.plot: import of MatDataPlot failed

The plotting tools start but I miss the interface buttons. Moreover both the x and y scale don't change according to data. I am using Fedora 18 and groovy. I don't know where to start for debugging because I have never used python. Thanks for your help.