Compressed image not showing
Closed this issue · 3 comments
Hello, I'm publishing a compressed image from a raspicam_node on my robot.
I can see the image through rqt image view widget, so I know it is being published.
However, the app is showing no image. The topics are set up properly. Connection works as well since I can publish cmd_vel with the joystick.
Any idea what could be the cause?
EDIT: the raspicam_node has a parameter enable_raw that makes it publish a sensor_msgs/Image message alongside the compressed image. When I enable it and try to show the image in ROS-mobile, it doesn't work either. Therefore the issue is probably not related to the compressed image, but there is some other more generic cause.
I will try it with a usb webcamera instead of the raspberry pi camera to see if it is caused by the raspicam_node or something else. Still, I can see both compressed and original image just fine in rqt.
Hey,
There are multiple possible reasons for this issue. The obvious one would be a simple connection error in some way. To check that, you could try to subscribe to another topic that is not an image like a Twist message or a simple String message with the Logger/Debug widget and then check if that messages are received.
In most cases that we know where one can send but not receive messages there is an issue with the system ROS variables which has to be set like the MASTER_URI.
Yes, it was the ROS_MASTER_URI. I've used an already made SD card image with preinstalled ROS. And even though I set up ROS_MASTER_URI and ROS_IP by hand into the .bashrc, the roscore still refused to start with those parameters. I had to disable some startup scripts before it started working. So nothing related to ROS-mobile after all.