Parameterize camera control properties

[y22ma]

Is there a reason why the camera control properties, such as Exposure, Constrast, Brightness, etc, are hard coded in uvc_cam.cpp?

With Logitech webcams, I find the images to be overexposed, and would like to change these properties without recompiling the driver.

[ktossell]

There's no good reason to have these parameters be hardcoded, except that no one felt like making them configurable, and no one's wanted that feature enough to implement it or to ask me to do so.

I remember the control numbers being kind of mysterious when I copied uvc_cam.cpp and wrapped it in the uvc_camera node, and I wasn't sure how I'd determine the right controls or control values for different cameras. (Keeping in mind the fact that uvc_camera also supports non-UVC cameras, as long as those cameras have Video4Linux drivers.) It seemed like the IDs in that file worked on a good variety of cameras; exposing them as ROS parameters would probably be wise.

[y22ma]

I can certainly generate a pull request from my fork.

[musicji83]

I want to change resolution value of width and height in 'stereo_node.launch'. But, after that time return to

"core service [/rosout] found
process[uvc_camera_stereo-1]: started with pid [27750]
terminate called after throwing an instance of 'std::runtime_error'
what(): unable to start capture
[uvc_camera_stereo-1] process has died [pid 27750, exit code -6, cmd /home/parallels/catkin_ws/devel/lib/uvc_camera/uvc_stereo_node __name:=uvc_camera_stereo __log:=/home/parallels/.ros/log/da1ff708-df7b-11e5-8dcd-001c4270c2d5/uvc_camera_stereo-1.log].
log file: /home/parallels/.ros/log/da1ff708-df7b-11e5-8dcd-001c4270c2d5/uvc_camera_stereo-1*.log
all processes on machine have died, roslaunch will exit
shutting down processing monitor...".