Default brightness setting makes image very dark for my integrated camera

[JStech]

The default brightness setting of 0 (defined here) makes the image from my integrated camera very dark. I have a Lenovo ThinkPad T490 with an Acer integrated camera (5986:2113), and v4l2-ctl -l reports the brightness range is [0, 255] with a default value of 128.

I'm able to work around this by just setting the brightness when I launch a libuvc_camera node, but I'm posting this in case anyone else runs into it, and on the off-chance that it'd be feasible to use the system defaults instead of hard-coded defaults that might not be appropriate for all systems.

[liangyuwei]

More concretely, add the following line in the node of libuvc_cam in the launch file:

<param name="brightness" value="128" /> <!-- range is 0-255 -->