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USB camera to ROS


(Clyde McQueen) #1

Hi, folks:

I’m trying to connect the low light USB camera to the usb_cam ROS node, and it works fine at 640x480, but I can’t seem to get higher resolutions to work. Can you provide details about the chipset and supported resolutions and encodings?


Color correcting the camera feed
(Jacob) #2

The camera presents two video devices to the OS (you might see more here if you have a webcam):

$ ls /dev/video*
/dev/video0  /dev/video1

The first device outputs MJPG format and the second device outputs H.264 format:

$ v4l2-ctl --device=0 --list-formats
ioctl: VIDIOC_ENUM_FMT
	Index       : 0
	Type        : Video Capture
	Pixel Format: 'MJPG' (compressed)
	Name        : Motion-JPEG

	Index       : 1
	Type        : Video Capture
	Pixel Format: 'YUYV'
	Name        : YUYV 4:2:2

Use--list-formats-ext to see the supported framesizes and frameintervals:

$ v4l2-ctl --device=1 --list-formats-ext
ioctl: VIDIOC_ENUM_FMT
	Index       : 0
	Type        : Video Capture
	Pixel Format: 'H264' (compressed)
	Name        : H.264
		Size: Discrete 1920x1080
			Interval: Discrete 0.033s (30.000 fps)
			Interval: Discrete 0.040s (25.000 fps)
			Interval: Discrete 0.067s (15.000 fps)
		Size: Discrete 1280x720
			Interval: Discrete 0.033s (30.000 fps)
			Interval: Discrete 0.040s (25.000 fps)
			Interval: Discrete 0.067s (15.000 fps)
		Size: Discrete 800x600
			Interval: Discrete 0.033s (30.000 fps)
			Interval: Discrete 0.040s (25.000 fps)
			Interval: Discrete 0.067s (15.000 fps)
		Size: Discrete 640x480
			Interval: Discrete 0.033s (30.000 fps)
			Interval: Discrete 0.040s (25.000 fps)
			Interval: Discrete 0.067s (15.000 fps)
		Size: Discrete 640x360
			Interval: Discrete 0.033s (30.000 fps)
			Interval: Discrete 0.040s (25.000 fps)
			Interval: Discrete 0.067s (15.000 fps)
		Size: Discrete 352x288
			Interval: Discrete 0.033s (30.000 fps)
			Interval: Discrete 0.040s (25.000 fps)
			Interval: Discrete 0.067s (15.000 fps)
		Size: Discrete 320x240
			Interval: Discrete 0.033s (30.000 fps)
			Interval: Discrete 0.040s (25.000 fps)
			Interval: Discrete 0.067s (15.000 fps)
		Size: Discrete 1920x1080
			Interval: Discrete 0.033s (30.000 fps)
			Interval: Discrete 0.040s (25.000 fps)
			Interval: Discrete 0.067s (15.000 fps)

Use --list-ctrls to see the v4l controls you can change:

$ v4l2-ctl --device=1 --list-ctrls
                     brightness (int)    : min=-64 max=64 step=1 default=0 value=0
                       contrast (int)    : min=0 max=64 step=1 default=32 value=32
                     saturation (int)    : min=0 max=128 step=1 default=56 value=56
                            hue (int)    : min=-40 max=40 step=1 default=0 value=0
 white_balance_temperature_auto (bool)   : default=1 value=1
                          gamma (int)    : min=72 max=500 step=1 default=100 value=100
                           gain (int)    : min=0 max=100 step=1 default=0 value=0
           power_line_frequency (menu)   : min=0 max=2 default=1 value=1
      white_balance_temperature (int)    : min=2800 max=6500 step=1 default=4600 value=4600 flags=inactive
                      sharpness (int)    : min=0 max=6 step=1 default=3 value=3
         backlight_compensation (int)    : min=0 max=2 step=1 default=1 value=1
                  exposure_auto (menu)   : min=0 max=3 default=3 value=3
              exposure_absolute (int)    : min=1 max=5000 step=1 default=156 value=156 flags=inactive
         exposure_auto_priority (bool)   : default=0 value=0

I don’t have any information on the chipset, and I don’t know how to deal with any of this on Windows.


(Clyde McQueen) #3

Thanks for the quick response and info! This appears to be a bug in the ROS usb_cam driver. You can follow along here, if you want: https://github.com/ros-drivers/usb_cam/issues/79