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About

This package contains an USB camera driver which is almost compatible to usb_cam but based on ros_control. Major enhancements over usb_cam are;

• impremented as a nodelet
• supports h264 pixel format (1/10 network usage compared with mjpeg)
• publishes raw packets from the camera (1/10 cpu usage and less latency compared with decoding mjpeg packets in the node)
• accepts 3rd party controllers

Slides from ROS Japan UG #28 (in Japanese)

Nodelets

usb_cam_hardware/USBCamHardware

an USB camera driver based on ros_control

Published Topics

<controller-defined> (<controller-defined>)

• see the controller section below

Parameters

~video_device (string, default: "/dev/video0")

• path to the camera device

~image_width (int, default: 640)

• image width in pixels

~image_height (int, default: 480)

• image height in pixels

~pixel_format (string, default: "mjpeg")

• pixel format of the camera device. supported formats are "grey", "h264", "mjpeg", "rgb24", "uyvy", and "yuyv".

~framerate (int, default: 30)

• desired framerate per second

Controllers

All topics and parameters are defined in each controller's namespace

usb_cam_controllers/CameraInfoController

publishes camera information syncronized to packets from the camera

Published Topics

camera_info (sensor_msgs/CameraInfo)

• camera info

Parameters

camera_frame_id (string, default: "head_camera")

• camera frame id

camera_info_url (string, default: "")

• camera info URI

camera_name (string, default: "head_camera")

• camera name

usb_cam_controllers/PacketController

publishes raw packets from the camera as images

Published Topics

image (sensor_msgs/Image)

• images in raw image format

Parameters

image_width (int, default: 640)

• value of Image::width

image_height (int, default: 480)

• value of Image::height

encoding (string, default: "bgr8")

• value of Image::encoding

skip (int, default: 0)

• number of packets skipped after publishment. useful to throttle network usage.

usb_cam_controllers/CompressedPacketController

publishes raw packets from the camera as compressed images

Published Topics

packet (sensor_msgs/CompressedImage)

• compressed images

Parameters

format (string, default: "jpeg")

• value of CompressedImage::format

skip (int, default: 0)

• number of packets skipped after publishment. useful to throttle network usage.

usb_cam_controllers/MjpegController

decodes mjpeg-compressed packets and publishes decoded images

Published Topics

image (sensor_msgs/Image)

• decoded images

usb_cam_controllers/H264Controller

decodes h264-compressed packets and publishes decoded images

Published Topics

image (sensor_msgs/Image)

• decoded images

usb_cam_controllers/RGB24Controller

converts rgb-formatted packets to bgr images and publishes them

Published Topics

image (sensor_msgs/Image)

• bgr-formatted images

Parameters

image_width (int, default: 640)

• value of Image::width

image_height (int, default: 480)

• value of Image::height

usb_cam_controllers/UYVYController

converts uyvy-formatted packets to bgr images and publishes them

Published Topics

image (sensor_msgs/Image)

• bgr-formated images

Parameters

image_width (int, default: 640)

• value of Image::width

image_height (int, default: 480)

• value of Image::height

usb_cam_controllers/YUYVController

converts yuyv-formatted packets to bgr images and publishes them

Published Topics

image (sensor_msgs/Image)

• bgr-formatted images

Parameters

image_width (int, default: 640)

• value of Image::width

image_height (int, default: 480)

• value of Image::height

Examples

See the github repository.

Related ROS packages

codec_image_transport

• for subscriber-side decoding of h264 packets published by the CompressedPacketController