rc_genicam_driver for ROS2

ROS2 driver to configure a Roboception rc_visard or rc_cube and receive images.

Please also consult the manuals for more details:

• https://doc.rc-visard.com
• https://doc.rc-cube.com

GenICam GenTL Transport Layer

The rc_genicam_driver uses rc_genicam_api for interfacing with the rc_visard or rc_cube via GenICam/GigE Vision and requires a transport layer called a GenTL producer (shared library with the suffix .cti). For convenience rc_genicam_api comes with producers from Baumer for common architectures.

The path to the producer can be set with the GENICAM_GENTL64_PATH environment variable (or GENICAM_GENTL32_PATH for 32 bit systems). If not set, rc_genicam_driver will fall back to searching for the Baumer producer where rc_genicam_api is installed.

If the producer .cti can’t be found and you will get an error message like

[ERROR] [1512568083.512790905]: No transport layers found in path /opt/ros/melodic/lib/rc_genicam_api

In this case you need either need to actually install rc_genicam_api properly or set the environment variable when running it. E.g. export:

GENICAM_GENTL64_PATH=/path/to/rc_genicam_api/baumer/Ubuntu-18.04/x86_64

Configuration

Read-only parameters

Parameters to be set to the ROS param server before run-time.

• device: The ID of the device, e.g. Roboception rc_visard sensor or rc_cube. This can be either the

  • serial number, e.g. 02912345

    IMPORTANT: preceed with a colon (:02912345) when passing this on the commandline or setting it via rosparam (see https://github.com/ros/ros_comm/issues/1339). This is not neccessary when specifying it as a string in a launch file.

  • user defined name (factory default is the name of the rc_visard’s model), must be unique among all reachable sensors

  • internal ID, which is generated by the used GenTL producer. Often, this ID contains the MAC address in some way. This ID can change with the implementation of the transport layer.

  See https://github.com/roboception/rc_genicam_api#device-id for more details. By default this parameter is set to *, which works with if only one compatible device can be found on the network.

At runtime changeable parameters

These parameters can be changed during runtime. Parameters will not be declared if they are not available on the device. This can happen if the device firmware is old and does not offer the parameter.

• ptp_enabled: Enable PTP slave (PrecisionTimeProtocol, IEEE1588)

• camera_fps: Frames per second that are published by this node. Publishing frames will be slowed down depending on this setting. Setting it higher than the real framerate of the specific device has no effect.

• camera_exp_auto: This parameter has been removed. Please use camera_exp_control instead.

• camera_exp_control: Expose control mode which can be “Manual” for setting exposure time and gain via camera_exp_value and camera_gain_value, “Auto” for auto exposure or “HDR” for high dynamic range mode. Default: Auto.

• camera_exp_auto_mode Auto-exposure mode which can be “Normal”, “Out1High” or “AdaptiveOut1”. Default: Normal.

• camera_exp_max: Maximum exposure time in seconds if exp_auto is true.

• camera_exp_auto_average_max: The auto exposure tries to set the exposure time and gain factor such that the average image intensity is between an upper and a lower bound. This parameter defines the upper bound. It can be reached if there is no saturation (e.g. due to reflections).

• camera_exp_auto_average_min: See camera_exp_auto_average_max. This parameter defines the lower bound. The average image intensity can be reduced to this value to reduce or avoid saturation (e.g. due to reflections).

• camera_exp_value: Exposure time in seconds if exp_auto is false.

• camera_gain_value: Gain factor in decibel if exp_auto is false.

• camera_gamma: Gamma factor. Default: 1.0.

• Auto exposure region: Definition of a region in the left image, if the region has zero size or is outside the image, then the full left and right image is used to determine the auto exposure.
  • camera_exp_width: Width of auto exposure region. 0 for whole image.
  • camera_exp_height: Height of auto exposure region. 0 for whole image.
  • camera_exp_offset_x: First column of auto exposure region
  • camera_exp_offset_y: First row of auto exposure region

• depth_acquisition_mode: Can be either SingleFrame or Continuous. Only the first letter will be checked, thus giving S or C is sufficient.

• depth_quality: Quality can be “Low”, “Medium”, “High” and “Full”. Only the first letter will be checked, thus specification of “L”, “M”, “H” or “F” is sufficient. The quality setting effectively downscales the image after the downscale factor as given above:

  • Full does not downscale the image, i.e. factor is 1 (e.g. 1280x960). NOTE: This mode requires the ‘stereo_plus’ license on the rc_visard.
  • High downscales by factor 2 (e.g. 640x480).
  • Medium downscales by factor 4 (e.g. 320x240).
  • Low downscales by factor 6 (e.g. 214x160).

• depth_static_scene: This parameter can be set to true if the scene and camera is static. It only has an effect if quality is either High or Full. If active, input images are accumulated and averaged for 300 ms to reduce noise. This limits the frame rate to a maximum of 3 Hz. The timestamp of the disparity image is taken from the first image that was used for accumulation.

• depth_fill: Higher numbers fill gaps with measurments with potentielly higher errors.

• depth_seg: Maximum size of isolated disparity regions that will be invalidated, related to full resolution.

• depth_smooth: Switching smoothing of disparities on or off. NOTE: Smoothing requires the ‘stereo_plus’ license on the rc_visard.

• depth_minconf: Minimal confidence. All disparities with lower confidence will be set to invalid.

• depth_mindepth: Minimum depth in meter. All disparities with lower depth will be set to invalid.

• depth_maxdepth: Maximum depth in meter. All disparities with higher depth will be set to invalid.

• depth_maxdeptherr: Maximum depth error in meter. All disparities with a higher depth error will be set to invalid.

• depth_exposure_adapt_timeout: Maximum time in seconds to wait after triggering in SingleFrame modes until auto exposure has finished adjustments.

• out1_mode: Mode for the digital GPIO out1. Possible values are:

  • Low for switching out1 permanently off.
  • High for switching out1 permanently on.
  • ExposureActive for switching out1 on for the exposure time of every image.
  • ExposureAlternateActive for switching out1 on for the exposure time of every second image.

  The value can only be changed if the rc_visard has an IO Control license. The default is Low.

• out2_mode: Mode for the digital GPIO out2. The functionality is the same as for out1_mode. The default is Low.

For color sensors, the following dynamic-reconfigure parameters are additionally available:

• camera_wb_auto: If true, then white balancing is done automatically. If false, then the red and blue to green ratios can be chosen manually.

• camera_wb_ratio_red: Red to green ratio for color balancing if camera_wb_auto is false.

• camera_wb_ratio_blue: Blue to green ratio for color balancing if camera_wb_auto is false.

Provided Topics

The following topics are provided. The node tries to request only data (e.g., images, poses) from the sensor if there is subscriber to the corresponding topic.

Images, Stereo Data, Point Clouds

• /stereo/left/camera_info (sensor_msgs::CameraInfo)
• /stereo/right/camera_info (sensor_msgs::CameraInfo)
• /stereo/left/camera_param (rc_common_msgs::CameraParam)
• /stereo/right/camera_param (rc_common_msgs::CameraParam)
• /stereo/left/image_rect (sensor_msgs::Image, MONO8)
• /stereo/right/image_rect (sensor_msgs::Image, MONO8)
• /stereo/disparity (stereo_msgs::DisparityImage)
• /stereo/disparity_color (sensor_msgs::Image, RGB8, visually pleasing)
• /stereo/depth (sensor_msgs::Image, TYPE_32FC1)
• /stereo/confidence (sensor_msgs::Image, TYPE_32FC1, values between 0 and 1)
• /stereo/error_disparity (sensor_msgs::Image, TYPE_32FC1)
• /stereo/error_depth (sensor_msgs::Image, TYPE_32FC1)
• /stereo/points2 (sensor_msgs::PointCloud2)

The proprietary CameraParam messages are sent for every image and contain information like the exposure time, gain and values of digital inputs and outputs at the time of image capture.

For color sensors, the following topics are additionally available:

• /stereo/left/image_rect_color (sensor_msgs::Image, format: RGB8)
• /stereo/right/image_rect_color (sensor_msgs::Image, format: RGB8)

If the connected rc_visard has an IO Control license, then the following topics are additionally provided for images where the GPIO out1 is either low or high. These topics only useful if out1_mode is set to the special mode ExposureAlternateActive.

• /stereo/left/image_rect_out1_low (sensor_msgs::Image, MONO8)
• /stereo/left/image_rect_out1_high (sensor_msgs::Image, MONO8)
• /stereo/right/image_rect_out1_low (sensor_msgs::Image, MONO8)
• /stereo/right/image_rect_out1_high (sensor_msgs::Image, MONO8)

For color sensors with an IO Control license, the following topics are additionally available:

• /stereo/left/image_rect_color_out1_low (sensor_msgs::Image, format: RGB8)
• /stereo/left/image_rect_color_out1_high (sensor_msgs::Image, format: RGB8)
• /stereo/right/image_rect_color_out1_low (sensor_msgs::Image, format: RGB8)
• /stereo/right/image_rect_color_out1_high (sensor_msgs::Image, format: RGB8)

Running multiple rc_visard’s in one ros environment

For operating multiple rc_visard’s in one ros environment, each ros node must be started in separate namespaces, e.g., my_visard. As a result, all frame_ids in all ros messages will be prefixed, e.g., to my_visard_world or my_visard_camera.

Services

The following service is offered to trigger stereo matching in SingleFrame mode. It returns an error if the depth_acquisition_mode is Continuous.

• depth_acquisition_trigger

Diagnostics

The rc_genicam_driver uses the diagnostics_updater class from the ROS diagnostics stack to regularly publish a DiagnosticStatus Message.

The regular publishing rate can be set via the diagnostic_updater.period parameter and defaults to 1 second.

Currently two status are published:

• Device: Information about the device that the driver is connected to. It covers the device serial number, mac address, user-defined GeV ID, and the firmware image version.

• Connection: Status of the current connection between rc_genicam_driver and device. It publishes 4 different messages:

  • Disconnected (Error): The driver is currently not (yet) connected to the sensor and might try to reconnect several times according to the max_reconnects parameter.
  • Idle (Ok): The driver is connected but not publishing any data because no one is subscribed to any.
  • No data (Warning): The driver is connected and required to publish data but itself does not receive any data from the sensor.
  • Streaming (Ok): The driver is connected and properly streaming data.

  The published status values are connection_loss_total, incomplete_buffers_total, image_receive_timeouts_total, and current_reconnect_trial. If not Disconnected, additionally the current ip_address and gev_packet_size are published.

Launching

• Run as node using command line parameters:

  ros2 run rc_genicam_driver rc_genicam_driver --ros-args -p "device:=:02912345"
  

• Run as component with command line parameters:

  ros2 component standalone rc_genicam_driver rc::GenICamDriver -p "device:=:02912345"
  

• In a separate namespace:

  run rc_genicam_driver rc_genicam_driver --ros-args -p "device:=:02912345" -r __ns:=/my_visard
  

Note that in this setup all frame_ids in all ros messages will be prefixed with my_visard, e.g., the frame_id of the published camera images will be my_visard_camera.

Acknowledgements

This FTP (Focused Technical Project) has received funding from the European Union’s Horizon 2020 research and innovation programme under the project ROSIN with the grant agreement No 732287.

ROSIN: ROS-Industrial Quality-Assured Robot Software Components: http://rosin-project.eu