libcaer_driver

A ROS2 driver for event based cameras using Inilab’s Libcaer (Davis, DvXplorer). This driver is not written or supported by Inilabs.

This driver is intended to be a successor to the University of Zuerich ROS1 driver. The ROS2 port addresses some deficiencies of the ROS1 driver, in particular the performance problems due to the message format. Usage of the event_camera_msgs format allows for higher bandwidth and more efficient storage.

The events can be decoded and displayed using the following ROS/ROS2 packages:

• event_camera_codecs has C++ routines to decode event_camera_msgs.
• event_camera_py module for fast event decoding in python.
• event_camera_renderer a node / nodelet that renders and publishes ROS image messages.
• event_camera_tools a set of tools to echo, monitor performance and convert event_camera_msgs to legacy formats.

Supported platforms

Tested on the following platforms:

• ROS2 Humble on Ubuntu 22.04 LTS
• ROS2 Jazzy on Ubuntu 24.04 LTS

Tested with the following hardware:

• Davis 346
• Davis 240C
• DvXplorer

Continuous integration testing covers ROS2 versions Humble and later.

Note: lead developer no longer has access to hardware for testing or developing.

Installation

From packages

sudo apt install ros-${ROS_DISTRO}-libcaer-driver

From source

The build instructions follow the standard procedure for ROS2. Set the following shell variables:

repo=libcaer_driver
url=https://github.com/ros-event-camera/${repo}.git

and follow the ROS2 build instructions here

Make sure to source your workspace’s install/setup.bash afterwards.

This driver provides its own version of libcaer (via the libcaer_vendor package), but you still need to copy the udev file into place and modify the group permissions:

sudo cp src/libcaer/lib/udev/rules.d/65-inivation.rules /etc/udev/rules.d/
sudo usermod -aG video ${USER}
sudo usermod -aG plugdev ${USER}
sudo udevadm trigger
sudo service udev restart

Now you need to log out and back in to the host in order for the updated group permissions to take hold.

Driver Features

Driver parameters (besides biases and other device-specific parameters):

• auto_exposure_enabled: (defaults to False) enables/disables driver-provided auto exposure for APS frames.
• auto_exposure_illumination: (0-255, defaults to 127) target brightness for APS frame exposure
• auto_exposure_hysteresis: (0-0.5, defaults to 0.0625) relative tolerance for brightness error before adjusting exposure time.
• camera_frame_id: the ROS frame id to use in the header of event and image messages
• camerainfo_url: location of the ROS camera calibration file.
• device_type: “davis”, “dvxplorer”, …
• device_id: the libcaer device id (defaults to 1).
• event_message_time_threshold: (in seconds) minimum time span of events to be aggregated in one ROS event message before message is sent. Defaults to 1ms.
• event_message_size_threshold: (in bytes) minimum size of events (in bytes) to be aggregated in one ROS event message before message is sent. Defaults to 1MB.
• event_send_queue_size: outgoing ROS message send queue size (defaults to 1000 messages).
• encoding: libcaer_cmp(compressed, default) or libcaer (uncompressed). The CPU usage for encoding is very small, and can actually reduce the CPU load on the driver because of the reduction of memory access when sending the message. Use of uncompressed libcaer is strongly discouraged. Only use libcaer encoding if low event rates are expected, and decompression latency is an issue.
• imu_frame_id: the ROS frame id to use in the header of imu messages
• imu_send_queue_size: (defaults to 10) max number of ROS messages to be buffered in send queue.
• master: (defaults to True) whether the device is acting as synchronization master.
• serial: specifies serial number of camera to open (useful if you have multiple cameras connected). You can learn the serial number via lsusb -v -d 152a: | grep iSerial, or just start the driver with the serial number left blank, and look at the console log.
• statistics_print_interval: time in seconds between statistics printouts.o
• time_reset_delay: integer time in seconds to wait before hardware resetting the sensor time. Defaults to 2.

How to use:

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Changelog for package libcaer_driver

1.5.1 (2025-05-22)

• stop using ament_target_dependencies
• Contributors: Bernd Pfrommer

1.5.0 (2025-04-10)

• 16 bit APS image and color cam support
• support for recording under Jazzy+
• updated installation instructions
• Contributors: Bernd Pfrommer

1.0.3 (2024-05-30)

• remove repos file, build only on recent distros
• use libcaer_vendor
• initial release on rolling?
• Contributors: Bernd Pfrommer, Thies Lennart Alff