This repository holds ROS/ROS2 tools for displaying and converting event_camera_msgs under ROS and ROS2. These messages are produced by the metavision_driver.
Currently tested on Ubuntu 20.04/22.04 under ROS Noetic and ROS2 Galactic/Humble.
Set the following shell variables:
repo=event_camera_tools
url=https://github.com/ros-event-camera/${repo}.git
and follow the instructions here
The republish
node converts event_camera_msgs to legacy formats
like dvs, prophesee, and decoded ("mono") event_camera messages. Note
that this nodelet will be consuming a significant amount of CPU
resources and should not be run unnecessarily while recording data.
The following command will start a conversion nodelet to republish
events from /event_camera/events
to
/event_camera/republished_events
and
/event_camera/republished_triggers
(similar syntax under ROS2, see launch file for remapping):
roslaunch event_camera_tools republish_nodelet.launch camera:=event_camera message_type:=event_packet
All tools are provided in ROS and ROS2 (syntax below is for ROS):
-
rosrun event_camera_tools echo [-b <bag>] <topic>
: displays messages inevent_camera_msgs
format, optionally from a bag file. Example output:------------------------------- res: 640 height: 480 enc: evt3 header stamp: 1664227781775114816 time base: 0 seqno: 129213 --- 6851488000 edge: 1 id: 6 6851510000 390 223 1 6851520000 33 326 0 ...
-
rosrun event_camera_tools perf <topic>
: Sample output:msgs: 219.48/s drp: 0 del: 13.72ms drft: 0.0033s ev: 0.0823 M/s %ON: 46 tr: 1758.38 1/s %UP: 50 msgs: 249.01/s drp: 0 del: 4.35ms drft: 0.0027s ev: 0.8497 M/s %ON: 52 tr: 1999.56 1/s %UP: 49
The meaning of the fields is as follows:
msgs
message rate per secondsdrp
number of drops per second (skip in sequence numbers)del
delay: average time difference between message header stamp and arrival time. This includes the delay due to the driver aggregating messages.drft
accumulated (from start of "perf") drift between message header stamp and sensor-provided time.ev
event rate in millions/sec%ON
ratio of ON events to total (ON + OFF) eventstr
rate of trigger messages%UP
ratio of UP trigger edges to total (UP + DOWN)
-
rosrun event_camera_tools sync_test <cam_0_event_topic> <cam_1_event_topic>
The output gives the average sensor time difference and how many samples where counted:avg sensor diff: 0.00846s, count: 360 avg sensor diff: 0.00377s, count: 466 ...
-
rosrun event_camera_tools bag_to_raw -t <topic> -b <bag_name> -o <outout_raw_file> -c <camera_type>
Converts bags with evt3 event_camera_msgs to raw file. The
camera_type
argument is necessary to produce a valid header for the raw file. -
rosrun event_camera_tools raw_to_bag -t <topic> -b <bag_file> -i <input_raw_file> -w <sensor_width> -h <sensor_height> -B <buffer_size>
Converts raw file into bag with evt3 event_camera_msgs. The buffer size determines the size and number of ROS messages in the bag.
-
rosrun event_camera_tools movie_maker -f <fps> -b <bag_name> -t <topic>
produces sequence of frame images.
-
rosrun event_camera_tools legacy_to_bag -b <input_bag_file> -o <output_bag_file> -t <topic1> [topic2 topic3 ...]
Converts bags with DVS or Prophesee messages to evt3 event_camera_msgs.
-
ros2 run event_camera_tools find_trigger_events -i input_bag -t topic_with_trigger_events
This tool is useful when aligning reconstructed image frames for datasets that use a pulse-per-second synchronization scheme. The
find_trigger_events
tool finds the ROS time and sensor time of the first trigger pulse in a rosbag. Output example:first trigger ROS time: 1702577874035860000 first trigger sensor time: 24809136000 num triggers: 1712 avg time between triggers: ROS time: 0.0499567s sensor time: 0.0499567s processed 202 number of messages
The ROS and sensor times of the first trigger event serve as inputs for image reconstruction tools such as
bag_to_frames
. -
ros2 run event_camera_tools plot_events -b name_of_bag -o name_of_plot_file -t topic
Creates file with 4 columns (time, x, y, polarity) for plotting. Also useful for clear text viewing of events in bag file.
This software is issued under the Apache License Version 2.0.