LaserScan

Intro

LaserScan is a ROS message type that contains 2D distance measurement data produced by a planar laser scanner.

sensor_msgs/LaserScan.msg

The LaserScan message provides the angle of each hit and its distance (range) from the scanner.

# Single scan from a planar laser range-finder
#
# If you have another ranging device with different behavior (e.g. a sonar
# array), please find or create a different message, since applications
# will make fairly laser-specific assumptions about this data
 
Header header            # timestamp in the header is the acquisition time of 
                         # the first ray in the scan.
                         #
                         # in frame frame_id, angles are measured around 
                         # the positive Z axis (counterclockwise, if Z is up)
                         # with zero angle being forward along the x axis
                         
float32 angle_min        # start angle of the scan [rad]
float32 angle_max        # end angle of the scan [rad]
float32 angle_increment  # angular distance between measurements [rad]
 
float32 time_increment   # time between measurements [seconds] - if your scanner
                         # is moving, this will be used in interpolating position
                         # of 3d points
float32 scan_time        # time between scans [seconds]
 
float32 range_min        # minimum range value [m]
float32 range_max        # maximum range value [m]
 
float32[] ranges         # range data [m] (Note: values < range_min or > range_max should be discarded)
float32[] intensities    # intensity data [device-specific units].  If your
                         # device does not provide intensities, please leave
                         # the array empty.
 

Inspect LaserScan data

• [ROS Q&A] 031 – How to read LaserScan data (ROS python)

Inspect Sample Laser Scan Message

scan = 
  ROS LaserScan message with properties:

       MessageType: 'sensor_msgs/LaserScan'
            Header: [1×1 Header]
          AngleMin: -0.5467
          AngleMax: 0.5467
    AngleIncrement: 0.0017
     TimeIncrement: 0
          ScanTime: 0.0330
          RangeMin: 0.4500
          RangeMax: 10
            Ranges: [640×1 single]
       Intensities: [0×1 single]

Related

• Converting a Laser Scan to a Point Cloud