Point Cloud Display; Coordinate Mapping; Reflectivity - RoboSense LiDAR RS-Ruby Plus User Manual

RS-Ruby Plus User Manual

4.2 Point Cloud Display

4.2.1 Coordinate Mapping

Since the data packet output by the LiDAR only provides the horizontal rotation angle and
distance parameters, in order to present a 3D point cloud image, the angle and distance
information in polar coordinates need to be converted into x, y, z coordinates in the Cartesian
coordinate system, and the conversion formula is as follows:
� = � ��� ( �) ��� ( �);
� = � ��� ( �) ��� ( �);
� = � ��� ( �);
Where � is the measured distance,
 
is the vertical angle of the laser, is the horizontal
rotation angle of the laser in the Polar Coordinate System, and x, y, z are the coordinate values in
the Cartesian Coordinate System
Note : SDK source code of RS-Ruby Plus has by default completed the coordinate conversion to conform to the
right-handed coordinate system of ROS. The X-axis of ROS is the positive Y direction in Figure 2-1, and the Y-axis
of ROS is the negative X direction in Figure 2-1.

4.3 Reflectivity

RS-Ruby Plus measures the reflectivity of objects. The reflectivity is an index that measures the
ability of an object to reflect light and is greatly related to the material of the object itself.
Therefore, the reflectivity information can be used to distinguish objects of different materials.
RS-Ruby Plus reports calibrated reflectivity values from 0 to 255, among which diffuse reflectors
report values from 0 to 100, and retroreflectors report values from 101 to 255. Black objects are
with low reflectivity values, white objects are with high reflectivity values, the most ideal
reflection reports the reflectivity value of 255.
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