The point cloud data can be defined as a group of data points in some coordinate system. In 3D, it has X, Y, and Z coordinates. PCL library is an open source project for handling 2D/3D image and point clouds processing.

Like OpenCV, it is under BSD license and free for academic and commercial purposes. It is also a cross platform, which has support in Linux, Windows, Mac OS, and Android/iOS.

The library consists of standard algorithms for filtering, segmentation, feature estimation, and so on, which is required to implement different point cloud applications. The main web page of point cloud library is http://pointclouds.org/.

The point cloud data can be acquired by sensors such as Kinect, Asus Xtion Pro, Intel Real Sense, and such others. We can use this data for robotic applications such as robot object manipulation and grasping. PCL is tightly integrated into ROS for handling point cloud data from various sensors. The perception_pcl stack is the ROS interface for PCL library. It consists of packages for pumping the point cloud data from ROS to PCL data type and vice versa. perception_pcl consists of the following packages:

• pcl_conversions: This package provides APIs to convert PCL data types to ROS messages and vice versa.
• pcl_msgs: This package contains definition of PCL related messages in ROS. The PCL messages are:
  • ModelCoefficients
  • PointIndices
  • PolygonMesh
  • Vertices
• pcl_ros: This is the PCL bridge of ROS. This package contains tools
  and nodes to bridge ROS messages to PCL data types and vice versa.
• pointcloud_to_laserscan: The main function of this package is to convert 3D point cloud into 2D laser Scan. This package is useful for converting an inexpensive 3D vision sensor such as Kinect and Asus Xtion Pro to a laser scanner. The laser scanner data is mainly used for 2D-SLAM for the purpose of robot navigation.