In LiDAR, laser light is sent from a source (transmitter) and reflected from objects in the scene. The reflected light is detected by the system receiver and the time of flight (TOF) is used to develop a distance map of the objects in the scene.

The object-wise feature extractors project LiDAR point clouds into 2D representations and generate the object proposals using 2D networks. Then, they regress the region proposals to predict the 3D bounding boxes.