Figure 5.

Geometric relationship between two coordinate systems. $O_C$ is the origin of the camera coordinate system. $O_W$ is the origin of LiDAR coordinate system. ${\mathsf{\Pi }}^{\infty }$ is the infinity plane in the space. ${\mathbf{X}}_1^{\infty }$, ${\mathbf{X}}_2^{\infty }$, and ${\mathbf{X}}_3^{\infty }$ are 3D infinity points in the world coordinate system. Actually, ${\mathbf{c}}_i$ and ${\mathbf{w}}_i$ coincide in the space.