A Review of Solutions for Perspective-n-Point Problem in Camera Pose Estimation

As there is a rapid development of robotics in the field of automation engineering, ego-motion estimation has become a most challenging task. In this review, we presented a model to help describe the PnP problems, and introduced two most common solutions. The P3P solution is the smallest subset of control points that yields a finite number of solutions. The EPnP solution is to reduce the complexity by expressing the n 3D points as a weighted sum of four virtual control points. The former solution is widely applied while there are 3 pairs of corresponding points in the problem. However, in most real cases, the latter is more used.