Some Discussion on the Conditions of the Unique Solution of P3P Problem

The multi-solution phenomenon of P3P problem limits its applications in practices. In some specific case, if we know the relative pose between control points and camera in advance, then it is likely to get the unique solution of P3P problem easily. Combined with predecessor's work, this paper presents a much more integrated analysis of the unique solution region of specific P3P problem. We find that there are seven regions in space which can lead to the unique solution of P3P problem when three control points of P3P problem form an isosceles triangle. And when the camera is within these regions, we can get the solution of P3P problem uniquely. The results we obtain are very useful for disposing control points and the camera in the practical applications