A simple pose estimation method based on co-planar feature points

This paper presents a simple method to solve the P4P problem based on co-planar feature points. By enhancing the geometric constraints of the feature points which attached to the target previously, we obtain the three-dimensional camera coordinates of the feature points in two different formulas. Then the translation vector and three rotation angles describing the relationship between target coordinate system and camera coordinate system are computed using a closed-form solution directly. In order to improve the precision about the extraction of the image center coordinate of the feature point, we use the morphology expansion operation to achieve it. The experimental results and theoretical analysis which were compared with the previous method demonstrate that our method is more fast and effective.