Detecting and handling unreliable points for camera parameter estimation

The popularly used DLT method sometimes fails to give reliable camera parameter estimation. It is therefore important to detect the unreliability and provide the corresponding solutions. Based on a complete framework of invariance for six points, we construct two evaluation functions to detect the unreliability. The two evaluation functions do not involve any computations for the camera projective matrix or optical center and thus are efficient to perform the detection. Then, the guidelines corresponding to the different detection results are presented. In particular, a filtering RANSAC method to remove the detected unreliable points is provided. The filtering RANSAC proves to be successful in removing the unreliable points even if these points are of a large proportion. © 2007 Springer Science+Business Media, LLC.