Calibrating a small field camera is a challenging task because the traditional target with visible feature points that fit the limited space is difficult and costly to manufacture. We demonstrate a novel combined target used in camera calibration. The tangent points supplied by one circle located at the center of a square are used as invisible features, and the perspective projection invariance is proved. Both visible and invisible features extracted by the proposed feature extraction algorithm are used to solve the calibration. The target supplies a sufficient number of feature points to satisfy the requirements of calibration within a limited space. Experiments show that the approach can achieve high robustness and considerable accuracy. This approach has potential for computer vision applications particularlv in small fields of view.
We propose an approach for realizing 3D reconstruction in small field of view or some extreme environments. We combine the stereo vision and the structured light technologies and change the traditional ways of applying them by employing two fiber bundles. The processes of calibration and 3D reconstruction are also introduced. Experiments are performed to verify the feasibility and effectiveness of our proposed approach.
