Global calibration method for non-overlapping cameras based on mobilephone screens in defocus scene

The global calibration of multi-camera vision systems with non-overlapping views has been widely studied. However, traditional global calibration methods that using planar targets with invariant relative positions are easily limited by the high cost of manufacturing high-precision large planar targets, and the difficulty of rigid connection between them. This paper proposes a low-cost and convenient global calibration method for non-overlapping multiple cameras using double mobile phone screens in defocus scene. During calibration, phase-shifting circular grating (PCG) arrays are displayed on the high-resolution mobile phone screens, and by phase-shifting methods, the PCG centers as feature points can be extracted accurately even if the phone is located at the defocus part of camera. Then the global calibration can be carried out based on the invariance of the relative positions between the two mobile phones. Experiment results show that this method is effective and has high accuracy.