| Fringe projection three-dimensional measurement is widely used in industrial production and other scenes,but it is often limited by the monocular or binocular measurement range,and it is difficult to accurately measure the shape of an object in a large field of view.In order to achieve accurate measurement within a large field of view and meet the production needs of large industrial sites,this paper studies the phase error correction and global calibration technology of the large field of view fringe projection three-dimensional measurement system.The main research contents are as follows:1.The basic principle of fringe projection 3D measurement is analyzed.The overall scheme of large field fringe projection 3D measurement system is designed,the hardware equipment required by the system is selected,and the large field fringe projection 3D measurement experimental device is built.2.The phase error correction method of the system is studied,and the phase error caused by the nonlinearity of DLP projector is analyzed.Comparing the two active correction models,a horizontal and vertical stripe level sub regional precoding active correction method is proposed,the correction steps are designed,and the experiment of correcting the phase error is carried out.The experimental results show that the system phase error is reduced by 80% compared with that before correction,and the ripple on the object surface is significantly reduced.3.The calibration method of fringe projection 3D measurement system with large field of view is studied.The accuracy of the two single target determination methods in local field of view is verified respectively.The vertical and horizontal phase mapping calibration has high accuracy because it is not affected by global factors.The global parameter optimization model and the steps of two global calibration methods are designed.The unification of multiple fields of view can be realized without overlapping fields of view between cameras.The experiments show that the global calibration accuracy based on pseudo binocular stereo calibration is higher.Through the system measurement experiment,the RMSE of the height difference measured in the global field of view is within 0.13 mm,and the RMSE measured in the large field of view is within 1.55 mm. |
