3D measurement for complex castings

As complex castings are characterized by larger sizes, complex structures and so many sheltered cavities, it is difficult to measure with higher efficiency and better measurability. Therefore, this paper proposes a stereo vision method combined a large-field binocular measuring subsystem with a small-field grating measuring subsystem. The former was used to measure the outer of the complex castings and the latter was used to measure the cavities of the complex castings. A data registration model for the two subsystems was established and also a method to calibrate the model parameters was proposed. The proposed method was validated by experimental tests. It is proved that the proposed method is suitable for measuring complex castings and the data registration Root Mean Square Error(RMSE) is 0.22 mm. Compared with traditional methods, this method has higher measuring velocity and can measure the complex castings with sheltered cavities. In conclusion, the research has great significance in applications.