| Towards large objects,a system about free mobile 3D scanning measurement is developed in this paper,which combines binocular sensor with structured-light sensor together.This system can complete portable 3D scanning measurement through mark points positioning without guide rails.In this way,the 3D information on the objects’ surface can be obtained.In this paper,the following tasks have been completed:According to the principle of measurement,the overall scheme of the system is proposed.The mechanical structure and software algorithm design towards the measurement system have been finished and cameras,lasers and other auxiliary devices are purchased according to the measurement requirements of the project.The system presents a newly binocular measurement model named Double-line Projection model,through which the system can get mark points’ three-dimensional coordinates.Based on the Double-line Projection model,the paper designs a structured-light model named Line-plane Constraint to get the modulated information of the light strips on the objects’ surface.With the aid of precise translation unit,the whole sensor system can complete the calibration and the unity of the binocular and structure light coordinate system.A new global positioning method of the whole sensor is put forward in the paper,the Double-line Projection model is used in the stereo matching of the mark points in the binocular sensor.According to mark points’ property of the space geometric invariance and the relationship between vector angles,the entire system can finish the global matching of mark points in sensor coordinate and global coordinate.Calibration experiment,binocular accuracy experiment measurement,and scanning measurement accuracy verification experiment are carried out in the laboratory.Through these experiments,the free mobile 3D scanning measurement system’s measurement precision and function are evaluated comprehensively.Experiments show that the system has high measurement precision,and can complete scanning measurement of large objects. |
