Research On The Precision Of Digital Industrial Photogrammetry

With the rapid development of modern industrial technology,especially the development of digital manufacturing technology,the precision of industrial measurement is continuously increasing.Digital industrial photogrammetry is one of the key technologies of modern industrial measurement.It has the advantages of non-contact,high efficiency,flexible station and easy portability.In view of the new demands of modern industrial measuring development,this paper focuses on the precision of digital industrial photogrammetry.The research work is mainly carried out from the aspects of camera calibration,bundle adjustment,reference ruler and optimization of stations.The main work and innovations are as follows:1.The theoretical basis,system composition,working process and precision evaluation index of digital industrial photogrammetry are introduced.The measuring precision of the Nikon D810 camera is evaluated by the design experiment.Combined with practice,the application of Digital Industrial Photogrammetry in practical engineering is introduced.2.A camera calibration method based on differential ridge estimation is proposed.The camera distortion model and camera calibration method used in digital industrial photogrammetry are summarized,and the existing problems are analyzed.The basic principle of robust ridge estimation is introduced,and the expression of error equation based on robust ridge estimation camera calibration method is derived,and the calibration process based on robust ridge estimation is described.Through the comparison experiment,it is proved that the calibration method of this paper is better.3.The bundle adjustment method based on IGG3 is proposed.The irrationality of taking the different coordinates of the image point in the bundle adjustment process as the equal weight observation value is analysed.By introducing the IGG3 weight factor function to improve the bundle adjustment model,a novel bundle adjustment model based on IGG3 is constructed.The effect of bundle adjustment model based on IGG3 is verified by repeated measurement experiments and common point conversion experiments.4.The influence of the length of scale-bar on the precision of digital industrial photogrammetry is researched.The comparison experiment of the photographic measuring results of different length of scale-bar is designed,and the results show that the measuring precision of selecting the longer scale-bar is higher than selecting the shorter.The influence of the combined error of the combined scale-bar on the precision of photogrammetry is discussed,and the results show that the influence of the combination error of the combined scale-bar on the precision of photogrammetry is negligible.Through the analysis of the experimental results,it is concluded that the influence of scale-bar on the precision of digital industrial photogrammetry is mainly from the measuring error and the longer the scale-bar is,the higher the precision of measurement is.5.The influence of the optimization of station on the precision of digital industrial photogrammetry is researched.First of all,the principle of the station distribution is summarized.Then,the 9 point method of station used in digital industrial photogrammetry is introduced and optimized.Finally,Through the comparison experiment,the effect of the optimized method is evaluated.