Research On 3-D Reconstruction Of Object Surface Based On Grating Projection

The three-dimensional surface reconstruction method based on grating projection belongs to one of the three-dimensional measurement methods of structured light vision,and is one of the most widely used active non-contact three-dimensional measurement techniques.Because of its advantages of high measurement accuracy,fast measurement speed and non-contact,this technology is widely used in workpiece measurement,quality control,biomedicine,abrasive design,cultural relics protection,reverse engineering and machine vision.Therefore,it has important theoretical and practical significance to study the three-dimensional reconstruction method of object surface based on grating projection.In this paper,based on the theory of computer vision inspection,the method of three-dimensional reconstruction of object surface based on grating projection is studied by combining theory with experiment.In this paper,the theoretical basis and research status of grating projection technology are introduced,and the research hotspots and difficulties of grating projection technology are analyzed.Combining the advantages and disadvantages of space phase unwrapping technology and time phase unwrapping technology,the value of time phase unwrapping technology based on multi-frequency projection fringes is pointed out.The key step in grating projection 3-D measurement is to get the absolute phase accurately from the phase diagram.Among many phase unwrapping methods,the time phase unwrapping method based on multi-frequency projection fringes is widely used because of its fast calculation speed,independent phase unwrapping of pixels and strong detail resolution.Based on the literature research of time phase unwrapping technology,this paper adopts a three-frequency heterodyne phase unwrapping algorithm,which improves the resolution ability of details of multi-frequency heterodyne solution,effectively suppresses the jumping error caused by phase unwrapping,and greatly reduces the non-linear error of phase unwrapping.The appropriate period projection fringes are selected and simulated and experimentally studied.The effectiveness of the algorithm is verified by adding disturbance and random error.The accuracy of the algorithm is verified by experiments.Based on the analysis of the existing system parameter calibration methods,this paper adopts a camera projector joint calibration method.Only one standard block combined with the known pixel information can get the high phase mapping relationship.The effectiveness of this method is verified by experiments.By building an experimental platform,the three-dimensional reconstruction and measurement of the target workpiece are carried out.The geometric parameters information is obtained,and the measurement error is reduced.The effectiveness and accuracy of the method described in this paper are further verified,and the expected goal is achieved.The research work has certain theoretical significance and practical application value.