High Precision Based On Monocular Structured Light Research On 3D Reconstruction Technology

Visual 3D reconstruction based on structured light can efficiently and accurately obtain the spatial 3D information of the measured object,and is widely used in industrial inspection,cultural relics protection,3D printing,VR,digital medical,bio-digital recognition and other fields.At present,the most common structured light measurement system is divided into monocular system and multi-eye system.Compared with binocular,monocular structured light three-dimensional measurement system has the advantages of lower cost and larger measurement range,but the measurement accuracy is affected by the environment.The light interference is large,so how to improve the anti-interference performance of three-dimensional imaging while improving the measurement accuracy and efficiency is becoming more and more important.In view of the above problems,this article has conducted in-depth research on structured light coding and decoding technology,system calibration,point cloud computing and model reconstruction.The main contents and innovations include:(1)This thesis has completed the calibration of the system parameters of the monocular 3D reconstruction system.Aiming at the problem of low accuracy of the existing system calibration or excessive manual operation,this thesis adopts the phase shift calibration method based on the homography matrix,and uses the improved high-frequency phase shift structured light proposed in this paper for calibration,which improves the pixel correspondence.The accuracy rate of the system has been better completed the high-precision calibration of the system.(2)Aiming at the interference of ambient light on the reconstruction accuracy of structured light,this thesis proposes a improved high-frequency phase-shift coding and decoding method,which uses high-frequency sinusoidal coded structured light to synthesize low-frequency phase-shifted sinusoidal structured light.The method proposed in this thesis can effectively reduce the interference of ambient light to structured light coding and decoding,and provide a reliable guarantee for the correct decoding of structured light.The high-frequency phase-shift structured-light coded proposed in this thesis obtains more accurate projection gray information by projecting high-frequency structured light,and then uses the multi-frequency fringe method to calculate the absolute phase of the corresponding synthesized structured light to complete the precise decoding of the structured light at the same time It also reduces the number of projected patterns,effectively reducing the system's calculation cost.(3)Aiming at the influence of the non-linear distortion of the system composed of the projector and the camera on the mismatch of structured light decoding,this paper proposes a modeling compensation method based on active projection phase,which uses polynomial modeling to establish the system nonlinearity The distortion model determines the system Gamma effect curve and obtains its inverse function.Therefore,the projection pattern is designed through the inverse function.Using this method,the nonlinear correction of the system is finally completed,and the mismatch rate of the codeword is reduced.Next,this article introduces the point cloud computing method in detail,optimizes it,completes filtering,stitching and other processing,generates high-precision point cloud data,and uses Delaunay triangle meshing to generate the continuous surface of the measured object model.(4)Finally,this thesis designs and builds a set of high-precision 3D reconstruction software and hardware systems based on monocular structured light,which integrates the algorithms proposed and improved in this paper,reduces the complexity of 3D reconstruction operations,and improves the system The practicability of using this system for 3D reconstruction,its accuracy reached0.0489 mm.The comparative experiments of 3D reconstruction show that the new high-frequency phase shift method proposed in this paper has good structured light coding and decoding performance.In the reconstruction system built in this paper,it can complete a variety of high-precision surface reconstructions with different levels of complexity.Practicability and application prospects.