Research On 3D Reconstruction Technology Based On Structured Light And Catadioptric Camera

3D reconstruction based on structured light is one of the most widely used active 3D reconstruction techniques.In large-scale 3D target reconstruction or 3D environment perception,the 3D reconstruction technology of structured light based on the traditional camera needs to be reconstructed for several times,and the unification of the reconstructed coordinate system is completed with the aid of auxiliary equipment or complex algorithm.For this purpose,a catadioptric imaging system is introduced for a large field of view.The catadioptric imaging system only needs a mirror and a camera to obtain images of 360°horizontal field of view.This advantage gradually appears in the large field of view visual measurement.Therefore,this paper studies 3D reconstruction technology based on structured light and catadioptric camera.A method to calibrate the catadioptric system with a traditional camera is proposed.The central unified sphere model of the catadioptric camera,the pinhole imaging model of the ordinary camera and the inverse camera imaging model of the projector are given in detail,and the parameters of these models are calibrated,respectively.With the aid of the traditional camera,the parameters outside the system between the catadioptric imaging system and the structured light projector are calibrated,and the parameters of the 3D reconstruction model of the whole system are obtained,which provides the basis for the subsequent 3D reconstruction.The structured light coding method is studied for catadioptric 3D reconstruction.A time-coded structured light and a space-coded structured light,namely binary coding and color De Bruijn coding,are proposed,respectively.The better decoding patterns are obtained in the process of binary coding and decoding by using positive and negative coding,median filtering,and background mask establishment.For color De Bruijn coding,De Bruijn sequence is combined with sinusoidal fringe in HSV color space.In the process of decoding,the fringe center,color segmentation and code word matching are extracted from the color image.In the V channel of HSV image,the generalized Morse wavelet is used as the parent wavelet for wavelet transform,and then the phase at the wavelet ridge is extracted and the decoding pattern is obtained after unwrapping.In view of the difference between the imaging models of the catadioptric camera and the traditional camera,the catadioptric image is projected onto the unit sphere through coordinate transformations,and the point coordinates of three-dimensional space are calculated using the line-line intersection model,the depth information of the catadioptric image or the point cloud of the object are obtained by inserting the catadioptric image into the decoded image.A 3D reconstruction experiment platform based on structured light and catadioptric camera is built.First,the system parameters of the catadioptric camera and the projector are calibrated.Then,binary patterns and color De Bruijn patterns are projected onto experimental object.Then the structured light decoding is performed,and the threedimensional reconstruction point coordinates of the object are calculated to obtain point cloud.The applicability of these two structured light coding and decoding algorithms to the catadioptric 3D reconstruction system is verified,and the correctness of the structured light reconstruction algorithm based on the center unified sphere model and the improved method is also verified.The 3D reconstruction errors are 3.85 mm and 1.093 mm,respectively,and the 3D reconstruction experiment based on structured light and catadioptric camera is completed.