Research On Wrapping Phase Unwrapping Method Of Grating Projection Method

The measurement technology based on the grating projection method is first solved by the inverse trigonometric function,and the phase of the obtained principal value is wrapped between-? and ?,and the real phase of the object must be recovered by phase unwrapping.After research by scholars,a variety of phase unwrapping algorithms have been developed,which can be roughly divided into two categories: one is a path-tracking-based phase unwrapping algorithm,and the other is a path-independent phase unwrapping algorithm.However,in practice,due to noise and discontinuous regions,phase unwrapping has become a difficult problem to solve.So far,there is still no method that can completely solve these problems in phase unwrapping.Approximate solution.In this paper,the commonly used phase unwrapping algorithms are studied.The main work is as follows:Firstly,the principles of one-dimensional phase unwrapping and two-dimensional phase unwrapping are analyzed.The most fundamental cause of phase unwrapping errors is the existence of residual points caused by various factors.The core problem of phase unwrapping is how to reduce or eliminate residual points.unfolding impact.Therefore,the commonly used numerical methods in path-dependent and path-independent phase unwrapping algorithms are studied,and their basic principles,steps,advantages and disadvantages,and applicability are introduced in detail.According to the basic principle of branch-and-cut phase expansion calculation and the current practical problems,and using the equivalence between branch-and-cut problem and travel quotient problem,the multi-population genetic simulated annealing algorithm is used to improve and perfect the branch-tangent line placement strategy of the Goldstein phase unwrapping algorithm.The sum of branch tangent lengths is effectively reduced,and the phenomenon of large-scale "isolated island" easily occurs when the branch tangent line is set by the classical branch tangent method.And the effectiveness of the method is verified by simulation.Aiming at the defects of phase discontinuity and occlusion in image acquisition of objects with discontinuous boundaries,which easily lead to data loss,form residual areas,and develop errors model,and propose a DMA error compensation algorithm to compensate the discontinuous boundary.Through experiments on workpieces with different apertures and thicknesses,it can be concluded that the unwrapping error of the phase unwrapping algorithm proposed in this paper is controlled within 0.05 mm.