Research On Phase Unwrapping Algorithm In 3D Topography Measurement

With the development of human society,emerging technologies such as machine vision,precision manufacturing,biomedicine,and 3D printing,the need to accurately measure the three-dimensional contour of objects has also increased.Under the huge demand,optical three-dimensional contour measurement technology has been rapidly developed.development of.Accuracy is the key to the optical topography measurement system,and the error affecting the accuracy is derived from the calibration process when constructing the system and the accurate solution of the phase when measuring.In the method of phase extraction,both the phase shift method and the Fourier method are applied to the arc tangent function,so the extracted phases are all package phase values enclosed between-? and ?,and three-dimensional measurement is required.The phase of the parcel is expanded to the true phase.The research direction of this paper is to study the phase unwrapping algorithm,simulate and analyze the unwrapping performance of each algorithm,and verify the experiment.First,the development of unwrapping algorithms at home and abroad is reviewed,and their advantages and disadvantages are analyzed.Then,the principle of the structural light detection surface profile is introduced in detail,and the phase extraction method of the phase extraction method is introduced.Then the phase expansion algorithm is introduced.The phase expansion algorithm,the path tracking method and the path-independent method are introduced in two parts.After that,the design of the path tracking algorithm and the path-independent algorithm,the preparation details and the flow are analyzed and introduced.According to the flow,a one-dimensional scanning algorithm,branch cutting and mass map method,and discrete cosine transform(DCT)and weighted pre-coding are written.The conjugate gradient method(PCG)provides possibilities for subsequent test algorithms.Afterwards,the principle and thought of the simulation program are introduced,the simulation program is designed and programmed,and the influence factors of the fracture and shadow are added.The influence of the fracture surface and the simulation on the path tracking algorithm and the path-independent algorithm is tested.Finally,the test system was calibrated,and the parameter information of the three-dimensional reconstruction was re-determined.Finally,the parameter information and the phase shift imaging device that had been built were used to take a picture of the fringe image.The experiment verified the pros and cons of the algorithm.