| In 1969,Boyle and Smith at the Bell Laboratory invented the Charge Couple Devices(CCD).In the late 1960 s,NASA’s Fossum invented the CMOS image sensor "camera-on-a-chip",CMOS stands for Complementary Metal Oxide Semiconductor(CMOS).But limited by the process technology at that time,area array optoelectronic devices did not begin to develop rapidly until the early 1990 s.Traditional holography uses a dry plate as a recording medium,which has the disadvantages of wet processing and difficulty in accurate restoration.Researchers have been unable to solve this problem.With the rapid development of area array optoelectronic devices,there has been an explosive breakthrough in the field of holography-digital holography.Digital holography technology uses data processing methods,which can convert recorded data and images into digital signals,and then store,process,process and reproduce them.Phase-shifting interferometry(PSI)is an interference technique that uses the phaseshift technique to measure the phase of an object’s light wavefront.The phase distribution information of the optical wavefront of the object to be measured can be obtained from multiple(two and more)interferograms carrying a certain amount of phase shift.With the application research of digital holography technology and the development of area array optoelectronic devices and computer image processing technology,digital holography technology is gradually combined with phase shift and generalized phase shift interference technology to produce phase shift and generalized phase shift digital holographic interference technology.Academia and industry continue to expand the application area of this technology,and now it has been widely used in many fields such as precision instrument manufacturing,engineering industry testing and scientific experiments.Phase-shifting and general-phase-shifting digital holographic interferometry have not been developed for a long time.There are still many problems for researchers to design practical interferometers that can be applied.This article is an attempt to build a complete set of phase shift and generalized phase shift interferometer systems.The systematic research is mainly carried out from three aspects of the phase shift interference system design,the generalized phase shift blind extraction algorithm and the phase unwrapping algorithm.The specific research content and main innovations are as follows:1.A two-step phase-shift synchronous interference system is proposed.This system uses circularly polarized light modulation technology.The design principle is based on the Twyman-Green interference structure,using a non-polarizing beam splitting prism as the polarization state maintaining unit,and using a combination structure of a polarizing beam splitting prism and a mirror as the beam splitting unit.A linear Polarization filter array with polarization direction of0and45 were taken as phase-shifting elements.Therefore,the interferometer can simultaneously capture two interferograms with phase-shifting of?2 with a single CMOS camera.A two-step phase-shifting synchronism interferometer was set up,and the surface information of the concave mirror and the evaporation process of the water droplets were measured respectively,and the feasibility and real-time detection capability of the interferometer were verified.2.An optimized method of accurately extracting the arbitrary unknown and unequal phase steps in phase-shifting interferometry is proposed.The approximate phase steps are first calculated based on the statistical nature of the diffraction field,and the mutated adaptive quantum-behaved particle swarm optimization is used to further extract the arbitrary unknown and unequal phase steps.We improve the mutated adaptive quantum-behaved particle swarm optimization by adding mutation operator with Gaussian probability distribution,thereby increasing the population diversity.The developed method here is fast,highly accurate,and can effectively overcomes the "sawtooth-solution phenomenon" often encountered in traditional direct search approach.We demonstrate the speed and quality of the solution by measuring the transmissive object with the four-step phase-shifting interference method,as is verified by both the computer simulations and optical experiments.3.A phase unwrapping algorithm based on the feeding model of Physarum polycephalum was proposed.The ability of the mathematical model of Physarum polycephalum to solve the shortest path problem,and the similarity between the shortest path problem and the branch tangent setting problem are used,and based on the positive feedback mechanism between the pipe diameter and the pipe flow during the feeding process of Physarum polycephalum,the Physarum Foraging Algorithm(PFA)was proposed.The application of the PFA algorithm solves the problem of setting the branch tangent(non-deterministic polynomial problem),which can solve the traditional phase unwrapping algorithm with a large number of errors and “Isolated island”,and achieve the optimal setting of the branch tangent.The performance of the proposed algorithm was tested on simulated wrapped phase diagrams,and compared with other traditional phase unwrapping algorithms,the superior unwrapping ability of the algorithm was verified. |
