Research On Phase Aberration Compensation In Phase-shifting Interferometry

As a technology in optical measurement system,phase-shifting interferometry has the advantages of high precision,fast speed and real-time measurement,and has been widely used in many fields.The technique is often used to observe the dynamic changes of neuron cells,measure the diffusion process of oil droplets on the glass surface and measure the three-dimensional morphology of samples.In the process of experimental operation,due to the defect of system components,the existence of the telecentric structure,measurement environment more uncontrollable factors,leading to between reference beam and object beams of a constant tilt aberration,causing phase values tilt,the CCD photoelectric detector receives the interference figure also has certain deviation,thus affecting the precision of the interferometry.With the continuous development of science and technology,the requirements of precision in various fields are constantly improving.Theoretically,to improve the measurement accuracy,on the one hand,the instruments used in the experiment and the measurement environment should be strictly controlled;On the other hand,necessary compensation for the inevitable aberration is the key to improve the measurement accuracy.Therefore,a large number of aberration compensation methods have been proposed,from the initial physical compensation to the later numerical compensation,these methods have advantages and disadvantages coexist.Therefore,the improvement of measurement accuracy is a great challenge for us.In this paper,the development and research status of phase shift interferometry are described in detail.The basic principle,experimental equipment,method of obtaining phase shift,algorithm of extracting phase,steps of unwrapping and classification of aberration are described.Then,regularization,norm regularization and iterative optimization algorithms are introduced.In this paper,the phase aberration compensation can be roughly divided into three steps:the first step is to use the least square solution to wrap the obtained phase to ensure the accuracy of the phase value and reduce the aberration caused by calculation;In the second step,according to the principle of aberration compensation,the image difference generated by the system is transformed into a surface fitting problem,and the traditional objective function is processed mathematically.Thirdly,aiming at the limitation of traditional problems,the objective function ofL₁ regularization is constructed,and the fitting coefficient is solved by separable substitute function algorithm,so as to obtain high-precision fitting aberration and finally complete phase compensation.Experimental results show that the proposed algorithm is feasible and efficient in phase aberration compensation.