Research On Real-time Measurement System Of Aberration Based On Wavefront Sensor

In recent years,with the development of refractive cataract surgery and the application of adaptive optical system in the field of human eye aberration measurement and correction,real-time measurement of human eye aberration in cataract surgery has became a hotspot in research of ophthalmology,and it brought new opportunity for a variety of eye surgeries.In this paper,the key technology of Hartmann-Shack wavefront sensor such as simulation of wavefront sensor,wavefront detection,and wavefront reconstruction were studied,and human eye's wavefront aberration measurement system containing hardware and software was established.Thus the foundation for real-time measurement of eye's aberration was laid in refractive cataract operation.The main content of the paper includes:1.The basic structure and optical principle of the human eye were researched,and the definition and classification of wavefront aberration of human eye were introduced.The theories of four kinds of wavefront sensor was analysesed in detail,the human eye's wavefront reconstruction model based on orthonormal Zernike polynomial was established,and the spatial light modulator was put forward to used to simulate the human eye aberration.2.The spot centroid localization error source was analyzed in detail on the basis of Hartmann-Shack wavefront sensor detecting principle and the theoretical model,and simulation of the wavefront detection of WFS150-5C Hartmann-Shack wavefront sensor was established.The noise suppressive effect of image enhancement technology in the wavefront detection of wavefront sensor is studied.3.The centroid detection algorithms and the wavefront reconstruction algorithms were further researched.The wavefront detection algorithm was proposed combining sequenced detection,threshold segmentation,morphological filter and high order moment calculation,and the parameters of algorithm applied to the wavefront sensor were designed.The wavefront reconstruction algorithm based on frequency domain analysis was put forward to improve the computing speed,and the frequency domain analysis method and the least square solution method were simulated and compared in the aspects of calculating accuracy and complexity.The influences of polynomial number used in wavefront reconstruction on reconstruction error were analyzed,and the optimal number of wavefront reconstruction was selected on the basis of analysis.4.According to the paper and on the basis of the above research achievements,combining with the interaction between laser and biological tissue,the aberration measurement system based on Hartmann-Shack wavefront sensor was built,and the LabVIEW's graphical programming language was used to write the measurement software.Author's theories were verified by applying the system to measurement of simulated human eyes,the system's ability to detect aberration in real time measurement was comfirmed,and the system was applied to record the changes in volatility of human eye aberration on 20 Hz sampling frequency in 5s.