摘要
在利用查找表(LUT)降低相位误差的同时,考虑到相位误差具有周期性和对称性,提出一种基于1/6周期LUT(sLUT)的误差补偿方法,极大地缩短了误差补偿的计算时间,实现了快速相位误差补偿。实验结果表明,在查找表的参数量降低83%的基础上,sLUT的误差补偿效果不受影响,同时sLUT的误差校正时间仅为LUT的1/8。
Objective Structured light technology has been widely used in industrial inspection,cultural relic protection,biomedical,and other fields due to its non-contact and full-field imaging advantages.As one of the mainstream three-dimensional(3D)imaging methods,phase-shifting profilometry(PSP)measures the target surface shape information by projecting multiple phase-shifted patterns and capturing the corresponding target patterns.Since the 3D shape information is closely related to the phase distribution,it is crucial to achieve high-accuracy measurements.However,due to the gamma nonlinearity in both the projector and camera,the ideal sinusoidal fringe patterns are distorted,thereby introducing errors.This kind of non-sinusoidal fringe pattern results in phase errors,which are a major error source affecting the three-dimensional reconstruction accuracy and further degrading the measurement precision.Although the large-step PSP can reduce the nonlinear error,it takes a long time.Therefore,it is very meaningful to develop a phase error correction algorithm with both high accuracy and fast speed.Methods The N-step PSP has the advantages of fast measurement speed,high accuracy,and a non-contact nature,making it widely used in the phase measurement field.Since the three-step PSP is most easily affected by gamma nonlinearity,we take the three-step PSP as an example to illustrate the principles.According to the calculation formula of nonlinear error in the three-step PSP,it can be deduced that the phase error has periodicity and symmetry within 2πperiod.Given the periodic characteristic of phase error,we first propose a 1/3 period lookup table(LUT)method and then a 1/6 period lookup table(sLUT)method considering the symmetry of phase error.A standard whiteboard is imaged to calculate the actual phase values using the three-step PSP and theoretical phase values using the twelve-step PSP(Fig.2).The number of elements for the constructed full-period LUT is 360.According to the periodicity of phase error,a 1/3 period LUT is con
作者
王子龙
徐洪志
杨玲玲
侯文慧
刘路
Wang Zilong;Xu Hongzhi;Yang Lingling;Hou Wenhui;Liu Lu(College of Engineering,Anhui Agricultural University,Hefei 230036,Anhui,China;Anhui Province Engineering Laboratory of Intelligent Agricultural Machinery and Equipment,Hefei 230036,Anhui,China)
出处
《光学学报》
EI
CAS
CSCD
北大核心
2024年第9期105-113,共9页
Acta Optica Sinica
基金
安徽省教育厅科研项目(2023AH040140)。
关键词
测量
相移轮廓术
伽马非线性
查找表
相位误差补偿
三维测量
measurements
phase-shifting profilometry
gamma nonlinearity
lookup table
phase error compensation
three-dimensional measurements
