【摘要】 在相位测量轮廓术中,测量系统的gamma非线性是相位误差的主要来源.系统gamma非线性使变形光栅条纹图像中出现高次谐波,从而引起展开相位存在周期性误差.对于四步相移法,三次谐波是引起周期性误差的主要因素.通过建立四步相移法的相位误差和主相位的关系模型,在系统gamma值未知的情况下,对非线性相位误差进行了补偿.计算机仿真表明,当系统的gamma值为2.2时,使用本方法补偿前后的相位误差波动幅值分别小于0.006 3rad和0.000 354rad;实验证明,一个平面白板展开相位的均方根(RMS)在误差补偿后从0.035rad降低到0.007rad,相位误差的最大值从0.086 7rad减小到0.030 8rad.更多还原

【Abstract】 Gamma nonlinearity of the projector-camera pair is a main source of phase error about phase measuring pro-filometry(PMP).It causes higher-order harmonics in deformed pattern captured by camera and leads to periodic phase error at unwrapped phase map.For four-step phase-shifting algorithm,the third harmonic is the main reason which leads to appearance of periodic phase error.In order to decrease the phase error caused by gamma nonlinearity,the model between phase error and wrapped phase was established and a phase error compensation method was proposed under the condition of gamma value unknown.The simulated measurement shows that the volatility of phase error before and after compensation is less than 0.0063 rad and 0.000354 rad respectively(γ=2.2,p=0.8).The experimental results show that RMS of unwrapped phase before and after compensation about a uniform is 0.035 rad and 0.007 rad respectively and the maximum phase error decrease from 0.0867 rad to 0.0308 rad after compensation.更多还原