CCD像元尺寸对移相干涉术相位测量精度的影响

针对移相干涉术中CCD探测器采集高密度干涉条纹的过程,对影响相位测量精度的主要因素进行了理论分析和仿真研究.结果表明,随着CCD像元尺寸及随机噪声标准差的增大,CCD探测得到的时域光强信号信噪比降低,引入的相位测量误差也增大.当信噪比约高于24时,相位测量精度可优于π/50rad,折合成光程差即优于λ/100,为后续研究扩展移相干涉术的测量范围提供了理论上的定量依据.

Influence of CCD Pixel Size on the Phase Measurement Accuracy in Phase-Shifting Interferometry

The main factors that affect the phase measurement accuracy were analyzed and simulated in detail for the case of detecting high-density fringes by CCD in phase-shifting interferometry.The influences of the pixel size of CCD,random noise and sampling quantized lever of the intensity in interferogram were discussed.The results indicate that,with the increase of CCD pixel size and random noise’s RMS,the signal to noise ratio of sequence intensity detected by CCD would be worse,and the phase measurement error is getting greater.When the signal to noise ratio is greater than about 24,the phase measurement accuracy could be better than π/50 rad,which is equivalent to the λ/100 better of optical path difference.This research provides a theoretical quantitative basis for the further study of extending the measuring range of phase-shifting interferometry.