基于相位分析的时间平均数字全息测振研究

Vibration Amplitude Distribution Measurement Using Phase of Recontructed Wave in Time-average Digital Holography

传统的时间平均全息术通过对再现像光强分布的测量来实现振幅分布的检测,由于噪音影响往往得不到满意的结果.第一类零阶贝塞尔函数相位只有0和π两个取值,所以利用再现光场的相位可以确定振幅分布.理论分析发现,以往的讨论忽略了照明光之间位移引起的相位变化,研究通过叠加一个相位因子对此进行了修正,并利用贝塞尔函数平方的相位特点提出了消除该相位因子的办法.实验结果表明,该相位因子确实存在并影响测量,用本文所提出的方法可以很好地消除该相位因子的影响,使利用时间平均数字全息再现光场的相位检测振动物体的振幅分布变得方便和准确.

In traditional digital holography,the measurement of amplitude of vibration is realized by detecting the intensity distribution of reconstructed image,and satisfied results can not be obtained.The phase of the first kind zero-order Bessel function has binary values,zero and π,thus,the distribution of amplitude of vibration can be measured through the phase of reconstructed wave.Theoretical analysis demonstrates that the phase change caused by the shift of illuminated light is ignored in discussion before.In this study,this method is corrected by overlapping a phase factor and a new method is put forward to eliminate the effects of this factor by utilizing the phase characteristics of squared Bessel function.Experiment shows that,this phase factor not only exist,but also influence final measurement.Using proposed method,this influence can be eliminated very well.Moreover,it will bring convenience into the measurement of amplitude of vibration via the phase of reconstructed wave in time-average digital holography.