二步相移数字全息中实际相移角的获取

Extraction of Real Phase-Shifting Angle in Two-Step Phase-Shifting Digital Holography

提出了一种在二步相移数字全息中提取实际相移角的方法,这种方法基于两幅强度图像之间的相关系数。通过在理论相移角附近改变重建所使用的相移角,当所使用的重建角度使得由CCD记录的物光波和由数字重建出来的物光波强度之间的相关系数最大时,该角度即为实际的相移角。首先进行了计算机模拟,该方法准确地提取出了实际的相移角。然后将其应用于基于LED光源的数字全息实验中,比较了分别使用提取的实际相移角和理论相移角重建出来的物光波的质量。计算机模拟和实验结果证实了该方法的有效性。

An approach based on the correlation between two intensity distribution images of the object wave is proposed to determine the phase-shifting value in two-step phase-shifting digital holography.By changing the phase-shifting values used for reconstruction in a certain range around the nominal phase-shifting value,a series of correlation coefficients between the object intensity recorded by CCD and the same intensity reconstructed by computer are obtained.The accurate phase-shifting value will be determined when the correlation coefficient reaches its maximum.The real phase-shifting value is successfully extracted in computer simulations by this method,thereafter the approach is employed in LED-based digital holography.The quality of the reconstructed field by using the obtained value and the nominal value are compared.The feasibility of this method has been verified by both computer simulations and experiments.