( 4 ) applications of digital holography in optical metrology are briefly discussed . we also present the fundamental principles of digital holographic interferometry and the two ways to realize it . and also the difference between digital holographic interferometry and optical holographic interferometry is considered ( 4 )阐述了数字全息干涉术的基本原理和两种实现方法，讨论了其与传统光学全息干涉术之间的联系与区别，并根据数字全息术自身的特点，讨论了诸如相位倍增因子等提高全息干涉计量精度的方法。
