一种新的单幅条纹图的相位解调方法

A Novel Approach for Phase Demodulation from a Single Fringe Pattern

基于非载波条纹图的条纹灰度分布的极值准确定位,提出了一种新的由单幅条纹图解调相位方法.该方法首先准确定位每个条纹灰度的极值包括最大和最小,再基于极值图将条纹的强度值分布线性地变换到1和1之间,最后利用arcos反余弦取代传统的atan2反正切算法求出相位,结合极值图就能快速准确地解调出含有封闭条纹的条纹图相位.本方法仅用一幅条纹图,不需要传统的条纹定级和对分数级条纹插值与拟合,自动判别条纹相位变化的波谷,准确获得条纹相位分布.这一方法使光测法研究动态和瞬态问题成为可能,而不需引入载波法调制条纹.文中通过实例说明了本方法的处理过程.

A new technique for phase demodulation from a single fringe-pattern image is presented in this paper. The method locates the extremes of fringes′ intensity distribution, and converts the intermediate gray-values into values between -1 and 1 using linear interpolation. Based on the extremes map, a wrapped phase distribution is demodulated from a single fringe-pattern and the phase values are computed by using an arcos mode rather than the traditional atan2 mode. Through the new method, wrapped phase values can be efficiently extracted from a single fringe-pattern without the need of carrier fringes. The phase demodulation can be processed without assigning fringe orders and making distinction between a depression and an elevation. The method is applied to the study of transient events. Experimental results and a new adaptive weighted filter are presented to demonstrate the validity of the method.