Spatial Frequency Multiplex Heterodyne Technique for Absolute Measurement of Instantaneous Phase Distribution, and Its Applications

本研究项目的目的是开发一种新的外差轮廓术方案，该方案可以对具有大高度不连续性和/或表面隔离的物体的绝对相位分布进行瞬时测量。主要成果概括如下：1.空间频率复用扫描绝对相位测量方法的发明作为对传统的使用频率可调光源的时间频率扫描方法的替代，提出了一种用于绝对相位测量的空间频率扫描方法。该方法利用空间频率复用技术，可以从单个条纹图中确定绝对相位，从而实现对瞬时相位分布的测量.阐明了时间频率扫描法和空间频率扫描法之间的关系对时间频率扫描法和空间频率扫描法的各种绝对相位测量技术的基本原理给出了统一的理论.新的相位展开算法的研究提出了一种消除相位奇异点的相位展开算法，并进行了实验验证.动态物体瞬时形状测量的实验验证搭建了一个实验系统，验证了空间频率复用和扫描方法对快速运动物体瞬时形状测量的有效性。

The purpose of this research project is to develop a new scheme of heterodyne profilometry that can perform the instantaneous measurement of the absolute phase distribution of an object with large height discontinuities and/or surface isolations. The main accomplishments are summarized in the following :1. Invention of Spatial Frequency Multiplex and Scan Method for Absolute Phase MeasurementAs an alternative to the conventional temporal frequency scan method using a frequency tunable light source, a spatial frequency scan method was proposed for the absolute phase measurement. By means of spatial frequency multiplexing, the proposed technique can determine the absolute phase from a single fringe pattern, which makes possible the measurement of instantaneous phase distribution.2. Clarification of the Relation between the Temporal and Spatial Frequency Scan MethodsA unified theory was given to the basic principles of the various absolute phase measurement technique using temporal and spatial frequency scanning methods.3. Development of New Phase Unwrapping AlgorithmA new phase unwrapping algorithm that eliminates phase singular points was developed and experimentally verified.4. Experimental Demonstration of the Instantaneous Shape Measurement of Objects in Dynamic MotionAn experimental system was constructed and the validity of the proposed spatial frequency multiplex and scan method was demonstrated for objects in fast motion.