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Phase recovery from holographic interferometry imagery.

机译：全息干涉术成像的相恢复。

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摘要

Holographic interferometry (HI) is an extremely high-resolution optical metrology technique frequently used for deformation measurement and vibration studies. The physical basis of a HI system is the interference of coherent radiation. The phase difference between two wavefronts, one modulated by a vibrating object, is captured as an interference or fringe pattern. The displacement field is implicitly contained in the fringe image as the phase differences. Thus, to obtain the displacement field. the phase difference map must be recovered in some manner. Various methods for phase map recovery have been developed. One such method involves indirect recovery from the fringe intensity image. For the second group of methods, special geometric imaging configurations and signal processing algorithms are exploited for direct phase map recovery.; Existing methods for indirect phase recovery are based upon a search of the fringe image for local intensity maxima that delineate 2pi radian contour lines of the underlying phase map. However, such algorithms do not perform well in the presence of noise and non-linear fringe contrast variation. A new algorithm developed for this dissertation exploits the topological relationships between the intensity image fringes and their maxima. Specialised filtering techniques, morphological image processing and computer algorithms are utilised to complete the task.; The methods of direct phase recovery, while providing greater resolution displacement field maps, suffer from a discontinuity problem. The numerical processing involved in the recovery has the effect of wrapping the recovered phase. That is, continuous phase maps are rendered discontinuous on the range [-pi,pi] with 2pi discontinuities. The task of phase unwrapping is to remove these discontinuities and thereby obtain the continuous phase map. Existing methods treat the problem of two-dimensional unwrapping and a series of independent, one-dimensional unwrapping tasks. A new approach presented in this dissertation utilises topological definitions of phase maps, multi-scale edge detection and computer vision techniques to perform the unwrapping. Also, by approaching the problem as a two-dimensional task, the final step of the algorithm, the unwrapping, is in fact collapsed to a one-dimensional problem.
机译：全息干涉术（HI）是一种非常高分辨率的光学计量技术，经常用于变形测量和振动研究。 HI系统的物理基础是相干辐射的干扰。两个波阵面之间的相位差（一个由振动物体调制）被捕获为干涉或条纹图案。位移场作为相位差隐式包含在条纹图像中。这样，获得位移场。必须以某种方式恢复相位差图。已经开发了用于相图恢复的各种方法。一种这样的方法涉及从条纹强度图像间接恢复。对于第二组方法，采用特殊的几何成像配置和信号处理算法进行直接相图恢复。间接相恢复的现有方法基于在条纹图像中搜索局部强度最大值的轮廓，该局部强度最大值描绘了基础相图的2pi弧度轮廓线。但是，这样的算法在存在噪声和非线性条纹对比度变化的情况下不能很好地执行。为此，本文开发了一种新的算法，利用强度图像条纹与其最大值之间的拓扑关系。利用专门的过滤技术，形态图像处理和计算机算法来完成任务。直接相恢复方法在提供更高分辨率的位移场图的同时，还存在不连续性的问题。恢复中涉及的数值处理具有包裹恢复相的作用。即，使连续相位图在具有2pi不连续的范围π-pi，pi上不连续。相位展开的任务是消除这些不连续，从而获得连续的相位图。现有方法处理二维展开和一系列独立的一维展开任务的问题。本文提出的一种新方法是利用相图的拓扑定义，多尺度边缘检测和计算机视觉技术来进行展开。同样，通过将问题作为二维任务来处理，算法的最后一步，即展开，实际上折叠为一维问题。

著录项

  • 作者

    Lichti, Derek D'Arcy.;

  • 作者单位

    University of Calgary (Canada).;

  • 授予单位 University of Calgary (Canada).;
  • 学科 Engineering Civil.; Engineering Electronics and Electrical.
  • 学位 Ph.D.
  • 年度 1999
  • 页码 151 p.
  • 总页数 151
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 建筑科学;无线电电子学、电信技术;
  • 关键词

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