Speckle Metrology

R.S. Sirohi

• Publisher: CRC Press
• Year: 2020
• eBook ISBN: 9781000148169
• Topic: Technology & Engineering
• Subtopic: Industrial Design
• Index: Technology & Engineering

This practical reference offers state-of-the-art coverage of speckle metrology and its value as a measuring technique in industry.;Examing every important aspect of the field, Speckle Metrology: surveys the origin of speckle displacement and decorrelation; presents procedures for deformation analysis and shape measurement of rough objects; explains particle image velocimetry (PIV), the processing of PIV records, and the design requirements of PIV equipment; discusses the applications of white light speckle methods and the production of artificial speckles; describes the measurement of surface roughness with laser speckles and polychromatic speckles; illustrates semiautomatic and automatic methods for the analysis of Young's fringes; calculates the variation of Young's fringes with the change in the microrelief of the rough surface; and explicates hololenses for imaging and provides design details with aberration corrections for hololense systems.;With over 1500 literature citations, tables, figures and display equations, Speckle Metrology is a resource for students and professionals in the fields of optical, mechanical, electrical and electronics engineering; applied physics; and stress analysis.

1

Theory and Applications of Speckle
Displacement and Decorrelation

I. Yamaguchi

Institute of Physical and Chemical Research (RIKEN)

Wako, Japan

1.1 Introduction

When a laser-illuminated diffuse surface undergoes displacement and/or deformation, the speckles appearing in the scattered field or in its image show displacement accompanied by change in structure. Because of the high contrast of laser speckles, speckle displacement can be easily observed everywhere in space. It is not, however, uniform in space but shows remarkable dependence on observation position and on the optical system as well as on object deformation. The purpose of this chapter is to discuss these dynamic behaviors theoretically and to describe several methods for detection of speckle displacement. Then we discuss the application of speckle displacement to the measurement of surface displacement, strain, and velocity.

1.2 General Survey

1.2.1 Definition and Origin of Speckle Displacement and Decorrelation

Speckle displacement is quantitatively represented by the peak position of the cross-correlation function between the intensity distributions of speckle patterns before and after object displacement or deformation [1]. Figure 1.1 shows speckle patterns taken by a video camera before and after in-plane translation of a paper. The two-dimensional cross-correlation was computed by a digital computer. For comparison, the autocorrelation of the pattern before the translation is also displayed. The peak of the autocorrelation is always located at zero. On the other hand, the peak position of the cross-correlation, which generally deviates from zero, corresponds to the speckle displacement whereas the decrease in peak height i...

Table of contents

• Cover
• Half Title
• Series Editor
• Title Page
• Copyright Page
• About the Series
• Preface
• Table of Contents
• Contributor
• Original Half Title
• 1 Theory and Applications of Speckle Displacement and Decorrelation
• 2 Techniques of Displacement and Deformation Measurements in Speckle Metrology
• 3 Speckle Methods in Experimental Mechanics
• 4 Recent Developments in Video Speckle Interferometry
• 5 Novel Applications of Speckle Metrology
• 6 Particle Image Velocimetry
• 7 White Light Speckle Metrology
• 8 Surface Roughness Evaluation
• 9 Automatic Fringe Analysis Procedures in Speckle Metrology
• 10 Speckle Metrology Using Hololenses
• 11 Correlation Speckle Interferometry in the Mechanics of Contact Interaction
• Index