Digital-speckle Angular-displacement Measurement

Laser speckle is a ubiquitous statistical optics phenomenon. Playing a significant role inmodern optical measurements, the method of laser speckle possesses many advantages, suchas whole field, non-contact, high response speed, simple optical arrangement and lowenvironmental factors requirements.To meet the high accuracy need in on-line measurement, a large amount of laser specklemeasurements come into being. Once rotate occurs, especially cylinder rotates on its axis, thedrawbacks of existing methods will emerge subsequently. Aim to solve this kind of problem,the paper proposes an angular-displacement measurement based on digital speckle and tries tostudy a system not only simple but also reliable, which can fulfill the system experimengtally.This paper describes the generation of laser speckle, then analyzes the action of specklefield by means of both first-order and second-order statistic properties.On basis of digital speckle correlation method, the angular-displacement measurementsystem is established. The speckle field transmits from a specimen surface is captured by aCCD camera, which is stored in a computer then. Digitial speckle correlation method is thefundamental algorithm in the next process, through which the rotate information between twospeckle patterns can be calculated.The following work concentrate on experiments which include two parts, one is planedisplacement, the other is angular-displacement. At last, the result concludes that themeasurement system shows its reliability, efficiency and stability.Take various kinds ofobjects being controlled in rotate actions into account, much more researches should be donein future.