The Research Of Three-Dimensional Measurement Techniques With Temporal Speckle Pattern Interferometry

Electronic speckle pattern interferometry(ESPI)is a sort of modern optical measurement technology.The main advantages of ESPI are non-contact,high sensitivity,high precision,and whole field measurement.The method of measurement can realize full-field and dynamic measurement of the roughness,displacement,deformation,vibration,and the surface stress strain of the object.However,the displacement measurements of traditional ESPI are all based on two states which are before and after the displacement without any time parameters.Temporal speckle pattern interferometry(TSPI)solves the problem effectively which the traditional electronic speckle pattern interferometry cannot,such as dynamic tracking measurement.TSPI only needs to improve the common electronic speckle pattern interferometry system to achieve high accuracy of the whole field phase measurement without a phase shift device.Because of TSPI,the measurement system can be simplified to eliminate easier the influence of harsh environment in the actual measurement process.Therefore,applying TSPI to three-dimensional measurement of the objects can make the measurement non-contact,high precision,and real-time and dynamic.It can realize full-field and dynamic three-dimensional measurement of the displacement,deformation,vibration,and stress and strain.It has been widely applied to aerospace industry,manufacturing industry,medical biology and other fields.It has become the focus of research both here and abroad.Given this reality,in this thesis,a new three-dimensional measurement system based on TSPI is proposed.And our system is improved according to the deficiencies of the existing speckle measurement system.Therefore,the system not only has the advantage of real-time dynamic measurement of TSPI,but also improves the existing three-dimensional measurement technology by using a 3 CCD camera to simplify the experimental device and improve the measurement accuracy.It mainly focuses on three aspects:the theoretical analysis of the principle,the composition of the experimental system and the design of the algorithm.The main works include:(1)Temporal speckle pattern interferometry technique is introduced into the three-dimensional measurement,and the theoretical derivation and experimental investigation and analysis are in progress.(2)A temporal speckle intensity analysis and processing algorithm is developed.The grey-scale maps of fringes in three directions are processed by wavelet transform and phase unwrapping to restore the object displacement information.(3)A new measurement system with three different wavelength lasers(473nm?532nm and 632.8nm)is designed and built to produce the speckle pattern interferograms of the two in-plane displacements and one out-of-plane displacement respectively.One 3 CCD camera is employed to collect these mixed speckle interferograms simultaneously.Then displacement information of the object in three directions can be acquired by processing the speckle interferograms.