Research On Three-dimensional Deformation Measurement Technology And Algorithm Based On Speckle Pattern Interference

Speckle pattern interferometry,as a full-field,high-precision,non-contact modern optical measurement method,has been widely used in three-dimensional deformation measurement,strain analysis and non-destructive testing.The traditional three dimensional deformation or strain measurement system of speckle interferometry usually adopts step-by-step measurement,but for the non-repeated deformation of the measured object,it is often required that the measurement system can realize the synchronous measurement of three-dimensional deformation and strain.In order to solve the above problem,this paper proposes a method for synchronous measurement of three-dimensional deformation and strain based on speckle pattern interferometry.The technical principles of this method are studied and discussed,and an experimental system is built to verify the feasibility of the measurement.At the same time,the single-source spectroscopic digital speckle interference three-dimensional deformation measurement scheme was used to design and study the instrumentation of the speckle interferometry measurement system.The specific research work of this paper is as follows:(1)The basic principle of speckle pattern interferometry is introduced,the relationship between three-dimensional deformation and phase is deduced,and the phase extraction technology and image processing technology related to fringe processing in speckle interferometry are studied and analyzed.(2)The unwrapping algorithms in phase image processing are studied,the basic principle and mathematical model of phase unwrapping are introduced,several typical phase unwrapping algorithms are implemented by programming,and their performances are compared by experiments.(3)A method of synchronous measurement of 3D deformation and strain based on speckle interferometry is proposed.Three types of lasers in different wavelength bands are used as light sources,and a color camera is used to collect speckle interferometry images.The phase information in different illumination directions are extracted from a single color speckle interferometry map,and the three-dimensional deformation and strain information of the object are calculated.The basic principle of the method is introduced,and a test system is established to verify the feasibility of the method.(4)A single-source spectroscopic digital speckle interferometry three-dimensional deformation measurement scheme was used for instrumental research,an experimental system was built to verify the scheme,various types of devices were analyzed and selected,the entire system was assembled and debugged,and experiments were carried out.