Stady Of Fourier-transform Speckle Profilometry Based On Michelson Interferometer

High-speed,high-resolution,un-touched,adjustability and low cost characterize the Optical 3D shape measurement technique.It has been widely used in engineering design,Numerica1 Control Machining,fast Moulding,CAD,product Quality Inspection and medieal science etc.Electronic speckle pattern interferometry(ESPI) is an important branch of optical measurement techniques. ESPI which uses fringe analysis for nondestrcture deformation field measurement has the characteristics of non-contact, whole field and high-precision measurement. And this technology has become an important technique in the recent twenty years. ESPI can measure the object, through forming a carrier pattern on the object surface(Carrier pattern modulation), analyze the relation between displacement field and altitude of the object surface.The method have high measure sensitivity because it is based on interference of light. Electronic speckle pattern shape interferometry based on the traditional ESPI, have the virtue of ESPI.In this dissertation, electronic speckle shape measurement by using Fourier transform(FTM) based on Michelson interferometer is detailedly discussed. The main contents are described as the following:1. The origin, producing method and correlative concept is introduced. A review of development of speckle metrology is presented.Electronic speckle pattern interferometry principle and phase measurement technology in the speckle interferes is introduced2. A review of development of the shape measurement. Several shape measurement methods are introduced ,especially is the combination of digital shadow moirémethod and FTM.3. We preprosed the novel carrier method for ESPI pattern modulation and FTM for demodulation. Carrier can be introduce by tilting the object and phase can be obtained by FTM .4. A shape measurement based on ESPI by using carrier is presented. In the typical setup of Michelso interferometer the test object is titled a small angle, which comes into being an air wedge between the object plane and the reference plane. The air wedge produces equal-thickness interference. A carrier pattern containing altitude information is formed on the object surface. The carrier pattern is captured by a CCD camera. Then the phase of the object can be derived by FTM and the shape measurement is realized. The principle of the method is introduced and proved by an experiment.