Study Of Shape Measurement Based On ESPI

In many of the light measurement techniques, Electronic Speckle Pattern Interferometry(ESPI)，which has an ocean of evolution high-speed，high-resolution，un-touched，adjustabilityand low cost characterize the un-touched optical 3D shape measurement technique has beenwidely used in scientific research, medical diagnosis, engineering design, automatic on-linetesting, quality control, robotics and many more industry. ESPI is in the modern high-techachievements, which brings together the laser technology, video technology, electronictechnology, breath and image processing technology, computer technology, holographicinterference and speckle pattern interferometry, precision instrument and automatic controltechnology, with full, non-contact, high precision and high sensitivity, not avoid light, notphotographing, don’t need special shock, fast real-time and can be online testing and otheradvantages. ESPI purpose is very wide, may be used in the detection of various kinds ofengineering machinery and equipment of deformation, vibration, impact, roughness, stiffness andstrength properties, but also can be used in civil structure, water conservancy facilitiesdeformation measurement. It can not only as a model design, analysis, prototype experimentaladvanced vehicles, but also can be used as a product inspection and production process control auseful tool. The technology also can be used to detect the composite materials, integrated circuit,pressure vessel and welding surface or internal defects, become X-ray, infrared and traditionalultrasonic nondestructive testing methods such as a kind of effective compensation method.Therefore, this technology in machinery, civil, water conservancy, electric appliances, aerospace,weapons industry and the biomedical sciences in the test with a very important position.In the past three decades, it becomes perfect. Multifunctional measuring instrument wasinvented to detect the 3 d information of the object. It becomes a very important opticalmeasurement technology.In this dissertation, Electronic Speckle Pattern Interferometry and the shape measurementtechnique are discussed. The main contents are described as the following:First, we made a simple introduction about all the optical measurement technologies andcompared their advantages and disadvantages and made a review of development of the speckle interference measurement.Second, a detailed introduction of the Electronic Speckle Pattern Interferometrymeasurement principle was introduced. This paper introduces the current two of the mostimportant phase extraction method: phase shift method and Fourier transform method, in view ofthe phase shift method which is widely applied characteristics, this paper introduces the phasethree, four step phase shift, five steps phase shift, Carre algorithm and the principle of phase shiftwith the formula. This paper introduces some common phase shift device, introduces the phaseof the solution of the package processing method.Third,the source and the shear principle of new large shear prism were illustrated. Whenusing large shear prism, ESPI could have simple optical path, strong anti-interference abilitycharacteristics. It is proved that the translation large shear prism can be introduced stable, linearadditional phase.Fourth, it can improve the stability and anti-jamming ability by using large shear prism inshape measurement .The experiment of ball of the crown morphology by using phase shiftmethod and Fourier transform method proved that the prism can replace big shear displacementprismatic crystals (Wollaston prism). Because of its good performance and price it has a goodfuture. It was found that second filtering method could effectively remove speckle noise .Thismethod was proved in experiment, which can effectively improve the accuracy of themeasurement.