Research Of White Light Digit Image Analysis In Frequency Domination Aera And Its Application

A new whole-field non-destructive and non-interferential-light-source displacement and strain measuring method which based on digital image frequency domaination l analysis has been presented in this paper. Images, before and after deformation or motion, recorded by CCD camera, then digitalized and analyzed by frequency domaination correlation arithmetic taking the random gray distribution and characteristic stripe as carrier, can be used to obtain the displacement information and the results can be displayed by point-by-point or whole-field fringes. Simple testing systems, no special disposal on the testing surface, illuminated by natural light or common lamp light in rooms, accordingly no special demands for surroundings and quakeproof are the strong points of this method.Theory deduction of basic expressions of white-light digital image frequency adomination analytical method (WDIF) is accomplished in this paper based on the Fourier optics and single-beam double-exposal speckle interference analysis.Aimed at the need of automatic data processing of WDIF, digital phase-stepping shift and digital doubling techniques which need no extra optical components and make full use of the digital image process of computers have been put forward in this paper.Deformation and rotation of simulation images, rotation of a disk and displacement measuring of the cantilever loaded beam at free end end all proved the feasibility and the validity of WDIF.Fracture characteristics of one special type of plexiglass, mechanical performance of molded paper pulp and displacement of scanning-microscope images have been studied as the application of WDIF. All the examples showed that the method with the...