Research On The Theory Of Non-Diffraction Structure Light And Its Generation Method

This dissertation states a novel non-diffraction structure light (NDSL). This novel light not only has characteristics of traditional non-diffraction beam, but also it is linear structure. It is a perfect lighting source for surface topography measurement, which can satisfy the requirements of large measurement range, high resolution and real-time measurement of the system. Measurement system based on this light can be used for quick 3D surface topography measurement of large workpieces e.g. bodies of automobiles and spacecrafts. It can also be used in NC machine tools as a system for quick measurement with derivation engineering. This dissertation states the research results of its characteristics, its generation theory and method, and its application in surface topography measurement with triangle method. The major work and innovation is showed as following: A novel non-diffraction structure light is generated. A method is put forward to generate the novel NDSL—a triangle prism method. Diffraction patterns of the triangle prism are analyzed and distribution of the optic field is calculated by exact diffraction method and approximated stable-phase method when the triangle prism incident by parallel wave. Optic field distributions with respect to spherical wave and gauss wave incident are extracted by stable-phase method. A system generating the novel NDSL is designed. Parameters of triangle prism are designed and several samples are manufactured. Triangle prism's diffraction modes are researched by experiment, and the experiment results are compared with the theoretical result. The optic field behind the triangle prism had been proved that it has the characteristics of non-diffraction and linear structure when the parallel wave incident. A research on image sample and process system of NDSL is made. NDSL's images are sampled by CCD camera, and then the sampled images are denoised, their contrasts are strengthened by Matlab software to improve quality. A theoretical research on triangle measurement system with NDSL is made, which is based on triangle measurement with non-diffraction beam.