A Research On Triangle Measurement Of Non-Diffraction Structure Light And CCD Calibration

This dissertation states a novel non-diffraction structure light (NDSL) which is applied to triangulation measurement as an incident light . 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, laser triangulation measurement theory and method, CCD calibration and image prelimilary processing. The major work and innovation are showed as following:All kinds of measurement methods of object surface topography are disserted and analyzed and compared. Instead of the traditional Gaussian light,non-diffraction structure light is adopted as an incident light in laser triangulation measurement. Then,high resolution,high accuracy and large measuring range can be satisfied in the meanwhile.For NDSL,since no focal adjustment device is needed ,the system structure will be simplified and the measuring speed will be quickened.In this dissertation,the experimental structure with NDSL and the relevant experimental results have been given.A research on image sample and process system of NDSL is made. A method of image prelimilary processing is proposed.NDSL's images are sampled by CCD , and then the sampled images are denoised, their contrasts are strengthened by Matlab software to improve quality.A method of CCD calibration with two stages is proposed. The method could obtain internal and outer parameters conveniencely by transform of spacial coordinate and acquire the 3-D information of the object on-measure.The simulated experiment shows that the in-and-out parameters is close to the real value,which meet the demand for measuring precision.