Vision Measurement Method Based On Camera Calibration

Vision measurement method based on camera calibration, which have some advantages like non-contact, high accuracy, and high intelligence making this technology in industrial production and machining of the shaft diameter measurement has a wide application prospect. Therefore, this article has designed the diameter of the shaft system based on machine vision, and studied the calibration technology and other. Based on these work, this paper builts up stalk path to measurement model, and proposes a measurement method for planar dimensions based on lens distortion correction.This paper mainly divides into four aspects:firstly, it is to do a lot of work based on machine vision technology, the design of the axial diameter measurement system, by the way, the corresponding camera calibration technique is studied. Secondly, it studies the moment method, interpolation method and the Gauss fitting sub-pixel edge detection method for legal and other common. Based on these work, the paper proposes an accuracy assessment of new subpixel edge detection method, and makes evaluation and analysis on the accuracy of several methods of the experiment; Thirdly, this paper establishes the WCS, which is based on the geometric characteristics of the imaging process and axis, and then, it establishes the diameter measurement model based on technology of machine vision. The fourth, this paper proposes a planar dimension measurement method with high precision based on technology of machine vision, and its superiority is verified by experiment.The first chapter analyzes the research status of machine vision technology in china and abroad research status of diameter measurement technology based on machine vision shaft. This chapter first starts with the actual project development status of diameter measurement accuracy requirements and the diameter measurement technology, expounds the importance of size measurement technology based on machine vision axis and development prospect. Then the article introduces the machine vision technology in detail from the two aspects of development course and the present situation, and explains the machine vision technology which has been widely used in many fields on people’s life and production. Finally this chapter analyzes the status of research in diameter measurement technology based on machine vision axis through listing the research situation of some scholars at home and abroad on the machine vision which is based on the shaft diameter measuring technology, that provides some valuable reference for the research of this subject.The second chapter mainly analyzes the design method of measurement system of shaft diameter from machine vision and the method of camera calibration. First of all, starting with the closed-loop control of shaft parts processing, it expounds the structure size measurement system based on machine vision technology of shaft, including the execution mechanism, measured shaft, lighting device, etc.. Then it analyses the hardware selection of system, design selection and image acquisition card selection, etc.. Finally, this chapter studies the principle and method of camera calibration technology which includes the method of establishment on the model that the camera becomes to be like and the method of establishment model in the coordinate system.The third chapter studies the detection of several common methods of sub pixel edge. Base on this work, this paper proposes a precision evaluation of new subpixel edge detection method, and makes evaluation and analysis on the several methods of the precision of the experiment for realizing the diameter measurement, meeting the requirement of real-time and high precision measurement.The next chapter researches the establishment of shaft diameter model. According to the geometric characteristics of the imaging process and axis, WCS is builted up. Base on this work, the shaft diameter measurement model and realization steps which are based on the technology of machine vision, and gives the calibration method for measuring the parameters of the model, and proposes the objective function of optimization for achieving the optimum solution.The fifth chapter proposes a measurement method with high precision for planar dimensions from machine vision. In the method, by means of a correction model, a new algorithm is researched and designed. And using this algorithm,, this paper can correct the lens distortion, and obtain the exact magnification coefficient imaging system, before measuring the shaft diameter. Experiments show that the method in the measurement of shaft diameter precision measurement at 40mm below the axis has reached 0.0045mm.