| The special type tube is widely used in many fields such as aerospace, energy, chemical industry, weapon system and etc. Measurement of the static parameters is a key technique process in designing, studying and using of the special type tube. With the development of study, manufacture of production and requirement of application, higher requirement is proposed for the measurement system, but it can not be fulfilled by the present measurement system. So it's very importance of theoretical significance and engineering value to develop a kind of high precision, efficiency and automatism measurement system.By thorough study of the measuring principle, measuring method, performance and limitation of the special type tube, a tube static parameters measurement system with high quality is designed and accomplished. Focused on the difficulty of technology in the special tube parameter measurement, the optimization of the visual measurement sub-system, image pre-processing of target, high precision location based on image measurement, and method of system parameter measuring is studied deeply and particularly, and the corresponding solution is proposed.1. Optimization of visual measurement sub-system is operated in the special type tube environment.An even illumination source is designed and realized for the visual measurement in the special type tube. The mathematical model is proposed for the optimal depth of field, which is used to optimize the optical imaging, so that the clear target image is acquired.2. According to the image characters of measuring target, the corresponding pre-processing algorithms are designed and implemented for the target image.An algorithm based on the local gradient is proposed to remove many kinds of noise on the target image, so that the noise can be removed effectively. In order to enhance the acquired image, a self-adaptive algorithm based on nonlinear sector-by-sector transformation with fuzzy logic is proposed, as a result, the contrast of target image is improved significantly. Aiming at different target image segmentation, a local domain otsu threshold method based on edge detection is proposed, so the precise segmentation of target image can be achieved.3. By using the measurement target, the onsite calibration is carried out for the camera of the visual measurement in the special type tube.A distortion calibration method with concentric circles as onsite standard is proposed to the curvature measurement of special tube, and another distortion calibration method based on scales property is designed for the static parameters of variable taper tube, as a result, the measuring precision of system is improved by using the methods proposed.4. For different measurement targets, the corresponding location methods of high precision are designed with realization.A self-adaptive location method based on feature corner match and cluster is proposed, so the influence of the moving disturbance can be eliminated effectively. Another method based on residual prune with geometric feature constraints is proposed for the complex laser spot on the target, and the precise center location can be obtained. The precision location method based on gray compensation of block match is proposed for the moving target scale, and the influence of the illumination change can be overcome.5. To fulfill the steep requirement of measurement in the complex tube, high accuracy measurement methods for the static parameter are designed with realization.A method based on CCD dual-laser collimation is proposed to overcome the influence of random disturbance in the moving measurement. Another method based on moving and crossing scales is proposed, the static parameters measurement of variable taper tube can be gained with high accuracy and large dynamic range.Finally, the errors of measurement and the sources of error are analyzed thoroughly for the tube static parameters measurement system, and the corresponding error compensation methods are proposed.
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