Design Of The Straightness Of Gun Barrel Measurement System Base On Image Processing

Gun barrel bending will not only seriously affect the firing accuracy of cannon, even lead to gun’s scraping. Therefore, in order to give full play to the artillery combat capability, improve the technical support, must regularly measure its straightness. Currently the precision and efficiency of artillery barrel straightness measurement system is low, and most are not suitable for industrial use. Therefore, this paper analyzes the current situation in the field of straightness measurement at home and abroad, introduces a variety of traditional existing and new measuring method and apparatus, the deficiencies of each measurement system are analyzed comprehensively, determine the measurement scheme of this system,, designed a new type of gun barrel axis straightness measurement system based on image processing.This design is a kind of straightness measurement system based on image processing, mainly involve many kinds of modern science and technology such as the image processing, visual measurement and so on and straightness error evaluation methods. In the process of image processing, choose Otsu for image binarization, Zhang fast parallel thinning algorithm is adopted to improve the image thinning, Harris corner detection algorithm for corner detection. Straightness error evaluation method chooses structure containing line method, but in order to make the system more flexible and user-friendly, this paper also gives the two line method and the least square method of software realization.This design senses the change of the center of gun barrel’s section circle through moving cross line target with scale in the gun barrel, using CCD camera, fixed at the end of the gun barrel, to collect target image information, and using image processing and straightness error evaluation to obtain the value of the straightness. This method can avoid the inevitable human error and low efficiency which is caused by artificial aiming and record. The device is simple and easy to implement, and suitable for use in the factory, and meet economy and real-time requirements.Based on the above implementation scheme, the research idea of this design which is determined mainly includes the following three parts: The first is the search of bull’s-eye, and the pixel coordinates of bull ’s-eye is obtained through the image processing and design algorithm; The second is size calibration, and the physical length of image unit pixel is obtained; The third is straightness calculation, and the practical and physical offsets and the value of straightness is calculated according to the results of the bull ’s-eye search and size calibration finally.After the scheme and idea of research is determined, this paper gives the systematic designs of hardware and software, and focus on completing the designs of various software modules. Finally in the laboratory environment, experimental platform is built with existing laboratory equipment, and this measurement method is verified by experiment on the platform. The experimental results show that this system meet the technical indicators of measured object, can measure barrel which its caliber is between25mm to160mm and its length is between1m to10m. Through the error analysis of the experiment, this paper draw the conclusion that system’s measurement error reach100μm/3000mm.