Study On Machine Vision Measure System For Position Of Hole Series On Curved Surface

Modern science and technology, especially, the development of some high-tech such as aviation, space flight, national defence and so on, require manufacture precision higher and more efficient, therefore, variety of advanced manufacturing technology appeared. The interdependent relation between manufacturing technologies and measuring technology determines that the inevitability and the urgency of the developing of precision measurement technology and strengthening the research of basic theory of precision measurement technology, developing the intelligent and real time measurement equipment to satisfy the spot, are emergency to promoting our manufacturing level and making our nation turned from large manufacturing to strong.This thesis is based on the military industry cooperative project ?Measurement of Positions for Hole Series on Curved Surface, worked on machine vision precision measure system by linear array CCD. It concerns the comparison of capacities of machine vision optical-electric sensor, implementing of image capturing, setting up movement controlling mode, image preprocessing and recognition etc. A series of problem when measuring positions of hole series on curved surface with machine vision was been solved in theory and practice,and then satisfied the total requirements that measuring time of every hole should less than twenty seconds and total error of optical-electric measurement is 3 less than 10 . The main context and innovation of this thesis are as follows:Firstly, in measurement scheme designing, brought in global optimization systematization ideology, put forward the measurement mode, which was transforming three-dimensional measurement mode to planar image recognition through locomotion control first; then, transformed planar positions to three-dimensional of hole series on curved surface by geometrical computing. Consequently, the difficulty of task was decomposed, worked at solving the technology problem of image capturing and identifying based on using mature technology adequately.Secondly, in general system controlling mode, used master-slave and multi-machine operation mode: the microcomputer was used as upper host controller to carry out image identifying, measurement data computing and human-machine communication interface; Image capturing and machine locomotion control were completed by two sets of SCM system. This mode takes the advantages of the upper host computer's capacities such as great memory, fast computer and slinky interface into playing sufficiently, and puts the real time task which is difficult for Windows system to slave computer, upon that the requirement of the item was satisfied. Furthermore, provides a referenced control mode for some similar systems, which have a great deal of data to process and strongly real time control.Thirdly, it brought forward a creationary idea which identify hole type automatically (through hole and blind hole) according to gray-level histogram, so the system could automatically carry out measuring holes' different type and diameter, and the intelligentizeddegree and the adaptability of measurement were enhanced.Fourthly, it analyzed different characteristic of images captured by two common image sensors -the area CCD and the linear CCD-of machine vision Measure System in depth; Anatomized the reason for the uniformity and repetition of the interval scanning effect on image identifying precision; expatiated on the effects upon measuring precision different among different CCD pixels, different raster resolution and different arc segments; put forward the searching principle of asymmetric precision image edged point and carried out sub-pixel precision recognition for image, resolved the problem theoretically that hard to advance the measuring precision of linear CCD. There is great significance to reduce the cost of measurement system.Fifthly, brought forward an ideology that merger processing the edged point recognition combining with binary image, proved the feasibility of searching the edged point by areas searching method in the t...