Research Of Image Measurement And Analysis System

Today,information technology change the world profoundly. With the development of computer technology ,especially the improvement of calculating speed,transferring speed and memory capacity,technology of image processing is developing fastly. Image measurement is a very important field of image processing applications ,and has been used widely for producing and researching. However, the general-purpose image measurement system yield a lot of discommodity and insufficiency in particular applications. So the development of this task has its essential and practical significance.This paper presents a type of image measurement and analysis system based on CCD plane array camera and general lens that can accomplish auto-focusing and collecting image and measuring and analyzing on-line assembly-gap of columned work-piece.In course of auto-focusing, the paper takes the sum of the square of gray difference as focal distance evaluation function to decided that image is in focus or not quickly and put forward an effective auto-focus searching way based on threshold value and curve fitting. These improve speed and precision of auto-focusing.The images to be processed is obtained in condition of nonuniform illumination.A threshold surface by interpolating zero-crossing points is used to segment image to avoid influence of nonuniform illumination. Then the destination region can be detected using the method of pattern recognition and the method advoid the influence of nonuniform illumination effectively.The contour description is obtained by fitting at least squares principle. So the precision and validity of assemble gap is ensured. This paper summarizes and analyzes the factor influencing upon the precision of image measurement and analysis system for all components,and brings forward that one can control over the computer program to compensate for these effects and establish a balance among the optics, camera, other harder portion and the algorithms used for processing and quantitative analysis of the digital images.Experiment indicates that the system has fast-speed, high precision, small bulk and dynamic range and well-extensible characteristics. The system possesses dynamic range of scores of millimeters and focusing time of five seconds and repeatability of seven microns and measurement precision of microns level.