Study And Implementation Of Image Measurement And Analysis System

The perpetually declining cost and increasing availability of hardware required and a steady flow of new applications in commercial, medical field and in scientific research indicate continued growth for the digital image-processing system field and play an important role in the future. Image measurement and analysis on-line and at high accuracy has been applied in many industrial filed widely. However, the general-purpose and some special-purpose image-processing 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.This paper summarizes and analyzes the factor influencing upon the precision of image measurement and analysis system for all components. This paper 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 so that the overall performance is adequate for the task when the system components is preset.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.This paper points out that one can take advantage of the function of image board to average them together with multiple images of the same scene to reduce the effects of additive random noise. The paper also analyzes synthetically the effects of some smooth filters prior to image segmentation and indicates that Gaussian lowpass filter, a alterable scale filter, is a good choice to establish a balance between the reservation of image details and removal of noise.On the basis of current investigation of actuality and trend of image segmentation at home and abroad, the paper adopts Marr operator, called by optimal edge detection to improve greatly efficiency of image segmentation and edge abstract. The sparse edgepoints are taken out by the means of PC-person interaction to fit at least squares principle. So the precision and validity of assemble gap is ensured. Calibration is taken by length grating at overall system and system error is reduced effectively.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.