Big Size Forging Measurement Based On Double CCD

Big forging is the key part of the important equipment and plays animportant role in many aspects of national economy. The dimension of the bigforging is one of the most important indexes measured in time during theprocess of production. And it will affect the quality of work piece and on-linemachining of the later period production.The measurement method of dual stereo vision is brought forwarded inthis thesis based on the analysis of domestic and international research presentin big dimension measurement. A detecting system is designed according to themethod of stereo vision. This system is based on optics, using electronictechnique, computer technique, image processing technique, having manymerits such as high accuracy, high efficiency and automatic degree, low costand so on. And this system can satisfy the need of field actual environment,realizing untouched measurement.A dual vision system is mainly made up of image input, image analysis,image processing and result output. The image input device CCD camerachanges image signal into electric charge signal. Vision board changes electricsignal into digital signal which can be processed by computer. And usingimage process software to deal with images, such as pretreatment, edge detect,figure distill, diameter calculate etc. Finally display and print the dataprocessing result.Camera calibration, image matching and reconstruction are the difficultiesof the system. Aim at the characteristics of big forging measurement andanalysis of the actual field environment, a kind of flexible and high precisecalibration method, called Zhang's plane calibration method, is adopted in thisthesis and can meet the need of measurement well. A kind of matching methodis put forward based on edge characteristic and is combined with the fiverestrictions to design a set of stereo vision matching arithmetic. This arithmeticis simple, practical, operation speed is fast, and can attain highly match rate forthe stereo image of clear edge , which acquired the better result in laboratoryuse. The mathematic principle of the detective algorithms used in themeasurement is thoroughly analyzed.The experiment proves the measurement system that can attain the idealexamination accuracy, which has directive meaning for the further research.