The Design Of Multiparameter Machine Vision Detection System For MOX Element

With the developing of computer and digital image process technology, machine vision is widely used in the fields of quality detection, medicine image, industry production, etc. As a visual method with great efficiency, it can improve the productivity and automatization level and achieves a lot of benefit.This paper designs a machine vision system for MOX element detection, which is a project of the fifth academe of nuclear technology for MOX element quality detection. The system can measure the diameter, height, surface damage and flaw, and it also can work online.For the online detection, a rotational workbench is designed, which is controlled by photoelectricity switch. When the workbench run to the appointed place, the switch is triggered and a signal is sent to the computer through parallel port, and then the computer starts to acquire the element images. The foreground and the background lights are used in the system. The foreground light can stand out the surface character of the element and the background light can enhance the contrast of the image. The lights improve the image quality so that it is easy for the computer to process the image. An approach based on LoG operator and interpolation is used to locate the edge of element image, so the detection accuracy can reach to sub-pixel level. The system is calibrated in real time by a standard element. Whenever the workbench turns a round, the system is automatically calibrated once. It can decrease the effect aroused by environmental variety. In the data acquisition, the problem how to drive the non-National Instruments (NI) Company's acquisition card in the LabWindows/CVI is solved so as to save the system cost. A database module is also designed for the system in order to record and administrate the result data.The professional virtual instrument software Lab Windows/ CVI produced by NI is used to develop the system software. It makes the system have a high performance efficiency and strong reliability. The control interface is beautiful and easy to be operated. It is proved by more tests that the system runs steadily and has reached to the request of detection.