CDT Shadow Mask Detection System Based On Image Measurement Technology

On the demand of the manufacture practice, we have designed the Testing System for Shadow Mask and developed the Image Testing Software, thus we also measured the geometry parameters of the Shadow Mask with the digital image processing technology.In response to performance of the testing system, we've taken synthetical design upon the components of the system, such as lamp-house, CCD camera, supporting platform etc. and the scanning manner for the shadow mask, sub-map scanning parameter and so on. What's more, we have developed the Testing Software based on Visual C++ 6.0 of Microsoft Company Ltd, with function to measure the tiny geometrical parameter, such as diameter, area, perimeter of the single mesh and the distance between two meshes. To enhance the precision of the edge detection for the system, we adopted Hough Transform to simulate circle and multinomial interpenetrating sub-pixel edge detection method as to get the resolving power up to 1/85.33 pixel, which bears the advantages of less operation capacity, and lower requirements to computers, compared with the traditional detection method,Considering Shadow Mask is the key component in CRT or CPT displays which affects the image quality, mesh aperture and shape of the mesh are even the most essential part in Shadow Mask detection, moreover, with high labor intensity, low measuring efficiency, incertutice of accuracy, difficulty of fulfilling on-line measurement and so on, detecting shadow mask has made it obstacle of the display enterprise development. The research aftermath of this paper can not only offer test technology for related enterprises, but also provide academic and experimental gist in spreading and applying image testing technology.