| Summary: | 碩士 === 國立屏東科技大學 === 機械工程系 === 92 === An automatic calibration system developed for inspecting analog display instrument is proposed in this study. The proposed system integrating hardware and software is applied to inspect whether the position of the pointer can correctly correspond with tick mark present in the display. In hardware part, two sets of light sources: rectangular and circular light sources are designed for lighting analogue and digital display that efficiently eliminate the shadows caused by plastic or glass plate used to cover and protect display, and distance between the pointer and background which allow pointer to be moveable. The disappearance of shadows would be a great benefit to the following analysis. Software mainly based on Wavelet Transform, Direction Code, Ring Projection and Straight Line Hough Transform, is used to detect the position of pointer in ADI correctly and quickly. The experiment results demonstrate three analogue display “Voltmeter”, ”TEMP”, and ”Oil Press” which are inspected by the proposed system, and the executive time with image size 565*477 pixels for first one is about 5 seconds/frame, second for about 4, third is about 6. The experimental data shows that the deviation of reading ADI’s value by operators and proposed method is almost the same. If the automatic calibration system is tested with more commercially, industry sample and various conditions, the capability of system will be more affirmative.
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