Study Of Optical Microscopy Pattern Measuring Instrument

Tool maker's microscope is the traditional tool that measures figure sign on the surface of printed circuit board in China. There are some inherent weaknesses of it, such as uneasy aiming, eye reading and high intension for longtime work. To overcome these weaknesses, an instrument, Microscope Image Measurer (MIM), based on computer vision that composed of optical system, image capture technique, image processing technique, software technique, has been propounded in this dissertation.In the dissertation, the working and configuration of MIM have been discussed. Principally, the arithmetic, including silhouette detection, geometrical shaping, of geometrical objects measuration of PCB has been analyzed. Among the arithmetic, the uppermost arithmetic is silhouette detection. Two different ways, image segmentation and edge operator, of edge detection has been checked and compared. After experimentation, it's found that image segmentation is more suitable. At the same time, the sub-pixel technique is used in image segmentation. It will improve the precision of measuration. Based on experimentation, some methods to improve the inspection were advanced, which are referenced to the optical inspection of PCB.Based on software compatible technique, the application software which can be used in most of the similar system like MIM has been established. The application software is independence on hardware system. At the same time, the arithmetic of figure sign on PCB is integrated in the application software. So, the capability of the application software has increased.