Wavelet transform based image template matching for automatic component inspection

The paper presents a new image template matching method for component inspection of electronic assembly systems. To recognize incorrectly assembled components, the input image of the components is matched with standard images, using a template matching algorithm. To produce a rapid inspection system, the processing time of the matching algorithm should be minimized. Since the standard images of all components located in a PCB are stored in the computer, it is desirable to minimize the memory size of the standard image. The discrete wavelet transformation is applied to minimize the image size as well as the processing time. Only 7% memory of the BMP image is used to discriminate between how well, or not, the components have been assembled. Comparative results are presented to verify the usefulness of the new proposed method.