Improved Active Shape Model for automatic optical phase identification of microdrill bits in Printed Circuit Board production

An improved active shape model (ASM), for automatic optical phase identification of microdrill bits in printed circuit board (PCB) production, is presented. To overcome the limitations of conventional ASM on fitting new instants of microdrill bits, six key landmarks are defined for the initialization and optimization of ASM, and a novel method based on projection profiles is also proposed for these key landmarks detection. In addition, local structures of landmarks are redefined according to the feature of microdrill bit images. The fitted shape points are employed for phase identification of microdrill bits with a correlation coefficient as the distance criterion. Experimental results show that our proposed method outperforms the conventional ASM and can improve the accuracy of phase identification of microdrill bits.