Abstract
With the proliferation of different types of IC packages, there is a need for machine-vision-based inspection systems to be able to efficiently identify the orientation of IC packages to ensure that they are shipped to end-users in the proper orientation. The orientation of IC packages can be determined by locating special features called notches or dimples, which are molded on the IC packages. This paper presents an algorithm that automatically checks the orientation of different types of IC packages. Our algorithm incorporates several procedures to achieve a fast and robust operation. Firstly, the boundary of the IC package is detected and aligned; then regions where the notch or dimple may exist are isolated. Adaptive double thresholding is applied in the selected regions to extract the possible notches or dimples. The extracted objects are then analyzed to determine whether they represent the notch or the dimple. In these procedures, intensity-based information as well as the gradient-based information is analyzed to generate a more comprehensive description of the features of interest.