Automatic IC orientation checks

With the proliferation of different types of IC packages, there is a need f or machine-vision-based inspection systems to be able to efficiently identi fy the orientation of IC packages to ensure that they are shipped to end-us ers in the proper orientation. The orientation of IC packages can be determ ined by locating special features called notches or dimples, which are mold ed on the IC packages. This paper presents an algorithm that automatically checks the orientation of different types of IC packages. Our algorithm inc orporates several procedures to achieve a fast and robust operation. Firstl y, the boundary of the IC package is detected and aligned; then regions whe re the notch or dimple may exist are isolated. Adaptive double thresholding is applied in the selected regions to extract the possible notches or dimp les. The extracted objects are then analyzed to determine whether they repr esent the notch or the dimple. In these procedures, intensity-based informa tion as well as the gradient-based information is analyzed to generate a mo re comprehensive description of the features of interest.