A don´t-care based image circuit for function verification

In this paper, we propose a novel way to build a "DC_image" circuit for the don\´t cares. The DC_image circuits are concatenated with the inputs of the two circuits under verification. By adding the image circuits, no matter how don\´t cares are in on-/off-sets, we can directly verify the two circuits with DC_image circuits and claim whether there exists an inconsistency between the original and optimized circuits. Our experimental results show that by the DC_image circuits, the verification process can be sped up tremendously.