| 摘要 |
<p>An image processing system processes a sequence of images using a bidirectional star topology hidden Markov model (HMM) to estimate facial expression intensity or other characteristics. The HMM has at least one neutral expression state and a plurality of expression paths emanating from the neutral expression state. Each of the expression paths includes a number of states associated with a corresponding facial expression, such as sad, happy, anger, fear, disgust and surprise. A given expression path may include an initial state coupled to the neutral state and a final state associated with an apex of the corresponding expression. The given path further includes a forward path from the initial state to the final state, associated with an onset of the expression, and a return path from the final state to the initial state, associated with an offset of the expression. Control of one or more actions in the image processing system may be based at least in part on which of the facial expressions supported by the model is determined to be present in the sequence of images and/or the intensity or other characteristic of that facial expression.</p> |
