Word Recognition based on Two Dimensional Lip Motion Trajectory

The visual information doesn't have an influence with the noise in comparison with the auditory information. However, lip-reading is earlier technology than speech recognition, there is a problem that recognition rate is low. This paper proposes a novel feature to obtain high recognition rate for lip-reading. The proposed lip-reading method is as follows. First, sampled active contour model is applied to detect lip contour during the input image sequences. The lip size is then normalized. Next, a time change of two lip shape features (area and aspect ratio) is expressed as a two-dimensional trajectory of the lip motion. The most similar trajectory in a database which is compared with the target trajectory by DP matching is selected as a result word. We recorded ten Japanese words that uses for the wheelchair control. As a result of comparative experiment with other features in which has already been proposed, trajectory feature obtained the highest recognition rate of 97.2%