Stereo Vision Lip-tracking for Audio-video Speech Processing

We present the first results from applying a recently proposed novel algorithm for the robust and reliable automatic extraction of lip feature points to an audio-video speech data corpus. This corpus comprises 10 native speakers uttering sequences that cover the range of phonemes and visemes in Australian English. The lip-tracking algorithm is based on stereo vision which has the advantage of measurements being in real-world (3D) coordinates, instead of image (2D) coordinates. Certain lip feature points on the inner lip contour such as the lip corners and the mid-points of upper and lower lip are automatically tracked. Parameters describing the shape of the mouth are derived from these points. The results obtained so far show that there is a correlation between width and height of the mouth opening as well as between the protrusion parameters of upper and lower lips.