Accuracy of a Markerless Acquisition Technique for Studying Speech Articulators

The main disadvantages of the existing methods for studying speech articulators (such as electromagnetic and optoelectronic systems) are the high cost and the discomfort to participants or patients. The aim of this work is to introduce a completely markerless low-cost 3D tracking technique in the context of speech articulation, and then compare it with a well-established marker-based one to evaluate the performances. A Kinect-like device was used in conjunction with an existing face tracking algorithm to track lips movements in 3D without markers. The method was tested on two subjects uttering 200 words and 100 sentences. For most of points of the lips the RMSE ranged between 1 and 3 mm. Although the image resolution used in this experiment was low, these results are very promising. Nevertheless, further studies should consider higher video resolutions in order to obtain better results.