Basic Study of Lip Motion Fluctuation Due to Vocalization for Command Input Interfaces

Abstract

Lip motion features such as changes in the lip width and length can provide important information for recognizing lip motions as commands. Unfortunately, lip motions can be significantly affected by vocalization; therefore, it is necessary to clarify the effects of vocalization on lip motions. This clarification will help improve the recognition rate in command recognition systems. In this paper, we investigated the fluctuations of lip movement attributable to vocalization. We focused on the cumulative sum of the rectangular region that bounds the lip and its aspect ratio and the number of utterance frames. The results of our experiments provide valuable information on the influence of vocalization on the differences in lip motion features. Furthermore, we also conducted a command recognition experiment to compare the accuracy of both utterance conditions. As a result, high recognition rates were obtained when the same voicing state data was used for input data and registered data compared to use difference voicing state data.