A Method for Detecting and Displaying Articulation Movements in Real-time MRI Movies Using Optical Flow

Abstract

Speech training methods using speech presentation are difficult to adapt to learning foreign languages or supporting the hearing impaired. Nonetheless, this issue could be resolved by displaying articulation movements. Therefore, it is necessary to devise a method of displaying articulation movements for speech training situations. In this study, real-time MRI (rtMRI) movie images of actual articulation movements were analyzed. However, the articulation movements imaged in rtMRI movies are incredibly fine and fast and impossible to discern with the naked eye. Therefore, we investigated a method for detecting articulation movements captured from rtMRI movies using optical flow. Analysis was performed on an rtMRI movie during /ra/ single-mora vocalizations, and movements of the tongue contacting and separating from the posterior part of the gums were well observed. These are considered to constitute detected articulation movements for /ra/ verbalizations. Thus, the proposed method could be used to confirm the movements during any mora speech. Furthermore, the proposed method could be useful for selecting articulation movements to be presented during speech training.