1. ICVGIP 2012 ICVGIP 2012 Speech training aids Visual feedback of the articulatory efforts during acquisition of speech production by a hearing-impaired child. Display of articulatory effort using LPC-based analysis of speech signal Oral cavity: fixed length tubular sections. LPC analysis of windowed speech frames >> LPC reflection coefficients >> Section area ratios >> Section areas, assuming constant glottis-end area >> Vocal tract shape [Wakita, 1973] >> Display of the articulatory efforts not visible on speaker's face. Introduction

2. ICVGIP 2012 ICVGIP 2012 Problem: Errors due to variation in glottis-end area during speech production [Wakita,1979]. Proposed solution Acquisition of speech as audio and facial image as video. Using mouth opening area estimated from the video as the reference area of the lip-end section, for scaling of the area ratios obtained from LPC analysis of simultaneously acquired speech signal [Nayak et al., 2012]. Investigation A technique for estimation of the mouth opening, without errors caused by teeth and tongue between the lips Contrast enhancement with multi-threshold binarization Connected component detection

3. ICVGIP 2012 ICVGIP 2012 Processing steps iv) Horizontal opening v) Vertical opening: segmentation, multi-threshold binarization, connected component detection vi) Det. of inner lip boundaries vii) Mouth opening area calculation i) Input frame ii) Face sub-image iii) Mouth sub-image [Viola & Jones, 2004] [Hsu et al., 2002]

4. ICVGIP 2012 ICVGIP 2012 Test results Test material: video recordings of vowels /a i u/ of 12 male speakers. Scatter plot of estimated values & values obtained manually Corr. coeffi.: 0.91