Robust contour tracking in ultrasound tongue image sequences

ABSTRACT

A new contour-tracking algorithm is presented for ultrasound tongue image sequences, which can follow the motion of tongue contours over long durations with good robustness. To cope with missing segments caused by noise, or by the tongue midsagittal surface being parallel to the direction of ultrasound wave propagation, active contours with a contour-similarity constraint are introduced, which can be used to provide ‘prior’ shape information. Also, in order to address accumulation of tracking errors over long sequences, we present an automatic re-initialization technique, based on the complex wavelet image similarity index. Experiments on synthetic data and on real 60 frame per second (fps) data from different subjects demonstrate that the proposed method gives good contour tracking for ultrasound image sequences even over durations of minutes, which can be useful in applications such as speech recognition where very long sequences must be analyzed in their entirety.

KEYWORDS:

• Active contour model
• automatic re-initialization
• contour tracking
• similarity constraint
• tongue

Funding

This work was partially funded by the European FP7 i-Treasures project (FP7-ICT-2011-9-600676-i-Treasures). The authors also thank the China Scholarship Council (CSC).

Declaration of interest

The authors report no conflicts of interest.

Additional information

Funding

This work was partially funded by the European FP7 i-Treasures project (FP7-ICT-2011-9-600676-i-Treasures). The authors also thank the China Scholarship Council (CSC).