Stabilization techniques for ultrasound imaging of speech articulations

Abstract

One challenge for the ultrasound imaging of the tongue during connected speech is stabilization of both speakers heads and the ultrasound transducer. To accurately analyze tongue shapes, researchers must ensure that differences among images result from changes in tongue shape, not head or transducer movement. In this validation study, we present an inexpensive, space-saving technique for stabilizing the head and transducer during the collection of ultrasound images in the laboratory. Four speakers were video-recorded producing 5 blocks of 19 sentences each. The speakers’ heads were immobilized with a moldable head stabilizer (Comfort Company, model ♯HSM) affixed to a wall while the transducer was held by a microphone stand. Markers were attached to points on the speakers’ faces and the transducer. Custom-written MATLAB software was used to find the center of the markers for every 10th frame of the recordings. Results indicate that the transducer does not move, and head movement beyond the measurement error of 1 mm is confined to the first block, while speakers are adjusting to the equipment. As compared to other stabilization techniques [Stone and Davis, J. Acoust. Soc. Am. 98, 3107–3112 (1995)], this method provides equivalent immobilization that is significantly less expensive and portable for fieldwork.

Morphological effects on the darkness of English intervocalic /l/

“…Each participant's 3 Some research indicates that a labial following consonant may be more likely to block coarticulation with the following vowel than /h/ (Scobbie and Pouplier 2010); thus, a significant difference between the stem condition and either pre-or post-boundary stimuli suggests that an effect is present and strong. head was fit into a moldable head stabilizer (Comfort Company) that is mounted on the wall, and the head was further stabilized with a Velcro strap around the forehead (Davidson and De Decker 2005;Davidson 2006). This method, when used together with an ultrasound transducer that is fixed in place with a BogenManfrotto Magic Arm, ensures that the same slice of tongue is imaged (Davidson 2012).…”

Indexing head movement during speech production using optical markers

“…Two types of approaches have been used in the literature to address this problem. The first approach involves stabilizing the head relative to the ultrasound probe, either by immobilizing the participant's head (e.g., Davidson and De Decker, 2005), or by attaching the probe to a helmet that the participant wears (e.g., Scobbie et al, 2008). Immobilization reduces natural head movements that accompany speech.…”

UltraFit: A Speaker-friendly Headset for Ultrasound Recordings in Speech Science

“…Ultrasound Tongue Imaging (UTI) is a non-invasive technique that allows researchers to observe the position, shape and movements of the tongue in real time during speech [1]. Although the UTI technique has made great strides forward in recent decades, stabilizing the ultrasound transducer under the speakers chin has remained a major challenge [2]. Many participants in experiments leave the data collection session due to the discomfort and pain they experience after a few minutes of recording.…”