In this paper we evaluate the accuracy, recording interference, and articulatory quality of two different ultrasound probe stabilization headsets: a metallic Ultrasound Stabilisation Headset (USH) and UltraFit, a recently developed headset that is 3D printed in Nylon. To evaluate accuracy, we recorded three native speakers of German with different head sizes using an optical marker tracking system that provides sub-millimeter tracking accuracy (NaturalPoint OptiTrack Expression). The speakers had to read C₁V₁C₂V_1/2 non-words (to diminish lexical influences) in three conditions: wearing the USH headset, wearing the UltraFit headset, and without a headset. To estimate the relative headset movement, we measured the movement between tracked points on the probe, headset, and speaker’s nose. By also tracking visual marker points on the speaker’s lip and chin, we compared the movement of the outer articulators with and without a headset and, thereby, measured how the headsets interfere with the articulatory space of the speaker. Additionally, we computed the differences in tongue profiles at the acoustic midpoint of V₁ under the three conditions and evaluated the articulatory recording quality with a distance index and an area index. In the final evaluation, we also compared formant measurements of recordings with and without headsets. With this objective evaluation we provide a systematic analysis of different headsets for Ultrasound Tongue Imaging (UTI) and also contribute to the discussion of using UTI stabilization headsets for recording natural speech. We show that both headsets have a similar accuracy, with the USH performing slightly better overall but introducing the largest error for one speaker, and that the UltraFit headset shows more flexibility during recordings. Each headset influences the lip opening differently. Concerning the tongue movement, there are no significant differences between different sessions, showing the stability of both headsets during the recordings. Acoustic analysis of formant differences in vowels revealed that the USH headset has a larger influence on formant production than the UltraFit headset.

在本文中，我们评估了两种不同的超声探头稳定头戴式耳机的准确性，记录干扰和咬合质量：金属超声稳定头戴式耳机（USH）和最近开发的3D尼龙打印头戴式耳机UltraFit。为了评估准确性，我们使用光学标记跟踪系统（可提供亚毫米级的跟踪精度）（NaturalPoint OptiTrack Expression）记录了三种头顶大小的德语为母语的德语。扬声器必须读取C ₁ V ₁ C ₂ V _1/2在以下三种情况下使用非单词（以减少词汇影响）：戴上USH耳机，戴上UltraFit耳机和不戴耳机。为了估计耳机的相对运动，我们测量了探头，耳机和扬声器鼻子上的跟踪点之间的运动。通过还跟踪说话者的嘴唇和下巴上的视觉标记点，我们比较了带或不带头戴式耳机的外部发音器的运动，从而测量了头戴式耳机如何干扰扬声器的发音空间。此外，我们计算了V ₁声学中点处的舌头轮廓差异在这三个条件下，用距离指数和面积指数评估了发音记录的质量。在最终评估中，我们还比较了带耳机和不带耳机的共振峰测量值。通过此客观评估，我们提供了用于超声舌成像（UTI）的不同头戴式耳机的系统分析，并且也为使用UTI稳定头戴式耳机记录自然语音的讨论做出了贡献。我们显示两种耳机的准确性都差不多，USH总体上表现略佳，但会给一个扬声器带来最大的误差，并且UltraFit耳机在录制过程中显示出更大的灵活性。每个耳机对唇部开口的影响不同。关于舌头的运动，不同时间段之间没有显着差异，在录音过程中显示两个耳机的稳定性。对元音中共振峰差异的声学分析表明，与UltraFit耳麦相比，USH耳麦对共振峰产生的影响更大。