Westbury John R, Lindstrom Mary J, McClean Michael D
Department of Communicative, Disorders and Waisman Center, University of Wisconsin-Madison, 53705-2280, USA.
J Speech Lang Hear Res. 2002 Aug;45(4):651-62. doi: 10.1044/1092-4388(2002/052).
Speech-related motions of small markers attached to the tongue, lower lip, and lower jaw of 44 normal young adult talkers of American English were analyzed to estimate the relative accuracy of selected methods for decoupling tongue and lip motions from ongoing jaw motion when all movements are originally measured relative to a common reference frame (such as the head). In general, results of the analysis show that a common "simple subtraction" method that ignores pitching rotation of the jaw yields larger errors in positions and speeds of decoupled tongue and lip markers than methods that do not ignore rotation. When the jaw is widely opened, is moving quickly, and/or when any decoupled marker is relatively far from the origin of a local coordinate system fixed to the jaw, positional and speed errors associated with the subtraction method can exceed 5 mm and 25 mm/s, respectively. We propose a simple procedure for estimating the pitching rotation of the jaw that can be applied when pitch cannot be measured. We then show that decoupled motions of tongue and lower lip markers based on estimated jaw rotation involve less error than those derived from any other decoupling method considered. Careful attention to processing methods should yield more accurate inferences about the nature and degree of coordination between speech-related movements of the tongue and lower lip that are decoupled from, and hence independent of, concurrent movements of the lower jaw.
对44名说美式英语的正常年轻成年说话者舌部、下唇和下颌所附着的小标记物的语音相关运动进行了分析，以估计在所有运动最初相对于一个共同参考系（如头部）进行测量时，从正在进行的下颌运动中解耦舌部和唇部运动的选定方法的相对准确性。总体而言，分析结果表明，一种忽略下颌俯仰旋转的常见“简单减法”方法，与不忽略旋转的方法相比，在解耦后的舌部和唇部标记物的位置和速度上会产生更大的误差。当下颌张开很大、运动很快和/或当任何解耦后的标记物离固定在下颌上的局部坐标系的原点相对较远时，与减法方法相关的位置和速度误差可能分别超过5毫米和25毫米/秒。我们提出了一种简单的程序来估计下颌的俯仰旋转，当无法测量俯仰时可以应用该程序。然后我们表明，基于估计的下颌旋转的舌部和下唇标记物的解耦运动比从任何其他考虑的解耦方法得出的运动涉及的误差更小。仔细关注处理方法应该能对与下颌同时运动解耦从而独立的舌部和下唇的语音相关运动之间的协调性质和程度做出更准确的推断。
