Modifications of the Vocal Tract and Determination of Associated Resonance Properties During Singing Via Real-Time Volumetric Magnetic Resonance Imaging

关于声道在歌唱过程中的作用，目前尚不完全清楚。这项资助申请涉及通过磁共振成像(MRI)对歌唱过程中的声道修改进行动态实时检查。我们的目的是利用三维序列在高场磁共振系统中测量专业歌唱者的歌唱过程，在第一次资助的范围内，我们成功地将采集的图像在中矢状面的时间分辨率从8帧每秒提高到24帧每秒，并分析了声道形态随歌唱者的声音类型、音域和体裁的动态变化。使用高速摄像机的喉镜检查表明，记录的改变也会导致侧向-内侧维度的改变，这在我们目前获得的平面上是无法感知的。假设这种变化与共振有关，即共振峰频率和带宽的变化。因此，需要将当前的MR序列扩展到全三维体采集。在这项资助过程中，我们有以下计划：-开发和实现三维MR体采集和实现图像重建算法。-实施半自动分割方法以从动态实时数据创建声道模型。-将先前应用的序列适配为二维多切片方法并比较2-D和3-D方法。-测量20名不同类型的专业歌手-使用三种不同来源比较声道的共振特性：1)从MR数据导出的数学模型，2)来自通过快速原型打印的相同分割的MR数据的声道的三维塑料，3)音频信号的逆滤波。所提出的研究方案将有助于揭示不同歌唱功能的特定声道改变与相关声学效果之间的联系。

The function of the vocal tract during singing is still not completely understood. This grant application deals with dynamic real-time examination of vocal tract modifications during singing via magnetic resonance imaging (MRI). Our aim is to measure professional singers in a high field MR system during singing with the help of a three-dimensional sequence.In the scope of the first grant we successfully improved the temporal resolution of the acquired pictures in the mid-sagittal plane from 8 to 24 frames per second and analyzed dynamic changes of the vocal tract configuration in dependence of voice type, register and genre of singers. Laryngoscopic examinations with a high speed camera suggest that register changes also lead to modifications in the lateral-medial dimension that cannot be perceived in our currently acquired plane. It is to be assumed that such changes are relevant for resonance, i.e. changes in formant frequencies and bandwidths. Thus, an extension of the current MR sequence into a full three dimensional volume acquisition is required.In the course of this grant we have the following program:- Development and implementation of a three-dimensional MR volume acquisition and implementation of an image reconstruction algorithm. - Implementation of a semi-automatic segmentation method to create models of the vocal tract from dynamic real-time data.- Adaptation of the previously applied sequence into a two-dimensional multi-slice method and comparison of the 2-D and 3-D method.- Measurement of 20 professional singers of different type- Comparison of resonance properties of the vocal tract using three different sources :1) mathematical models derived from the MR data, 2) three dimensional plastics of the vocal tract from the same segmented MR data that are printed via rapid prototyping, and 3) inverse filtering of the audio signal.The proposed research program will help reveal the connections between specific modifications of the vocal tract and related acoustic effects in respect to different singing functions.