Oncologic therapy of laryngeal cancer may necessitate a total excision of the larynx which results in loss of voice. Voice rehabilitation can be achieved using mucosal tissue vibrations at the upper part of the esopha...
详细信息
Oncologic therapy of laryngeal cancer may necessitate a total excision of the larynx which results in loss of voice. Voice rehabilitation can be achieved using mucosal tissue vibrations at the upper part of the esophagus which serves as substitute voice generating element (pe segment). The quality of the substitute voice is closely related to vibratory characteristics of the pe segment. By means of a highspeed camera the dynamics of the pe segment can be recorded in real-time. Using image processing the deformations of the pe segment are extracted from the image series as deforming contours. Commonly, the characterization of pe dynamics bases on the spectral analysis of the time varying contour area. However, this constitutes an integral approach which masks most of the specific dynamics of pe deformations. We present an algorithm that automatically registers one segmented contour in a frame of the video sequence to the contour in the next frame to derive discrete 2-D trajectories of pe vibrations. By concatenation of the obtained transformations this approach provides a total registration of pe segment contours. We suggest a mixed-integer programming formulation for the problem that combines an advanced outlier and deformation handling with the introduction of dummy points in regions that newly open up, and that includes normal information in the objective function to avoid unwanted deformations. Numerical experiments show that the implemented alternate convex search algorithm produces robust results which is demonstrated at the example of five high-speed recordings of laryngectomee subjects. (C) 2007 Elsevier B.V. All rights reserved.
After total larynx excision due to laryngeal cancer, the tracheoesophageal substitute tissue vibrations at the intersection between the pharynx and the esophagus [pharyngoesophageal segment (pe segment)] serve as voic...
详细信息
After total larynx excision due to laryngeal cancer, the tracheoesophageal substitute tissue vibrations at the intersection between the pharynx and the esophagus [pharyngoesophageal segment (pe segment)] serve as voice generator. The quality of the substitute voice significantly depends on the vibratory characteristics of the pe segment. For improving voice rehabilitation, the relationship between the pe dynamics and the resulting substitute voice quality is a matter of particular interest. Precondition for a comprehensive analysis of this relationship is an objective quantification of the pe vibrations. For quantification purposes, a method is proposed, which is based on the reproduction of the tissue vibrations by means of a biomechanical model of the pe segment. An optimization procedure for an automatic determination of appropriate model parameters is suggested to adapt the model dynamics to tissue movements extracted from high-speed (HS) videos. The applicability of the optimization procedure is evaluated with ten synthetic data sets. A mean error of 8.2% for the determination of previously defined model parameters was achieved as well as an overall stability of 7.1%. The application of the model to six HS recordings presented a mean correlation of the vibration patterns of 82%.
After a total excision of the larynx, mucosal tissue at the upper part of the esophagus can be used as a substitute voice generating element. The properties of the tissue dynamics are closely related to the substitute...
详细信息
After a total excision of the larynx, mucosal tissue at the upper part of the esophagus can be used as a substitute voice generating element. The properties of the tissue dynamics are closely related to the substitute voice quality. The process of substitute voice is investigated by recording simultaneously the acoustic signal with a microphone and the vibrations of the voice generator with a digital high-speed camera. We propose an automatic image-processing technique which is applied to analyze the vibration pattern of the substitute voice generating element. First, an initialization step detects the voice generator within a high-speed sequence. Second, a combination of a threshold technique and an active contour algorithm tracks the tissue deformations of the substitute voice generator. The applicability of the algorithm is shown in three high-speed recordings. For the first time, tissue deformations of substitute voice generating elements are successfully tracked. The results of the image processing procedure are used to describe quantitatively the temporal properties of the substitute voice generator. Comparisons of the spectral components of tissue deformations and tracheoesophageal voice signals reveal the close relationship between the vibration pattern of the substitute voice generator and the quality of substitute voice.
暂无评论