SYNTHESIZING DYSARTHRIC SPEECH USING MULTI-SPEAKER TTS FOR DSYARTHRIC SPEECH RECOGNITION

Dysarthria is a motor speech disorder often characterized by reduced speech intelligibility through slow, uncoordinated control of speech production muscles. Automatic Speech recognition (ASR) systems may help dysarthric talkers communicate more effectively. However, robust dysarthria-specific ASR requires a significant amount of training speech is required, which is not readily available for dysarthric talkers. In this dissertation, we investigate dysarthric speech augmentation and synthesis methods. To better understand differences in prosodic and acoustic characteristics of dysarthric spontaneous speech at varying severity levels, a comparative study between typical and dysarthric speech was conducted. These characteristics are important components for dysarthric speech modeling, synthesis, and augmentation. For augmentation, prosodic transformation and time-feature masking have been proposed. For dysarthric speech synthesis, this dissertation has introduced a modified neural multi-talker TTS by adding a dysarthria severity level coefficient and a pause insertion model to synthesize dysarthric speech for varying severity levels. In addition, we have extended this work by using a label propagation technique to create more meaningful control variables such as a continuous Respiration, Laryngeal and Tongue (RLT) parameter, even for datasets that only provide discrete dysarthria severity level information. This approach increases the controllability of the system, so we are able to generate more dysarthric speech with a broader range. To evaluate their effectiveness for synthesis of training data, dysarthria-specific speech recognition was used. Results show that a DNN-HMM model trained on additional synthetic dysarthric speech achieves WER improvement of 12.2% compared to the baseline, and that the addition of the severity level and pause insertion controls decrease WER by 6.5%, showing the effectiveness of adding these parameters. Overall results on the TORGO database demonstrate that using dysarthric synthetic speech to increase the amount of dysarthric-patterned speech for training has a significant impact on the dysarthric ASR systems

Models and analysis of vocal emissions for biomedical applications

This book of Proceedings collects the papers presented at the 3rd International Workshop on Models and Analysis of Vocal Emissions for Biomedical Applications, MAVEBA 2003, held 10-12 December 2003, Firenze, Italy. The workshop is organised every two years, and aims to stimulate contacts between specialists active in research and industrial developments, in the area of voice analysis for biomedical applications. The scope of the Workshop includes all aspects of voice modelling and analysis, ranging from fundamental research to all kinds of biomedical applications and related established and advanced technologies

Statistical parametric speech synthesis based on sinusoidal models

This study focuses on improving the quality of statistical speech synthesis based on sinusoidal models. Vocoders play a crucial role during the parametrisation and reconstruction process, so we first lead an experimental comparison of a broad range of the leading vocoder types. Although our study shows that for analysis / synthesis, sinusoidal models with complex amplitudes can generate high quality of speech compared with source-filter ones, component sinusoids are correlated with each other, and the number of parameters is also high and varies in each frame, which constrains its application for statistical speech synthesis. Therefore, we first propose a perceptually based dynamic sinusoidal model (PDM) to decrease and fix the number of components typically used in the standard sinusoidal model. Then, in order to apply the proposed vocoder with an HMM-based speech synthesis system (HTS), two strategies for modelling sinusoidal parameters have been compared. In the first method (DIR parameterisation), features extracted from the fixed- and low-dimensional PDM are statistically modelled directly. In the second method (INT parameterisation), we convert both static amplitude and dynamic slope from all the harmonics of a signal, which we term the Harmonic Dynamic Model (HDM), to intermediate parameters (regularised cepstral coefficients (RDC)) for modelling. Our results show that HDM with intermediate parameters can generate comparable quality to STRAIGHT. As correlations between features in the dynamic model cannot be modelled satisfactorily by a typical HMM-based system with diagonal covariance, we have applied and tested a deep neural network (DNN) for modelling features from these two methods. To fully exploit DNN capabilities, we investigate ways to combine INT and DIR at the level of both DNN modelling and waveform generation. For DNN training, we propose to use multi-task learning to model cepstra (from INT) and log amplitudes (from DIR) as primary and secondary tasks. We conclude from our results that sinusoidal models are indeed highly suited for statistical parametric synthesis. The proposed method outperforms the state-of-the-art STRAIGHT-based equivalent when used in conjunction with DNNs. To further improve the voice quality, phase features generated from the proposed vocoder also need to be parameterised and integrated into statistical modelling. Here, an alternative statistical model referred to as the complex-valued neural network (CVNN), which treats complex coefficients as a whole, is proposed to model complex amplitude explicitly. A complex-valued back-propagation algorithm using a logarithmic minimisation criterion which includes both amplitude and phase errors is used as a learning rule. Three parameterisation methods are studied for mapping text to acoustic features: RDC / real-valued log amplitude, complex-valued amplitude with minimum phase and complex-valued amplitude with mixed phase. Our results show the potential of using CVNNs for modelling both real and complex-valued acoustic features. Overall, this thesis has established competitive alternative vocoders for speech parametrisation and reconstruction. The utilisation of proposed vocoders on various acoustic models (HMM / DNN / CVNN) clearly demonstrates that it is compelling to apply them for the parametric statistical speech synthesis

Phone-based speech synthesis using neural network with articulatory control.

by Lo Wai Kit.Thesis (M.Phil.)--Chinese University of Hong Kong, 1996.Includes bibliographical references (leaves 151-160).Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Applications of Speech Synthesis --- p.2Chapter 1.1.1 --- Human Machine Interface --- p.2Chapter 1.1.2 --- Speech Aids --- p.3Chapter 1.1.3 --- Text-To-Speech (TTS) system --- p.4Chapter 1.1.4 --- Speech Dialogue System --- p.4Chapter 1.2 --- Current Status in Speech Synthesis --- p.6Chapter 1.2.1 --- Concatenation Based --- p.6Chapter 1.2.2 --- Parametric Based --- p.7Chapter 1.2.3 --- Articulatory Based --- p.7Chapter 1.2.4 --- Application of Neural Network in Speech Synthesis --- p.8Chapter 1.3 --- The Proposed Neural Network Speech Synthesis --- p.9Chapter 1.3.1 --- Motivation --- p.9Chapter 1.3.2 --- Objectives --- p.9Chapter 1.4 --- Thesis outline --- p.11Chapter 2 --- Linguistic Basics for Speech Synthesis --- p.12Chapter 2.1 --- Relations between Linguistic and Speech Synthesis --- p.12Chapter 2.2 --- Basic Phonology and Phonetics --- p.14Chapter 2.2.1 --- Phonology --- p.14Chapter 2.2.2 --- Phonetics --- p.15Chapter 2.2.3 --- Prosody --- p.16Chapter 2.3 --- Transcription Systems --- p.17Chapter 2.3.1 --- The Employed Transcription System --- p.18Chapter 2.4 --- Cantonese Phonology --- p.20Chapter 2.4.1 --- Some Properties of Cantonese --- p.20Chapter 2.4.2 --- Initial --- p.21Chapter 2.4.3 --- Final --- p.23Chapter 2.4.4 --- Lexical Tone --- p.25Chapter 2.4.5 --- Variations --- p.26Chapter 2.5 --- The Vowel Quadrilaterals --- p.29Chapter 3 --- Speech Synthesis Technology --- p.32Chapter 3.1 --- The Human Speech Production --- p.32Chapter 3.2 --- Important Issues in Speech Synthesis System --- p.34Chapter 3.2.1 --- Controllability --- p.34Chapter 3.2.2 --- Naturalness --- p.34Chapter 3.2.3 --- Complexity --- p.35Chapter 3.2.4 --- Information Storage --- p.35Chapter 3.3 --- Units for Synthesis --- p.37Chapter 3.4 --- Type of Synthesizer --- p.40Chapter 3.4.1 --- Copy Concatenation --- p.40Chapter 3.4.2 --- Vocoder --- p.41Chapter 3.4.3 --- Articulatory Synthesis --- p.44Chapter 4 --- Neural Network Speech Synthesis with Articulatory Control --- p.47Chapter 4.1 --- Neural Network Approximation --- p.48Chapter 4.1.1 --- The Approximation Problem --- p.48Chapter 4.1.2 --- Network Approach for Approximation --- p.49Chapter 4.2 --- Artificial Neural Network for Phone-based Speech Synthesis --- p.53Chapter 4.2.1 --- Network Approximation for Speech Signal Synthesis --- p.53Chapter 4.2.2 --- Feed forward Backpropagation Neural Network --- p.56Chapter 4.2.3 --- Radial Basis Function Network --- p.58Chapter 4.2.4 --- Parallel Operating Synthesizer Networks --- p.59Chapter 4.3 --- Template Storage and Control for the Synthesizer Network --- p.61Chapter 4.3.1 --- Implicit Template Storage --- p.61Chapter 4.3.2 --- Articulatory Control Parameters --- p.61Chapter 4.4 --- Summary --- p.65Chapter 5 --- Prototype Implementation of the Synthesizer Network --- p.66Chapter 5.1 --- Implementation of the Synthesizer Network --- p.66Chapter 5.1.1 --- Network Architectures --- p.68Chapter 5.1.2 --- Spectral Templates for Training --- p.74Chapter 5.1.3 --- System requirement --- p.76Chapter 5.2 --- Subjective Listening Test --- p.79Chapter 5.2.1 --- Sample Selection --- p.79Chapter 5.2.2 --- Test Procedure --- p.81Chapter 5.2.3 --- Result --- p.83Chapter 5.2.4 --- Analysis --- p.86Chapter 5.3 --- Summary --- p.88Chapter 6 --- Simplified Articulatory Control for the Synthesizer Network --- p.89Chapter 6.1 --- Coarticulatory Effect in Speech Production --- p.90Chapter 6.1.1 --- Acoustic Effect --- p.90Chapter 6.1.2 --- Prosodic Effect --- p.91Chapter 6.2 --- Control in various Synthesis Techniques --- p.92Chapter 6.2.1 --- Copy Concatenation --- p.92Chapter 6.2.2 --- Formant Synthesis --- p.93Chapter 6.2.3 --- Articulatory synthesis --- p.93Chapter 6.3 --- Articulatory Control Model based on Vowel Quad --- p.94Chapter 6.3.1 --- Modeling of Variations with the Articulatory Control Model --- p.95Chapter 6.4 --- Voice Correspondence : --- p.97Chapter 6.4.1 --- For Nasal Sounds ´ؤ Inter-Network Correspondence --- p.98Chapter 6.4.2 --- In Flat-Tongue Space - Intra-Network Correspondence --- p.101Chapter 6.5 --- Summary --- p.108Chapter 7 --- Pause Duration Properties in Cantonese Phrases --- p.109Chapter 7.1 --- The Prosodic Feature - Inter-Syllable Pause --- p.110Chapter 7.2 --- Experiment for Measuring Inter-Syllable Pause of Cantonese Phrases --- p.111Chapter 7.2.1 --- Speech Material Selection --- p.111Chapter 7.2.2 --- Experimental Procedure --- p.112Chapter 7.2.3 --- Result --- p.114Chapter 7.3 --- Characteristics of Inter-Syllable Pause in Cantonese Phrases --- p.117Chapter 7.3.1 --- Pause Duration Characteristics for Initials after Pause --- p.117Chapter 7.3.2 --- Pause Duration Characteristic for Finals before Pause --- p.119Chapter 7.3.3 --- General Observations --- p.119Chapter 7.3.4 --- Other Observations --- p.121Chapter 7.4 --- Application of Pause-duration Statistics to the Synthesis System --- p.124Chapter 7.5 --- Summary --- p.126Chapter 8 --- Conclusion and Further Work --- p.127Chapter 8.1 --- Conclusion --- p.127Chapter 8.2 --- Further Extension Work --- p.130Chapter 8.2.1 --- Regularization Network Optimized on ISD --- p.130Chapter 8.2.2 --- Incorporation of Non-Articulatory Parameters to Control Space --- p.130Chapter 8.2.3 --- Experiment on Other Prosodic Features --- p.131Chapter 8.2.4 --- Application of Voice Correspondence to Cantonese Coda Discrim- ination --- p.131Chapter A --- Cantonese Initials and Finals --- p.132Chapter A.1 --- Tables of All Cantonese Initials and Finals --- p.132Chapter B --- Using Distortion Measure as Error Function in Neural Network --- p.135Chapter B.1 --- Formulation of Itakura-Saito Distortion Measure for Neural Network Error Function --- p.135Chapter B.2 --- Formulation of a Modified Itakura-Saito Distortion (MISD) Measure for Neural Network Error Function --- p.137Chapter C --- Orthogonal Least Square Algorithm for RBFNet Training --- p.138Chapter C.l --- Orthogonal Least Squares Learning Algorithm for Radial Basis Function Network Training --- p.138Chapter D --- Phrase Lists --- p.140Chapter D.1 --- Two-Syllable Phrase List for the Pause Duration Experiment --- p.140Chapter D.1.1 --- 兩字詞 --- p.140Chapter D.2 --- Three/Four-Syllable Phrase List for the Pause Duration Experiment --- p.144Chapter D.2.1 --- 片語 --- p.14

Models and Analysis of Vocal Emissions for Biomedical Applications

The International Workshop on Models and Analysis of Vocal Emissions for Biomedical Applications (MAVEBA) came into being in 1999 from the particularly felt need of sharing know-how, objectives and results between areas that until then seemed quite distinct such as bioengineering, medicine and singing. MAVEBA deals with all aspects concerning the study of the human voice with applications ranging from the neonate to the adult and elderly. Over the years the initial issues have grown and spread also in other aspects of research such as occupational voice disorders, neurology, rehabilitation, image and video analysis. MAVEBA takes place every two years always in Firenze, Italy. This edition celebrates twenty years of uninterrupted and succesfully research in the field of voice analysis

Models and analysis of vocal emissions for biomedical applications: 5th International Workshop: December 13-15, 2007, Firenze, Italy

The MAVEBA Workshop proceedings, held on a biannual basis, collect the scientific papers presented both as oral and poster contributions, during the conference. The main subjects are: development of theoretical and mechanical models as an aid to the study of main phonatory dysfunctions, as well as the biomedical engineering methods for the analysis of voice signals and images, as a support to clinical diagnosis and classification of vocal pathologies. The Workshop has the sponsorship of: Ente Cassa Risparmio di Firenze, COST Action 2103, Biomedical Signal Processing and Control Journal (Elsevier Eds.), IEEE Biomedical Engineering Soc. Special Issues of International Journals have been, and will be, published, collecting selected papers from the conference