New single-ended objective measure for non-intrusive speech quality evaluation

peer-reviewedThis article proposes a new output-based method for non-intrusive assessment of speech quality of voice communication systems and evaluates its performance. The method requires access to the processed (degraded) speech only, and is based on measuring perception-motivated objective auditory distances between the voiced parts of the output speech to appropriately matching references extracted from a pre-formulated codebook. The codebook is formed by optimally clustering a large number of parametric speech vectors extracted from a database of clean speech records. The auditory distances are then mapped into objective Mean Opinion listening quality scores. An efficient data-mining tool known as the self-organizing map (SOM) achieves the required clustering and mapping/reference matching processes. In order to obtain a perception-based, speaker-independent parametric representation of the speech, three domain transformation techniques have been investigated. The first technique is based on a perceptual linear prediction (PLP) model, the second utilises a bark spectrum (BS) analysis and the third utilises mel-frequency cepstrum coefficients (MFCC). Reported evaluation results show that the proposed method provides high correlation with subjective listening quality scores, yielding accuracy similar to that of the ITU-T P.563 while maintaining a relatively low computational complexity. Results also demonstrate that the method outperforms the PESQ in a number of distortion conditions, such as those of speech degraded by channel impairments.acceptedpeer-reviewe

Prosodic feature extraction for assessment and treatment of dysarthria

Dysarthria, a neurological motor speech disorder caused by lesions to the central and peripheral nervous system, accounts for over 40% of neurological disorders referred to pathologists in 2013[1]. This affects the ability of speakers to control the movement of speech production muscles due to muscle weakness. Dysarthria is characterised by reduced loudness, high pitch variability, monotonous speech, poor voice quality and reduced intelligibility [2]. Current techniques for dysarthria assessment are based on perception, which do not give objective measurements for the severity of this speech disorder. There is therefore a need to explore objective techniques for dysarthria assessment and treatment. The goal of this research is to identify and extract the main acoustic features which can be used to describe the type and severity of this disorder. An acoustic feature extraction and classification technique is proposed in this work. The proposed method involves a pre-processing stage where audio samples are filtered to remove noise and resampled at 8 kHz. The next stage is a feature extraction stage where pitch, intensity, formants, zero-crossing rate, speech rate and cepstral coefficients are extracted from the speech samples. Classification of the extracted features is carried out using a single layer neural network. After the classification, a treatment tool is to be developed to assist patients, through tailored exercises, to improve their articulatory ability, intelligibility, intonation and voice quality. Consequently, this proposed technique will assist speech therapists in tracking the progress of patients over time. It will also provide an acoustic objective measurement for dysarthria severity assessment. Some of the potential applications of this technology include management of cognitive speech impairments, treatment of speech difficulties in children and other advanced speech and language applications

"Can you hear me now?":Automatic assessment of background noise intrusiveness and speech intelligibility in telecommunications

This thesis deals with signal-based methods that predict how listeners perceive speech quality in telecommunications. Such tools, called objective quality measures, are of great interest in the telecommunications industry to evaluate how new or deployed systems affect the end-user quality of experience. Two widely used measures, ITU-T Recommendations P.862 âPESQâ and P.863 âPOLQAâ, predict the overall listening quality of a speech signal as it would be rated by an average listener, but do not provide further insight into the composition of that score. This is in contrast to modern telecommunication systems, in which components such as noise reduction or speech coding process speech and non-speech signal parts differently. Therefore, there has been a growing interest for objective measures that assess different quality features of speech signals, allowing for a more nuanced analysis of how these components affect quality. In this context, the present thesis addresses the objective assessment of two quality features: background noise intrusiveness and speech intelligibility. The perception of background noise is investigated with newly collected datasets, including signals that go beyond the traditional telephone bandwidth, as well as Lombard (effortful) speech. We analyze listener scores for noise intrusiveness, and their relation to scores for perceived speech distortion and overall quality. We then propose a novel objective measure of noise intrusiveness that uses a sparse representation of noise as a model of high-level auditory coding. The proposed approach is shown to yield results that highly correlate with listener scores, without requiring training data. With respect to speech intelligibility, we focus on the case where the signal is degraded by strong background noises or very low bit-rate coding. Considering that listeners use prior linguistic knowledge in assessing intelligibility, we propose an objective measure that works at the phoneme level and performs a comparison of phoneme class-conditional probability estimations. The proposed approach is evaluated on a large corpus of recordings from public safety communication systems that use low bit-rate coding, and further extended to the assessment of synthetic speech, showing its applicability to a large range of distortion types. The effectiveness of both measures is evaluated with standardized performance metrics, using corpora that follow established recommendations for subjective listening tests

Voice Feminization: Voice Therapy vs. Surgical Intervention: A Systematic Review

Abstract Purpose: Transgender individuals often seek to alter their vocal characteristics. For Male to Female (MtF) transgender individuals, attaining a feminine voice may be particularly challenging. The objective of this systematic review is to determine whether MtF transgender individuals who receive voice feminization therapy alone or Wendler’s Glottoplasty (WG) surgical intervention with subsequent voice therapy yield greater outcomes in frequency and self-perception. Method: A systematic review of the literature was conducted by using PubMed and Ovid to search terms pertaining to voice feminization. The articles were reviewed and appraised by the authors for inclusionary criteria, exclusionary criteria, and quality. Inclusionary criteria included: 1) adult MtF Transgender individuals, 2) pre and post measures of fundamental frequency (fo), 3) post puberty age, 4) measure of perception of femininity, and 5) patients who underwent WG (articles pertaining to surgical intervention only). Results: A total of 82 articles were identified and 12 met inclusionary criteria for this systematic review. Overall, the quality of the studies was moderate. Outcome measures included frequency range and frequency gain. The authors were unable to compare measurements of self-perception and perception of femininity due to the variability in assessments. Conclusions: Patients who opted for surgical intervention experienced a greater increase in fo but a decrease in frequency range. Conversely, patients who participated in voice feminization therapy alone were found to exhibit smaller gains in fo and an increase in frequency range. This implies that both voice feminization therapy and surgical intervention are effective methods for increasing the frequency of voice. Limitations of this research include the subjective nature of self-perception measures, variability in measurements of perception of femininity, and overall limited research regarding this population.https://scholarworks.uvm.edu/csdms/1009/thumbnail.jp

Aspects of voice irregularity measurement in connected speech

Applications of the use of connected speech material for the objective assessment of two primary physical aspects of voice quality are described and discussed. Simple auditory perceptual criteria are employed to guide the choice of analysis parameters for the physical correlate of pitch, and their utility is investigated by the measurement of the characteristics of particular examples of the normal-speaking voice. This approach is extended to the measurement of vocal fold contact phase control in connected speech and both techniques are applied to pathological voice data

Objective measures for predicting the intelligibility of spectrally smoothed speech with artificial excitation

A study is presented on how well objective measures of speech quality and intelligibility can predict the subjective in- telligibility of speech that has undergone spectral envelope smoothing and simplification of its excitation. Speech modi- fications are made by resynthesising speech that has been spec- trally smoothed. Objective measures are applied to the mod- ified speech and include measures of speech quality, signal- to-noise ratio and intelligibility, as well as proposing the nor- malised frequency-weighted spectral distortion (NFD) measure. The measures are compared to subjective intelligibility scores where it is found that several have high correlation (|r| ≥ 0.7), with NFD achieving the highest correlation (r = −0.81

Relating Objective and Subjective Performance Measures for AAM-based Visual Speech Synthesizers

We compare two approaches for synthesizing visual speech using Active Appearance Models (AAMs): one that utilizes acoustic features as input, and one that utilizes a phonetic transcription as input. Both synthesizers are trained using the same data and the performance is measured using both objective and subjective testing. We investigate the impact of likely sources of error in the synthesized visual speech by introducing typical errors into real visual speech sequences and subjectively measuring the perceived degradation. When only a small region (e.g. a single syllable) of ground-truth visual speech is incorrect we find that the subjective score for the entire sequence is subjectively lower than sequences generated by our synthesizers. This observation motivates further consideration of an often ignored issue, which is to what extent are subjective measures correlated with objective measures of performance? Significantly, we find that the most commonly used objective measures of performance are not necessarily the best indicator of viewer perception of quality. We empirically evaluate alternatives and show that the cost of a dynamic time warp of synthesized visual speech parameters to the respective ground-truth parameters is a better indicator of subjective quality

A European perspective on auditory processing disorder-current knowledge and future research focus

Current notions of \u201chearing impairment,\u201d as reflected in clinical audiological practice, do not acknowledge the needs of individuals who have normal hearing pure tone sensitivity but who experience auditory processing difficulties in everyday life that are indexed by reduced performance in other more sophisticated audiometric tests such as speech audiometry in noise or complex non-speech sound perception. This disorder, defined as \u201cAuditory Processing Disorder\u201d (APD) or \u201cCentral Auditory Processing Disorder\u201d is classified in the current tenth version of the International Classification of diseases as H93.25 and in the forthcoming beta eleventh version. APDs may have detrimental effects on the affected individual, with low esteem, anxiety, and depression, and symptoms may remain into adulthood. These disorders may interfere with learning per se and with communication, social, emotional, and academic-work aspects of life. The objective of the present paper is to define a baseline European APD consensus formulated by experienced clinicians and researchers in this specific field of human auditory science. A secondary aim is to identify issues that future research needs to address in order to further clarify the nature of APD and thus assist in optimumdiagnosis and evidence-based management. This European consensus presents the main symptoms, conditions, and specific medical history elements that should lead to auditory processing evaluation. Consensus on definition of the disorder, optimum diagnostic pathway, and appropriate management are highlighted alongside a perspective on future research focus