Improving Objective Speech Quality Indicators in Noise Conditions

Kąkol, Krzysztof; Korvel, Gražina; Kostek, Bożena

doi:10.1007/978-3-030-39250-5_11

Cited by 4 publications

(3 citation statements)

References 12 publications

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“…They indicated that one of the most important factors impairing SI or AI is fluctuating noise, especially speech embedded in fluctuating maskers, e.g., competing talkers [3,23,24]. Lombard effect is another factor impeding SI or speech quality evaluation [25]. More limitation factors were identified in the context of hearing aids, i.e., peak-clipping and center-clipping distortions in the speech signal [26], cochlear implants, i.e., STOI (Short-Time Objective Intelligibility) [27], or noise suppression algorithms [28].…”

Section: State-of-the-art Of the Speech Intelligibility Assessment Me...mentioning

confidence: 99%

A Novel Method for Intelligibility Assessment of Nonlinearly Processed Speech in Spaces Characterized by Long Reverberation Times

Kurowski

Kotus

Odya

et al. 2022

Sensors

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Objective assessment of speech intelligibility is a complex task that requires taking into account a number of factors such as different perception of each speech sub-bands by the human hearing sense or different physical properties of each frequency band of a speech signal. Currently, the state-of-the-art method used for assessing the quality of speech transmission is the speech transmission index (STI). It is a standardized way of objectively measuring the quality of, e.g., an acoustical adaptation of conference rooms or public address systems. The wide use of this measure and implementation of this method on numerous measurement devices make STI a popular choice when the speech-related quality of rooms has to be estimated. However, the STI measure has a significant drawback which excludes it from some particular use cases. For instance, if one would like to enhance speech intelligibility by employing a nonlinear digital processing algorithm, the STI method is not suitable to measure the impact of such an algorithm, as it requires that the measurement signal should not be altered in a nonlinear way. Consequently, if a nonlinear speech enhancing algorithm has to be tested, the STI—a standard way of estimating speech transmission cannot be used. In this work, we would like to propose a method based on the STI method but modified in such a way that it makes it possible to employ it for the estimation of the performance of the nonlinear speech intelligibility enhancement method. The proposed approach is based upon a broadband comparison of cumulated energy of the transmitted envelope modulation and the received modulation, so we called it broadband STI (bSTI). Its credibility with regard to signals altered by the environment or nonlinear speech changed by a DSP algorithm is checked by performing a comparative analysis of ten selected impulse responses for which a baseline value of STI was known.

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Section: State-of-the-art Of the Speech Intelligibility Assessment Me...mentioning

confidence: 99%

A Novel Method for Intelligibility Assessment of Nonlinearly Processed Speech in Spaces Characterized by Long Reverberation Times

Kurowski

Kotus

Odya

et al. 2022

Sensors

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“…The so-called Lombard effect is a widely known phenomenon that is induced when the speaker unconsciously changes acoustic features of uttered speech in noise conditions. Even though this effect is known from 1911, there are many studies that have analyzed Lombard speech in the last two decades [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ], especially as there are no indicators or measures that apply directly to assessing the quality of speech in such conditions [ 13 , 14 , 15 ]. In contrast, there are not too many works on the effect of reverberation on speech uttering and to what degree it affects speech intelligibility [ 16 , 17 , 18 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

“…In Lombard speech, effects such as the following are observed: increasing the level of sound energy, raising the fundamental frequency of the signal, shifting energy from lower frequency bands to higher frequency bands, increasing formants, the duration of vowels, the spectral tilt, etc. [ 8 , 10 , 20 , 21 ]. On the other hand, reverberation enforces persons to slow down their speech, but the differences in slowed speech over uttered word distribution are not uniform [ 17 , 18 ].…”

Section: Introductionmentioning

confidence: 99%

Acoustic Sensing Analytics Applied to Speech in Reverberation Conditions

Odya

Kotus

Kurowski

et al. 2021

Sensors

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The paper aims to discuss a case study of sensing analytics and technology in acoustics when applied to reverberation conditions. Reverberation is one of the issues that makes speech in indoor spaces challenging to understand. This problem is particularly critical in large spaces with few absorbing or diffusing surfaces. One of the natural remedies to improve speech intelligibility in such conditions may be achieved through speaking slowly. It is possible to use algorithms that reduce the rate of speech (RoS) in real time. Therefore, the study aims to find recommended values of RoS in the context of STI (speech transmission index) in different acoustic environments. In the experiments, speech intelligibility for six impulse responses recorded in spaces with different STIs is investigated using a sentence test (for the Polish language). Fifteen subjects with normal hearing participated in these tests. The results of the analytical analysis enabled us to propose a curve specifying the maximum RoS values translating into understandable speech under given acoustic conditions. This curve can be used in speech processing control technology as well as compressive reverse acoustic sensing.

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