Encontrados 5 documentos, a visualizar página 1 de 1
Spectral normalization MFCC derived features for robust speech recognition
Lima, C. S.; Tavares, Adriano; Silva, Carlos A.; Oliveira, Jorge F.This paper presents a method for extracting MFCC parameters from a normalised power spectrum density. The underlined spectral normalisation method is based on the fact that the speech regions with less energy need more robustness, since in these regions the noise is more dominant, thus the speech is more corrupted. Less energy speech regions contain usually sounds of unvoiced nature where are included nearly h...
Blind source separation by independent component analysis applied to electroenc...
Lima, C. S.; Silva, Carlos A.; Tavares, Adriano; Oliveira, Jorge F.Independent Component Analysis (ICA) is a statistical based method, which goal is to find a linear transformation to apply to an observed multidimensional random vector such that its components become as statistically independent from each other as possible. Usually the Electroencephalographic (EEG) signal is hard to interpret and analyse since it is corrupted by some artifacts which originates the rejection of...
HMM modeling of additive noise in the western languages context
Lima, C. S.; Oliveira, Jorge F.This paper is concerned to the noisy speech HMM modelling when the noise is additive, speech independent and the spectral analysis is based on sub-bands. The internal distributions of the noisy speech HMM’s were derived when Gaussian mixture density distributions for clean speech HMM modelling are used, and the noise is normally distributed and additive in the time domain. In these circumstances it is showed th...
Spectral bi-normalisation for speech recognition in additive noise
Lima, C. S.; Oliveira, Jorge F.The changing on peaks structure of the speech spectrum is perhaps the most important cause of degradation of speech recognition systems under adverse conditions. Another drawback concerned to the additive noise effect occurs on the flat spectral zones which are usually raised proportionally to the noise level. These combined effects on both the peaked and the flat spectral zones can be alleviated by trying to r...
On Separating Environmental and Speaker Adaptation
Lima, C. S.; Silva, Carlos A.; Tavares, Adriano; Oliveira, Jorge F.This paper presents a maximum likelihood (ML) approach, concerned to the background model estimation, in noisy acoustic non-stationary environments. The external noise source is characterised by a time constant convolutional and a time varying additive components. The HMM composition technique, provides a mechanism for integrating parametric models of acoustic background with the signal model, so that noise com...
| Financiadores do RCAAP | |||||||
|
|
|
|
|
|
||