Speech quality assessment with noise masking
First Claim
1. An apparatus for assessing the perceptual quality of speech signals transmitted via a telecommunications network and recorded acoustically from an acoustic terminal device comprising:
- a front end processor for aligning a mono reference signal comprising a single channel with a degraded stereo signal comprising a first channel and a second channel, said front end processor comprising a leveller for adjusting the power levels of said signals and a time aligner for determining the estimated delays for each of said channels of said degraded signal;
an auditory transformer for generating a set of perceptually relevant parameters for each of said signals; and
a comparator for comparing said perceptually relevant parameters to generate disturbance profiles; and
a modeller for generating a speech quality prediction in dependence upon said disturbance profiles;
in which said front end processor further comprisesa noise masking determiner for comparing signal parameters of each of said channels of said degraded signal and generating a noise masking indicator in dependence upon said parameters; and
in which said disturbance profiles are dependent upon said noise masking indicator.
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Abstract
A method and apparatus for assessing the perceptual quality of stereo speech signals transmitted via a telecommunications network and recorded acoustically from an acoustic terminal device in which a mono reference signal comprising a single channel is aligned with a degraded stereo signal comprising a left and a right channel; a delay between each channel of said degraded signal and said reference signal is estimated; a noise masking indicator in dependence upon said estimated delays is generated; the level of the stereo signals is adjusted in dependence upon said noise masking indicator; a set of perceptually relevant parameters for each of said reference and degraded signals are generated; the perceptually relevant parameters of the reference signal with the perceptually relevant parameters of the degraded signal to generate a disturbance profile are compared; and a speech quality prediction is generated in dependence upon said disturbance profile.
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Citations
19 Claims
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1. An apparatus for assessing the perceptual quality of speech signals transmitted via a telecommunications network and recorded acoustically from an acoustic terminal device comprising:
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a front end processor for aligning a mono reference signal comprising a single channel with a degraded stereo signal comprising a first channel and a second channel, said front end processor comprising a leveller for adjusting the power levels of said signals and a time aligner for determining the estimated delays for each of said channels of said degraded signal; an auditory transformer for generating a set of perceptually relevant parameters for each of said signals; and a comparator for comparing said perceptually relevant parameters to generate disturbance profiles; and a modeller for generating a speech quality prediction in dependence upon said disturbance profiles; in which said front end processor further comprises a noise masking determiner for comparing signal parameters of each of said channels of said degraded signal and generating a noise masking indicator in dependence upon said parameters; and
in which said disturbance profiles are dependent upon said noise masking indicator.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
b) to adjust the level of each of said channels of the degraded signal independently when noise masking is not indicated.
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8. An apparatus according to claim 7, in which said leveller is arranged to adjust the level of both channels in order to achieve a first predetermined RMS power level for said one channel at step a) and in which said levelling means is arranged to adjust the level of each of said channels to achieve a second predetermined RMS power level for both channels at step b).
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9. An apparatus according to claim 8, in which said second predetermined level is greater than said first predetermined level.
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10. A method of assessing the perceptual quality of stereo speech signals transmitted via a telecommunications network and recorded acoustically from an acoustic terminal device comprising the steps of:
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aligning a mono reference signal comprising a single channel with a degraded stereo signal comprising a first channel and a second channel; estimating a delay between each channel of said degraded signal and said reference signal; generating a noise masking indicator in dependence upon a comparison of corresponding signal parameters for each channel; generating a set of perceptually relevant parameters for each of said reference and degraded signals; comparing said perceptually relevant parameters of the reference signal with the perceptually relevant parameters of the degraded signal to generate disturbance profiles; and generating a speech quality prediction in dependence upon said disturbance profiles;
wherein said generated disturbance profiles are dependent upon said noise masking indicator. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification