Method for determining speech quality by comparison of signal properties
AssigneeDeutsche Telekom AG
InventorJens Berger
Life of this patent
Estimating the term…
Abstract
In a method for determining speech quality using an objective measure, in order to enhance prediction reliability of the evaluated quality parameters, distortions of the mean spectral envelope are extensively corrected with a weighting function WT(f) before comparing spectral properties. Additionally, the fixed band limits for integration of spectral power density are suppressed and other band limits are searched for instead in a predetermined optimization area in which the resulting spectral intensity representations of the voice signal to be evaluated and the reference voice signal have maximum similarity. The solutions described can supplement known methods and can be incorporated into their structures.
Claims7
A method for determining speech quality using an objective measure, the method comprising:
- calculating a speech quality characteristic value by comparing respective spectral short-time properties of an assessed speech signal and of a reference speech signal;
- prior to the comparing the respective spectral short-time properties, reducing differences in respective mean spectral envelopes of the assessed speech signal and of the reference speech signal by weighting spectral short-time properties of the assessed speech signal and the reference speech signal in a predetermined number of time segments using a spectral weighting function so as to include differences in the respective mean spectral envelopes in the speech quality characteristic value to a limited extent, the spectral weighting function being calculated from the respective mean spectral envelopes;
- and
- calculating a respective intensity value for each of a plurality of frequency bands in a signal segment respectively for the assessed speech signal and the reference speech signal using variable limits for the frequency bands so that a respective difference between each calculated respective intensity of the assessed speech signal and the reference speech signal is reduced, wherein the calculating of the respective intensity value for each of the plurality of frequency bands is performed before the calculating the quality characteristic value and is performed by integrating a respective signal intensity, the width of the frequency bands being constant on a pitch scale and further comprising calculating a respective specific loudness from the respective intensity values in the respective frequency bands, the limits for the frequency bands being selected so that differences in the calculated respective specific loudnesses between the assessed signal and the reference speech signal are a respective minimum in each frequency band in the signal segment.
A method for determining speech quality using an objective measure, the method comprising:
- calculating a speech quality characteristic value by comparing respective spectral short-time properties of an assessed speech signal and of a reference speech signal;
- prior to the comparing the respective spectral short-time properties, reducing differences in respective mean spectral envelopes of the assessed speech signal and of the reference speech signal by weighting spectral short-time properties of the assessed speech signal and the reference speech signal in a predetermined number of time segments using a spectral weighting function so as to include differences in the respective mean spectral envelopes in the speech quality characteristic value to a limited extent, the spectral weighting function being calculated from the respective mean spectral envelopes;
- and
- calculating a respective intensity value for each of a plurality of frequency bands in a signal segment respectively for the assessed speech signal and the reference speech signal using variable limits for the frequency bands so that a respective difference between each calculated respective intensity of the assessed speech signal and the reference speech signal is reduced, wherein the calculating of the speech quality characteristic value is performed based on a similarity of respective spectral representations of the assessed speech signal and the reference speech signal in a plurality of time segments, the respective similarity representing a respective correlation coefficient between the respective spectral representations of the assessed speech signal and the reference speech signal in a respective time segment of the plurality of time segments averaged over the plurality of time segments.
Dependencies are inferred from the claim text.