Patent ID: 6609092
Filing Date: 2003-08-19
Classification: G10L

Abstract:
A method of estimating audio signal quality, the method comprising the steps of:generating a mapping function between a plurality of actual subjective measures determined for a given set of audio signals and corresponding objective distortion measures determined for the given set of audio signals; and utilizing the mapping function to generate an estimated subjective measure from an objective distortion measure determined for another audio signal; wherein a portion of at least one of the objective distortion measures associated with an mth frame of a given source speech sequence is given by D&it;(m)=&Sum;i=1Nb&it;â€ƒ&it;C&it;(m,i)&it;&LeftBracketingBar;X&it;(m,i)-Y&it;(m,i)&RightBracketingBar;where X(m, i) and Y(m, i) are auditory representations of source and processed speech, respectively, for the sequence, 1&lE;i&lE;Nb denotes a frequency bin index, Nb is the dimension of a frame vector, and C(m, i) is an asymmetric weighting factor;wherein an overall auditory-based objective distortion measure between the source and processed speech sequences X and Y is determined by D=&ggr;Dsp1+(1âˆ’&ggr;)Dnsp where &ggr; is a weighting factor for active speech frames, and Dsp and Dnsp are distortions for speech and non-speech portions of the sequences, respectively; andwherein the distortions for the speech portion Dsp and the non-speech portion Dnsp are defined as Dsp=1maxm&it;LY&af;(m)&CenterDot;Tsp&it;&Sum;m,LX&af;(m)>K&it;â€ƒ&it;D&af;(m)Dnsp=1maxm&it;LY&af;(m)&CenterDot;Tnsp&it;&Sum;m,LX&af;(m)&leq;K&it;â€ƒ&it;D&af;(m)where Lx (m) and Ly (m) are pseudo-loudness of the source speech and the processed speech at the mth frame, respectively, K is a threshold for speech/non-speech decision, and Tsp and Tnsp are the number of active speech frames and the number of non-speech frames, respectively.