摘要 |
Objective measurement methods and devices for predicting perceptual quality of speech signals degraded in speech processing/transporting systems may have poor prediction results for degraded signals including extremely weak or silent portions. Improvement is achieved by applying a first scaling step in a pre-processing stage with a first scaling factor (S(Y+ DELTA )), which is a function of the reciprocal value of the power of the output signal increased by an adjustment value ( DELTA ), and by a second scaling step with a second scaling factor (S< alpha )<Y+ DELTA ) ; S< alpha i)<Y+ DELTA i), with i=1,2), which is substantially equal to the first scaling factor raised to an exponent having a adjustment value ( alpha ) between zero and one. The second scaling step may be carried out on various locations in the device. The adjustment values are adjusted using test signals with well defined subjective quality scores. <IMAGE> |