Instrumental Speech Distortion Assessment of Black Box Speech Enhancement Systems

An important parameter in quality assessment of speech enhancement systems is speech distortion, measured in terms of quality of the speech component. In fact, in the context of noise reduction, the user tends to prefer a certain degree of residual noise over distorted speech with suppressed background noise. The challenge of instrumental speech component quality evaluation lies, among others, in the mere availability of the enhanced output signal mixture rather than its speech portion. In this paper we present a method to extract the speech component from the enhanced output signal with high accuracy, given the input signal components speech, noise, and echo. We apply this method to a black box speech component quality comparison of two speech enhancement systems and report on instrumental and subjective tests with focus on double-talk.