Patent ID: 9224395
Filing Date: 2015-12-29
Classification: G10L,H03G

Abstract:
1. A method of voice discrimination in an automatic volume control, to identify a voice component in an audio waveform containing both a user's voice and a background noise, so that the voice component can be subtracted from the audio waveform, so that the automatic volume control is able to adjust a volume based on the background noise and not the user's voice, the method comprising: transducing acoustic waves from a user into a corresponding voice signal V(t) using a voice microphone; transducing acoustic ambient waves into a corresponding composite signal using a noise microphone, the composite signal containing both the background noise N(t) and an unknown measure of the user's voice cV(t), wherein the unknown measure is represented by an unknown proportionality constant c; providing a first processing period, the first processing period comprising: sampling the composite signal N(t)+cV(t); repeating the sampling of the composite signal; calculating a variance in all samples in the processing period to determine if the user's voice cV(t) is a significant factor in the composite signal N(t)+cV(t); transforming the composite signal to produce a signal corresponding to an amplitude of each frequency component within a transform spectrum; identifying a dominant voice frequency according to said amplitude in the transform spectrum of the composite signal; determining a line strength of said dominant voice frequency in both the noise microphones and the voice microphones; calculating the unknown proportionality constant c from a ratio of the line strength in the noise and voice microphones; solving for cV(t); and subtracting cV(t) from the composite signal N(t)+cV(t), determining N(t); increasing or decreasing the automatic volume control based on said determining N(t); and repeating actions of the first processing period in second and subsequent processing periods so that the automatic volume control is able to adjust a volume based on the background noise and not the user's voice.