Patent ID: 8160732
Filing Date: 2012-04-17
Classification: G10L

Abstract:
1. A noise suppressing method, comprising: extracting a part of an observation signal that progresses with time and in which noise is superimposed on a sound, every time a prescribed interval of time with which the observation signal progresses elapses, in a first signal length that is longer than or equal to the prescribed time interval; analyzing, as a first spectrum, a spectrum of the observation signal that is extracted in the first signal length; extracting a part of the observation signal every time the prescribed time interval or a proper time elapses in a second signal length that is longer than the first signal length in such a manner that its head coincides with a head of the observation signal that is extracted in the first signal length; analyzing, as a second spectrum, a spectrum of the observation signal that is extracted in the second signal length; estimation-calculating a spectrum of noise included in the observation signal on the basis of the second spectrum; subtracting the noise spectrum from the first spectrum every time the prescribed time interval elapses to calculate a noise-suppressed sound spectrum; converting the calculated sound spectrum into a signal in the time domain every time the prescribed time interval elapses; and obtaining a continuous noise-suppressed sound by connecting the converted time-domain signals to each other, wherein the estimation-calculating process includes: smoothing-processing the second spectrum; comparing a smoothing-processed second spectrum with the second spectrum that is not smoothing-processed; choosing larger values at respective frequency points in the comparing process to eliminate a dip in the second spectrum; and estimation-calculating a noise spectrum on the basis of a dip-eliminated second spectrum.