Noise detection apparatus, noise removal apparatus, and noise detection method

A noise removal apparatus, comprising:

• a time-frequency transform unit configured to transform an input signal from a time domain to a frequency domain to produce a spectrum;
• a power spectrum calculating unit configured to obtain powers of frequencies from the spectrum;
• a peak stationarity detecting unit configured to use peaks of the powers of frequencies in each frame to detect frequencies at which a stationary peak of the powers exists;
• a power stationarity detecting unit configured to use magnitudes of the powers of frequencies in each frame to detect frequencies at which the magnitudes of the powers are stationary;
• a check unit configured to use the frequencies detected by the peak stationarity detecting unit and the frequencies detected by the power stationarity detecting unit to check whether there is a noise that has peak and power stationarity in the frequency domain;
• a noise removal unit configured to synthesize sinusoidal waves corresponding to the spectrum of the frequencies for which the check unit has detected presence of the noise to produce a noise signal, and to invert a phase of the produced noise signal for addition to the input signal.

A noise detection method, comprising:

• a time-frequency transform procedure of transforming an input signal from a time domain to a frequency domain to produce a spectrum;
• a power spectrum calculating procedure of obtaining powers of frequencies from the spectrum;
• a peak stationarity detecting procedure of using peaks of the powers of frequencies obtained by the power spectrum calculating procedure in each frame to detect frequencies at which a stationary peak of the powers exists;
• a power stationarity detecting procedure of using magnitudes of the powers of frequencies detected by the power spectrum calculating procedure in each frame to detect frequencies at which the magnitudes of the powers are stationary;
• and
• a check procedure of using the frequencies detected by the peak stationarity detecting procedure and the frequencies detected by the power stationarity detecting procedure to check whether there is a noise that has at least one of peak stationarity and power stationarity in the frequency domain.