Speech characteristics are obtained using a minimum of parameters, which correspond to auditory perception characteristics, without carrying out spectral analysis, by determining an ACF (autocorrelation function) of a speech signal collected by a microphone, and deriving from the ACF a value Phi (0) of when a delay time of the ACF is 0, a delay time tau1 and an amplitude phi1 of a first peak of the ACF, and an effective duration time taue of the ACF. Furthermore, it is possible to achieve highly accurate recognition that reflects human perception in actual sound fields by determining an interaural crosscorrelation function (IACF) of the speech signal, and extracting from the IACF a maximum value IACC of the IACF, a delay time tauIACC of a peak of the IACF, and a width WIACC of the maximum amplitude of the IACF, and including these IACF factors, that is, spatial information of the sound field.
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