System for analyzing human speech

A method of analyzing human speech for determining the pitch of speech segments while using more than one pitch detection algorithm, characterized by comprising the steps of:

• (a) determining an amplitude spectrum of a speech segment in a first elementary pitch meter, and determining significant peak positions in said spectrum,
• (b) determining an autocorrelation function and significant peak positions therein in a second elementary pitch meter,
• (c) utilizing said significant peak positions of the amplitude spectrum and the autocorrelation function, respectively, as input data for selecting a value for the pitch and period, respectively, and determining a sequence of consecutive integral multiples of said value, and the determination of intervals around said value and the multiples thereof, these intervals defining apertures of a mask, said apertures corresponding to harmonic multiplication factors,
• (d) computing a quality figure for each pitch and period, respectively, in accordance with a criterion indicating the degree to which the significant peak positions and mark apertures match,
• (e) repeating steps (c) and (d) for consecutive higher values of the pitch and period, respectively, up to a predetermined highest value, to provide a sequence of quality figures associated with these pitch and period values, respectively,
• (f) selecting a predetermined number of values of said pitch and period, respectively, having the highest quality figures,
• (g) converting the values for the respective periods into values for pitch, and
• (h) combining the predetermined numbers of selected values for pitch, and for pitch converted from period, with their associated quality figures to form an estimation of the most likely pitch.