Patent ID: 6243672
Filing Date: 2001-06-05
Classification: G10L

Abstract:
A pitch detection method for detecting a pitch corresponding to a fundamental period of an input speech signal using an open-loop pitch search, the method comprising the steps of:detecting an approximate pitch from the input speech signal under a pre-set pitch detecting condition;setting a high-reliability pitch by evaluating a reliability of the pitch based on the approximate pitch detected by the step of detecting, a speech level of the input speech signal, and an autocorrelation peak value of the input speech signal; anddetermining the pitch using said open-loop pitch search by evaluating the high-reliability pitch and the approximate pitch, wherein the pitch is an improved estimation from the high-reliability pitch and the approximate pitch,wherein when the high-reliability pitch is maintained for a pre-set time the high-reliability pitch is updated if the high-reliability pitch is within a pre-set range to a next pitch detected in a next encoding unit, said preset-range indicates whether the high-reliability pitch and the next pitch are one of substantially twice, thrice, one-half, and one-third relative to each other, andthe high-reliability pitch is discarded if the high-reliability pitch is not updated within the preset time.