Explicit estimation of speech boundaries

Estimation of signal length is one of the first steps in many speech processing systems, for it provides us with the initial and final points between which the speech signal is comprised. Nevertheless, endpoint detection can be affected by different types of background noise over which we have no control. This study presents an explicit detector that aims to resolve the problems created by two types of noise: quasi-stationary background noise and the noise generated by the speaker. The system is based on very simple measurements, energy, zero crossing rate and band crossings, and has been implemented on a personal computer. We have tested the system under real-life conditions, and it has attained a success rate of 97-98% in the location of the extremes for both the left and the right limit of a series of words comprising all the possible beginnings and endings in Spanish