Effect of Noise on Vowel Onset Point Detection

This paper discuss the effect of noise on vowel onset point (VOP) detection performance. Noise is one of the major degradation in real-time environments. In this work, initially effect of noise on VOP detection is studied by using recently developed VOP detection method. In this method, VOPs are detected by combining the complementary evidence from excitation source, spectral peaks and modulation spectrum to improve VOP detection performance. Later spectral processing based speech enhancement methods such as spectral subtraction and minimum mean square error (MMSE) are used for preprocessing to improve the VOP detection performance under noise. Performance of the VOP detection is analyzed by using TIMIT database for white and vehicle noise. In general, performance of VOP detection is degraded due to noise and in particular performance is effected significantly due to spurious VOPs introduced at low SNR values. Experimental results indicate that the speech enhancement techniques provides the improvement in the VOP detection performance by eliminating spurious VOPs under noise.