Simulations

To show that the proposed method can segregate the desired vowel from noisy vowel even in waveforms, we performed the following three simulations:

1.

vowel segregation (/a/, /i/, /u/, /e/, /o/) from a noisy vowel: the dataset size was 160 (five vowels, four speakers, four noise signals, and two types of noise);

2.

vowel segregation (/aoi/) from a noisy vowel: the dataset size was 32 (one vowel, four speakers, four noise signals, and two types of noise); and

3.

vowel segregation from another vowel (double vowel condition): one vowel was (/a/, /i/, /u/, /e/, /o/) from the male (mau) or female (fkn) speaker and the other was /aoi/ from the female (fsu) or male (mht) speaker, and the dataset size was 40 (five vowels, two speakers, and four noise signals).

The speech signals were the Japanese vowels of four speakers (two males and two females) in the ATR-database [ATR Tech. Rep.1988]. The noise was pink or white noise and the SNRs of noisy signals ranged from 5 to 20 dB in 5-dB steps.