Vocal tract area based artificial bandwidth extension

In this paper we present a method of artificial bandwidth extension based on vocal tract areas. This method exploits the many-to-one mapping between the vocal tract areas and linear prediction polynomial, and the quasi-stationary nature of speech to estimate the high-frequency (4 kHz to 8 kHz) components of speech given the narrowband signal (0 to 4 kHZ). Contrary to some of the pre-existing methods, this algorithm does not estimate the missing high-frequency components but directly estimates the broadband vocal tract areas using codebook mapping and ergodic HMMs, to synthesize broadband speech.