Renetta G. Tull
Janet C. Rutledge
Jerry J. Mahler
Elec. Eng./Comput. Sci. Dept., Northwestern Univ., Evanston, IL 60208
Linear predictive synthesis was applied to female alaryngeal speech as an enhancement technique to reduce gender ambiguity during speaker identification. Esophageal speech, a form of alaryngeal speech resulting from the removal of the larynx due to cancer, perturbs the theoretical acoustic models for laryngeal speech. This form of pathological speech also changes the expected spectral characteristics and affects perception. The female esophageal speaker's low fundamental frequency often causes her to be identified as a male speaker over telephone lines. The errors made in speaker identification can be reduced by obtaining vocal tract parameters of the aperiodic, esophageal speech input from a linear predictive coding (LPC) model and resynthesizing the LPC prediction coefficients using an appropriate pitch period that is better suited for female voice. This enhancement technique was implemented using the TMS320C30 floating point digital signal processor from Texas Instruments. This implementation supports the potential of a portable processor that enhances the perceptual quality of the female alaryngeal voice and improves the input speech signal used by both human listeners and automatic speech and speaker identification systems.