Spectral Dynamics as a Source of Discontinuity in Concatenative Speech Synthesis

Abstract

The quality of concatenative speech synthesis depends on the cost function employed for unit selection. Effective cost functions for spectral continuity have proven difficult to define and standard measures do not accurately reflect human perception of spectral discontinuity in concatenated speech. Previous studies on spectral join costs have focused predominantly on static spectral measures extracted from the unit boundary. In this paper spectral dynamic behaviour is investigated as a source of discontinuity in concatenated speech. A number of measures representing spectral dynamics are tested for the task of detecting discontinuities. The spectral dynamic measures tested contain information correlating with human perception of discontinuities, suggesting that spectral dynamics are a source of discontinuity in concatenated speech. A strategy to effectively combine dynamic and static measures is proposed using principal component analysis (PCA).

Removal of Spectral Discontinuity in Concatenated Speech Waveform

“…Audible spectral discontinuities in concatenated signals were researched in [4]. Signal components can change in a number of ways at the join; an abrupt termination of signal components, an abrupt onset of signal components and more subtle changes in signal components sustained across the join [5]. The synthesised speech can sound very natural if the discontinuities at the concatenation points are inaudible.…”

Βελτίωση Της Ποιότητας Συνθετικής Φωνής Και Εφαρμογή Σε Σύγχρονα Τηλεπικοινωνιακά Περιβάλλοντα Και Υπηρεσίες

“…Οι παράμετροι που αποτελούν το διάνυσμα χαρακτηριστικών είναι ζήτημα του σχεδιαστή. Τα πιο συχνά χρησιμοποιούμενα χαρακτηριστικά είναι η θεμελιώδης συχνότητα (pitch) και κάποια φασματική αναπαράσταση ενώ πολλές φορές συμπεριλαμβάνονται μεγέθη όπως η ένταση (intensity) και η διάρκεια καθώς και οι πρώτες και δεύτερες παράγωγοι όλων των προηγούμενων μεγεθών [Hunt, 1996;Fraser, 2007;Plumpe, 1998;Blouin, 2002;Hirchfeld, 2000;Kirkpatrick, 2007]. Κάθε χαρακτηριστικό συνοδεύεται και από μια μετρική η οποία παίζει το ρόλο τους επιμέρους κόστους.…”