Reconstruction of Normal Sounding Speech for Laryngectomy Patients Through a Modified CELP Codec

Abstract

Whispered speech can be useful for quiet and private communication, and is the primary means of unaided spoken communication for many people experiencing voice-box deficiencies. Patients who have undergone partial or full laryngectomy are typically unable to speak anything more than hoarse whispers, without the aid of prostheses or specialized speaking techniques. Each of the current prostheses and rehabilitative methods for post-laryngectomized patients (primarily oesophageal speech, tracheo-esophageal puncture, and electrolarynx) have particular disadvantages, prompting new work on nonsurgical, noninvasive alternative solutions. One such solution, described in this paper, combines whisper signal analysis with direct formant insertion and speech modification located outside the vocal tract. This approach allows laryngectomy patients to regain their ability to speak with a more natural voice than alternative methods, by whispering into an external prosthesis, which then, recreates and outputs natural-sounding speech. It relies on the observation that while the pitch-generation mechanism of laryngectomy patients is damaged or unusable, the remaining components of the speech production apparatus may be largely unaffected. This paper presents analysis and reconstruction methods designed for the prosthesis, and demonstrates their ability to obtain natural-sounding speech from the whisper-speech signal using an external analysis-by-synthesis processing framework.

A Hybrid Approach to Electrolaryngeal Speech Enhancement Based on Noise Reduction and Statistical Excitation Generation

“…On the other hand, the latter method is capable of significantly improving natural-ness by converting acoustic parameters of EL speech into those of natural voices using statistical VC techniques [5], [6]. The use of statistics extracted from a parallel data set consisting of EL speech and natural voices makes it possible to achieve more complex conversion processes than that of other signal processing approaches, such as formant manipulation [7]. For example, it is possible to convert from a spectral parameter sequence of EL speech into F 0 patterns of natural voices.…”

Phonated speech reconstruction using twin mapping models

“…Couple of methods are available for converting whispers to normal speech [19], [20], [21], [22], [23]. The driving idea of all these methods is based on the assumption of whispers are missing some acoustic and spectral features comparing with normal speech; hence, the problem of converting whispers to normal speech is formalised as a reconstruction issue [4], [24].…”

“…These reconstruction methods (either training-based or nontraining) have different disadvantages such as problems in converting continuous speech (due to using phoneme switching) [20], being computationally expensive (due to using highly overlapped frames for spectral enhancement, or using jump Markov linear system for pitch and voicing parameters) [19], [4], and more importantly lack of naturalness in regenerated output (due to simplified time alignment and spectral features assumptions) [21], [23]. In this paper, we focus on a trainingbased approach, and propose a novel reconstruction algorithm to improve the efficiency in phonated speech regeneration.…”

Speech Driven by Artificial Larynx: Potential Advancement Using Synthetic Pitch Contours

“…However, whispering is usually too weak in volume to be practical in everyday conversation. To overcome these problems researchers have also attempted to capture whispered speech and re-synthesize normal speech externally [8]. However, this approach is sensitive to background noise in the environment.…”