This work package will identify a set of baseline automatic speaker verification (ASV) systems. Whereas all components form part of the background technology, they will be enhanced as part of the collaborative effort in WP3 with the central aim of improving ASV robustness to varying acoustic environments and threats from spoofing. Outcomes will take the form of pluggable software modules for integration into the OCTAVE Trusted Biometric Authentication Service (TBAS).
WP3 aims to establish a set of TBAS enhancement modules necessary to ensure (i) its proper functioning in relevant operational environments and (ii) protection from spoofing attacks. The objectives are to:
- identify existing, baseline text-independent and text-dependent voice biometric systems to meet OCTAVE application requirements;
- assess the vulnerability of such systems to diverse spoofing attacks;
- innovate new countermeasures to improve their robustness to spoofing attacks;
- deliver new solutions to ensure the proper functioning of speaker recognition in the face of variable acoustic conditions and
- establish specific technology and modules for integration into the OCTAVE platform.
DESCRIPTION OF WORK
To embrace the widest possible array of application scenarios, OCTAVE targets unsupervised speaker verification scenarios. In such cases the ambient conditions are uncontrolled and there is potential for systems to be attacked through spoofing.
Unsupervised settings entail unknown acoustic conditions involving varying amounts and types of background and channel noise. Background noise results in a lower signal-to-noise ratio and also leads to increased vocal effort. Both result in speech signals whose acoustic properties can differ significantly from those at enrolment. Channel variation can also introduce acoustic mismatch which generally degrades speaker recognition performance. Thus, noise reduction, speech enhancement and acoustic normalization techniques will be integrated into the OCTAVE platform so as to ensure satisfactory performance for all operating conditions.
Almost all biometric systems are vulnerable to spoofing, whereby a malicious user masquerades as a legitimate user in order to gain access to systems or services to which they are not entitled. Automatic speaker verification systems are no exception and a growing body of work shows that, when presented with spoofed speech, then the performance of such systems can degrade to below that expected by chance. Spoofing is a genuine threat to security in biometric access control applications that needs to be properly analysed and effectively addressed. Emerging anti-spoofing technology, which aims to counter the threat of spoofing in automatic speaker verification, will be integrated into the OCTAVE platform. This will entail innovative, automatic detection approaches which have the aim of deciding whether a given speech signal is the result of genuine access attempt, or an illegitimate access attempt, stemming from replayed speech, converted or synthesized speech.