Introduction

It is a common belief that many biometric systems are capable of detecting liveness in biometric samples. Liveness detection in a biometric system ensures that only "real" fingerprints, facial images, irises, and other characteristics are capable of generating templates for enrollment, verification, and identification. From a security and accountability perspective, requiring a live biometric characteristic makes it difficult for an individual to repudiate that he or she executed a transaction, accessed a secure facility, or applied for a benefit.