Facial Expressions as a Vulnerability in Face Recognition

This work explores facial expression bias as a security vulnerability of face recognition systems. Face recognition technology has experienced great advances during the last decades. However, despite the great performance achieved by state of the art face recognition systems, the algorithms are still sensitive to a large range of covariates. This work presents a comprehensive analysis of how facial expression bias impacts the performance of face recognition technologies. Our study analyzes: i) facial expression biases in the most popular face recognition databases; and ii) the impact of facial expression in face recognition performances. Our experimental framework includes four face detectors, three face recognition models, and four different databases. Our results demonstrate a huge facial expression bias in the most widely used databases, as well as a related impact of face expression in the performance of state-of-the-art algorithms. This work opens the door to new research lines focused on mitigating the observed vulnerability.