Periocular biometrics and its relevance to partially masked faces: A survey

Periocular is one of the promising biometric traits for human recognition. It encompasses a surrounding area of eyes that includes eyebrows, eyelids, eyelashes, eye-folds, eyebrows, eye shape, and skin texture. Its relevance is more emphasize during the COVID-19 pandemic due to the masked faces. So, this article presents a detailed review of periocular biometrics to understand its current state. The paper first discusses the various face and periocular techniques, specially designed to recognize humans wearing a face mask. Then, different aspects of periocular biometrics are reviewed: (a) the anatomical cues present in the periocular region useful for recognition, (b) the various feature extraction and matching techniques developed, (c) recognition across different spectra, (d) fusion with other biometric modalities (face or iris), (e) recognition on mobile devices, (f) its usefulness in other applications, (g) periocular datasets, and (h) competitions organized for evaluating the efficacy of this biometric modality. Finally, various challenges and future directions in the field of periocular biometrics are presented.