Periocular Biometrics: A Modality for Unconstrained Scenarios
This is an incremental review paper that addresses biometric identification challenges for applications in uncooperative or occluded environments, such as surveillance or security.
This paper tackles the problem of biometric identification in unconstrained scenarios by reviewing periocular biometrics, which uses the eye region for recognition when other modalities like iris or face are unreliable, highlighting its increased relevance during the COVID-19 pandemic due to mask usage.
Periocular refers to the externally visible region of the face that surrounds the eye socket. This feature-rich area can provide accurate identification in unconstrained or uncooperative scenarios, where the iris or face modalities may not offer sufficient biometric cues due to factors such as partial occlusion or high subject-to-camera distance. The COVID-19 pandemic has further highlighted its importance, as the ocular region remained the only visible facial area even in controlled settings due to the widespread use of masks. This paper discusses the state of the art in periocular biometrics, presenting an overall framework encompassing its most significant research aspects, which include: (a) ocular definition, acquisition, and detection; (b) identity recognition, including combination with other modalities and use of various spectra; and (c) ocular soft-biometric analysis. Finally, we conclude by addressing current challenges and proposing future directions.