Methods and apparatuses for adaptively updating enrollment database for user authentication

A non-transitory computer-readable medium comprising program code that, when executed by a processor, executes an adaptive updating method of an enrollment database, the method comprising:

• extracting a first feature vector from an input image of a user:
• determining whether the input image is to be enrolled in the enrollment database based on the first feature vector, second feature vectors of enrollment images including initial enrollment images enrolled in the enrollment database, and a representative vector determined through statistical calculation of the second feature vectors of the initial enrollment images;
• and
• enrolling the input image in the enrollment database based on a result of the determining.

An adaptive updating method of an enrollment database, the method comprising:

• authenticating an input image;
• determining whether the input image is an outlier based on a representative vector determined through statistical calculation of feature vectors of initial enrollment images;
• determining whether a feature range of the enrollment database including enrollment images is extended by the input image;
• and
• replacing one of remaining enrollment images excluding the initial enrollment images included in the enrollment images with the input image.