Biometric modality: Ear – key considerations
External ear recognition
Ears change in shape during childhood and again in later life (approximately 70 years and older). However, in the intervening years they retain their identifying features and these are not normally subject to the same forms of wear and damage that may affect, for example, the fingerprints on a person’s hand. The characteristics of the ear can be captured, at a distance, on one or more cameras. This approach is non-invasive and does not require the cooperation or knowledge of the subject but is subject to the challenges of operating in a real world environment e.g. poor lighting, unsatisfactory camera angles, subjects’ pose and behaviour and occlusions such as hair, headwear, ear phones etc.
It should be noted that facial recognition examiners consider the ear to be one of the most unique and stable features for comparison purposes.
Images of ears can also be captured on smartphone cameras to potentially create an additional or alternative biometric authentication process.
Ear acoustic authentication
A different method of capturing and processing unique features of the ear is Ear acoustic authentication. This method sends sounds from an ear-bud, placed in the user’s ear, down the ear canal and the reflected sound waves map the exact shape of the ear canal which is unique to each ear. The advantages of this type of technology is that it can be used by persons wearing protective headwear, masks, gloves etc. and, as the ear canal is part of a hidden structure within the body, this helps to protect against presentation attacks (‘spoofing’) (Refer to the Biometrics Institute Good Practice Framework D.2.1).
