Score Normalization Rules in Iris Recognition

Synonyms

Commensurability; Decision criterion adjustment; Error probability non-accumulation; Normalized Hamming distance

Definition

All biometric recognition systems are based on similarity metrics that enable decisions of “same” or “different” to be made. Such metrics require normalizations in order to make them commensurable across comparison cases that may differ greatly in the quantity of data available or in the quality of the data. Is a “perfect match” based only on a small amount of data better or worse than a less perfect match based on more data? Another need for score normalization arises when interpreting the best match found after an exhaustive search, in terms of the size of the database searched. The likelihood of a good match arising just by chance between unrelated templates must increase with the size of the search database, simply because there are more opportunities. How should a given “best match” score be interpreted? Addressing these questions on a principled...