By Dr Risco Mutelo
It is essential to be familiar with the characteristics of biometrics systems in order to better understand how to think objectively about each type and make rational decisions about purchasing and using the technology. Any human anatomical or behavioural trait can be used as a biometric identifier to recognise a person as long as it satisfies the following characteristics:
Universality: Each person should possess the biometric trait. For instance, nearly everyone in Namibia will have at least one finger for fingerprint biometrics and a face for face recognition, but gait-based biometrics may be more difficult for wheelchair users.
Distinctiveness: Each person should be sufficiently unique in terms of their biometric traits. This is how well the particular biometric distinguishes people. DNA and fingerprints are among the best.
Permanence: Biometric trait should be invariant (with respect to the matching criterion) over time. A good biometric system should measure something that changes slowly (if at all) over time. For example, DNA and fingerprints are among the best and hardly change while handwriting and voice may change from time to time.
Collectability: Biometric trait should be measured quantitatively. How easily the biometric can be measured can be significantly important in some applications. For example, fingerprint biometrics are easy to measure while DNA can be difficult to measure or collect. DNA biometrics might not be ideal for e-passport application.
However, a practical biometric system must consider other issues such as:
Performance: recognition accuracy, speed (throughput), resource requirements and robustness to operational and environmental factors. For example, fingerprint readers are small, compact and accurate while DNA biometrics tend to be costly, slow and labour intensive
Acceptability: The extent to which users are willing to accept the biometric identifier in their daily lives. For example, Retina scans may make some people uncomfortable when putting their eye really close to something that seems intrusive while photographs of the face for face recognition may appear natural.
Circumvention: ease with which the biometric system can be circumvented by fraudulent methods.
In short, a practical biometric system should have acceptable recognition accuracy and speed with reasonable resource requirements, harmless to the users, accepted by the intended population and sufficiently robust to various fraudulent methods.
Although a number of biometric traits are in use in numerous applications, each biometric trait has its own strengths and weaknesses. The choice is usually dependent on the application because no single trait is expected to effectively meet the requirements of all the applications.
Dr Risco Mutelo is a Namibian who currently works for the Bank of America stationed in London where he studied Biometrics Engineering at New Castle University in the United Kingdom.