Background to Biometrics
- What are the different biometrics modalities and what are their advantages/disadvantages?
- Why are there so many different biometric modalities?
- Can I change my biometrics?
- What if identical twins use a biometric device?
- Are biometrics safe to use?
- Are biometrics a new idea?
- Are biometrics intrusive?
- Are biometric systems difficult to use?
- What is the difference between biometrics and forensics?
- What is biometric authentication?
- Do biometric features remain constant over time?
- What factors contribute to the development of a person’s biometric?
- How do biometric systems determine “matches”?
Fingerprint
Advantages- Subjects have multiple fingers
- Easy to use, with some training
- Some systems require little space
- Large amounts of existing data to allow background and/or watchlist checks
- Has proven effective in many large scale systems over years of use
- Fingerprints are unique to each finger of each individual and the ridge arrangement remains permanent during one's lifetime.
- Public Perceptions
- Privacy concerns of criminal implications
- Health or societal concerns with touching a sensor used by countless individuals
- Collection of high quality nail-to-nail images requires training and skill, but current flat reader technology is very robust
- An individual’s age and occupation may cause some sensors difficulty in capturing a complete and accurate fingerprint image
Iris
Advantages- No contact required
- Protected internal organ; less prone to injury
- Believed to be highly stable over lifetime
- Difficult to capture for some individuals
- Easily obscured by eyelashes, eyelids, lens and reflections from the cornea
- Public myths and fears related to “scanning” the eye with a light source
- Acquisition of an iris image requires more training and attentiveness than most biometrics
- Lack of existing data deters ability to use for background or watchlist checks
- Cannot be verified by a human
Face
Advantages- No contact required
- Commonly available sensors (cameras)
- Large amounts of existing data to allow background and/or watchlist checks
- Easy for humans to verify results
- Face can be obstructed by hair, glasses, hats, scarves, etc.
- Sensitive to changes in lighting, expression, and pose
- Faces change over time
- Propensity for users to provide poor-quality video images yet to expect accurate results
Hand Geometry
Advantages- Easy to capture
- Believed to be a highly stable pattern over the adult lifespan
- Use requires some training
- Not sufficiently distinctive for identification over large databases; usually used for verification of a claimed enrollment identity
- System requires a large amount of physical space
Speaker/Voice
Advantages- Public acceptance
- No contact required
- Commonly available sensors (telephones, microphones)
- Difficult to control sensor and channel variances that significantly impact capabilities
- Not sufficiently distinctive for identification over large databases
Others
Many other biometric modalities exist and are in various stages of research or commercialization. Examples include gait (the manner of walking), retina and other vascular pattern recognition, ear structure, odor, and palm prints.
Why are there so many different biometric modalities?
Different applications and environments have different constraints. For instance, adequate fingerprint samples require user cooperation; whereas, a face image can be captured by a surveillance camera. Furthermore, fingerprints are not available for many of the suspects on watchlists. There are also multiple biometric modalities for technical and financial reasons. Many scientists become interested in developing a system based on their own research. Upon a successful implementation, venture capitalist, interested in the implementation of such a system, commercialize a product. Therefore, wide varieties of modalities are being researched and are available on the market.
Can I change my biometrics?
Biological biometrics cannot easily be changed (there have been cases of mutilated or surgically altered fingerprints), but they can be disguised. It may be possible to change a behavioral biometric.
What if identical twins use a biometric device?
Although identical twins may appear the same to the human eye, their biological and behavioral characteristics are usually subtly different. The automated methods implemented in some biometric devices can often identify such differences and differentiate between two seemingly identical twins.
Are biometrics safe to use?
Biometrics are typically passive and designed to be safe to use. Biometric systems usually implement ordinary computing and video technology, such as that encountered in a person’s day-to-day activities.
Are biometrics a new idea?
No, methods of recognizing humans have existed for centuries. The most obvious example is the human use of face recognition. Also, handprints were discovered surrounding cave paintings, estimated to be 31,000 years old, and are believed to be the artists' signatures. However, the means for automating such identification is fairly new, dating only to the early 1960s. Automation recognition became possible within the last few decades with the advancement of computer processing capabilities. The individual biometric modalities vary in their stages of maturity. Fingerprint began the transition to automation in the late 1960s, while iris is a little over a decade old. Many methods, such as gait, are still in the research and development stage and are not yet ready for deployment.
Are biometrics intrusive?
This is a subjective question that would be answered differently by various individuals. In general, most biometrics are non-intrusive, requiring only the placement of a finger, a look in the proper direction, or a statement to be said aloud.
Are biometric systems difficult to use?
This question is subjective and depends on each individual. Those users more familiar with electronics technology tend to have fewer issues than those who are not familiar or are skeptical about using technology. From the operational perspective, most people are able to use a biometric system with very little training. Once I register my biometric, will that registration be good anywhere that specific technology is used? In general, no. A biometric registered on one system will typically not be valid for another system on which that biometric might be used. However, if the system on which the biometric was registered is connected to another system, e.g. via a network, then yes, a biometric could also be accepted at the alternate system location.
What is the difference between biometrics and forensics?
While both biometrics and forensics involve human recognition, biometrics is typically applied using automated techniques to the pre-event situation application, such as gaining access to sensitive information or to a secured facility. Forensic applications typically occur after a crime has occurred, and may not use fully automated methods. Forensic methods are often used to assist in the adjudication (legal) process. Forensics usually requires days of processing (versus seconds for biometrics) and are held to much higher accuracy requirements.
What is biometric authentication?
“Biometric authentication” is a generic term for the process of verification. It involves presenting a biometric for query, comparing the presented biometric to a stored template or model, and determining whether the individual has made a legitimate claim.
Do biometric features remain constant over time?
The permanence of biometrics varies between modalities. For instance, fingerprints remain constant over one’s lifespan, except for surface wear degrading the prominence and definition of the ridges. Fingerprints are based on physical dermal structures that are defined during fetal development. Temporary or permanent scarring can affect the original fingerprint patterns developed before birth. Aging affects faces more dramatically. Detailed studies of the effects of aging on other modalities have not yet been performed.
What factors contribute to the development of a person’s biometric?
A biometric is first affected by the individual’s unique genetic makeup. An individual's biometric is also affected by the individual’s environment. For example, characteristics such as fingerprints and iris structures are affected by the environmental factors encountered by a fetus in the prenatal environment.
How do biometric systems determine “matches”?
Biometric systems can be described, albeit in an oversimplified manner, by a three-step process. The first step in this process involves an observation, or collection, of the biometric data. This step uses various sensors, which vary between modality, to facilitate the observation. The second step converts and describes the observed data using a digital representation called a template. This step varies between modalities and also between vendors. In the third step, the newly acquired template is compared with one or more templates stored in the database. The results of this comparison are a “match” or a “non-match” and are used for actions such as permitting access, sounding an alarm, etc.
