With the emergence of biometrics technology, different types of identification and verification techniques arise with each having their own advantages and disadvantages. 

In general, biometrics can be classified under two categories:

a.  Physiological traits are characteristics that human possess since birth like fingerprints, iris, retina, palm, vein, and DNA.

b.  Behavioral traits are characteristics that human develop over time like voice patterns, signature, gait (walking pattern), or keystroke.

Listed below are some of the common biometrics recognition systems found in the market:

a. Iris Scan

Iris is the colored portion of the eye.  The iris recognition uses camera technology and subtle IR illumination to capture the intricate image structure of the iris and transform it to digital templates providing mathematical representations of the iris.  The technology can perform under a distance of 3-14 inches, even reaching up to 3 foot, and its efficacy is hardly ever impeded by glasses or contact lenses.  Iris recognition is considered to be more accurate than the rest of the biometrics technology due to its extreme uniqueness that only one in 10⁷⁸ would have an identical iris.  On the down side, the system can be easily breached using a high resolution facial picture which makes it inappropriate to deploy for door security systems. 

b. Retina Scan

Retina Scanning Technology uses a low-intensity coherent light that scans the fine network of capillary (small vein) patterns within the neural portion of the eye called retina. It is extremely hard to fool the retinal scanner as it requires intact retinas to complete a scan.  The technology, though powerful, possesses lots of disadvantages.  Retinal patterns of a person changes in case of diabetes, glaucoma, retinal degenerative disorders or cataracts; which makes the technology inapplicable to all.  In terms of the initial scanning phase, it will take a min. of 5 scans that lasts approximately 12 sec and it will take 10-15 sec to authenticate an individual.

c. Fingerprint

Fingerprint is the most widely implemented technology and is considered the most economical among all biometrics technology.  A fingerprint comprises a series of ridges and furrows on the surface of the finger.  The fingerprint identification technology maps the pattern of ridges and furrows and translates the acquired data to encrypted fingerprint patterns after which storing it into the database. 

d. Palm Vein

Palm Vein authentication uses the vascular patterns of an individual’s palm for recognition.  It uses infrared lights to capture the palm image.  According to Fujitsu research, this technology offers a high level of accuracy with a false rejection rate of 0.01% and false acceptance rate of 0.00008%.  Another advantage is that regardless of the position, movement or change in complexion of the palm, the sensor can still acquire the image and perform comparison with the database.  Moreover, the authentication process utilizes contactless identification system, hence, eliminating hygienic issues.

e. Voice Recognition

Voice Recognition is probably one of the oldest method used for identification.  It is the technology by which sounds, words, phrases spoken by humans are converted into electrical signals and these signals are transformed into coding patterns.  In the early 80’ s, this technology is widely adopted especially in mansions whereupon rich people places emphasis on security.  However, it is easy to fool the system as human speaking and voice pattern can be imitated. 

f. Facial Recognition

Facial Recognition analyzes the image of human face where numerous, distinguishable landmarks, (different peaks and valleys that make up the facial feature) can be traced.  These landmarks are referred to as nodal points and each human face has approximately 80 nodal points.  The system calculates the distance between eyes, width of the nose, depth of eye sockets, shape of cheekbones, length of jaw line etc and transfers the figures into numerical code.  This technology hasn’t been widely implemented due to its low accuracy rate and incapability to correctly identify an individual from the crowd.  A change in appearance, texture of a person’s face or a change of 45 degrees in the camera angle rendered the system useless.  Governments have made several attempts to adopt this technology, however, the system failed to realize its functions accurately.

g. Facial Thermogram

The underlying vascular system in the human face produces a unique facial signature when heat passes through the facial tissue and is emitted from the skin.  Like iris scanning and palm vein technology, facial thermogram also utilized contactless identification system.  It is claimed that this technology is distinct and hard to disguise even plastic surgery cannot falsify.  However, there are a number of factors such as individual’s emotional state, body temperature or angle of identification, affecting the authentication process.