Biometric Development

Once it became apparent that truly positive identification could only be based on the physical attributes of the person, two questions had to be answered. First, what part of the body could be used? Second, how could identification be accomplished with sufficient accuracy, reliability, and speed so as to be viable in field performance? However, had the pressures demanding automated personal identification not been rising rapidly at the highest levels (making necessary resources and funds available), this research would not have occurred.

At the time, the only measurable characteristic associated with the human body that was universally accepted as a positive identifier was the fingerprint. Contact data collected using special inks, dusting powders, and tape, for example, are matched by specially trained experts. Uniquely positioned whorls, ridge endings, and bifurcations were located and compared against templates. A sensor capable of reading a print made by a finger pressed against a piece of glass was required. Matching the collected print against a stored template is a classic computer task. Fortuitously, at the time these identification questions were being asked, computer processing capabilities and speed were increasing rapidly, while size and cost were falling. Had this not been the case, even the initial development of biometric systems would not have taken place. It has taken an additional 25 years of computer and biometric advancement, and cost reduction, for biometrics to achieve widespread acceptability and field proliferation.

Predictably, the early fingerprint-identifying verification systems were not successful in the marketplace, but not because they could not do what they were designed to do. They did. Key problems were the slow decision speed and the lack of ability to detect counterfeit fingerprints. Throughput of two to three persons per minute results in waiting lines, personal frustration, and lost productive time. Failure to detect counterfeit input (i.e., rubber fingers, photo images) can result in false acceptance of impostors.

Continued comprehensive research and development and advancements in sensing and data processing technologies enabled production of systems acceptable in field use. Even these systems were not without problems, however. Some systems required high levels of maintenance and adjustment for reliable performance. Some required lengthy enrollment procedures. Some required data templates of many thousands of bytes, requiring large amounts of expensive storage media and slowing processing time. Throughput was still relatively slow (though acceptable). Accuracy rates (i.e., false accept and mostly false reject) were higher than would be acceptable today. However, automated biometric identifying verification systems were now performing needed functions in the field.

The value of fast, accurate, and reliable biometric identity verification was rapidly recognized, even if it was not yet fully available. Soon, the number of organized biometric research and development efforts exceeded 20. Many were fingerprint spinoffs: thumb print; full finger print; finger pattern (i.e., creases on the underside of the finger); and palm print. Hand topography (i.e., the side-view elevations of the parts of the hand placed against a flat surface) proved not sufficiently unique for accurate verification, but combined with a top view of the hand (i.e., hand geometry) it became one of the most successful systems in the field. Two-finger geometry is a recently marketed variation.

Other technologies that have achieved at least some degree of market acceptance include voice patterns, retina scan (i.e., the blood-vessel pattern inside the eyeball), signature dynamics (i.e., the speed, direction, and pressure of pen strokes), and iris recognition (i.e., the pattern of features in the colored portion of the eye around the pupil). Others that have reached the market, but have not remained, include keystroke dynamics (i.e., the measurable pattern of speed and time in typing words) and signature recognition (i.e., matching). Other physical characteristics that have been and are currently being investigated as potential biometric identifiers include finger length (though not sufficiently unique), wrist veins (underside), hand veins (back of the hand), knuckle creases (when grasping a bar), fingertip structure (blood vessel pattern under the skin), finger sections (between first and second joint), ear shape, and lip shape. One organization has been spending significant amounts investigating biometric identification based on body odor.

Another biometric identifying verification area receiving significant attention (and funding) is facial recognition. This partially results from the ease of acquiring facial images with standard video technology and from the perceived high payoff to be enjoyed by a successful facial recognition system. Facial thermography (i.e., heat patterns of the facial tissue) is an expensive variation because of high camera cost.

The history of the development of biometric identifying verification systems is far from complete. Entrepreneurs continue to see rich rewards for faster, more accurate, and reliable technology, and advanced development will continue. However, advancements are expected to be improvements or variations of current technologies. These will be associated with the hands, eyes, and face for the “what we are” systems and the voice and signature for the “what we do” systems.