Fingerprint scanning
Digital fingerprint recognition technology uses varied techniques. Early research and development efforts produced optical scanning techniques, which used digital cameras to capture an image of a fingerprint and software to deconstruct that image into a recognisable pattern.
The scanning devices were far from reliable; careful placement was required and oily residual imprints could be picked up on subsequent scans.
But with improved software to compensate for smears and smudges, optical scanners today remain one of the more popular approaches to fingerprint scanning.
The most prevalent form of fingerprint scanning is based on an approach called capacitive scanning. This method uses a sophisticated silicon chip to read and analyse electromagnetic signals generated below the skin's surface. Most of today's fingerprint recognition devices use these chips.
A more recent addition to the range of fingerprint recognition technologies, called thermal scanning, is also a solid-state device. This newer technology uses a chip to detect differences in temperature in the ridges and valleys of a fingerprint.