Fingerprint Image Enhancement

Conventional fingerprint imaging sensors, based on total internal reflectance (TIR), capture the image of the fingerprint ridge surfaces that come into contact with the sensor. Under ideal conditions, a TIR fingerprint sensor can produce high-contrast fingerprint images with excellent feature definition. Unfortunately, this approach yields a significant number of fingerprint images that are inadequate because of common issues such as environmental conditions, differences in the quality of the fingerprint ridges, and less-than-ideal use.

Multispectral Imaging Technology

Lumidigm’s multispectral imaging technology uses multiple illumination wavelengths rather than the monochromatic illumination used in TIR imaging. In addition, polarizers may be used to emphasize the light that penetrates the surface of the skin and undergoes multiple scattering events before emerging from the skin toward the imaging array. This technology permits the Lumidigm sensor to enhance traditional fingerprint images for vastly improved results.

Extreme Environmental Conditions

Lumidigm’s technology can reliably operate under extreme environmental conditions. Water, ambient light, and dryness will not prevent the multispectral imaging system from working. For example, Lumidigm’s multispectral imaging sensors are not impaired by water, an environmental condition that occurs outdoors or in a humid environment where the user is likely to be sweaty. This condition thwarts a conventional imager. However, the Lumidigm sensor is not impaired and instead produces a usable fingerprint image.

Poor Fingerprints

Sometimes the ridges on a person’s finger are not prominent. They may be dry, worn from age or profession, or even obscured by “normal” city grime. These “poor fingerprints” pose a problem for conventional fingerprint sensors. However, because multispectral technology does not even require direct contact to work, the multispectral imaging sensor from Lumidigm can construct a usable image from these poor fingerprints.

Marginal Contact

Even improper use of a multispectral imaging device is significantly more likely to yield a high-quality image than a conventional TIR device. Marginal contact with the platen can provide sufficient information to a Lumidigm sensor to produce an accurate skeletonized image of the fingerprint ridges.

Lumidigm’s multispectral imaging technology can tolerate extreme environments, untrained use, and differences in skin condition to reliably produce high-quality fingerprint images. Common effects and conditions that adversely affect a conventional TIR sensor have little or no effect on Lumidigm’s multispectral imaging technology.

For more information on how Lumidigm’s multispectral imaging sensors enhance conventional fingerprint images , please contact us.

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