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Capturing fingerprints in direct sunlight

In contrast to fingerprint access control devices which are generally installed in a fixed position, mobile fingerprint authentication scanners are more likely to be used in varied positions and locations.

This brings about certain challenges as a result mainly of environmental factors, in particular with regard to light (ambient light), which can influence the fingerprint capturing process and will often cause a decrease in the quality of captured fingerprint images.

In response to this significant challenge, Suprema developed and patented its multi-dynamic range (MDR) technology, to ensure consistency in the quality of fingerprint images regardless of lighting conditions and the moisture level of finger skin.

Suprema’s patented MDR technology is available in selected BioMini models, namely BioMini Plus2, BioMini Combo and BioMini Slim as well as in the SFU range, including the BM-Slim2, SFU-S20 and SFU-550 which allows hardware engineers to integrate biometrics into solutions which are used in environments where direct sunlight poses a problem.

Working in a similar manner to HDR used by cameras, Suprema’s MDR technology makes use of a unique image processing algorithm and thereby smartly blends high-brightness images and dark images of the same object to gain optimal image quality, regardless of lighting conditions.

This fingerprint image acquisition method exquisitely enhances the bright and dark part of the image, producing optimal results without any loss in details. With MDR technology, BioMini scanners can produce uncompromised image quality even under direct sunlight of up to 100 000 LUX.

This technology is used to obtain optimal images, without any problems, for both dry and wet fingers. MDR technology makes the highlights appear lighter and shadows appear darker and in this manner fine-tuned fingerprint images are acquired in accordance with express contrast.

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