Each was recorded in 570 milliseconds at 2116 dpi showing both the subsurface fingerprint and sweat ducts. Thirteen FF-OCT images could be acquired at different depths by stepping a reference reflector every 50 µm between the acquisitions, resulting in images acquired in the range of 0 µm to 600 µm. The sensor was controlled by an Adventech microcomputer with one PCIex16 slot dedicated to the BitFlow frame grabber. To address this problem, the BitFlow Cyton-CXP4 frame grabber - capable of transferring the data at the maximum speed of 25 Gb/s - was installed. One of the challenges the researchers faced was running the camera at a maximum speed of 720 frames per second (fps), which together with the large number of pixels put a high demand on the data transfer requirements between the camera and the computer. This design helped to retain as much of the LED’s light as possible, which was necessary to operate the camera close to its saturation level and to ensure the homogeneous illumination of the entire sample area. Light was magnified 5X by lenses so that the divergence of the emerging light from the LED is decreased. LED illumination provided 900 mW of spatially incoherent light at 850 nm. The system enables recording of 1.7 cm × 1.7 cm images of subsurface finger features, such as internal fingerprints and sweat ducts. A lightweight slab of plexiglass of 30 cm × 30 cm × 1 cm in size was used to cover the top of the system, against which a hand could be rested during the fingerprint imaging for a more stable acquisition. The newly designed system is comprised of an Adimec two-megapixel camera, a BitFlow Cyton-CXP4 CoaXPress four-lane frame grabber, an interferometer and a NIR light emitting diode. To overcome these limitations, researchers at the PSL Research University (Paris, France), the Polish Academy of Sciences (Warsaw, Poland), and the Norwegian University of Science (Gjøvik, Norway) developed a more compact, mobile and inexpensive FF-OCT that may lay grounds for enabling more widespread use of this technology.
While effective, FF-OCT can be expensive and cumbersome, despite its proven ability for biometric use, and is limited to large benchtop systems. One of the most promising identification technologies for imaging below the surface of an external fingerprint is full-field optical coherent tomography (FF-OCT). It essentially has the same topography as the finger surface.
However, a collection of skin layers, around 200−400 µm beneath the finger surface, is composed of live cells that is collectively called the "viable epidermis" or internal fingerprint. Obliterating them seemingly provides a clean slate. Since then, criminals looking to evade capture have had their fingerprints sanded off, burned off with cigarettes, and have applied super glue so the ridges were not identifiable.įingerprints link people to their arrest records and outstanding warrants. May 17, 2021 - In an effort to disguise his fingerprints, the prohibition-era gangster John Dillinger famously had doctors cut away the outer layer of his skin, the epidermis, and dip his fingertips into hydrochloric acid. BitFlow Frame Grabber Aids in Development of Compact, Cost-effective Subsurface Fingerprint System High-Speed Cyton CXP-4 transmits data of 13 subsurface images at various depths captured at 720 frames per second and 2116 DPI with no latency.