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Identifikacija na osnovu vena u šaci

Послато: 07 Јун 2012, 13:57
од Zuki
It turns out that the pattern of veins in your hand is just as unique to you as the pattern of skin on your fingertip.

The module shines near-infrared light onto a person’s hand. The deoxygenated blood in the veins absorbs the near-infrared light, while the rest of the hand lets the light pass through. A sensor in the module records the image of the hand, where the veins show up as dark lines.

Više na: http://spectrum.ieee.org/video/telecom/ ... ign=060712

Re: Identifikacija na osnovu vena u šaci

Послато: 07 Јун 2012, 16:31
од markone
Aj da probamo ovo - mislim konceptualno.
Znam neke momke koji imaju iskustva sa skidanjem IC filtra sa web kamere :mrgreen:

Re: Identifikacija na osnovu vena u šaci

Послато: 08 Јун 2012, 01:42
од Гаврило
Знам ја један проблем који настане, ако се појави један момак са докторском титулом :D

Re: Identifikacija na osnovu vena u šaci

Послато: 08 Јун 2012, 01:47
од Vukanić
Što kaže Aca Lukas, reci.

Re: Identifikacija na osnovu vena u šaci

Послато: 08 Јун 2012, 01:51
од Binary
Samo pošto stalno pominju "near-infrared light" kontam da je bitna talasna dužina.
Eve šta nađoh na tu temu: http://books.google.rs/books?id=0bQbOYV ... um&f=false
Biologically, the hemoglobin has the highest absorption of infrared light in the range of 800-900 nm. Therefore, the wavelength of the infrared source should be selected to be within the near infrared region with wavelength around 800-900 nm.
The infrared light should emit peak infrared radiation at about a wavelength of 850 nm. In order to obtain an image with this reflected infrared light from the hand, a CCD camera is needed whose spectral response also peaks at around 850 nm.

Re: Identifikacija na osnovu vena u šaci

Послато: 21 Јун 2012, 21:47
од Zuki
Evo i detaljnog članka : http://spectrum.ieee.org/biomedical/ima ... c-wallet/0

Najzanimljivijih delova:
Hitachi picked the fingers, while Fujitsu chose the palm. They also use different lighting methods, with Hitachi transmitting light through the fingers and picking up the resulting image on the other side. Fujitsu bounces light off the palm and uses a sensor to record the light that the veins don’t absorb, which is scattered through the palm.
“The distribution of brightness on the images tends to be uneven,” he says, pointing to thicker parts of the finger that create areas of darker gray. “Typical image-filtering methods are not enough to extract vein patterns,”. .... “The distribution of brightness on the images tends to be uneven,” he says, pointing to thicker parts of the finger that create areas of darker gray. “Typical image-filtering methods are not enough to extract vein patterns,” .....
the journal articles that he and his colleagues have published suggest that they didn’t use the method typically used in fingerprint analysis, which compares tiny, distinct features in the print pattern (they’re actually called “minutiae”). Instead, to cope with the ghostly, grayscale image, the Hitachi team devised a line-tracking method, in which a software program scans the digital image for dark spots and then tries to follow them, pixel by pixel, to see if they form lines. When the program has done that enough times, it yields a pattern of veins.
The team has worked to miniaturize the optical system with a CMOS sensor that collects the image; the next-generation sensor they’re working on is 15 millimeters long by 10 mm wide, about the size of a woman’s thumbnail. The other breakthrough that made the technology commercially viable, Nagasaka says, was the construction of an open-top unit that shines the light on both sides of the finger, with the CMOS sensor below the finger.
I Hitachi rada http://www.cse.unr.edu/~bebis/CS790Q/Pa ... s/vein.pdf (zanimljivost:
The mismatch ratio is slightly higher during cold weather because the veins of the finger can become unclear.
:) )