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2021-06-18T13:40:38+09:00
2021-06-18T13:40:38+09:00
2021-06-18T13:40:38+09:00
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Ritsumeikan Univ.KO-430
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1 g
10 36 574.5 780 re
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BT
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14.25 0 0 14.25 86.2762 788.25 Tm
(Liveliness Detection based on Color Variations in Fingerprint Images)Tj
/C0_0 1 Tf
12 0 0 12 511 757.5 Tm
<0C3E04AA>Tj
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2 0.187 Td
( )Tj
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0.25 -0.187 Td
<08000925>Tj
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-41.125 -2.125 Td
(Fingerprint sensors are accepted in the world gradually. However, the th\
reat of finger replicas is also)Tj
-1 -1.5 Td
(reported. Liveliness detection of a finger is desired for unattended fin\
gerprint identification systems. Here, we)Tj
0 -1.5 TD
(have studied the technique based on the area and color variations in a s\
eries of fingerprint images acquired)Tj
T*
(during an input action.)Tj
1 -2.5 Td
(First, a fingerprint sensor based on scattered-light detection was const\
ructed with a quasi-white LED.)Tj
-1 -1.5 Td
(Series of fingerprint images were captured and the area and color variat\
ions were extracted from these)Tj
T*
(images. Analysis on the 158 input trials performed by 37 volunteers and \
one replica proved that the live)Tj
T*
(fingers and the replica could be separated completely. Next, six kinds o\
f replicas were created with various)Tj
T*
(materials and the same experiment was repeated. The ratio of successful \
trials for liveliness detection)Tj
T*
(decreased to 82.9 % on condition that all the replicas were rejected.)Tj
1 -2.5 Td
(Second, we studied the design of the light source in order to improve th\
e reliability for liveliness detection.)Tj
-1 -1.5 Td
(Its emission spectra were adjusted so that the finger color varied signi\
ficantly during an input action. It turned)Tj
T*
(out that a light source having a red and a green LED was promising. The \
intensity ratio at each peak)Tj
T*
(wavelength was G:R=0.65:1. We constructed a fingerprint sensor with this\
dual-LED source and acquired)Tj
T*
(150 input trial data with 42 volunteers' live fingers and 8 kinds of rep\
licas. We were able to set up some)Tj
T*
(indices for liveliness detection that separated the living fingers and t\
he replicas completely. Such an index)Tj
T*
(was effective by itself and combination of these indices would improve t\
he reliability of liveliness detection)Tj
T*
(further.)Tj
1 -2.5 Td
(Third, the finger temperature might influence its color variation. We co\
oled our fingers in iced water and)Tj
-1 -1.5 Td
(repeated input trials while its temperature recovered to the normal leve\
l. We applied our detection algorithm)Tj
T*
(for each of the input trials. Even if the finger temperature varied betw\
een 15 to 34)Tj
/C2_0 1 Tf
32.765 0 Td
<108F>Tj
/TT1 1 Tf
(, the temperature did not)Tj
-32.765 -1.5 Td
(affect the results of the liveliness detection.)Tj
1 -2.5 Td
(Finally, a fingerprint sensor based on scattered-light detection previou\
sly needed a lid in order to decrease)Tj
-1 -1.5 Td
(the ambient light intensity. However, it was not comfortable for us to i\
nsert a finger under such a lid. So we)Tj
T*
(re-designed the sensor hardware to remove the lid and demonstrated norma\
l fingerprint acquisition as well as)Tj
T*
(the liveliness detection under 3,000 lx.)Tj
ET
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