DESCRIPTION
Title of Invention
AUTHENTICATION SYSTEM, AUTHENTICATION PROGRAM, AND METHOD
OF AUTHENTICATION
Technical Field
The present invention relates to an authentication
system, an authentication program, and an authentication
method, for authenticating an individual by making use of
biometric features.
Background Art
A human body includes biometric information items
which make it possible to identify an individual, and some
of the biometric information items are used as information
for identifying and authenticating the individual. For
example, it is known that the biometric information items
which are considered to be capable of being used for
authentication include fingerprints, eye retinas and irises,
a face, veins, DNA (deoxyribonucleic acid), and so forth.
In recent years, with the development of a
biometric authentication technique, there have been
provided various types of apparatuses for authenticating an
individual by recognizing biometric features of part of a
human body. In this biometric authentication, the
authentication of an individual is performed by comparing
biometric information acquired during registration thereof
and biometric information acquired during authentication.
To improve the accuracy of individual
authentication using such biometric information, it is
desirable to acquire accurate biometric information, and
therefore the authentication apparatuses acquire biometric
information under sensing conditions made identical. To
this end, there has been proposed an authentication
apparatus that announces the user {person to be
authenticated) that a portion for biometric feature
detection of a living body is required to have an
appropriate positional relationship with a sensor, to
thereby guide the portion for biometric feature detection
to a position ensuring the appropriate positional
relationship with the sensor (see e.g. PTLl).
Further, to provide an efficient guide to
conditions under which an image is picked up for
registration, there has been proposed an authentication
apparatus that displays a photographed image in a manner
superimposed on the silhouette of a registered hand (see
e.g. PTL2).
For example, the authentication apparatus that
guides the portion for biometric feature detection to a
position having an appropriate positional relationship with
the sensor performs a conventional authentication control
process, as illustrated in FIG. 15.
The authentication control process 90 acquires an
image from the sensor 95, and outputs a result of
verification to a user application 97. The authentication
control process 90 acquires the image from the sensor 95 by
an image acquiring process 91, and passes the acquired
image to a position and posture determination process 92.
The position and posture determination process 92
determines the position and the posture of a portion for
biometric feature detection, and passes a result of
determination together with the acquired image to a guide
GUI (graphical user interface) display process 93. If the
position and posture determination process 92 determines
that the position and the posture of the portion for
biometric feature detection is not appropriate, the
position and posture determination process 92 requests the
image acquiring process 91 to acquire an image. The guide
GUI display process 93 displays a guide GUI display image
96 on a monitor or the like, to thereby guide the living
body portion for biometric feature detection to a position
having an appropriate positional relationship with the
sensor 95. Further, the position and posture determination
process 92 requests a verification process 94 to perform
verification, and passes the acquired image to the
verification process 94. The verification process 94
verifies the acquired image against an image or a feature
of the living body, registered in advance, and outputs a
result of the verification.
Further, there has been proposed a technique for
assisting in photographing by inversion of the luminance of
contour information or display on the monitor by gradation
correction (see e.g. PTL3).
Citation List
Patent literature
PTL1: Japanese Laid-Open Patent Publication No.
2006-42880
PTL2: Japanese Laid-Open Patent Publication No.
2008-71158
PTL3: Japanese Laid-Open Patent Publication No.
2009-5273
Summary of Invention
Technical Problem
However, a photographed image displayed for
guiding the portion for biometric feature detection to a
position having an appropriate positional relationship with
the sensor sometimes does not have sufficient visibility
for user's recognition, and therefore the photographed
image sometimes does not properly function as a guide
silhouette unless further processing is executed thereon.
Further, when the photographed image is subjected to
special processing, for display, the display of the image
is delayed from an actual movement, which sometimes hinders
the photographed image from properly functioning as a guide
silhouette.
Further, when a photographed image including
biometric information is displayed, a privacy or security
problem sometimes occurs, and hence such a photographed
image is sometimes inappropriate as a display image
depending on an environment where authentication is
performed.
The present invention has been made in view of
these points, and an object thereof is to provide an
authentication apparatus, an authentication program, and an
authentication method, which are capable of displaying a
guide display screen that is excellent in visibility and is
reduced in the risk of occurrence of privacy or security
problems, without an increase in processing load.
Solution to Problem
To solve the above problems, an authentication
apparatus that authenticates an individual by using a
biometric feature of a living body includes photographed
data generation means, display data generation means, and
display means.
The photographed data generation means photographs
the living body, and generates photographed image data
including a monochromatic palette formed by arranging
indexed colors to which monochromatic colors are assigned
in order of density. The display data generation means
generates display data by replacing the monochromatic
palette included in the photographed image data with a
color palette in which one of arrangements formed by
dividing the arrangement of the indexed colors by a
predetermined background boundary threshold value is set as
a background display arrangement of indexed colors to which
a background color is assigned, and the other of the
arrangements is set as a living body display arrangement of
indexed colors to which a specific color is assigned in
order of density. Ths display means displays the living
body using the display data.
Further, to solve the above problems, an
authentication program for causing a computer to execute
processing for authenticating an individual by using a
biometric feature of a living body causes the computer to
function as the photographed image data generation means,
the display data generation means, and the display means.
Further, to solve the above problems, an
authentication method of authenticating an individual by
using a biometric feature of a living body includes
photographing the livir.g body, and generating photographed
image data including a monochromatic palette formed by
arranging indexed colors to which monochromatic colors are
assigned in order of density, generating display data by
replacing the monochromatic palette included in the
photographed image data with a color palette in which one
of arrangements formed by dividing the arrangement of the
indexed colors by a predetermined background boundary
threshold value is set as a background display arrangement
of indexed colors to which a background color is assigned,
and the other of the arrangements is set as a living body
display arrangement of indexed colors to which a specific
color is assigned in order of density, and displaying the
living body using the display data.
Advantageous Effects of Invention
According to the above-described authentication
apparatus, authentication program, and authentication
method, it is possible to display a guide display screen
that is excellent in visibility and is reduced in the risk
of occurrence of privacy or security problems, without an
increase in processing load.
The above and other objects, features and
advantages of the present invention will become apparent
from the following description when taken in conjunction
with the accompanying drawings which illustrate preferred
embodiments of the present invention by way of example.
Brief Description of Drawings
[FIG. 1] FIG. 1 illustrates an authentication
system according to an embodiment.
[FIG. 2] FIG. 2 illustrates conversion of a
photographed image to a display image, performed by an
authentication apparatus according to the embodiment.
[FIG. 3] FIG. 3 illustrates examples of the
display image according to the embodiment.
[FIG. 4] FIG. 4 is a block diagram of the
authentication system according to the embodiment.
[FIG. 5] FIG. 5 illustrates an example of the
hardware configuration of the authentication apparatus
according to the embodiment.
[FIG. 6] FIG. 6 illustrates the data structure of
8-bit (256-color) uncompressed DIB according to the
embodiment.
[FIG. 7] FIG. 7 illustrates an example of the data
structure of a source image DIB according to the embodiment.
[FIG. 8] FIG. 8 illustrates an example of an RGB
gradation graph of a 256-level gradation grayscale palette
according to the embodiment.
[FIG. 9] FIG. 9 illustrates an example of the data
structure of a display image DIB according to the
embodiment.
[FIG. 10] FIG. 10 illustrates an example of an RGB
gradation graph of a color palette dedicated for a palm
vein GUI, according to the embodiment.
[FIG. 11] FIG. 11 illustrates a processing flow of
a guide GUI display process according to the embodiment.
[FIG. 12] FIG. 12 is a flowchart of a process for
creating the dedicated color palette, according to the
embodiment.
[FIG. 13] FIG. 13 illustrates examples (1) and (2)
of display on a guide GUI display window according to the
embodiment.
[FIG. 14] FIG. 14 illustrates examples (3) and (4)
of display on a guide GUI display window according to the
embodiment.
[FIG. 15] FIG. 15 illustrates a conventional
authentication control process.
Description of Embodiments
Embodiments of the present invention will be
explained below with reference to the accompanying drawings.
FIG. 1 illustrates an authentication system
according to an embodiment. Although in the present
embodiment, an authentication system 1 is illustrated as an
authentication system that performs authentication of an
individual, using veins of a palm, by way of example, this
is not limitative, but it is applicable to a system which
performs the authentication using another portion of a
living body for biometric feature detection.
The authentication system 1 is one which
identifies and authenticates an individual by recognizing a
biometric feature, and can be used for logging on to an
information system or controlling the entrance and exit to
and from a room. The authentication system 1 includes an
authentication apparatus 10 and a database server 40
connected to the authentication apparatus 10 via a network
2.
The database server 40 stores identification
information for identifying individuals and biometric
information registered in advance for biometric
authentication in a manner associated with each other. The
identification information for identifying an individual is
unique ID. (identification) information given to a user
directly (e.g. an employee number) or indirectly (e.g. a
bank account number). The biometric information registered
in advance includes feature information acquired by
extracting a feature portion from image information, and
encoded information acquired by encoding the image
information or the feature information.
The authentication apparatus 10 comprises a
processing device 11, a display 12, and a sensor unit 20.
The authentication apparatus 10 further comprises a
keyboard 13, a mouse 14, an IC (integrated circuit) card
reader/writer 30, and so forth, as required. The sensor
unit 20, which includes an image pickup device, photographs
an image of a palm of the user, and outputs the
photographed image to the processing device 11. The IC
card reader and writer 30 reads and writes information of
an IC card 31 of the user. The keyboard 13 and the mouse
14 receive user input operations.
Now, a description will be given of palm vein
authentication. A user requesting authentication inputs
identification information (e.g. user ID) for identifying
the user using the keyboard 13 and the mouse 14 or the IC
card reader and writer 30. The authentication apparatus 10
requests, via the display 12, the user to input biometric
information for authenticating the user. The user holds a
hand over the sensor unit 20 to thereby input the biometric
information. The authentication apparatus 10 having an
image of the palm input therein as the biometric
information verifies the image of the palm against
biometric information stored in advance in a storage
section of the database server 40 or the IC card 31 of the
user.
Next, the conversion of a photographed image to a
display image will be described with reference to FIGS. 2
and 3. FIG. 2 illustrates the conversion of a photographed
image to a display image, which is performed by the
authentication apparatus according to the present
embodiment. FIG. 3 illustrates examples of the display
image according to the present embodiment.
The photographed image 50 is acquired by the user
by holding a palm over the sensor unit 20. The
photographed image 50 is an image acquired by irradiating
near infrared rays onto the palm and photographing
reflected light from the palm. Since hemoglobin in red
cells flowing through veins of the palm has lost oxygen,
the hemoglobin (reduced hemoglobin) has the property of
absorbing near infrared rays in the vicinity of 760 nm.
Therefore, when near infrared rays are irradiated onto the
palm, there is little reflection of the near infrared rays
only from a portion where the veins extend, whereby it is
possible to recognize positions of the veins by the degree
of the intensity of the reflected light of the near
infrared rays. Although the photographed image 50 is made
easy to extract characteristic information by using a
specific light source, it becomes an achromatic image.
Further, when the photographed image 50 is handled
as data, if colors are designated on a pixel-by-pixel basis,
the amount of information becomes too large. To cope with
this inconvenience, a table (color palette) defining usable
colors is prepared, and an indexed color (reference
information for referring to the color palette) is
designated for each pixel, whereby the amount of
information is reduced.
Since the photographed image 50 is grayscale data
represented by (8-bit) pixel values (0-255), it is possible
to use a grayscale color palette (grayscale palette) of 256
levels. A photographed image palette 51 is a grayscale
palette of 256 levels formed by arranging colors between
white as a light color and black as a dark color in the
order of density. If displayed e.g. on a display, the
photographed image palette 51 has a sufficient
monochromatic resolution, thereby making it possible to
represent the photographed image 50.
Conventionally, the photographed image 50 has been
used in a palm vein system as a silhouette image for
guiding a position of the palm, but even if the
photographed image 50 is displayed after being smoothed by
image processing, the image of veins is conspicuous, which
has caused not a small number of users to have an
unpleasant feeling of "grotesque and scary". Further, also
from the viewpoint of privacy or security, it is not
desirable to display the vein image as it is. Furthermore,
when the hand is distant from the sensor unit 20, the
photographed image 50 sometimes ceases to sufficiently
function as a silhouette image since the hand is darkened
to degrade the visibility of the contour of the hand.
To solve the above problem, the authentication
apparatus 10 does not use the photographed image 50 as it
is, as a silhouette image, but uses the same as a
silhouette image after converting the photographed image 50
to a display image 52 by a guide GUI. At this time, if
advanced image conversion is performed, a time lag occurs
between the movement of the hand and display of the
silhouette image, and hence it is required to prevent the
load of processing for converting the photographed image 50
to the display image 52 from becoming too large.
To meet this requirement, the authentication
apparatus 10 displays the display image 52 by replacing the
photographed image palette 51 used for displaying the
photographed image 50 with a display image palette 53. The
display image palette 53 comprises a background palette 55
and a palm palette 56. The background palette 55 and the
palm palette 56 are not independent color palettes but are
parts of the display image palette 53.
The background palette 55 ranges from an indexed
color [0] of the background palette 53 to an indexed color
[35] , which is a background boundary threshold value 54.
The background palette 55 is a color palette formed by
assigning monochromatic background colors to all the
indexed colors from [0] to [35] .
The palm palette 56 ranges from an indexed color
[36], which is next to the background boundary threshold
value 54, to an indexed color [255] of the display image
palette 53. The palm palette 56 is a color palette of 220
levels formed by arranging specific colors (e.g. of light
orange color) from a light color to a dark color.
Further, while the photographed image palette 51
is formed by arranging indexed colors from a dark color to
a light color in the order of density, the palm palette 56
is formed by arranging indexed colors from a light color to
a dark color in a direction opposite to the direction of
arrangement of the indexed colors in the photographed image
palette 51. As a consequence, the vein image displayed in
dark colors in the photographed image 50 is displayed in
light colors in the display image 52, thereby making it
difficult to visually recognize the vein image.
Further, the palm palette 56 is set such that the
range of density of the colors used therein is smaller than
that of density of the colors used in the photographed
image palette 51. As a consequence, the vein image has
reduced differences in density from the portions of the
palm, which makes it more difficult to visually recognize
the vein image.
Therefore, the display image 52 as a silhouette
image reduces the unpleasant feeling that the user has had
when viewing the display image 52. Further, when used a
silhouette image, the display image 52 makes it difficult
for a third person to visually recognize the vein image,
and therefore the display image 52 also reduces the
possibility of occurrence of the problem of privacy or
security.
Further, the background color that the background
palette 55 assign to all the indexed colors can be set to
be the complementary color of a boundary color of the
photographed image palette 51 {color assigned to the
indexed color [36] ) . In this case, the background color
emphasizes the contour of the palm.
Further, the palm palette 56 has the indexed
colors arranged in the order of density though opposite in
the direction of arrangement of the indexed colors to the
photographed image palette 51, and hence it is possible to
express variation in density of the hand represented by the
grayscale, which makes it possible to favorably grasp e.g.
how the hand is inclined.
As described above, by replacing the photographed
image palette 51 of image data desired to be displayed,
with the display image palette 53, it is possible to
display an image, such as a display image 60 or a display
image 61. The display images 60 and 61 are clear in the
contrast between the palm and the background, thereby
making it possible to easily grasp the contour of the palm.
Further, the display images 60 and 61 make it difficult to
visually identify the vein image, and hence reduce the
unpleasant feeling that the user has had when viewing the
display images 60 and 61, and the possibility of occurrence
of the problem of privacy or security. Further, the
display images 60 and 61 sufficiently represent differences
in density between the colors, caused by the inclination of
the palm, thereby making it possible to favorably grasp how
the hand is inclined and sense the distance between the
hand and the sensor unit 20.
Next, the arrangement of the sensor unit 20 and
processes executed by the authentication system will be
described with reference to FIG. 4. FIG. 4 is a block
diagram of the authentication system according to the
present embodiment.
The sensor unit 20 has an image pickup device 24
mounted thereon. The image pickup device 24 includes an
infrared ray sensor {e.g. CMOS (complementary metal oxide
semiconductor) sensor), not shown, a condenser lens 23, and
a distance sensor 22, which are provided in a central
portion thereof, and is equipped with a plurality of near
infrared ray-emitting devices (LEDs) 21 oriented in an
imaging direction. The near infrared ray-emitting devices
21 are provided e.g. in eight peripheral portions of the
infrared ray sensor, for emitting near infrared rays upward
(in the imaging direction).
The sensor unit 20 delivers a photographed image
and measured distance information measured by the distance
sensor 22 to the processing device 11. The processing
device 11 executes a photographed image-acquiring process
111, a guide GUI display process 112, a vein image-
extracting process 113, a photographing state-determining
process 114, a registration process 115, a feature
verification process 116, and a search process 117.
The photographed image-acquiring process 111
acquires the measured distance information and the
photographed image from the sensor unit 20, and notifies
the photographing state-determining process 114, the guide
GUI display process 112, the vein image-extracting process
113, and the registration process 115 of the acquired
measured distance information and photographed image.
The guide GUI display process 112 displays a guide
GUI for guiding a palm of a user to an appropriate position
on the display 12. When displaying the guide GUI on the
display 12, the guide GUI display process 112 changes the
color palette for use in displaying the photographed image
from the photographed image palette 51 to the display image
palette 53, as described above. Note that the guide GUI
display process 112 acquires information indicative of
whether or not the position of the palm is appropriate,
from an imaging state-determining process 114, described
hereinafter.
The vein image-extracting process 113 extracts a
vein image (biometric feature data) of veins from the
photographed image, and notifies the vein image to the
registration process 115.
The registration process 115 operates, when
registering a user, to register a photographed image,
photographing conditions, biometric feature data, and so
forth, in a storage section 118 of the database server 40.
Note that the storage section 118 may be provided in the IC
card 31.
The search process 117 uses a user ID input at the
time of verification, to search the storage section 118 for
a photographed image, photographing conditions, and
biometric feature data associated with the user ID. The
imaging state-determining process 114 determines whether or
not an imaging state is appropriate, by comparing the
photographed image and photographing conditions acquired
from the storage section 118 by the search process 117 and
the photographed image and photographing conditions input
from the sensor unit 20.
The imaging state-determining process 114
determines whether or not the palm is positioned at an
appropriate distance from the sensor unit 20, and whether
or not the contour (position and posture) of the palm
detected from the photographed image is in an appropriate
position, compared with standard conditions or the
photographing conditions input during the user registration.
If it is determined that the photographed image and the
photographing conditions input at the time of
authentication are appropriate, the imaging state-
determining process 114 notifies the feature verification
process 116 that feature verification can be performed.
Further, the imaging state-determining process 114 notifies
the guide GUI display process 112 of evaluations of the
photographed image and the photographing conditions input
at the time of authentication.
The feature verification process 116 determines
the degree of coincidence {degree of similarity) between
the biometric feature data acquired from the storage
section 118 by the search process 117 and the biometric
feature data (vein image data) extracted by the vein image-
extracting process 113, and notifies a user application of
whether or not the user is authenticated, as a result of
the verification.
Next, an example of the hardware configuration of
the authentication apparatus according to the present
embodiment will be described with reference to FIG. 5. FIG.
5 illustrates the hardware configuration of the
authentication apparatus according to the present
embodiment.
The authentication apparatus 10 comprises the
processing device 11, the display 12, the keyboard 13, the
mouse 14, the sensor unit 20, and the IC card reader and
writer 30.
The overall operation of the processing device 11
is controlled by a CPU (Central Processing Unit) 101. A
RAM (Random Access Memory) 102, an HDD (Hard Disk Drive)
103, a communication interface 104, a graphic processor 105,
and an input/output interface 106 are connected to the CPU
101 via a bus 107.
The RAM 102 temporarily stores at least part of
the program of an OS (operating system) and application
programs which the CPU 101 is caused to execute. Further,
the RAM 102 stores various data required by the CPU 101 for
processing. The HDD 103 stores the OS and the application
programs.
The display 12 is connected to the graphic
processor 105. The graphic processor 105 displays images
on the screen of the display 12 according to commands from
the CPU 101.
To the input/output interface 106 are connected
the keyboard 13, the mouse 14, the sensor unit 20, and the
IC card reader and writer 30. Further, the input/output
interface 106 is configured to be connectable to a portable
recording medium interface which is capable of writing
information into a portable recording medium 110, and
reading out information fro"v« the portable recording medium
110. The input/output interface 106 transmits signals sent
from the keyboard 13, the mouse 14, the sensor unit 20, the
IC card reader and writer 30, and the portable recording
medium interface, to the CPU 101 via the bus 107.
The communication interface 104 is connected to
the network 2. The communication interface 104 transmits
and receives data to and from the database server 40.
With the above-described hardware configuration,
it is possible to realize the processing functions
according to the present embodiment. Note that database
server 40 as well can be realized by the same hardware
configuration.
Note that each processing device 11 can also be
configured to include a module formed by an FPGA (Field
Programmable Gate Array), a DSP (Digital Signal Processor),
and so forth, and can also be configured without the CPU
101. In this case, each processing device 11 is equipped
with a nonvolatile memory (an EEPROM (Electrically Erasable
and Programmable Read Only Memory), a flash memory, or a
flash memory semiconductor device, for example), and stores
a firmware of the module. The firmware can be written in
the nonvolatile memory via the portable recording medium
110 or the communication interface 104. Thus, the
processing device 11 can also update the firmware by
rewriting the firmware stored in the nonvolatile memory.
Next, the data structure of photographed image
data will be described with reference to FIG. 6. FIG. 6
illustrates the data structure of 8-bit (256-color)
uncompressed DIB according to the present embodiment.
The photographed image data has a data structure
300 of the 8-bit (256-color) uncompressed DIB (Device-
Independent Bitmap) . The data structure 300 of the 8-bit
(256-color) uncompressed DIB is formed by a bitmap
information header, a color palette, and pixel data.
The bitmap information header includes information
of the number of horizontal pixels of an image, the number
of vertical pixels of the image, the number of planes, the
number of bits per pixel, a compression method, the size of
whole image data.
For example, in a case where 256-colors are
designated, the color palette has an array structure from
the indexed color [0] to the indexed color [255] . Each
array has array elements "B", "G", "R", and "-" as data.
Each array element "B" stores data representing a B (blue)
luminance of a pixel in one of 256 levels of gradation by 1
byte of data. Each array element "G" stores data
representing a G (green) luminance of a pixel in one of 256
levels of gradation by 1 byte of data. Each array element
"R" stores data representing an R (red) luminance of a
pixel in one of 256 levels of gradation by 1 byte of data.
The array element "-" stores "0" by 1 byte of reservation
data.
The pixel data stores the array element index
numbers of indexed colors (color information) of all the
pixels on a pixel-by-pixel basis.
Next, the data structure of a source image DIB
will be described with reference to FIGS. 7 and 8. FIG. 7
illustrates an example of the data structure of the source
image DIB according to the present embodiment. FIG. 8
illustrates an example of an RGB gradation graph of the
256-level gradation grayscale palette according to the
present embodiment.
The photographed image data has the data structure
300 of the 8-bit (256-color) uncompressed DIB. More
specifically, the photographed image data has a data
structure as illustrated by a source image DIB 301. The
source image DIB 301 has the 256-level gradation grayscale
palette.
The 256-level gradation grayscale palette is a
grayscale color palette in which the indexed colors from
the indexed color [0] for designating the dark color of
black to the indexed color [255] for designating the light
color of white are arranged in 256 levels in the order of
density.
Assuming that n is an integer from 0 to 255, to
represent the grayscale, the 256-level gradation grayscale
palette can be represented by an indexed color [n] = (n, n,
n, 0). Here, the elements within the parenthesis represent
the above-mentioned B luminance, G luminance, R luminance,
and reserved data 0 in the mentioned order. Specifically,
the 256-level gradation grayscale palette is represented by
the indexed color [0] = (0, 0, 0, 0), the indexed color [1]
= (1, 1, 1, 0), ..., the indexed color [255] = {255, 255,
255, 0), as illustrated by an RGB gradation graph 311 of
the 256-level gradation grayscale palette .
The pixel data stores the array element index
numbers of the indexed colors of all the pixels on a pixel-
by-pixel basis according to the photographed image.
Next, the data structure of a display image DIB
will be described with reference to FIGS. 9 and 10. FIG. 9
illustrates an example of the data structure of the display
image DIB according to the present embodiment. FIG. 10
illustrates an example of an RGB gradation graph of a color
palette dedicated for a palm vein GUI according to the
present embodiment.
The display image data has the data structure 300
of the 8-bit (256-color) uncompressed DIB. More
specifically, the display image data has a data structure
as illustrated by a display image DIB 302. The display
image DIB 302 has the color palette dedicated for the palm
vein GUI.
The color palette dedicated for the palm vein GUI
is a color palette comprising a background palette having
the indexed colors from the indexed color [0] to the
indexed color [35] for designating the background color,
and a palm palette in which the indexed colors from the
indexed color [36] for designating a specific light color
to the indexed color [255] for designating a specific dark
color are arranged in the order of density.
Assuming that m is an integer from 0 to 35, to
represent a background, the background palette of the color
palette dedicated for the palm vein GUI can be represented
by an indexed color [m] = (175, 110, 100, 0) . More
specifically, the background palette is represented by the
indexed color [0] = (175, 110, 100, 0), the indexed color
[1] = (17 5, 110, 100, 0) , . . ., the indexed color [35] =
(175, 110, 100, 0), as illustrated by an RGB gradation
graph 312 of the color palette dedicated for the palm vein
GUI.
Assuming that n is an integer from 36 to 255, to
represent the palm, the palm palette of the color palette
dedicated for the palm vein GUI can be represented by an
indexed color [n] = (fl(n), f2(n), f3(n), 0). Here, the
fl(n), the f2(n), and the f3(n) are functions of n
determined in advance, such as f1(n) = 210 - int((n-35)/2)
- mod(n-35, 2), f2(n) = 250 - int((n-35)/2) - mod(n-35, 2),
f 3 (n) = 255, provided that the function int (x) is the
largest integer not larger than x, and the function mod (x,
y) is a remainder of the quotient of x divided by y. More
specifically, the background palette is represented by the
indexed color [36] = (209, 249, 255, 0), the indexed color
[37] = (209, 249, 255, 0), the indexed color [38] = (208,
248, 255, 0),..., the indexed color [255] = (100, 140, 255,
0) , as illustrated by the RGB gradation graph 312 of the
color palette dedicated for the palm vein GUI.
The pixel data stores the array element index
numbers of the indexed colors of all the pixels on a pixel-
by-pixel basis according to the photographed image. Note
that the pixel data of the display image data is the same
as the pixel data of the photographed image data.
As described hereinabove, the photographed image
data and the display image data have the data structure 300
of the 8-bit (256-color) uncompressed DIB, and the pixel
data thereof are the same. The photographed image data and
the display image data use different palettes, thereby
making it possible to display different images. At this
time, the processing device 11 does not perform any
processing on the pixel data, so that it is possible to
perform high-speed image conversion.
Next, the guide GUI display process 112 executed
by the processing device 11 will be described in detail
with reference to FIG. 11. FIG. 11 illustrates a
processing flow of the guide GUI display process according
to the present embodiment.
The guide GUI display process 112 is for
displaying the guide GUI for guiding a palm to an
appropriate position, on the display 12, based on the
photographed image acquired from photographed image-
acquiring process 111.
Further, the guide GUI display process 112 is for
acquiring guide information 320 from the imaging state-
determining process 114. The guide information 320
includes position information 321 and a photographed image
322.
[Step Sll] The processing device 11 executes a
dedicated color palette-creating process for creating a
dedicated color palette (color palette dedicated for a palm
vein GUI) as an initialization process, to thereby create
the color palette dedicated for the palm vein GUI. The
dedicated color palette-creating process will be described
hereinafter in detail with reference to FIG. 12.
[Step S12] The processing device 11 waits for the
guide information 320 to be acquired.
[Step S13] The processing device 11 acquires the
guide information 320. Now, the acquired photographed
image 322 has the data structure of the source image DIB
301, and has the 256-level gradation grayscale palette set
therefor.
[Step S14] The processing device 11 replaces the
256-level gradation grayscale palette set for the
photographed image 322 with the color palette dedicated for
the palm vein GUI.
[Step S15] The processing device 11 displays the
guide GUI for guiding the palm to the appropriate position,
based on a display image formed by setting the color
palette dedicated for the palm vein GUI, for the
photographed image acquired from photographed image-
acquiring process 111, and then proceeds to the step S12.
Next, the dedicated color palette-creating process
executed by the processing device 11 will be described with
reference to FIG. 12. FIG. 12 is a flowchart of the
dedicated color palette-creating process according to the
present embodiment.
The dedicated color palette-creating process is a
process for creating the color palette dedicated for the
palm vein GUI.
Note that although the creation of the color
palette dedicated for the palm vein GUI is performed only
once at the start-up of the authentication apparatus 10, it
may be performed whenever authentication is carried out.
[Step S21] The processing device 11 initializes
the values of the elements "B", "G" and "R" of the indexed
colors of the color palette. The elements WB", "G" and "R"
are initialized to the largest gradation values set in
advance. For example, the processing device 11 sets the
element "B" = "210", the element "G" = "250", and the
element "R" = "2 55", as initial values. This color is the
light orange color, and is considered not to cause a
feeling of strong wrongness. However, the color sometimes
causes a feeling of wrongness depending on countries or
regions, and therefore the initial values may be set as
desired according to environments or tastes of individuals.
[Step S22] The processing device 11 initializes
the background boundary threshold value. Note that the
initial value of the background boundary threshold value
may be set in advance or an appropriate value dependent on
photographing environments may be set as the initial value
of the background boundary threshold value e.g. by
searching for a value that will make it possible to
favorably reproduce the contour of the hand. For example,
the processing device 11 sets the background boundary
threshold value "Thr" = "35" as the initial value.
[Step S23] The processing device 11 initializes
the array element index number of the indexed color of the
color palette, by setting "n" = "0".
[Step S24] The processing device 11 determines
whether or not the array element index number is not larger
than the background boundary threshold value. If the array
element index number is not larger than the background
boundary threshold value, the processing device 11 proceeds
to a step S25, whereas if the array element index number is
larger than the background boundary threshold value, the
processing device 11 proceeds to a step S26.
[Step S25] The processing device 11 set the
respective elements "B", "G" and "R" of the indexed colors
of the array element index number [n] to values for the
background color. For example, the processing device 11
sets the element WB" to "175", the element "G" to "110",
and the element "R" to "100". The complementary color of
the light orange color is selected as the background color,
which makes clear the boundary between the background color
and the light orange color adjacent to the background color,
thereby enhancing the visibility of the contour of the palm.
The processing device 11 determines in a step S30
whether or not the array element index number has reached
the upper limit value "255". If the array element index
number has not reached the upper limit value "255", the
processing device 11 proceeds to a step S31, to increment
the array element index number by "1" for updating the same,
and proceeds to the step S24.
As described above, the processing device 11 sets
each element of the indexed colors of the array element
index numbers "0" to "35" to the background color.
[Step S2 6] The processing device 11 determines
whether or not a remainder of the quotient of the array
element index number "n" divided by "2" is equal to "0".
In other words, the processing device 11 determines whether
or not the array element index number "n" is divided by 2
without a remainder. If the' remainder acquired by dividing
the array element index number wn" by "2" is equal to "0",
the processing device 11 proceeds to a step S27, whereas if
the remainder acquired by dividing the array element index
number wn" by w2" is not equal to "0", the processing
device 11 proceeds to a step S29.
With this, the update of the values of the
elements "B", "G" and "R" of the indexed colors in the step
S27, referred to hereinafter, is executed every two times
of execution of the loop, whereby the processing device 11
reduces the range of gradation of colors used for
displaying the palm. By reducing the range of gradation of
the colors used for displaying the palm, it is possible to
prevent a vein image in a display image of the palm from
becoming conspicuous. Note that a number by which the
array element index number xvn" is divided can be set, as
desired. As the number by which the array element index
number "n" is divided is set to a larger value, it is
possible to reduce the range of gradation of the colors
used for displaying the palm, and the vein image can be
made more inconspicuous as the range of gradation is made
smaller.
[Step S27] The processing device 11 calculates
values to which the respective elements "B", "G" and "R" of
the indexed colors are to be set, based on the indexed
color [n] = (fl(n), f 2 (n) , f3(n), 0). For example, in a
case where fl(n) = 210 - int((n-35)/2) - mod(n-35, 2),
f2(n) = 250 - int( (n-35)/2) - mod(n-35, 2), f3(n) = 255,
the processing device 11 calculates the values to which
the elements "B", "G" are to be set, by decrementing
current values thereof by "1", while the value to which the
element "R" is to be set is calculated as a fixed value.
[Step S28] The processing device 11 corrects the
values to which the respective elements "B", "G" and WR" of
the indexed colors are to be set, such that they become
values not smaller than 0 and not larger than 255. For
example, the processing device 11 corrects a calculated
value decremented to a negative value, to "0".
[Step S29] The processing device 11 sets the
elements "B", "G" and "R" of the indexed colors of the
array element index number [n] to the values calculated in
the steps S27 and S28. The processing device 11 determines
in the step S30 whether or not the array element index
number has reached the upper limit value "255". If the
array element index number has not reached the upper limit
value "255", the processing device 11 proceeds to the step
S31, to increment the array element index number by "1" for
updating the same, and proceeds to the step S24.
As described above, the processing device 11 sets
the respective elements of the indexed colors of the array
element index numbers "36" to "255" to colors used for
displaying the palm. If the array element index number has
reached the upper limit value "255", the processing device
11 terminates the dedicated color palette-creating process.
Note that the dedicated color palette-creating
process can b£ executed in desired timing, e.g. at the
start-up of the authentication apparatus 10 or during
authentication. For example, the dedicated color palette-
creating process may be executed at the start-up of the
authentication apparatus 10 such that all the users use the
same color palette dedicated for the palm vein GUI.
Further, the dedicated color palette-creating process may
be executed during authentication of users such that a
different color palette dedicated for the palm vein GUI is
used on a user basis.
The color palettes dedicated for palm vein GUIs,
used on a user basis, are created by generating color
palettes with different color arrays by using as parameters
e.g. user-specific information, such as the skin colors,
blood circulations, genders, or ages of users, or
alternatively external environments {time, weathers,
regions, ambient brightness). This makes it possible for
the dedicated color palette-creating process to generate
optimum palettes according to conditions at the time of
authentication of the users.
Next, examples of displays on a guide GUI display
window which is displayed by the authentication apparatus
10 on the display 12 will be described with reference to
FIGS. 13 and 14. FIG. 13 illustrates examples (1) and (2)
of the display on a guide GUI display window according to
the present embodiment. FIG. 14 illustrates examples (3)
and (4) of the display on a guide GUI display window
according to the present embodiment.
A guide GUI display window 7 0 is the example (1)
of the guide GUI display window which is displayed by the
authentication apparatus 10 on the display 12. The guide
GUI display window 70 includes a guide GUI display image
701, a correct position image 702, a guide display 703, a
guide message 704, and a result message 705, in the window.
The guide GUI display image 7 01 is an image
displayed by replacing a photographed image palette for a
photographed image with a display image palette. The guide
GUI display image 701 displays a background, a palm image,
and the guide display 703 indicating a correct position of
the palm. The guide display 703 displays a true circle
indicating the correct position of the palm, and an ellipse
indicating that the palm of the user is inclined, for
example. The correct position image 702 is displayed for
guiding the palm of the user to the correct position.
The guide message 704 is displayed for guiding the
palm of the user to the correct position. For example, the
guide message 704 displays a message of "Please hold your
hand level." for notifying the user that the palm of the
user is inclined. The result message 705 is displayed for
notifying the user of the result of user verification by
the authentication apparatus 10. For example,, in the case
where the palm of the user is inclined, no message is
displayed as the result message 705 since it is impossible
to perform authentication.
A guide GUI display window 71 is the example (2)
of the guide GUI display window which is displayed by the
authentication apparatus 10 on the display 12. The guide
GUI display window 71 includes a guide GUI display image
711, a correct position image 712, a guide display 713, a
guide message 714, and a result message 715, in the window.
The guide GUI display image 711 is an image
displayed by replacing the photographed image palette for a
photographed image with the display image palette. The
guide GUI display image 711 displays a background, a palm
image, and the guide display 713 indicating a correct
position of the palm. The guide display 713 displays a
true circle indicating the correct position of the palm,
and an arrow indicating that the palm of the user is
displaced from the center position, for example. The
correct position image 712 is displayed for guiding the
palm of the user to the correct position. Note that an
image registered as the palm of the user may be used for
the correct position image 712. Alternatively, the correct
position image 712 is displayed by replacing the
photographed image palette with display image palette, in
displaying the display for guiding the palm of the user to
the correct position or in displaying the image registered
as the palm of the user.
The guide message 714 is displayed for guiding the
palm of the user to the correct position. For example, the
guide message 714 displays a message of "Please slightly
draw back your hand." for notifying the user that the palm
of the user is displaced from the center position. The
result message 715 is displayed for notifying the user of
the result of user verification by the authentication
apparatus 10. For example, in the case where the palm of
the user is displaced from the center position, no message
is displayed as the result message 715 since it is
impossible to perform authentication.
A guide GUI display window 72 is the example (3)
of the guide GUI display window which is displayed by the
authentication apparatus 10 on the display 12. The guide
GUI display window 72 includes a guide GUI display image
721, a correct position image 722, a guide display 723, a
guide message 724, and a result message 725, in the window.
The guide GUI display image 721 is an image
displayed by replacing the photographed image palette for a
photographed image with the display image palette. The
guide GUI display image 721 displays a background, a palm
image, and the guide display 723 indicating a correct
position of the palm. The guide display 723 displays a
true circle indicating the correct position of the palm,
and an arrow indicating that the palm of the user is
displaced counterclockwise, for example. The correct
position image 722 is displayed for guiding the palm of the
user to the correct position.
The guide message 724 is displayed for guiding the
palm of the user to the correct position. For example, the
guide message 724 displays a message of "Please place your
hand parallel to the sensor." for notifying the user that
the palm of the user is displaced counterclockwise. The
result message 725 is displayed for notifying the user of
the result of user verification by the authentication
apparatus 10. For example, in the case where the palm of
the user is displaced counterclockwise, no message is
displayed as the result message 725 since it is impossible
to perform authentication.
A guide GUI display window 73 is the example (4)
of the guide GUI display window which is displayed by the
authentication apparatus 10 on the display 12. The guide
GUI display window 73 includes a guide GUI display image
731, a correct position image 732, a guide display 733, a
guide message 734, and a result message 735, in the window.
The guide GUI display image 731 is an image
displayed by replacing the photographed image palette for a
photographed image with the display image palette. The
guide GUI display image 731 displays a background, a palm
image, and the guide display 733 indicating a correct
position of the palm. The guide display 733 displays only
a true circle indicating the correct position of the palm
of the user, for example, since the inclination of the palm
and the position thereof in front-rear and left-right
directions are correct though the palm is closer to the
sensor unit 20 than the correct position. The correct
position image 732 is displayed for guiding the palm of the
user to the correct position.
The guide message 734 is displayed for guiding the
palm of the user to the correct position. For example, the
guide message 734 displays a message of "Please hold your
hand at a more distant position" for notifying the user
that the palm of the user is closer to the sensor unit 20
than the correct position. The result message 735 is
displayed for notifying the user of the result of user
verification by the authentication apparatus 10. For
example, as the result message 735, there is displayed
"Authenticated" as a result of successful verification by
the authentication apparatus 10.
Note that the processing functions of the above-
described embodiments can be realized by a computer. In
this case, there is provided a program describing the
details of processing of the functions which the
authentication apparatus 10 and the database server 40 are
to have. By executing the program by the computer, the
processing functions described above are realized on the
computer. The program describing the details of processing
can be recorded in a computer-readable storage medium
(including a portable recording medium). Examples of the
computer-readable recording medium include a magnetic
recording device, an optical disk, a magneto-optical
recording medium, and a semiconductor memory. Examples of
the magnetic recording device include a hard disk drive
(HDD), a flexible disk (FD), and a magnetic tape. Examples
of the optical disk include a DVD (digital versatile disk),
a DVD-RAM, a CD-ROM, a CD-R (recordable)/RW (rewritable).
Examples of the magneto-optical recording medium include an
MO (magneto-optical disc).
In case of distributing programs, for example,
portable recording mediums, such as DVD, CD-ROM or the like
in which the program is recorded are marketed. Further, it
is also possible to store the program in a storage device
of a server computer, and transfer the program from the
server computer to the other computer via a network.
The computer which carries out the program stores,
for example, the program which is recorded in the portable
recording medium, or is transferred from the server
computer in the storage device thereof. Then, the computer
reads out the program from the storage device thereof, and
carries out the processes according to the program. Note
that the computer is also capable of directly reading out
the program from the portable recording medium, and
carrying out the processes according to the program.
Further, the computer is also capable of carrying out the
processes according to the program which is received, each
time the program is transferred from the server computer.
The above-described embodiment can be changed
without departing from the spirit and scope of the present
invention.
Further, since numerous modifications and changes
will readily occur to those skilled in the art, it is not
desired to limit the above-described embodiment to the
exact construction and applications shown and described.
The foregoing is considered as illustrative only
of the principles of the present invention. Further, since
numerous modifications and changes will readily occur to
those skilled in the art, it is not desired to limit the
invention to the exact construction and applications shown
and described, and accordingly, all suitable modifications
and equivalents may be regarded as falling within the scope
of the invention in the appended claims and their
equivalents.
Reference Signs List
1 authentication system
2 network
10 authentication apparatus
11 processing unit
20 sensor unit
40 database server
50 photographed image
51 photographed image palette
52 display image
53 display image palette
54 background boundary threshold value
55 background palette
56 palm palette
We Claim:
[Claim 1] An authentication program for causing a
computer to execute processing for authenticating an
individual by using a biometric feature of a living body,
the authentication program causing the computer to function
as:
photographed data generation means for
photographing the living body, and generating photographed
image data including a monochromatic palette formed by
arranging indexed colors to which monochromatic colors are
assigned in order of density;
display data generation means for generating
display data by replacing the monochromatic palette
included in the photographed image data with a color
palette in which one of arrangements formed by dividing the
arrangement of the indexed colors by a predetermined
background boundary threshold value is set as a background
display arrangement of indexed colors to which a background
color is assigned, and the other of the arrangements is set
as a living body display arrangement of indexed colors to
which a specific color is assigned in order of density; and
display means for displaying the living body using
the display data.
[Claim 2] The authentication program according to
claim 1, wherein the order of density of the indexed colors
arranged in the monochromatic palette, and the order of
density of the indexed colors arranged in the living body
display arrangement are opposite in direction to each other.
[Claim 3] The authentication program according to
claim 2, wherein a range of density of the indexed colors
arranged in the living body display arrangement is smaller
than a range of density of the indexed colors arranged in
the monochromatic palette.
[Claim 4] The authentication program according to
claim 2, wherein one of the indexed colors arranged in the
background display arrangement, adjacent to the living body
display arrangement, and one of the indexed colors arranged
in the living body display arrangement, adjacent to the
background display arrangement, have a complementary color
relationship with each other.
[Claim 5] The authentication program according to
claim 4, wherein the background color is a monochromatic
color.
[Claim 6] The authentication program according to
claim 1, wherein the monochromatic palette is a grayscale
palette.
[Claim 7] The authentication program according to
any one of claims 1 to 6, wherein the order of density of
the indexed colors arranged in the living body display
arrangement is opposite to an order of density of the
indexed colors to which the specific color is assigned.
[Claim 8] An authentication apparatus that
authenticates an individual by using a biometric feature of
a living body, the authentication apparatus comprising:
photographed data generation means for
photographing the living body, and generating photographed
image data including a monochromatic palette formed by
arranging indexed colors to which monochromatic colors are
assigned in order of density;
display data generation means for generating
display data by replacing the monochromatic palette
included in the photographed image data with a color
palette in which one of arrangements formed by dividing the
arrangement of the indexed colors by a predetermined
background boundary threshold value is set as a background
display arrangement of indexed colors to which a background
color is assigned, and the other of the arrangements is set
as a living body display arrangement of indexed colors to
which a specific color is assigned in order of density; and
display means for displaying the living body using
the display data.
[Claim 9] An authentication method of
authenticating an individual by using a biometric feature
of a living body, the authentication method comprising:
photographing the living body, and generating
photographed image data including a monochromatic palette
formed by arranging indexed colors to which monochromatic
colors are assigned in order of density;
generating display data by replacing the
monochromatic palette included in the photographed image
data with a color palette in which one of arrangements
formed by dividing the arrangement of the indexed colors by
a predetermined background boundary threshold value is set
as a background display arrangement of indexed colors to
which a background color is assigned, and the other of the
arrangements is set as a living body display arrangement of
indexed colors to which a specific color is assigned in
order of density; and
displaying the living body using the display data.