JP2005202798A - Fingerprint reader and fingerprint matching device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fingerprint matching device by which a clear fingerprint pattern is obtained, and a fingerprint image with a good contrast is obtained even when fingernails are manicured. <P>SOLUTION: The fingerprint matching device comprises a light radiating means 11 for irradiating a finger tip with light from two directions, an image sensor 2 for generating a fingerprint image from the transmittance light that transmits through finger tip, an area cutting out means 12 for cutting out a frame area based on the irradiation direction from the generated fingerprint image, an image composing means 13 for composing the frame area cut out for each fingerprint image and generating a new fingerprint image, a fingerprint image storage means 15 for storing a fingerprint image for each user, and a fingerprint identification means 14 for identifying a user based on the generated fingerprint image. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fingerprint reading apparatus and a fingerprint collation apparatus, and more particularly to an improvement of a fingerprint reading apparatus that generates a fingerprint image based on transmitted light that is irradiated with light and transmitted through a fingertip.

  As a means for performing personal authentication, there is a fingerprint collation device using a fingerprint. The fingerprint collation device collates a fingerprint image for each user stored in advance with a fingerprint image obtained from transmitted light that is irradiated with light and transmitted through the fingertip, and performs personal authentication based on the collation result (for example, Patent Document 1).

In this fingerprint collation device, light is emitted from above the finger and a fingerprint image is generated based on the transmitted light. Therefore, a finger bone or blood vessel shadow is photographed as the fingerprint image, and the fingerprint for fingerprint collation There was a problem that the pattern became unclear. In addition, when nail polish is applied to the nail, light is reflected or absorbed on the surface of the nail, so that the intensity of transmitted light is reduced and the contrast of the fingerprint image is lowered. There was also a problem that it ended up. In this way, in the fingerprint image with the lowered image quality, the fingerprint pattern cannot be extracted, and a new fingerprint image cannot be registered or a fingerprint collation error occurs, so that the authentication accuracy is lowered.
JP 2003-44838 A

  As described above, the conventional fingerprint collation device has a problem that the fingerprint pattern for fingerprint collation becomes unclear. Further, when nail is painted on the nail, there is a problem that the contrast of the fingerprint image is lowered.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a fingerprint reading device and a fingerprint collation device with improved authentication accuracy. In particular, an object of the present invention is to provide a fingerprint reader capable of obtaining a clear fingerprint pattern. Another object of the present invention is to provide a fingerprint reader that can obtain a fingerprint image with good contrast even when nail polish is applied to the nail.

  A fingerprint reading apparatus according to the present invention is a fingerprint reading apparatus that irradiates light and generates a fingerprint image based on transmitted light that passes through the fingertip, and includes a light irradiation means that irradiates light on the fingertip from two or more directions. The image generating means generates a fingerprint image from transmitted light that passes through the fingertip.

  According to such a configuration, light is emitted from two or more directions, and a fingerprint image is generated based on the transmitted light, so that the image quality of the fingerprint image is prevented from being deteriorated due to the shadow of the finger bone or blood vessel. can do. That is, since the bones and blood vessels of the finger are present at a position higher than the abdominal surface where the fingerprint is, if, for example, two or more light sources are installed as light irradiating means, and these light sources are turned on all at once, Shadow formation can be suppressed. In addition, if two or more light sources are sequentially turned on so that fingerprint images are sequentially generated based on transmitted light having different irradiation directions, the position at which a shadow is formed according to the irradiation direction. Since it is different, the shadow can be removed from the fingerprint image. Accordingly, a decrease in image quality due to finger bones and blood vessel shadows is suppressed, and a clear fingerprint pattern can be obtained. Further, even when nail is coated with nail polish or the like, similarly, a deterioration in image quality is suppressed, and a fingerprint image with good contrast can be obtained.

  A fingerprint collation apparatus according to the present invention is a fingerprint collation apparatus that irradiates light and generates a fingerprint image based on transmitted light that passes through the fingertip, and includes a light irradiation means that irradiates light on the fingertip from two or more directions. The image generating means for generating a fingerprint image from the light transmitted through the fingertip, the fingerprint image storing means for storing the fingerprint image for each user, and the fingerprint identifying means for performing user identification based on the generated fingerprint image Is done.

  According to the fingerprint reading device and the fingerprint collation device according to the present invention, light is emitted from two or more directions, and a fingerprint image is generated based on the transmitted light. Is suppressed, and a clear fingerprint pattern can be obtained. Further, even when nail is coated with nail polish or the like, a fingerprint image with good contrast can be obtained. Therefore, the authentication accuracy can be improved.

Embodiment 1 FIG.
FIG. 1 is a plan view showing an example of light irradiating means in the fingerprint collation apparatus according to Embodiment 1 of the present invention. A plurality of light irradiation units arranged above the fingertip A1 placed on the fingerprint reading surface of the image sensor 2 are shown. A light source 1 is shown. The fingerprint collation apparatus according to the present embodiment includes a light irradiation unit that emits light and an image sensor 2 that generates a fingerprint image based on transmitted light that passes through the fingertip A1.

  The image sensor 2 is an imaging unit in which light receiving elements such as photosensors are arranged in an array, reads a fingerprint from the fingertip A1 placed on the fingerprint reading surface, and outputs it as a fingerprint image. The fingerprint is a skin wrinkle on the belly of the fingertip A1, and the shape includes a vortex shape, a bow shape, a hoof shape, and the like. Fingerprint reading is performed with the abdominal surface having such a fingerprint in contact with the fingerprint reading surface.

  The light irradiating means is a light projecting means that irradiates light to the fingertip A1 from two or more directions, and includes, for example, a plurality of light sources 1 that irradiate light from both sides of the finger and before and after the nail A2. Here, it is assumed that each light source 1 is uniformly arranged with respect to the fingerprint reading surface, and each light source 1 that irradiates light from the left side, the central part, and the right side of the finger, and from the front, central part, and rear of the nail A2 Nine light sources 1 are used in combination with each light source 1 that emits light. The irradiation light may be any light that can be transmitted through the fingertip A1 and read the fingerprint, and for example, visible light is used. When reading a fingerprint, these light sources 1 are turned on all at once.

  In general, the bones and blood vessels in the center of the finger are positioned higher than the abdominal surface, and the height thereof is larger than the unevenness of the fingerprint. For this reason, since the positions where the shadows of bones and blood vessels are formed differ according to the irradiation direction, the formation of shadows can be suppressed by simultaneously lighting the light sources 1 having different irradiation directions. In particular, shadows of bones and blood vessels formed along the finger can be effectively removed by irradiation light from both sides of the finger. Accordingly, a decrease in image quality due to finger bones and blood vessel shadows is suppressed, and a clear fingerprint pattern can be obtained.

  In addition, when nail polish or the like is applied to the nail A2 for glazing or coloring, since the coating layer such as nail polish reflects and absorbs light, the intensity of transmitted light transmitted through the nail A2 decreases. According to the present embodiment, it is possible to suppress the formation of the shadow of the nail A2 by simultaneously lighting the light sources 1 having different irradiation directions. In particular, the shadow of the nail A2 can be effectively removed by irradiation light from before and after the nail A2. Therefore, it is possible to obtain a fingerprint image with a good contrast by suppressing a decrease in image quality due to a decrease in transmitted light intensity.

  In the present embodiment, an example in which the light sources 1 are turned on all at once has been described, but the present invention is not limited to this. For example, a fingerprint image may be generated by lighting each light source 1 one by one in time series. Even with such a configuration, it is possible to suppress deterioration in image quality in the fingerprint image.

Embodiment 2. FIG.
In the first embodiment, an example in which a fingerprint image is generated based on irradiation light from a plurality of light sources having different irradiation directions has been described. In contrast, in the present embodiment, a case where fingerprint images for each irradiation direction are sequentially generated will be described.

  FIG. 2 is a block diagram showing a configuration example of a fingerprint collation apparatus according to Embodiment 2 of the present invention. A fingerprint collation apparatus 10 according to the present embodiment includes a fingerprint reading unit 16 that generates light based on transmitted light that irradiates and transmits through a fingertip, and a fingerprint image storage unit 15 that stores a fingerprint image for each user. And fingerprint identification means 14 for performing user identification based on the generated fingerprint image. The fingerprint reading unit 16 includes a light irradiation unit 11, an image sensor 2, a region cutout unit 12, and an image composition unit 13.

  The light irradiation unit 11 is a light projecting unit that irradiates light to the fingertip A1 from two directions, and includes a plurality of light sources 1 that irradiate light from both sides of the finger. For example, two light sources 1 are used that are arranged to face the fingerprint reading surface of the image sensor 2 and emit light from the left and right sides of the finger. When reading a fingerprint, the light sources 1 are sequentially turned on one by one.

  The image sensor 2 sequentially generates fingerprint images based on transmitted light with different irradiation directions. That is, when one light source 1 is turned on, the image sensor 2 generates a fingerprint image (first fingerprint image) based on the transmitted light from the light source 1, and then the other light source 1 is turned on. Then, a fingerprint image (second fingerprint image) is generated based on the transmitted light from the light source 1.

  The area cutout unit 12 performs a cutout process for cutting out a predetermined frame area from the fingerprint image generated by the image sensor 2 based on the irradiation direction. This cut-out process is performed for each fingerprint image obtained by sequentially turning on each light source 1, and for example, an area in which a bone or blood vessel shadow of the fingertip A1 is expected to be photographed from the irradiation direction is determined. A region in the frame not including the region is cut out from the fingerprint image. That is, since the position where the shadow is formed differs according to the irradiation direction, it is possible to cut out a frame region where no shadow is superimposed from the fingerprint image.

  The image synthesizing unit 13 synthesizes the frame regions cut out for each fingerprint image, and generates a new fingerprint image (third fingerprint image). In the synthesis of the frame regions, matching processing between the frame regions cut out from the first fingerprint image and the second fingerprint image is performed, thereby preventing the fingerprint pattern from being shifted. In this manner, a high-quality fingerprint image (third fingerprint image) can be obtained without blurring the fingerprint pattern due to the bone or blood vessel of the fingertip A1.

  The fingerprint identification means 14 performs user identification and user registration based on the generated third fingerprint image. For example, a fingerprint pattern is extracted from the fingerprint image, and collation processing with the fingerprint image stored in the fingerprint image storage unit 15 is performed based on the fingerprint pattern. Personal authentication is performed based on the collation result. That is, when the user places the fingertip A1 on the fingerprint reading surface of the image sensor 2, the light source 1 is sequentially turned on, and the first and second fingerprint images are sequentially generated. A frame area is cut out from these fingerprint images to synthesize a third fingerprint image, and personal authentication of the user is performed based on the fingerprint image. At the time of user registration, the third fingerprint image is stored in the fingerprint image storage unit 15 together with user information such as a name.

  FIGS. 3A and 3B are cross-sectional views showing an example of a state at the time of reading a fingerprint in the fingerprint collation apparatus of FIG. 2 in comparison with the proportionality, and FIG. The state of the fingertip A1 placed on the fingerprint reading surface of the image sensor 2 in the fingerprint collating device 10 according to the form is shown, and FIG. 3B shows a comparative state in which light is irradiated only from one direction. Has been.

  In the case of irradiating light from only one direction, the bone of the fingertip A1 and the shadow of the blood vessel B1 are superimposed on the fingerprint B2, so that the image quality of the fingerprint image is deteriorated and the fingerprint pattern becomes unclear. On the other hand, in the fingerprint collation apparatus 10 according to the present embodiment, it is possible to generate fingerprint images with different positions where shadows are formed by sequentially irradiating light from both sides of the bone or blood vessel B1. For this reason, a high-quality fingerprint image with a clear fingerprint pattern can be obtained by cutting out and synthesizing a region where the shadow of the bone or blood vessel B1 is not superimposed.

  FIGS. 4A and 4B are diagrams showing an example of a fingerprint image generated by the fingerprint collation apparatus in FIG. 2 for each direction of transmitted light irradiation. FIG. 4A shows the right side of the finger. A fingerprint image 21a read from the fingertip A1 based on the irradiation light from the finger is shown, and FIG. 4B shows a fingerprint image 21b read based on the irradiation light from the left side of the finger.

  In the fingerprint images 21a and 21b, the contour 22 and the fingerprint pattern 23 of the fingertip A1 read by the image sensor 2 from the user's hand are respectively photographed. In the fingerprint image 21a read based on the irradiation light from the right side of the finger, a shadow 24 of a bone or blood vessel B1 is formed on the left side of the center of the finger, and is read based on the irradiation light from the left side of the finger. In the fingerprint image 21b, a shadow 24 of a bone or blood vessel B1 is formed on the right side of the center of the finger.

  Thus, since the position where the shadow 24 is formed is different for each irradiation direction, it is possible to cut out and synthesize a region where the shadow 24 of the bone or blood vessel B1 is not superimposed. That is, in the fingerprint image 21a, the right side area 25a including the center part of the finger is cut out, and in the fingerprint image 21b, the left side area 25b including the center part of the finger is cut out.

  FIG. 5 is a diagram showing an example of a fingerprint image generated by the fingerprint collation apparatus of FIG. This fingerprint image 26 is a third fingerprint image generated by the image synthesizing unit 13, and includes a right region 25a cut out from the fingerprint image 21a by the region cutout unit 12 and a left region 25b cut out from the fingerprint image 21b. . In this way, a high-quality fingerprint image 26 with a clear fingerprint pattern 23 can be obtained.

  According to the present embodiment, since the position where the shadow 24 is formed differs depending on the irradiation direction, the shadow can be removed from the fingerprint image, and the deterioration of the image quality due to the finger bone or the shadow 24 of the blood vessel B1 is suppressed. As a result, a clear fingerprint pattern 23 can be obtained.

Embodiment 3 FIG.
In the second embodiment, the example in which the two light sources 1 are used to irradiate the fingertip A1 from two directions has been described. In contrast, in the present embodiment, a case where the movable light source 31 is used will be described.

  FIG. 6 is a diagram showing an example of state transition at the time of fingerprint reading in the fingerprint collation device according to Embodiment 3 of the present invention. In the fingerprint collation device according to the present embodiment, the movable light source 31 is used to irradiate the fingertip A1 with light from either the right side or the left side of the finger, and when the first fingerprint image is generated, the light source 31 is moved. The second fingerprint image is generated by irradiating the fingertip A1 with light from the other of the right side or the left side of the finger. For example, when the generation of the first fingerprint image based on the irradiation light from the right side of the finger is completed, the light source 31 is moved to the left side, and the generation of the second fingerprint image based on the irradiation light from the left side of the finger is started. .

  FIG. 7 is a diagram showing an example of a fingerprint image generated by the fingerprint collation apparatus according to the third embodiment of the present invention for each direction of transmitted light. The image sensor 2 generates a fingerprint image 32a read from the fingertip A1 based on the irradiation light from the right side of the finger and a fingerprint image 32b read based on the irradiation light from the left side of the finger in time series. The right region 33a and the left region 33b are cut out from the fingerprint images 32a and 32b generated in this way, and a fingerprint image without the shadow 24 of the bone or blood vessel B1 is synthesized. Even with such a configuration, a high-quality fingerprint image 26 with a clear fingerprint pattern 23 can be obtained.

  According to the present embodiment, the image quality of the fingerprint image 26 can be improved, and the number of light sources used for light irradiation can be reduced, so that the manufacturing cost can be suppressed.

Embodiment 4 FIG.
In the second embodiment, an example in which light is irradiated from both sides of the finger has been described. On the other hand, this Embodiment demonstrates the case where light is irradiated from before and after nail | claw A2.

  8 (a) and 8 (b) are side views showing an example of a state at the time of fingerprint reading in the fingerprint collation device according to the fourth embodiment of the present invention in comparison with the comparative example. FIG. 8 (a) FIG. 8B shows the state of the fingertip A1 placed on the fingerprint reading surface of the image sensor 2 in the fingerprint collation device according to the present embodiment, and FIG. 8B is a comparison in which light is irradiated only from one direction. Is shown.

  When nail polish is applied to the nail A2 for glazing or coloring, the coating layer such as nail polish reflects and absorbs light. It is superimposed on the fingerprint B2 and the contrast is lowered. On the other hand, in the fingerprint collation device according to the present embodiment, the two light sources 41 are used to sequentially irradiate light from the front and back of the nail A2, thereby generating a fingerprint image with different positions where shadows are formed. can do. For this reason, a high-quality fingerprint image with good contrast can be obtained by cutting out and synthesizing the area where the shadow of the nail A2 is not superimposed.

  Here, it is assumed that the irradiation direction is angled so that the shadow of the nail A2 is formed in front of or behind the center of the fingerprint pattern. That is, light is irradiated at an appropriate angle from the back or front of the nail A2.

  FIGS. 9A and 9B are diagrams showing an example of a fingerprint image generated by the fingerprint collation device according to the fourth embodiment of the present invention for each irradiation direction. FIG. 9A shows a nail. A fingerprint image 42a read from the fingertip A1 based on the irradiation light from the back of A2 is shown, and FIG. 9B shows a fingerprint image 42b read based on the irradiation light from the front of the nail A2. Yes.

  In the fingerprint image 42a read based on the irradiation light from the back of the nail A2, a shadow 44 of the nail A2 is formed in front of the central portion of the fingerprint pattern 23, and based on the irradiation light from the front of the nail A2. In the read fingerprint image 42b, a shadow 45 of the nail A2 is formed behind the center of the fingerprint pattern 23, and the contrast of the fingerprint pattern 23 is lowered.

  In this way, since the positions where the shadows 44 and 45 are formed are different for each irradiation direction, a region where the shadows 44 and 45 of the nail A2 are not superimposed, that is, a region with good contrast can be cut out and combined. it can. For example, in the fingerprint image 42a, a rear region 43a including the central portion of the fingerprint pattern 23 is cut out, and in the fingerprint image 42b, a front region 43b including the central portion of the fingerprint pattern 23 is cut out. By combining the rear region 43a and the front region 43b, a fingerprint image with good contrast is generated.

  According to the present embodiment, even when nail A2 is coated with nail polish or the like, it is possible to obtain a fingerprint image in which deterioration in image quality is suppressed and contrast is good.

Embodiment 5 FIG.
In the fourth embodiment, an example in which two light sources 41 are used to irradiate light on the fingertip A1 from before and after the nail A2 has been described. In contrast, in the present embodiment, a case where the movable light source 51 is used will be described.

  FIG. 10 is a diagram illustrating an example of state transition at the time of fingerprint reading in the fingerprint collation device according to the fifth embodiment of the present invention. In the fingerprint collation device according to the present embodiment, light is applied to the fingertip A1 from one of the back and front of the nail A2 using the movable light source 51, and when the first fingerprint image is generated, the light source 51 is turned on. The fingertip A1 is irradiated with light from the other side behind or in front of the nail A2 to generate a second fingerprint image. For example, when the generation of the first fingerprint image based on the irradiation light from the back of the nail A2 is finished, the light source 51 is moved to the front side, and the generation of the second fingerprint image based on the irradiation light from the front of the nail A2 is started. Is done.

  FIG. 11 is a diagram illustrating an example of a fingerprint image generated by the fingerprint collation apparatus according to the fifth embodiment of the present invention for each irradiation direction. The image sensor 2 generates a fingerprint image 52a read from the fingertip A1 based on the irradiation light from the back of the nail A2 and a fingerprint image 52b read based on the irradiation light from the front of the nail A2. The rear region 53a and the front region 53b are cut out from the fingerprint images 52a and 52b generated in this way, and a fingerprint image without the shadows 44 and 45 of the nail A2 is synthesized. Even with such a configuration, a high-quality fingerprint image with good contrast can be obtained.

  According to this embodiment, the image quality of a fingerprint image can be improved and the number of light sources used for light irradiation can be reduced, so that the manufacturing cost can be suppressed.

It is the top view which showed an example of the light irradiation means in the fingerprint collation apparatus by Embodiment 1 of this invention. It is the block diagram which showed the example of 1 structure of the fingerprint collation apparatus by Embodiment 2 of this invention. FIG. 3 is a cross-sectional view illustrating an example of a state at the time of reading a fingerprint in the fingerprint collation device of FIG. It is the figure which showed an example of the fingerprint image produced | generated by the fingerprint collation apparatus of FIG. 2 for every irradiation direction of the transmitted light. It is the figure which showed an example of the fingerprint image produced | generated by the fingerprint collation apparatus of FIG. It is the figure which showed an example of the state transition at the time of the fingerprint reading in the fingerprint collation apparatus by Embodiment 3 of this invention. It is the figure which showed an example of the fingerprint image produced | generated by the fingerprint collation apparatus by Embodiment 3 of this invention for every irradiation direction of the transmitted light. It is the side view which showed an example of the state at the time of the fingerprint reading in the fingerprint collation apparatus by Embodiment 4 of this invention compared with the comparison. It is the figure which showed an example of the fingerprint image produced | generated by the fingerprint collation apparatus by Embodiment 4 of this invention for every irradiation direction. It is the figure which showed an example of the state transition at the time of the fingerprint reading in the fingerprint collation apparatus by Embodiment 5 of this invention. It is the figure which showed an example of the fingerprint image produced | generated by the fingerprint collation apparatus by Embodiment 5 of this invention for every irradiation direction.

Explanation of symbols

1, 31, 41, 51 light source, 2 image sensor, 10 fingerprint verification device,
DESCRIPTION OF SYMBOLS 11 Light irradiation means, 12 Area extraction means, 13 Image composition means, 14 Fingerprint identification means, 15 Fingerprint image storage means, 16 Fingerprint reading part,
21a, 21b, 26, 32a, 32b, 42a, 42b, 52a, 52b fingerprint image, 22 fingertip outline, 23 fingerprint pattern, 24 bone / blood vessel shadow, 44, 45 nail shadow,
A1 fingertip, A2 nail, B1 bone / blood vessel, B2 fingerprint

Claims (7)

In a fingerprint reader that irradiates light and generates a fingerprint image based on transmitted light that passes through the fingertip,
Light irradiation means for irradiating light on the fingertip from two or more directions;
A fingerprint reading apparatus comprising: an image generating unit configured to generate a fingerprint image from light transmitted through a fingertip.   The fingerprint reading apparatus according to claim 1, wherein the image generation unit sequentially generates fingerprint images based on transmitted light having different irradiation directions. Area cutout means for cutting out a predetermined frame area from the fingerprint image based on the irradiation direction;
The fingerprint reading apparatus according to claim 2, further comprising: an image synthesizing unit that synthesizes the cut frame regions and generates a new fingerprint image.   3. The fingerprint reading apparatus according to claim 2, wherein the light irradiating means comprises a movable light source.   2. The fingerprint reading apparatus according to claim 1, wherein the light irradiation means irradiates light from both sides of the finger.   2. The fingerprint reading apparatus according to claim 1, wherein the light irradiating means irradiates light from before and after the nail. A fingerprint collation device that irradiates light and generates a fingerprint image based on transmitted light that passes through a fingertip,
Light irradiation means for irradiating light on the fingertip from two or more directions;
Image generating means for generating a fingerprint image from transmitted light passing through the fingertip;
Fingerprint image storage means for storing a fingerprint image for each user;
A fingerprint collation apparatus comprising: fingerprint identification means for performing user identification based on a generated fingerprint image.

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