JP5182341B2 - Personal authentication apparatus and method - Google Patents

Description

  The present invention relates to a personal authentication apparatus using a living body, and more particularly to an apparatus for performing authentication using a blood vessel pattern obtained by imaging light transmitted through a living body.

  As interest in security technologies for personal property and information increases, there is little risk of unauthorized use due to theft or loss, and authentication is performed using human biometric information such as fingerprints, irises, and veins as a highly convenient personal authentication technology. The biometric authentication technology that performs is attracting attention. Above all, finger vein authentication technology that identifies individuals by using the difference in finger blood vessel pattern has little psychological resistance because it does not resemble a criminal investigation like a fingerprint, so that it uses features inside the living body. It is characterized by a low risk of theft.

  Authentication using the finger vein is realized as follows. When the finger is irradiated with infrared light, the light is scattered inside the finger and then emitted to the outside. At this time, hemoglobin in the blood absorbs infrared light more than the surrounding tissue, so when imaging light transmitted through the finger, blood vessels distributed under the finger, that is, the finger veins, have a dark shadow pattern. And visualized. The feature data of the finger vein pattern obtained from this image is registered in advance, and it is determined whether or not it is a registrant by obtaining the correlation with the feature data of the finger vein pattern obtained from the presented finger image, Perform personal authentication.

  In the conventional finger vein authentication device, a guide unit for fixing the finger position is installed in the authentication device so that the user can present the finger with good reproducibility. By presenting the finger on the guide unit, the reproducibility of the captured vein image is enhanced, and high-accuracy authentication is possible. In addition, since the finger presentation position is stable, the light from the light source can be reliably irradiated onto the finger, and strong light does not leak from the periphery of the finger. As a result, a clear vein pattern image can be taken. However, it is necessary for the conventional apparatus to make a part of contact between the finger and the apparatus when performing authentication, and it is difficult to use in an environment in which hygiene is important.

  As an authentication apparatus that solves this problem, Patent Document 1 discloses a personal authentication apparatus that acquires and verifies a vein image in a completely non-contact manner. In the non-contact authentication device, the finger cannot be positioned by touching the guide portion, so the finger presentation position is likely to change, and the reproducibility of the captured image is lowered. Therefore, this authentication apparatus includes means for performing rotation correction using the contour of the finger in the captured image and means for normalizing with the position of the fingertip as a reference. This enables authentication even when the position of the finger in the captured image varies.

  However, the problem caused by the fluctuation of the finger presentation position is not only that the reproducibility of the finger position in the captured image is deteriorated. In an authentication device in which the finger presentation position is not stable, it is difficult to reliably irradiate only the finger with light from the light source. For this reason, strong light that should originally be applied to the finger leaks around the finger and adversely affects the imaging unit itself. For example, when strong leakage light is irradiated on the imaging unit, reflection occurs in optical components such as a lens and a filter, and a shadow of the component itself is reflected. In addition, smear noise or the like for the image sensor may occur. Such an adverse effect on the imaging unit due to the leaked light can be suppressed by weakening the light output from the light source, but in this case, the light transmitted through the finger is also reduced, and a vein image cannot be acquired. As another method for preventing an adverse effect due to leaked light, a method of blocking the leaked light incident on the imaging unit by installing a light shielding unit on the input interface is also conceivable. However, in the non-contact authentication apparatus, the finger presentation position is likely to fluctuate, and depending on the finger position, the light shielding means may block not only leaked light but also light transmitted through the finger. In this way, the light shielding means cannot be installed because it may be an obstacle to obtaining a vein image.

Japanese Patent Laid-Open No. 2002-83298

  In the present invention, the presenting position of the living body is open and the presenting position of the living body can be used in an environment in which hygiene is important and the personal authentication is performed without giving the user a feeling of pressure due to the device shape. It is an object to realize a completely non-contact type vein authentication device that can irradiate a living body with appropriate light without irradiating the imaging unit with strong light leakage from the light source even when the imaging unit fluctuates, and can acquire a clear vein image.

  An infrared light source that irradiates the finger presented in the presentation area with infrared light, an opening that transmits light transmitted through the finger, and an imaging unit that captures light transmitted through the finger that has passed through the opening A height detecting means for detecting a height of installation of the finger, wherein the height detecting means irradiates light on the surface of the finger. The height is detected by the positional relationship on the surface of the finger of the light emitted from the plurality of light sources.

  According to the present invention, it is possible to realize a completely non-contact type vein authentication device that can be used in an environment where importance is placed on hygiene and can perform authentication without giving the user a feeling of pressure due to the shape of the device.

An example of the structure of the finger vein authentication apparatus which implement | achieves this invention. 1 shows a configuration example of an input interface of a finger vein authentication device that implements the present invention. Explanatory drawing which shows the installation method of a light source. An example of the flowchart of an authentication process. 1 shows a configuration example of an input interface including a blowing means for positioning a finger. 1 shows a configuration example of an input interface including a blowing means for positioning a finger. An example of an input interface provided with a visible light source for finger positioning. An example of an input interface provided with a plurality of visible light sources for finger positioning. An example of composition of an input interface provided with a light source for detecting the height of a finger. An example of the configuration of an input interface provided with a plurality of imaging units. A configuration example of a small input interface that performs authentication with a fingertip vein. An example of the apparatus which applied this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this embodiment, the finger vein authentication device will be described in particular. However, even with other living bodies such as palms, which perform authentication using an image generated by the irradiated light passing through the inside of the living body. Adaptable.

  FIG. 1A is a schematic diagram of a configuration of a non-contact type finger vein authentication device that realizes the present invention. FIG. 1B shows the memory 12 and the storage device 14 in FIG. 1A in detail.

  An input interface 2 for a finger vein pattern, which is a portion where a user presents a finger, includes an infrared light source 3 and an imaging unit 4. When the user presents a finger on the input interface, light is emitted from the light source 3 to the finger 1. The light is scattered inside the finger 1, and the light transmitted through the finger 1 is photographed by the imaging unit 4. The light is converted into an electrical signal by the imaging unit 4 and is taken into the authentication processing unit 10 as an image via the image input means 18. The captured image is stored in the memory 12 via the interface 13. Registered data 200 registered in advance is stored in the memory 12 of the authentication processing unit 10 from the storage device 14. At this time, the registration data 200 of a plurality of registrants may be stored in the memory 12, or only the registration data 200 corresponding to information such as user IDs input by the input unit 16 may be stored. The CPU 11 creates authentication data 250 from the input image in accordance with the authentication program 100 stored in the memory 12 and collates with the registration data 200. In the collation processing, a correlation between the two data to be compared is calculated, and it is determined whether or not it matches the registered data according to the value. An individual is authenticated according to this result. The authentication result is displayed on the display unit 15 or is transmitted to the user by transmitting voice from the speaker 17. When correctly authenticated, the authentication process is performed on the control target of the authentication system.

  FIG. 2 is a configuration example of the input interface 2 of the non-contact type finger vein authentication device that realizes the present invention. In the following description and claims, it is described that the finger presentation position is higher than the imaging unit, and the light source is higher than the finger presentation position. However, this is an explanation for easy understanding, and if the desired effect is obtained by maintaining the relative positional relationship of the imaging unit, the finger presentation position, and the light source, the incident angle relationship of light, etc., the whole Forms such as being installed at different angles (for example, tilted toward the user side), and the back wall where the light source is installed form an angle other than 90 degrees with respect to the imaging unit are also included in the scope of the present invention.

  The input interface 2 acquires a finger vein image by the user holding the finger 1. In order to capture the palm-side vein pattern when the user holds the finger 1, the imaging unit 4 is installed below the finger presentation position (palm side). In order to block unnecessary light, the imaging unit 4 is provided with a filter 6 that transmits only infrared light. In order to acquire a clearer vein image, the light source 3 is installed at a position higher than the presentation position of the finger 1 (back side of the hand).

  At this time, when the light source is installed right above the finger, the presentation position of the finger is closed by the structure for installing the light source, and the psychological resistance of the user is increased. In order to avoid this, a light source is installed on the upper side of the finger or on the upper front side of the fingertip. In this embodiment, the light source 3 is installed in front of the finger presentation position. Thereby, the space above the finger can be opened, and the psychological resistance felt by the user when the finger is presented in the closed space can be reduced.

  If installed on the side of the finger, the light emitted from the light source toward the finger strongly illuminates a wide area on the side of the finger, and as a result, the vein pattern contained in the transmitted light is canceled by the light, The contrast of the vein image is reduced. On the other hand, when it is installed in front of the fingertip side, only a narrow area near the fingertip is illuminated and the contrast is hardly lowered. This problem can also be solved by the light source installation method of this embodiment.

  However, when the light source is installed in front of the finger in this way, it becomes difficult for light to reach the base side of the finger. In order to obtain a clear vein pattern, it is important to capture an image with less luminance unevenness by making the amount of light applied to the finger uniform. Therefore, it is desirable to install a plurality of light sources 3 and to decrease the light amount as the light source is closer to the fingertip and to increase the light amount as closer to the root side. In this embodiment, a plurality of light sources are controlled independently so that the amount of light reaching the finger is uniform. Alternatively, the light amount may be adjusted in advance so that the light amount of the light source that irradiates the base side becomes stronger than the light amount of the light source that irradiates the fingertip side, and a plurality of light sources may be controlled simultaneously. Thereby, control can be simplified. The light sources 3 are not limited to a single row in the vertical direction, and a plurality of light sources may be arranged in a planar shape. Thereby, the tolerance | permissible_range of a presentation position can be expanded in the left-right direction. When the light source is arranged in a planar shape, it may be controlled to detect the presentation position of the finger using the captured image and turn on only the light source in front of the finger. As a result, the power consumption of the authentication device can be suppressed.

  Lines 21 to 23 are provided on the surface of the input interface 2 as guides for determining the presentation position of the finger. The user determines the finger presentation position by aligning the finger height with the line 21, the center axis of the finger with the line 22, and the position of the fingertip with the line 23. This guide can be presented while confirming the position of his / her finger at the time of authentication, so the reproducibility of the presentation position is enhanced. Or you may provide a point in an applicable position instead of a line.

  As described above, the non-contact authentication device has a problem that when the finger is displaced, strong light from the light source enters the imaging unit and a clear image cannot be obtained. In the present embodiment, the irradiation direction of the light source 3 is adjusted so that the presented finger is irradiated with light and strong light that adversely affects the imaging unit does not enter the imaging unit. Specifically, as shown in FIG. 3A, the light source 3 is installed in such a direction as to irradiate the left side further than the imaging unit 4.

  Hereinafter, the direction in which the light source 3 is installed to ensure that an image of sufficient quality can be taken even when light that should have originally passed through the finger and reach the imaging unit 4 is directly incident due to the positional deviation of the finger. Describes how to determine.

  First, the direction of the light source in which strong light does not enter the imaging unit 4 will be described. When strong light reaches the image pickup unit 4, smear noise occurs on the image pickup device, or reflection occurs in an optical component such as a lens or a filter, and a shadow of the component is reflected. In particular, noise due to reflection of parts is likely to occur even when the amount of light is small. Therefore, by checking the amount of noise due to reflection in the captured image, it is possible to confirm whether or not light that has an adverse effect has reached the imaging unit. In order to quantitatively determine the influence of this noise, the following experiment was conducted.

  FIG. 3A is a layout diagram of parts of the apparatus used in this experiment. The light source used was an LED with a directional characteristic of 15 degrees and a rating of 100 mw / Sr. In addition, the light source 3 has a structure in which an angle α formed by the imaging plane and the irradiation direction of the light source can be moved within a range of 0 degrees to 90 degrees.

  First, the light quantity of the light source 3 was set to 100 mw / Sr which is the rating of this LED. Next, the space above the imaging device was photographed by the imaging device 4 while α was varied from 0 degrees to 90 degrees. Since the purpose of this experiment is to examine the effect of light when the finger presentation position is significantly deviated, shooting was performed with the finger position most deviated, i.e., without presenting the finger on the device. It was. Thereafter, a feature amount extraction process S109 described later was applied to the photographed image. The amount of features extracted by this processing was used as the amount of noise. In order to examine how much this noise affects authentication, the amount of vein pattern and the amount of noise obtained by actually capturing a finger vein image with the above device and performing feature extraction processing on the captured image Was the noise influence level.

  FIG. 3B is a graph showing the relationship between the installation direction α of the light source 3 and the degree of influence of noise generated by the light of the light source 3. From this graph, it can be seen that when the value of α is small and when α is close to 90, the ratio of noise to the vein pattern is small, and otherwise the ratio of noise is large. As the ratio of noise increases, the authentication result is adversely affected. In general, in vein authentication, correct authentication cannot be performed if the amount of noise exceeds about 25%. Therefore, the light source 3 is installed at an angle at which noise is suppressed to 25% or less. It can be seen from the graph of FIG. 7B that noise can be suppressed to 25% or less when α = 24 degrees or less and α is 81 degrees or more. Therefore, when the camera and the light source are installed at the position shown in FIG. 3A, the light source is installed so that α is 24 degrees or less or α is 81 degrees or more. Thereby, even when the presentation position of the finger is deviated, the adverse effect from the light source 3 can be suppressed, and an image with sufficient quality can be taken.

  Next, of the angles that do not adversely affect the imaging unit, the direction of the light source that emits light to the presented finger will be described. When α is 81 degrees or more, the light from the light source 3 is emitted to the right side of the imaging unit, so that a sufficient amount of light that can acquire a vein image does not reach the finger presented above the imaging unit. On the other hand, when the direction of the light source is adjusted so that α is 24 degrees or less, a sufficient amount of light reaches the space above the imaging unit, and a finger vein image can be acquired.

  From the above, when the light source and the imaging unit are installed in the positional relationship as shown in FIG. 3A, it is desirable to install the light source so that α = 24 degrees or less. And an input interface in which strong light does not enter the imaging unit can be realized. In particular, when the direction of the light source is adjusted so that α is 24 degrees, the ratio of the amount of light irradiated to the finger with respect to the amount of light output from the light source 3 becomes the highest, so that power consumption can be suppressed.

  According to another expression, light from the light source is incident on the presented finger, and transmitted light from the finger is incident on the imaging unit, but direct light (most of the light) from the light source is incident on the imaging unit. If the direction of the light source is set so as not to occur, the input of the imaging unit can be prevented from being saturated.

  Hereinafter, an example of a processing procedure performed by the authentication program 100 will be described with reference to FIG.

  First, processing for detecting presentation of a finger is performed (S101). In order to acquire a vein image with the input interface 2, the finger needs to be presented at a position lower than the light source 3. As a method of detecting that the finger is presented at an appropriate height, a method of irradiating a finger with a plurality of light sources and calculating the height based on the irradiation position, as described later, or the same height as the light source 3 Another light source installed so as to be reflected in the imaging unit is always lighted slightly, and a method of detecting a state where the light is shielded can be used.

  When the presentation of the finger is detected, the light amount of the light source 3 is adjusted so as to obtain the clearest image (S103). For this purpose, the average luminance value of the image is constantly monitored, the light amount is feedback-controlled according to that value, and an evaluation function that determines the sharpness of the pattern is applied to the finger vein pattern image, and the result is optimized. For example, a method for adjusting the amount of light can be used.

  Next, the contour of the finger is detected (S104). As a detection method, there are a method of enhancing an edge of an image, a method of tracking an edge portion, and the like.

  After the contour detection, the direction correction in the parallel direction or the rotation direction in the plane is performed (S106). There is a method of estimating the direction of the finger in the longitudinal direction from the contour information and rotating the image so that the angle is constant. Next, blood vessel pattern feature extraction processing is performed (S108). As this technique, a method using an edge emphasis filter or a matched filter for emphasizing a line segment, a method of extracting a line pattern by tracking a line component, and a method of extracting a local depression position of a luminance value in a cross-sectional profile of an image Etc. can be used.

  Thereafter, feature quantities are extracted from the extracted or emphasized blood vessel pattern (S109). As the feature amount, a method of using the image itself as a feature amount, a method of detecting a branch point or an end point, and the like can be used.

  Finally, the generated feature value is compared with the feature value registered in advance. (S112). In the case where the image itself is used as a feature amount, the images are overlapped and the pixel values are compared to calculate the coincidence rate. When a branch point or an end point is used as a feature amount, the coincidence rate is calculated by comparing information such as the position, the number, the angle of the branch line, and the relative distance. Whether the patterns are the same pattern or different patterns is determined based on the matching rate obtained here. The threshold for determination can be statistically calculated in advance. If the coincidence rate is higher than the threshold, it is determined as a registrant, and if it is lower, it is considered that an unregistered finger has been presented and authentication is rejected.

  If it is determined that the user is a registered person, post-authentication processing such as opening a door is performed (S114).

  FIG. 5 is a configuration example of the input interface 2 of the non-contact type finger vein authentication device provided with a blowing unit for positioning a finger. FIG. 5A is a schematic diagram of the input interface, and FIG. 5B is a side view.

  As shown in FIG. 5, the input interface 2 is provided with a blowing unit 41 at a lower part of the fingertip at the finger presentation position. When the presentation of the finger 1 is detected, blowing is started from the blowing unit 41 in the vertical upward direction. The user can determine the finger presentation position without directly touching the input interface by holding the finger over the position where the wind hits the fingertip. As a result, the finger vein image can be taken with high reproducibility, so that the authentication accuracy is increased. In addition, convenience can be improved because the presenting position of the finger can be easily understood tactilely.

  The air blowing means may be installed not only at the position of the fingertip but also at the lower part on the base side of the finger. As a result, the two positions of the fingertip and the finger base can be positioned, and the rotation of the finger 1 can be prevented. Furthermore, the ventilation means 41 for determining the height which shows a finger may be installed in the wall surface ahead of a finger, and you may ventilate toward a fingertip. If a plurality of air blowing means for positioning are installed, fluctuations in the finger presentation position can be further suppressed, so that more stable authentication can be performed.

  FIG. 6 is a configuration example of the input interface 2 of the non-contact type finger vein authentication device provided with a blowing means for positioning a finger. FIG. 6A is a schematic diagram of the input interface, and FIG. 6B is a side view of the input interface.

  As shown in FIG. 6, the input interface 2 is provided with a blowing means 41 so as to surround an appropriate presentation position of the finger 1. When the presentation of the finger 1 is detected, air is blown upward from the blowing means 41. When the presentation position of the finger 1 deviates from the predetermined position, this wind hits the finger 1. The user moves his / her finger to avoid the wind. By moving the finger so that the wind from all the blowing means does not hit, it is possible to naturally guide to the correct presentation position. Thus, the natural movement of avoiding the wind can prevent the finger 1 from being displaced in the left-right direction and rotating in the horizontal plane.

  FIG. 7 is a configuration example of the input interface 2 of the non-contact type finger vein authentication apparatus provided with a visible light source for finger positioning. FIG. 7A shows a schematic diagram of the input interface 2 and FIG. 7B shows a side view.

  A visible light source 61 for instructing the finger presentation position is installed in the wall surface in front of the finger. The user positions the finger by presenting the finger at a position where the visible light emitted from the visible light source 61 hits a predetermined finger part such as the center or joint of the nail. In this way, by performing positioning using visible light, the finger can be held at a stable position each time without directly touching the input interface 2. This improves the authentication accuracy. In the present embodiment, the visible light source 61 and the infrared light source 3 may be a single light source using LEDs that can emit a plurality of wavelengths.

  FIG. 8 is a configuration example of the input interface 2 of the non-contact type finger vein authentication device in which a plurality of visible light sources are installed for finger positioning. 8A is a schematic diagram of the input interface 2, FIG. 8B is a side view, and FIG. 8C is a top view.

  As shown in FIG. 8, two visible light sources 61 are installed on the front upper side of the finger. The visible light emitted from each light source is irradiated inward so that it intersects at the presentation position of the fingertip. The user determines the presentation position of the finger by holding the finger so that the light from the two light sources overlaps with a predetermined part such as a nail or a joint. When light from a plurality of light sources is used as a guide for the finger presentation position, the finger 1 presentation position can be uniquely determined in the vertical direction in addition to the horizontal direction. Thereby, the positional deviation of the finger can be further reduced, and the authentication accuracy is improved.

  FIG. 9 is a configuration example of the input interface 2 of the finger vein authentication device that calculates the finger height using a plurality of infrared light sources. FIG. 9A is a schematic diagram of the input interface, and FIG. 9B is a side view. FIGS. 9C, 9D, and 9E are diagrams showing changes in the position irradiated with light from the infrared light sources 63 and 64 when the vertical position of the finger 1 changes.

  As shown in FIG. 9A, in the input interface 2, in order to detect the presentation position of the fingertip, an infrared light source 63 is installed in the lower part on the fingertip side, and an infrared light 64 is installed in the lower part on the base of the finger. ing. As shown in FIG. 9B, the two light sources 63 and 64 are installed in such a direction that the light from each light source intersects at an appropriate presentation position of the fingertip. When the user holds a finger over the input interface, the two light sources 63 and 64 strongly irradiate the palm side of the fingertip. At this time, when the imaging unit 4 captures a finger, the irradiated portion appears as a point. When the finger 1 is presented at the correct position, as shown in FIG. 9C, the light from the two light sources irradiates the same position on the palm side surface, so the two points overlap. When the finger 1 is presented at a position higher than the correct presentation position, the light from the light source 64 is emitted toward the fingertip side with respect to the light from the light source 63 as shown in FIG. Conversely, when the finger 1 is presented at a low position, the light from the light source 64 is emitted toward the base of the finger as compared with the light from the light source 63, as shown in FIG. Therefore, the height at which the finger is presented can be automatically calculated by detecting the position of the point where the two lights are reflected by image processing.

  At this time, it is necessary to distinguish from which of the two light sources the point on the finger surface is emitted. This can be realized by a method of irradiating light of different sizes and shapes from the light source 63 and the light source 64, a method of shifting the timing for turning on the light source 63 and the light source 64, and the like.

  Thus, the presentation position of the finger can be known by using a plurality of light sources. Thus, authentication can be performed after confirming that the finger is presented at the correct position. Moreover, you may guide a user using the information of the calculated presentation position of the finger.

  As a guide method, there are a method of installing an LED indicating whether to move up or down on the input interface 2, a method of displaying a direction of movement on the display unit 15, and the like. As a result, the user can present the finger with good reproducibility and the authentication system is improved.

  FIG. 10 shows a configuration example of the input interface 2 of the non-contact type finger vein authentication device in which an imaging unit for detecting the position and rotation of the finger is installed. As shown in FIG. 10, an image pickup unit 121-1 for photographing the finger 1 from the front and an image pickup unit 121-2 for photographing the side surface of the finger 1 are provided in the wall surfaces installed on the front and side surfaces of the finger. is set up.

  In the authentication apparatus shown in the present embodiment, when the user presents the finger 1 on the input interface, the finger presentation position may change or rotate. Among them, the positional deviation and rotation in the imaging plane of the imaging unit 4 can be corrected by performing a rotation correction process using the contour information. However, when the finger is held over the input interface, not only the rotation of the imaging unit 4 in the imaging plane but also the axis rotation with respect to the major axis and minor axis of the finger and the positional deviation in the vertical and horizontal directions and the front and rear direction of the finger occur. sell. Therefore, in order to allow the user to present the finger with good reproducibility, the imaging units 121-1 and 121-2 are installed in addition to the imaging unit 4. When the user presents a finger, an image 300-1 in front of the finger and a side image 300-2 of the finger are captured by the imaging unit 121-1 and the imaging unit 121-2. A plurality of images obtained at this time are used to detect a three-dimensional positional shift and rotation of the finger 1, and the user is guided based on the detection. Hereinafter, an example of a finger position / rotation detection method will be described.

  First, using the captured image 300-1 from the front of the finger, the position of the finger 1 in the left-right and up-down directions and the axial rotation with respect to the long axis of the finger are detected. In order to obtain the vertical and horizontal positions of the finger, the finger region is extracted from the captured image 300-1. For this, a method for enhancing the edge of an image, a method for tracking an edge portion, or the like can be used. The calculated center position of the finger area is calculated and used as the finger presentation position. Next, the rotation of the finger is detected. For this, a method of detecting the orientation of the hand shown in the captured image 300-1 or a method of detecting the orientation of the nail can be used. Since the nail area is exposed to light from the light source 3 and can be photographed more clearly, in this embodiment, a method of detecting the direction of the nail is used. First, the nail region is detected from the finger region obtained by the above procedure. For this, a method of enhancing an edge or a method of detecting light from a difference in reflectance by applying light to a fingertip can be used. Next, the rotation of the obtained nail region is detected. When a finger is photographed from the front as in the photographed image 300-1, the nail region is photographed in a horizontally long elliptical shape. Therefore, the amount of nail rotation can be calculated by estimating the direction of the long axis direction of the nail region and calculating the angle between the long axis and the horizontal direction in the captured image. Thereby, the shaft rotation with respect to the long axis of the finger can be detected.

  The same process is performed on the captured image 300-2, and the short axis of the finger is rotated and the position in the front-rear direction is detected. The contour of the finger is extracted from the captured image 300-2, and the center position of the extracted finger region is obtained as the finger position. Furthermore, the rotation of the finger relative to the short axis is detected by examining the orientation of the finger region in the longitudinal direction.

  It is determined whether the finger is presented at an appropriate position based on the finger position and rotation information thus obtained. This is done by comparing the finger position and rotation during registration with the presentation position and rotation during authentication. When the difference between the positional deviation and the rotation angle at the time of registration and at the time of authentication is larger than the permissible range defined in advance, the user is guided to re-present the finger.

  In addition, by using a wide-angle lens for the imaging units 121-1 and 121-2, it is possible to catch a wide range of position shift even when the distance between the finger and the imaging unit is short.

  FIG. 11 shows a configuration example of the input interface 2 of a small non-contact finger vein authentication device that performs authentication with a fingertip vein. FIG. 11A is a schematic diagram of the input interface, and FIG. 11B is a side view of the input interface.

  In this embodiment, the palm-side vein near the first joint from the fingertip is presented in a non-contact manner and authentication is performed. When authentication is performed using the veins of the entire finger, the captured image may change due to bending of the finger and authentication accuracy may be reduced. However, if the fingertip part is used, the effect of such finger shape changes is reduced. And stable authentication can be performed. In addition, since the shooting range is narrow, the input interface can be downsized. Furthermore, since the irradiation range is also narrowed, the number of light sources 3 can be reduced.

  As shown in FIG. 11, a light shielding plate 111 for blocking external light is installed on the side of the input interface. Since the light shielding plate having a size that can shield light from the fingertip to the first joint portion is sufficient, it is difficult for another finger or the base of the finger to come into contact, and an authentication device that is easy to use for the user can be realized.

  A visible light source 61 for instructing a finger presentation position and an infrared light source 3 for photographing a vein image are installed in a wall surface at the upper front of the apparatus. These light sources may be a single light source using LEDs that can emit a plurality of wavelengths. This further reduces the size of the input interface. As shown in FIG. 11B, the user presents a finger so that the light from the visible light source 61 hits the center of the nail and performs authentication. At this time, if the light source 3 is installed so as to irradiate the fingernails, a clearer image can be taken.

  FIG. 12 shows an example in which the authentication apparatus of this embodiment is applied to a folding mobile phone. 12A is a view of the mobile phone as viewed from above, and FIG. 12B is a side view.

  The imaging device 4 is installed on the same surface as the button installation surface of the mobile phone, and the light source 3 is installed at a position facing it. The mobile phone terminal equipped with the authentication device is automatically locked when the terminal is closed. In the locked state, all data such as phonebook, mail, and images are locked, and operations other than turning the power on and off cannot be performed. When using a mobile phone, the user presents a finger as shown in the figure. At this time, if the finger is presented so that the position of the fingertip and the center axis of the finger are aligned with the button of the mobile phone, the same effect as the positioning lines 22 and 23 shown in FIG. 2 can be obtained. A line as shown in FIG. 12 is displayed on the display 125 of the mobile phone. The user can determine the height presented by the finger by matching the height of the finger to this position. When a finger is presented, light is emitted from the light source 3 and a vein pattern image is captured by the imaging unit 4. Using this image, it is determined whether or not the user is a correct user of the mobile phone. If authenticated correctly, the mobile phone is unlocked. This authentication function can also be used to unlock the mail function, unlock dialing restrictions, lock the IC card function, and so on.

  This authentication device can be installed in any device that has an L-shaped structure, such as a mobile phone, notebook PC, ATM, or PDA.

  DESCRIPTION OF SYMBOLS 1 ... Finger, 2 ... Input interface, 3 ... Light source, 4 ... Imaging part, 10 ... Authentication process part, 11 ... CPU, 12 ... Memory, 13 ... Interface, 14 ... Storage device, 15 ... Display unit, 16 ... Input unit, 17 ... Speaker, 18 ... Image input means, 100 ... Authentication program, 200 ... Registration data , 250 ... authentication data, 21 ... positioning wire, 22 ... positioning wire, 23 ... positioning wire, 41 ... air blowing means, 61 ... visible light source, 111 ... Light-shielding plate, 121-1 ... Imaging unit, 121-2 ... Imaging unit, 63 ... Light source, 64 ... Light source, 125 ... display.

Claims (8)

An infrared light source that irradiates the finger presented in the presentation area with infrared light;
An opening for passing light transmitted through the finger;
An imaging unit for imaging light transmitted through the finger that has passed through the opening,
A height detecting means for detecting a setting height of the finger for causing a finger to be presented at a predetermined presentation position in the presentation area;
The height detection means includes a plurality of light sources that irradiate light on the surface of the finger,
The plurality of light sources are arranged so that the light focuses at the predetermined presentation position, and the height is detected by the positional relationship of the light emitted from the plurality of light sources on the surface of the finger. Personal authentication device. The personal authentication device according to claim 1, wherein shapes of light projected onto the finger by the plurality of light sources are different from each other.   The personal authentication apparatus according to claim 1, wherein the plurality of light sources emit light having different wavelengths. 4. The personal authentication device according to claim 1, wherein height detection by the height detection unit is performed by irradiating the surface of the finger with each of the light emitted from the plurality of light sources, A personal authentication device characterized in that reflected light that reflects the surface of the image is picked up by the image pickup unit, and the height of the finger is detected from the picked-up image.   The personal authentication apparatus according to claim 4, further comprising an image processing unit that detects a height of the finger from the captured image. 6. The personal authentication apparatus according to claim 1, wherein the plurality of light sources are irradiated at different timings. 6. The personal authentication device according to claim 1, wherein a beam spot diameter of light emitted from the plurality of light sources is different on a surface of the finger. The personal authentication device according to claim 1, further comprising a guide unit that guides a presentation position of the finger so that the finger is placed at the predetermined presentation position after the height is detected. Personal authentication device.

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