JP4736502B2 - Personal authentication device, personal authentication method - Google Patents

Description

  The present invention relates to a personal authentication device using a living body, and more particularly to a biometric personal authentication device based on a blood vessel pattern of a finger.

  Biometric authentication that uses a part of the body of a person such as a fingerprint, iris, or blood vessel pattern as a key as a security method that does not require the use of a key or the like, is highly convenient, and is less likely to be illegally used due to loss or theft. Yes. Among them, the authentication method using a blood vessel pattern has little psychological resistance because it does not associate a criminal investigation like a fingerprint or irradiates light directly on an eye like an iris. There is an advantage that counterfeiting is difficult because of the internal characteristics rather than the observable biological surface.

  Such a blood vessel pattern inside a living body can be obtained by illuminating a target site with a near-infrared light source and photographing it with an imaging system such as a camera or image sensor sensitive to the near-infrared. Hemoglobin in blood absorbs near-infrared light well, so light is absorbed in blood vessels and appears darker than surrounding tissues. The pattern due to the difference in brightness becomes a blood vessel pattern.

  Here, there are two methods for photographing the blood vessel pattern. One is a reflected light system that irradiates light to the target part from the same direction as the camera and images the reflected light, and the other is a transmitted light system that images the transmitted light that is irradiated from the back side. It is. For example, Patent Document 1 discloses an apparatus that uses a blood vessel pattern obtained by imaging transmitted light of light irradiated on a finger for personal authentication.

  The reflected light system has an advantage that the light source and the imaging system can be integrally arranged on the same side, so that the apparatus can be compactly accommodated and can be opened without occupying the space on the opposite side of the finger. However, when shooting with reflected light, the light emitted from the light source is reflected by the epidermis, and the intensity of the light that reaches and reflects near the blood vessels in the dermis below the epidermis is relatively weak. . For this reason, the captured image lacks the clearness of the pattern. As a result, it is difficult to obtain a reproducible pattern unless the blood vessel is clear enough to be visible under visible light, such as a vein on the back side of the hand with a thin epidermis. This means that the pattern can be easily copied, and there is a serious problem as a security technique in terms of anti-counterfeiting. In addition, due to the strong light reflection at the epidermis, the effect on the photographed image when the skin surface changes due to injury, rough skin, wrinkles, etc. is inevitably large.

On the other hand, although there is a limit to the thickness of the living body through which light can be transmitted, the transmitted light method only returns the light irradiated from the light source and reflected by the epidermis to the light source side, and does not affect the imaging system. The finger has a thickness that allows light to pass through. Especially, the blood vessel pattern on the palm side is thin, and the epidermis is thicker than the back side. Even though it is not visible, it has excellent anti-counterfeiting properties.
However, in order to photograph with transmitted light, it is necessary to place a finger so as to be sandwiched between the light source and the imaging system. For this reason, as shown in FIG. 9, if the light source unit, the finger, and the camera unit are arranged in a vertical row in order, the light source unit covers the finger like a cover from the eye position during operation. For an authenticating user, the fact that his / her finger cannot be seen is a feeling of pressure. Further, when an operation button or the like is arranged at the fingertip position, it may be difficult to grasp the button position. On the other hand, if the light source unit, the finger, and the camera unit are arranged in a horizontal row as shown in FIG. 10, the finger can be seen from the viewpoint position without covering the top like a cover. However, this time, there is a problem that the hand that can be used for authentication is limited to the left hand or the right hand depending on the positional relationship between the light source and the camera. FIG. 10 shows the case where the light source is on the right side, but if the palm of the finger is pointed at the camera unit with the right hand, there is no artifact. However, with the left hand, it is necessary to forcibly twist the arm when the palm is directed toward the camera. That is, in an authentication apparatus in which the camera unit is arranged on the left side and the light source unit is arranged on the right side, it is not practical except for authentication with the right hand. In the reverse arrangement, authentication with the left hand is forced. Of course, it is sufficient to prepare two sets of light source and camera symmetrically for the right hand and the left hand, respectively, but there are many problems such as an increase in cost and switching of the camera.

JP 2002-83298 A

  As a solution to the above problem, the light source and the finger / imaging system are arranged in the vertical direction, but not simply arranged vertically, but as shown in FIG. 12, the light source is inclined obliquely above the finger. Can be considered. Thereby, compared to the conventional vertical arrangement method shown in FIG. 11, there is no need to hide the finger from the position of the eyes during operation, and the feeling of pressure can be eased. Also, it is not necessary to limit the hand used for authentication to either the left or right.

However, even if the light source is disposed obliquely upward, the side walls that support the light source are still required to have the same height, and a feeling of pressure remains. Moreover, the overall size of the device has hardly changed. Of course, as shown in FIG. 13, if the side wall is lowered, the feeling of pressure is eliminated. Even in this case, since the light emitted from the light source to the finger side surface is scattered and bent inside, it reaches the palm side of the finger that is not on the straight line in the incident direction. That is, the transmitted light exists on the palm side of the finger in the same way as the light source is arranged on the back side of the finger. However, if the light source is arranged at a low position, light is directly applied to the side surface of the finger, particularly the palm side portion, and reflected, and for the same reason as the above-described reflected light system, it is difficult to obtain a blood vessel pattern from that portion. As shown as a typical example in FIG. 13, in the captured image, since the amount of light reflected by the side surface of the finger is large, a region where the luminance is saturated at the maximum value is formed, and a part of the blood vessel pattern is lost. If the output intensity of the light source is adjusted, the area of the saturation region can be reduced. However, in that case, there is a problem that the amount of light reaching the center of the palm surface of the finger is insufficient and a blood vessel pattern cannot be obtained. That is, a correct blood vessel pattern cannot be obtained unless the ratio of reflected light and transmitted light is adjusted appropriately. Moreover, when the side wall is low, external light other than the light source is also directly inserted into the side surface of the finger from the side or obliquely. Therefore, the authentication performance under strong external light such as the West is a factor that deteriorates.
The present invention has been made in view of the realization of a compact authentication device that does not have a feeling of pressure for a user and is strong against external light in imaging of a finger blood vessel pattern using transmitted light. It is to obtain a clear finger blood vessel pattern by reducing the saturation region of the imaging pattern.

  In order to achieve the above object, a typical example of the invention disclosed in the present application will be outlined as follows.

A light source that emits light that passes through the finger, an imaging unit that images the transmitted light obtained by irradiating the finger with the light emitted from the light source, and
A personal authentication device comprising means for adjusting the amount of light transmitted from the finger and the amount of reflected light from the side surface of the finger.

  More specifically, a configuration is disclosed in which light shielding means for limiting the irradiation area is provided as the light amount changing means, or a light source with strong directivity such as a laser is focused on the upper half surface of the finger.

  According to the present invention, since the light source and the external light are not excessively applied to the lower half of the finger, the captured image of the blood vessel pattern by the transmitted light becomes clear, and the accuracy of authentication can be improved. .

Hereinafter, an embodiment of the present invention will be described in detail.
In the present specification, the lower surface of the finger and the lower half of the finger are the palm side or the imaging unit side, the upper surface of the finger or the upper half of the finger is the opposite side of the surface of the upper side and the imaging unit, and the finger side is the palm side of the finger. It shall mean the surface of the finger other than the upper side, or the surface other than the upper surface of the finger and the lower surface of the finger.

  Further, in the present specification, transmitted light means light passing through the inside of the finger, and is used to distinguish from light reflected on the skin surface and epidermis.

  The saturation region of the finger side surface as typically shown in FIG. 13 is generated because light from the light source is directly reflected by the skin surface and reaches the camera. A correct blood vessel pattern cannot be obtained unless the ratio of reflected light and transmitted light is adjusted appropriately. The solution means of the present invention will be described below.

  FIG. 1 is a schematic diagram of an authentication device 100 that implements the present invention. The main body has a guide groove 108 on the upper surface that presents a place where the finger 102 is placed in an easily understandable manner, and a light source unit 104 is disposed on the left and right sides thereof. This guide groove also has a function as a side wall that is low enough to hide the lower half of the finger. The light source is inside the apparatus, the upper surface is covered, and the light is irradiated toward the finger placed on the guide groove 108 through the light source opening 106. The cover on the upper surface of the light source unit also serves to suppress the light diffused outside the desired irradiation direction from being reflected by a finger or palm other than the authentication finger and affecting the imaging as disturbance light. When a finger is placed in accordance with the guide groove 108, a button switch 118 is provided in a portion corresponding to the fingertip, and the photographing opening 110 is located in the front and rear portions of the first and second joints of the finger, and a camera (photographing) located below. Part) 112 can shoot a finger. The camera (imaging unit) 112 is equipped with a filter that passes only wavelengths in the near-infrared region, suppresses the influence of light in the visible light region, and captures a blood vessel pattern clearly. The photographing opening 110 is covered with a transparent glass or acrylic plate together with the light source opening 106, and prevents foreign matter from entering the authentication apparatus while allowing light to pass through. By using an optical filter plate that allows only light in the near-infrared region to pass instead of the glass or acrylic plate, the two functions of device protection and visible light removal can be combined into a single plate. Further, the housing including the light source opening and the photographing opening may be integrally made of an optical filter material.

  The saturated region of the finger side surface as shown in FIG. 13 is generated because the light from the light source is directly reflected by the skin surface and reaches the camera. That is, the saturation region can be reduced by absolute or relative suppression of the amount of light applied to the palm side of the finger, the lower half surface portion in the figure. Therefore, in the present application, by adjusting the amount of irradiation light to a specific region of the finger (especially on the upper half of the finger), the area of the region where the luminance is saturated is reduced even in the captured image by the side surface irradiation method. Solve the problem of losing some. For example, the light intensity and amount of light applied to the upper half of the finger are increased.

  Specifically, a light source 114 that emits near-infrared light is mounted on a light shielding plate 116 inside the light source unit shown in FIG. The light shielding plate prevents light from traveling to the lower half of the finger, and also serves as a part of a guide groove that serves as a guide for the position where the finger is placed. By making the surface of this light-shielding plate and the optical axis of the light source substantially coincide and directing the optical axis to the upper half of the finger, the lower half of the light is shielded while effectively using the strongest part of the light from the light source. enable. Further, if the light shielding plate is sufficiently inclined and the light source is placed on the lower end side, the light source is accommodated at a position lower than the guide groove, and the apparatus can be made thin. At this time, the guide groove including a part of the light shielding plate is surface-treated with matte paint, material or pattern, and the light reflected from the upper surface of the back of the finger is reflected again by the guide groove and illuminates the finger side surface. Try to avoid. In addition, when the range in which the light irradiation is suppressed is a width when viewed from the side of the finger and is about 1/2 to 2/3 from the imaging unit surface, an experimentally clear blood vessel pattern can be obtained.

  Here, when the finger side surface portion other than the palm side and the back side is viewed, the direction from the palm side to the back side is defined as the height direction, and the direction from the tip of the finger to the base of the finger is defined as the width direction. FIG. 17 shows measurement data in the case where the finger width in the width direction is constant and the light shielding area on the side surface of the finger is changed from the imaging unit surface to the height direction.

  FIG. 17 shows the relationship between the ratio of the range in which light irradiation is suppressed to the entire finger side surface (the light shielding ratio of the finger side surface) and the ratio of the saturated region to the imaging unit surface of the finger (the ratio of the saturated region of the finger pad). , Twelve test fingers.

  From this graph, although there is some variation due to individual differences, the saturation area disappears when the finger side area of about 2/3 from the imaging area is shielded, and it can be suppressed to about 10% even at about 1/2. I understand. In addition, it is more effective to place the light source on the upper side of the finger so that the light is irradiated from below, because the intensity of the light that wraps around the lower half of the finger can be suppressed. The elevation angle at that time can be easily obtained from the directivity angle indicating the degree of spread in the traveling direction of the light, which is unique to the light source, and the ideal finger side-shielding ratio.

  On the other hand, although it is slightly expensive without using a light shielding plate as a structure as described above, it is also possible to focus on the upper half surface of a finger with a highly directional light source such as a laser by focusing on the lower half surface. Can be suppressed. Moreover, even if the light source is left as it is, it is controlled so that the irradiation direction is only the upper half of the finger using a deflection plate or the like, or the deflection plate is placed just before the imaging system, and only the direction of light unique to the reflected light Can also be weakened. Furthermore, there is a method of acquiring an image in which the influence of the reflection on the lower half surface is relatively suppressed by irradiating the upper half surface with stronger light instead of physically weakening the reflection on the lower half surface of the finger. .

  As described above, by providing means for adjusting the amount of light irradiated to the upper half surface and lower half surface of the finger to an optimum amount, the position of the light source is not limited to just above the finger. A clear blood vessel pattern can be obtained. Further, in this embodiment, a means for irradiating light to the upper half of the finger and blocking light to the lower half is provided, but the idea of the present application is not strictly limited to only the upper half and the lower half. It goes without saying that light is applied to a finger part necessary for obtaining an imaging pattern, and the light quantity to other finger parts is relatively suppressed.

Authentication begins when the user places his finger on the guide groove 108 and presses the button switch 118. However, the button switch is not essential, and it may be detected by other means that the finger is correctly placed in the guide groove. For example, a touch sensor using a change in capacitance or electrical conductivity of a living body may be used, or a captured image captured by the camera 112 is monitored in real time, and a finger is placed is detected by image processing. It's okay. However, in the case of a touch sensor, attention is necessary because the user does not always react in a state where the user is ready for authentication. By using the button switch, the user can explicitly determine the start timing of the authentication process, and the authentication system can be kept in a standby state until the switch is pressed, so that there is an advantage that power consumption can be reduced. In addition, an authentication function can be naturally added to a device that has conventionally performed some operation using a button switch without forcing the user to change the operation procedure. The button switch in this case is not limited to a mechanical type. For example, any pressure sensor such as a pressure sensor may be used as long as the contact occurs only when the user intentionally operates.

  In addition to the button switch, the accuracy of personal authentication can be improved by mounting a pressure sensor on the transparent plate of the photographing opening 110. A living human blood vessel collapses when a strong pressure is applied, and the blood vessel expands. That is, the line pattern of the pattern becomes thick, and when the pressure is further applied, the blood flow stops and the blood vessel becomes invisible. If the precondition for authentication is that such a time-series change peculiar to the living body is seen in the captured image when the pressure sensor reacts, impersonation using a forged finger becomes very difficult, and safety is increased. Increase. For authentication, an image before the blood vessel pattern is not visible is stored in a buffer memory or the like, or an image after the blood vessel pattern is visible again after the finger is released is used. Note that a pressure sensor is not necessary as long as this time-series change is constantly monitored by an image and the change is used as an authentication timing.

  FIG. 2 is an example of a schematic block diagram of a system configuration for realizing the present invention. The finger 102 is inserted between the light source 114 and the camera 112, and an image signal of the blood vessel pattern is acquired in accordance with the depression of the switch 118. The image signal of the camera 112 is converted into digital data by the image input device 200 and stored in the memory 208 via the input / output interface 204 of the computer 202. Similarly, the switch 118 is also connected via the input / output interface, and the on / off state is stored in the memory 208, or an interrupt signal is generated to the CPU 206 at the same time when it is turned on. When the CPU 206 confirms that the switch 118 is turned on or detects an interrupt signal that is turned on, the CPU 206 activates and executes a software program for authentication. Then, based on the processing result of the program, various kinds of control are performed such as displaying the result on the display 210 or opening / closing the door by sending an appropriate signal to the control object 214. The keyboard 212 is used, for example, for inputting auxiliary information related to authentication such as a password.

  In the personal authentication system represented by FIG. 2, various processes can be performed according to the result of collation between the vein imaging pattern captured by the imaging unit and the registered pattern.

  FIG. 3 shows an example of a software flow executed by the hardware, particularly the CPU 206. In process 300, initial values are substituted into temporary variables required for initialization of the entire hardware and program execution. When the transition to the initial state is completed, the program enters an idling state and waits for the switch 118 to turn on (302). When the switch is turned on, the finger image captured by the camera 112 is taken into the memory 208 (304). The captured image data is subjected to image processing, the blood vessel pattern features are extracted (306), and a collation search is performed to see if there is a match with the already registered pattern (308). Here, the registered pattern refers to data stored by a legitimate registrant in the same manner up to the above-described processing 306 prior to authentication, and then stored in the memory 208 in association with information for identifying the registrant. It is. At this time, a non-volatile memory in which information is not lost when the power is turned on / off can be used as the memory for registering the pattern, in addition to the memory for processing execution. For the same purpose, a recording medium such as a hard disk may be used. If a matching pattern exists (310), a signal indicating that the right access right has been authenticated for the control target such as a device or software program that requires authentication, or for identification of the authenticated individual Data is transmitted (312). If no matching pattern exists, no signal is transmitted, or a signal indicating that unauthorized access has been received is transmitted as necessary. Then, it waits again until the switch is turned on next time.

  Here, since the thickness of the finger varies from person to person, some people may or may not appear well with a uniform light amount. Therefore, until the blood vessel pattern appears best, the accuracy of authentication can be improved by continuously capturing images while changing the brightness while controlling the amount of power supplied to the light source. For power control, for example, high-speed switching control such as PWM (Pulse Width Modulation) using a power transistor can be used. Furthermore, if a sensor for measuring the thickness of the finger is added, the optimal blood vessel pattern can be obtained with a smaller number of images by calculating and storing the relationship between the thickness of the finger and the optimum light amount in advance.

  Also, individual differences in finger thickness are closely related to the light shielding performance. Because, if the finger is thick, the finger height will be much higher than the shading plate, and the side surface area of the finger that exceeds the shading plate will be large enough to absorb the transmitted light, but the lower half of the finger can also be exposed to light Sex occurs. On the other hand, if it is thin, the upper half of the finger does not exceed the height of the light shielding plate, and the area that is exposed to light is small, and the amount of light may be insufficient. That is, when the inclination of the light shielding plate is constant, if the finger is thick, the light shielding on the lower surface side of the finger is insufficient, and conversely, if the finger is thin, there is a risk that the light amount on the upper surface side of the finger is insufficient. Therefore, the direction of the light source may be automatically adjusted according to the thickness of the finger, depending on whether the inclination of the light shielding plate is variable or the light is reflected by a movable mirror or the like. In the case of automatic adjustment, for example, the optimal position is detected by, for example, monitoring the captured image of the camera in real time to obtain the area of the saturated region of the finger side surface, and the area is minimized within the range where the blood vessel pattern appears clearly Control may be performed as follows. Whether or not the blood vessel pattern is clear can be measured based on whether the luminance ratio between the black line representing the blood vessel and the white portion of the surrounding tissue satisfies a certain condition. Further, the area of the saturated region can be extracted as a region in which pixels having the maximum luminance value continue from the vicinity of the both-side boundary of the finger. If such a movable mechanism of the light shielding plate is further applied, the light source unit 104 that is raised like a hill in FIG. 1 can be stored in the apparatus housing 100 except during authentication. . As a result, the apparatus shape during standby is further thin and has no protrusions, which is suitable for mounting on a mobile phone or a portable information terminal, for example.

  Furthermore, the saturation region on the side surface of the finger can be made to appear only on one side by sequentially turning on the light sources arranged on both sides of the finger at different timings. It is possible to obtain a finger image without a saturated region by cutting out only one half surface without a saturated region in the captured image of the finger and combining them into two images taken at the lighting timing of each light source. . In the case of this method, a light shielding plate is not necessary. However, the following trade-offs exist: It takes a little more time because two images must be taken continuously as the light source is turned on. Since the two images to be combined are not always obtained with the same amount of light, the boundary between the images may be noticeable. If smoothing processing is performed so that the boundary is not noticeable, the sharpness of the image may be lost.

  FIG. 4 is an enlarged view of a portion 108 on which a finger is placed as viewed from the side in one variation of the authentication device 100. There is a photographing opening 110 at the bottom, and a camera 112 below it. The part on which the finger is placed may be a flat plane, but as shown in the figure, it may be designed to draw an arc so that the finger naturally bends from the opening 110 to the fingertip part. If the finger is stretched straight, the skin of the finger may become tense, thereby compressing blood vessels and making it difficult for blood to flow, and a blood vessel pattern may not be obtained. As shown in the figure, if the shape draws an arc, the finger bends naturally, so the blood vessel is not compressed. Further, in a naturally bent state, the finger does not touch the transparent plate surface of the opening 110, and the blood vessel is not pressed by the contact with the transparent plate surface, or dirt is not attached. Further, by installing a transparent plate forming the opening 110 further downward or by providing a finger rest 400, the base of the finger is lifted with respect to the opening 110, whereby the opening 110 and the finger are It is also possible to more reliably prevent vascular compression due to contact. In addition, the height of the guide groove on the fingertip is limited so that the abdomen of the fingertip can be accommodated, and by opening the upper part, people who have extended their nails for a long time or are using artificial nails are comfortable. A finger can be placed at a predetermined position.

  FIG. 5 is an example in which the authentication device 100 is thinned. In the above apparatus configuration, since a camera is used for imaging a blood vessel pattern, a fixed focal length is required, and since the camera itself is thick with a lens or the like, the housing of the imaging unit becomes large. Tend to. Therefore, it is possible to reduce the thickness by using a contact image sensor instead of the camera. For example, as a contact image sensor, a phototransistor having sensitivity in the near infrared is arranged in a grid. By sequentially reading the value of the phototransistor, two-dimensional image data can be obtained in the same way as with a camera. As shown in FIG. 5, in the case of modeling in which an arc is drawn, the phototransistor can be mounted on the film-like flexible substrate according to the curvature of the arc. It is also possible to replace the transparent cover part of the photographing opening 110 and mount it.

  FIG. 6 is another example in which the authentication device 100 is thinned. By photographing with a camera using the mirror 600, it is possible to suppress the thickness of the housing by folding the light traveling path while having the same focal length as that in FIG.

  FIG. 7 shows an example in which the present invention is applied to a cash dispenser such as a bank. Reference numeral 700 denotes a cash dispenser housing, and a display 702 with a touch panel and an authentication device 100 are juxtaposed on a table-like operation surface. When withdrawing cash, the user first places the finger of one hand at a designated position on the authentication device 100. Then, with the other hand as it is, an operation such as inputting an amount is performed in accordance with the message displayed on 702. The operation is performed in parallel with the personal authentication. When authentication is possible, cash comes out from the cash doorway 708. If authentication is not possible, cash is not issued, prompting re-entry, or if the number of mistakes is large, the transaction is temporarily invalidated. Reference numeral 704 denotes a card insertion slot for inserting a cash card or a passbook 706 as necessary. When performing personal authentication in a living body, a user is generally forced to perform a special operation involving stress for authentication. For example, in the conventional finger blood vessel pattern authentication, it is required to insert a finger into a hole or deep groove having a psychological resistance. In the case of fingerprint authentication, it is necessary to press the sensor unit with great effort. In the case of iris authentication, you must look at the sensor camera without blinking. In the authentication device of the present invention, it is possible to perform authentication only by placing a finger lightly in a shallow groove with a feeling of opening, so it is difficult to feel stress. In addition, since excessive force is not required, it is easy to operate with the other hand while keeping one hand as it is. As a result, even if a lower-cost computing device is used or high-accuracy authentication with a larger amount of processing is performed, if the authentication process is completed within the time of the input operation such as the amount of money, the processing time is increased. It is not necessary for the user to notice this.

FIG. 8 shows another embodiment of the authentication device 100 of the present invention. The light shielding plate 116 is integrated with the rail 800, and the 800 is coupled to the spring 802. Thereby, the light shielding plate 116 is movable so as to be sucked into the light source side of the side surface. A groove is formed between the light shielding plate 116 and the photographing opening 110 so that the lower half of the finger is just hidden. If the user attempts to place a finger on the photographing opening during authentication, the light shielding plate 116 is inevitably slid left and right. In this case, since the spring 802 applies a force to return the light shielding plate to the original position, the light shielding plate is in close contact with the side surface of the finger, and exhibits a higher light shielding effect on the lower half surface of the finger. When the user lifts his / her finger, the spring automatically returns to the original position, and also serves to prevent dust and dirt in the photographing opening 110. At this time, the shading plate can be smoothly slid by applying the cut-out modeling 120 to the near side of the light shielding plate and moving the finger back so as to slide from the near side. In addition, when the user tries to place a finger on the photographing opening, the finger is moved to the photographing opening by controlling the left and right light shielding plates to have the same movement amount by a combination of a gear / tooth plate. It can also be guided to be placed in the center. With this guide function, the same finger is placed at the same position every time authentication is performed, and the accuracy of matching is increased.

  FIG. 15 shows another embodiment of the authentication apparatus 100 of the present invention. The structure around the part where a finger is placed is schematically shown. In the example of this figure, the light from the finger is not directly emitted from the light source, but the light from the light source 114 is emitted after the direction is once changed by the mirror 1500. As a result, the position of the light source, the fixing method and the degree of freedom of wiring can be further increased, and the height of the side wall can also be suppressed.

  In FIG. 16, the light source 114 is arranged on one side of the finger, and the mirror 1500 is arranged on the other side. The light emitted from the light source 114 not only irradiates one side surface of the finger, but also reaches the opposite side through the finger and the sky. This light can be reflected by a mirror and used as a light source for illuminating the opposite side of the finger. Thereby, power consumption can be suppressed as compared with the case of using a plurality of light sources.

  In the above, an example has been shown in which the light source is arranged at two positions on the left and right sides of the finger in order to obtain an accurate blood vessel pattern without unevenness. However, the present invention is not limited thereto, and necessary and sufficient performance is obtained. If possible, the light source may be arranged only on either the left or right side. This is advantageous in terms of cost.

  Note that the present invention is not limited to personal authentication based only on the blood vessel pattern of a finger, and may be combined with, for example, fingerprint authentication. By photographing a fingerprint of a fingertip with a common imaging system, high-accuracy personal authentication can be performed by using a plurality of biometric features without increasing costs.

It is an example of the apparatus form which implement | achieves this invention. It is an example of the apparatus system configuration | structure which implement | achieves this invention. It is an example of the software flow which implement | achieves this invention. It is an example of sectional drawing of the finger insertion part in an apparatus. It is an example of the apparatus using a plane imaging system. It is an example of the apparatus which used the mirror for imaging. It is an example of the apparatus to which this invention is applied. It is another example of the apparatus form which implement | achieves this invention. It is the schematic showing the problem of the conventional system. It is the schematic showing the problem of the conventional system. It is the schematic which shows the change of the captured image by a light source position. It is the schematic which shows the change of the captured image by a light source position. It is the schematic which shows the change of the captured image by a light source position. It is the schematic which shows the change of the captured image by a light source position. It is an example of the apparatus which used the mirror for the light source. It is an example of the apparatus which used the mirror for the light source. It is data which shows the relationship between the light-shielding ratio of a finger | toe side surface, and a saturation area | region.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Authentication apparatus housing | casing, 102 ... Finger, 104 ... Authentication apparatus light source part, 106 ... Light source opening part, 108 ... Guide groove, 110 ... Imaging | photography opening part, 112 ... Camera, 114 ... Near infrared light source, 116 ... Light-shielding plate , 118 ... button switch, 120 ... notch modeling, 200 ... image input device, 202 ... computer, 204 ... input / output interface, 206 ... central processing unit, 208 ... memory, 210 ... display, 212 ... keyboard, 214 ... control Object: 400: Finger rest, 500: Flat image sensor, 600: Mirror, 700: Cash dispenser housing, 702: Display with touch panel, 704: Card insertion slot, 706: Card / passbook, 708: Cash doorway, 800 ...
Rail, 802 ... Spring.

Claims (17)

A light source that illuminates the finger from the side of the finger placed;
An opening through which light from the light source transmitted through the finger passes,
An imaging unit that is located on the opposite side of the finger with respect to the opening and that images the light transmitted through the opening;
A light-shielding portion that partially restricts light irradiation from the light source to the imaging surface side of the finger ,
Personal authentication apparatus characterized by extracting features of a blood vessel pattern of the finger from the transmitted light image of the finger that is the imaging. An installation surface on which to place a finger;
A light source that emits light from the side to the placed finger;
An imaging unit that images light from the light source that is installed under the finger and transmitted through the finger, when the installation surface side of the finger to be placed is downward.
A light-shielding unit that partially restricts light irradiation from the light source toward the imaging surface side of the finger toward the imaging unit side ;
A personal authentication device that extracts features of a blood vessel pattern of the finger from the captured transmitted light image of the finger. The personal authentication device according to claim 2, wherein the light source irradiates the finger from the left and right directions. The light source is located on the opposite side to the imaging unit with respect to the light shielding unit,
2. The light-shielding part is positioned such that a surface that shields irradiation of the finger is substantially coincident with an optical axis of the light source, and an optical axis of the light source faces an upper half surface of the finger. The personal authentication device described in 1. Further comprising means for measuring the thickness of the finger;
The personal authentication device according to claim 4, wherein an inclination of the light shielding unit is changed according to the measured thickness of the finger to adjust the direction of the light source. Two light sources that illuminate the finger to be placed from the left and right directions;
An opening through which light from the light source transmitted through the finger passes,
An imaging unit that is installed on the side opposite to the finger with respect to the opening and that images the light transmitted through the opening;
A light-shielding unit that is positioned between the light source and the imaging unit and between the light source and the finger and partially shields light from the light source toward the opening toward the imaging surface of the finger. Have
A personal authentication apparatus that extracts features of a blood vessel pattern for personal authentication of the finger from the captured transmitted light image of the finger. The personal authentication device according to claim 1, wherein the imaging unit images light transmitted through the finger from the palm side of the finger. A recording unit for recording the blood vessel pattern of the finger of the person;
2. The personal authentication apparatus according to claim 1, wherein the personal authentication is performed by comparing the extracted blood vessel pattern characteristics with a blood vessel pattern registered in the recording unit in advance. The personal authentication device according to claim 1, further comprising a guide unit for positioning the finger, the guide unit having a finger rest for supporting the base of the finger and a guide in contact with a tip portion of the finger.
. A switch is installed on the fingertip installation part of the guide part,
The personal authentication apparatus according to claim 9, wherein the personal authentication is started when the switch is pressed. The shading part is connected to a spring,
The personal authentication apparatus according to claim 9, wherein when the finger is placed on the guide portion, the light shielding portion slides by the spring. The two light sources are turned on with the finger shifted in timing from two directions,
The imaging unit captures images according to the timing,
The personal authentication device according to claim 1, wherein the characteristics of the blood vessel pattern are extracted using the captured images captured respectively. A light source that illuminates the finger from the side of the finger placed;
An opening through which light from the light source transmitted through the finger passes,
An imaging unit that is located on the opposite side of the finger with respect to the opening and that images the light transmitted through the opening;
A light-blocking part that partially restricts light irradiation from the light source to the imaging surface side of the finger;
In a personal authentication method using a personal authentication device that extracts features of the blood vessel pattern of the finger from the captured transmitted light image of the finger,
Irradiate the finger with light from the side of the placed finger,
The light irradiated to the finger and transmitted through the opening is imaged from the side opposite to the finger with respect to the opening,
Extracting the characteristics of the blood vessel pattern of the finger from the captured transmitted light image of the finger;
A personal authentication method using the personal authentication device, wherein light from the side surface of the finger irradiated to the imaging surface side of the finger is limited by the light shielding unit. An installation surface on which to place a finger;
A light source that emits light from the side to the placed finger;
An imaging unit that images light from the light source that is installed under the finger and transmitted through the finger, when the installation surface side of the finger to be placed is downward.
A light-shielding portion that partially restricts the light that is irradiated from the light source and incident on the imaging surface side of the finger toward the imaging unit side;
In a personal authentication method using a personal authentication device that extracts features of the blood vessel pattern of the finger from the captured transmitted light image of the finger,
Irradiate the finger from the side against the finger placed on the installation surface,
Image the light transmitted through the finger from below the finger,
Extracting the characteristics of the blood vessel pattern of the finger from the captured transmitted light image of the finger;
The personal authentication method using the personal authentication device, wherein irradiation of the finger to the image pickup side with respect to the image pickup surface side of the finger is restricted by the light shielding unit. The personal authentication method according to claim 13, wherein the finger is irradiated from the left and right directions with respect to the finger. Measure the thickness of the above finger,
The personal authentication method according to claim 13, wherein a traveling direction of light that irradiates the finger is adjusted according to the measured thickness of the finger. Record the finger blood vessel pattern of each person,
The personal authentication method according to claim 13, wherein the identity of the person is authenticated by comparing the characteristic of the extracted blood vessel pattern with the previously recorded blood vessel pattern.

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