JP2008181468A - Infrared face authentication apparatus, and portable terminal and security apparatus including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an infrared face authentication apparatus which performs face authentication by an infrared image to achieve a very high face recognition rate. <P>SOLUTION: An infrared face authentication apparatus (100)includes a light source (60) radiating infrared light having a wavelength of 760 nm or higher onto a face, an imaging unit (110) detecting reflected light of the radiated infrared light to output an infrared image, and an authenticator (130) performing authentication of the face using the infrared image. The infrared face authentication apparatus further includes a display (30) displaying the infrared image outputted from the imaging unit (110), and a surface of the image unit (110) and a surface of the display (30) are provided on one surface. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technique for performing face authentication by using an infrared light image from reflected light obtained by irradiating a face with infrared light.

  Authentication methods for confirming the identity can be roughly divided into three categories. The first authentication method is authentication by possession with a key or an ID card. However, security is threatened by the loss or theft of property authentication. The second authentication method is authentication based on knowledge using a password or the like. However, knowledge authentication also has security problems due to forgetting and snooping.

  A third authentication method that has attracted attention in recent years is biometric authentication based on biometric information such as fingerprints, palm prints, irises, veins, voice prints, or faces. In biometrics authentication, security concerns due to “losing” associated with authentication based on property and knowledge shown above are significantly suppressed. In addition, biometric authentication has an advantage that security can be improved because other people cannot obtain authentication, and it is considered that authentication systems using biometrics will continue to spread.

Of these, biometric authentication using fingerprints or palm prints often makes the skin of the surface thin because of the frequent use of fingertips or hands, and the recognition rate often deteriorates significantly. At present, biometrics authentication using voiceprints has a poor recognition rate. Biometric authentication using an iris or vein has a higher recognition rate than fingerprint or palm print authentication, but it has been necessary to bring the person's eyes or hands closer to the authentication device. Biometrics authentication devices using irises or veins are large and can be attached to large fixed devices such as ATMs such as banks, but cannot be mounted on portable devices that can be carried by people. In biometrics authentication using faces, in order to improve accuracy under visible light, it is necessary to raise the threshold of authentication in order to lower the acceptance rate of others, and this will increase the rejection rate of the person. There's a problem. Further, a face authentication device using visible light cannot distinguish between a face photograph and an actual human face. For this reason, in Patent Document 1, biometric authentication using a face is combined with biometric authentication using an iris to improve authentication accuracy.
Japanese Patent Application Laid-Open No. 2005-242777

  Combining facial biometric authentication with iris biometric authentication will increase the biometric authentication device. Therefore, space restrictions become a problem particularly when such a biometric authentication device is mounted on a mobile device such as a mobile phone or a PDA (Personal Digital Assistance). In addition, biometrics authentication using a conventional face has been performed using a visible light image, so the authentication accuracy is poor.

  Also, when performing face authentication using visible light images when entering a building, etc., the difference in illuminance between daytime and night is large, so face authentication is performed by illuminating the face with an incandescent lamp at night. However, there is a problem that authentication accuracy is low. Even when the face authentication device is attached to the car to prevent theft of the car, the difference in illuminance between daytime and night is large, so the face authentication apparatus using visible light has poor authentication accuracy.

  This invention is made | formed in view of such a subject, The objective is to provide the infrared face authentication apparatus with a high face authentication rate using an infrared-light image. Moreover, it is providing the portable terminal device or security device provided with this infrared face authentication apparatus.

An infrared face authentication apparatus according to a first aspect includes a light source that irradiates a face with infrared light having a wavelength of 760 nm or more, an imaging unit that detects reflected light of the irradiated infrared light, and outputs the reflected light as an infrared light image; An authentication unit that performs face authentication using an infrared light image.
According to this configuration, the face can be authenticated even under various conditions such as under the illumination of a fluorescent lamp, in the sun, or in the dark. It is not necessary to combine biometrics authentication using the face with biometrics authentication using the face, and authentication can be realized with a highly accurate small device.

In the infrared face authentication apparatus according to the second aspect, the authentication unit performs authentication by specifying the outline of the entire face from the infrared light image and further specifying the positions of both eyes of the face.
With this configuration, since infrared light is transmitted into the eye and transmitted through the eye position, there is little probability of erroneous recognition. In the infrared light image, even the face authentication of the person wearing the glasses is hardly affected by the lens of the glasses.

In the infrared face authentication device of the third aspect, the authentication unit specifies the outline of the entire face from the infrared light image, and further specifies the position of both eyes of the face, the position of the nostril, and the position of the mouth, Authenticate.
With this configuration, an image transmitted to the bottom of the skin with infrared light can be obtained, on which the positions of both eyes of the face, the position of the nostril, and the position of the mouth are specified. Even if you apply dark makeup and resemble a face that is similar to someone else's face, the identification is based on the image that penetrates to the bottom of the skin, so there is little chance of false recognition.

In the infrared face authentication apparatus according to the fourth aspect, the light source is one or more diodes, and the total radiation intensity of the one or more diodes is 0.3 mW / sr or more.
It is necessary to irradiate the face with infrared light with a limited capacity power supply. On the other hand, the face recognition rate deteriorates when the infrared light is too weak, and the face recognition rate deteriorates when the predetermined distance is increased. For example, when an infrared face authentication device is provided in a portable terminal, a person can hold the hand and adjust the distance between the face and the light source or imaging unit. When a highly sensitive light receiving element is used, face authentication can be performed with a diode of about 0.3 mW / sr.

The light source according to the fifth aspect is a plurality of diodes, and infrared light emitted from one of the plurality of diodes and infrared light emitted from another diode have different wavelengths.
Basically, the infrared wavelength suitable for infrared face authentication may be 760 nm, but a wavelength region that does not interfere with the infrared light of sunlight is preferable. There are a plurality of wavelength regions that do not interfere with the infrared light of sunlight. For this reason, you may provide multiple diodes from which the wavelength of the infrared light irradiated to a face differs.

In the infrared face authentication apparatus according to the sixth aspect, the imaging unit is a single photoelectric conversion element, and the visible light receiving element in which a visible light filter that receives visible light is disposed and a red light of 760 nm or more are disposed in the photoelectric conversion element. An Ir light receiving element on which an infrared filter for receiving external light is disposed is disposed, and element switching means for electrically switching between the visible light receiving element and the Ir light receiving element is provided.
According to this configuration, it is not necessary to separately provide a visible light camera and an infrared light camera, and even a small device such as a portable terminal can effectively use a space. In addition, since the visible light receiving element and the Ir light receiving element are electrically switched, the response is quick and there is little failure.

In the infrared face authentication device according to the seventh aspect, the imaging unit is a single photoelectric conversion element, the visible light filter that is disposed so as to cover the entire surface of the photoelectric conversion element and transmits light having a wavelength of visible light, and photoelectric conversion Filter switching means is provided for mechanically switching between an infrared filter that is disposed so as to cover the entire surface of the element and transmits infrared light having a wavelength longer than 760 nm.
According to this configuration, it is not necessary to provide a visible light camera and an infrared light camera separately, and the limited space of the portable terminal can be used effectively. Further, since the visible light receiving element and the Ir light receiving element are mechanically switched, the area of each light receiving element can be increased.

An infrared face authentication device according to an eighth aspect includes a display unit that displays an infrared light image output from an imaging unit, and the surface of the imaging unit and the surface of the display unit are provided on the same surface.
The operator can recognize the face while checking the size and position of his / her face displayed on the display unit, so if it is a small device such as a portable terminal, move his / her arm up / down / left / right The recognition rate can be improved by stretching or shrinking. Further, if the security device is fixed, the recognition rate can be improved by adjusting the sitting position or standing position while confirming the size and position of the face displayed on the display unit.

In the infrared face authentication apparatus according to the ninth aspect, the infrared filter is an infrared filter that transmits a wavelength of 760 nm or more.
Thereby, since visible light can be interrupted when an infrared light image is captured, the imaging unit can output a clean infrared light image without being affected by visible light.

An infrared face authentication device according to a tenth aspect is the infrared filter according to the ninth aspect, wherein the infrared filter transmits a wavelength of a drop region of the radiation amount of sunlight on the ground surface.
Even in a region of infrared light of 760 nm or more, particularly if the infrared filter is a region that transmits the wavelength of the infrared radiation drop amount of sunlight on the ground surface, it interferes with infrared light included in sunlight. Less. Especially when the sunlight in summer is strong, the infrared light is also strong, so the authentication rate for face recognition by infrared light is lowered, but if the wavelength of this infrared ray radiation amount falls, the authentication rate is high. Can be maintained.

In the infrared face authentication device according to the eleventh aspect, the light source includes a wavelength of a drop region of a radiation amount of infrared light of sunlight on the ground surface.
Even in a region of infrared light of 760 nm or more, particularly if the infrared filter is a region that transmits the wavelength of the infrared radiation drop amount of sunlight on the ground surface, it interferes with infrared light included in sunlight. Less. If the wavelength of this region is irradiated from the light source, the interference with the infrared light of sunlight is reduced.

A portable terminal device according to the twelfth aspect includes the infrared face authentication device according to any one of the first aspect to the eleventh aspect, and the authentication unit starts using the portable terminal device or starts monetary settlement. Start at time.
When the mobile terminal has important information such as personal information or money settlement function, it can access the mobile terminal after passing the face authentication, so important information leaks or money is illegally withdrawn. Is less likely to occur.

The security device attached to the moving object or the fixed object according to the thirteenth aspect includes the infrared face authentication device according to any one of the first aspect to the eleventh aspect, and the authentication unit approaches the moving object or the fixed object. Authenticate the face of the person.
Since the security device authenticates the face of the person with infrared light, complete security can be guaranteed.

  According to the present invention, since face authentication is performed using an infrared light image, the recognition rate of face authentication, which has been said to be low until now, can achieve a very high recognition rate.

  Hereinafter, preferred embodiments of the present invention will be described. This embodiment relates to an infrared face authentication apparatus that performs face authentication by irradiating a face with infrared light and capturing an infrared light image from the reflected light.

<Configuration of mobile terminal>
FIG. 1 is an external view showing an example of a mobile terminal according to an embodiment of the present invention. FIG. 1A is a perspective view of a foldable mobile phone 10. When the foldable mobile phone 10 is opened, the monitor 30 is disposed in the first housing 10, and the input button 40 is disposed in the second housing 12. Furthermore, on the same surface as the monitor 30 of the first housing 11, one camera 110 and four IrLEDs (Laser Emitting Diodes) 60 that emit four infrared lights are arranged. The camera 110 and the IrLED 60 are components of the infrared face authentication apparatus 100 described below. The camera 110 can capture at least an infrared light image. When a predetermined input button 40 is pressed or the foldable mobile phone 10 is opened, the IrLED 60 and the camera 110 are activated.

  FIG. 1B is a rear view of the rotary mobile phone 20 having a rotation function. A large monitor (not shown) is provided on the front surface of the first housing 21, and a small monitor 30 is disposed on the back surface. The input button 40 and the like of the rotary mobile phone 20 are disposed on the back surface of the second housing 22. On the back surface of the first housing 21, one camera 110 and two IrLEDs 60 that emit two infrared lights are arranged on the same surface as the small monitor 30. When a predetermined input button 40 is pressed or the rotary mobile phone 20 is rotated, the IrLED 60 and the camera 110 are activated.

  As an example of the mobile terminal, FIG. 1 shows a foldable mobile phone 10 and a rotary mobile phone 20. However, the portable terminal of the present invention is not limited to this, and may be a straight type or a slide type cellular phone or a PDA. Furthermore, a portable notebook computer equipped with a USB camera is also included in the portable terminal. The portable terminal device of the present invention refers to a portable terminal that can be held by a person and the distance between the camera 110 and the face can be changed.

<Configuration of infrared face authentication device>
FIG. 2 is a configuration diagram of the infrared face authentication apparatus 100. The infrared face authentication apparatus 100 includes an IrLED 60 that emits infrared light, a camera 110 that can capture at least an infrared light image, and a face authentication unit 130 that performs face authentication using the infrared light image captured by the camera 110. And a monitor 30 for displaying an infrared light image. In the present embodiment, the foldable mobile phone 10 and the rotary mobile phone 20 may be such that the camera 110 can capture a visible light image in addition to an infrared light image. When capturing a visible light image, the visible light image from the camera 110 is sent to the visible light image processing unit 140. Details of the camera 110 will be described with reference to FIG. The visible light image sent to the visible light image processing unit 140 is sent to the monitor 30 to display the visible light image. Thus, the monitor 30 may display a visible light image in addition to the infrared light image, or may include a separate monitor.

  The face authenticating unit 130 will be described in detail. The face authenticating unit 130 performs an image processing unit 131 that performs image processing of an infrared light image, a face image file 135 that stores the person's face image data, and face authentication. It has a face authentication calculation unit 133 that extracts the outline or feature of the face and compares it with the face data from the face image file 135, and an image control unit 137 that performs these controls. The image control unit 137 is connected to an I / F unit 160 that receives an instruction signal from the input button 40 (see FIG. 1) or a switch. Further, the image control unit 137 is connected to the IrLED 60 and the camera 110, and controls the IrLED 60 and the camera 110 based on a command signal sent via the I / F unit 160.

<Operation of infrared face authentication device>
Here, the operation of the infrared face authentication apparatus 100 will be described with reference to FIG. First, when the I / F unit 160 receives an instruction signal from the input button 40 (see FIG. 1) or a switch, the command signal is transmitted to the image control unit 137. Then, the image control unit 137 drives the IrLED 60 and the camera 110. The IrLED 60 may be constantly lit during face authentication or may blink in accordance with the imaging timing of the camera 110. The image control unit 137 may display a frame 32 indicating the position and size of the face on the monitor 30 in the image processing unit 131.

  The infrared light emitted from the IrLED 60 is applied to the face of the person, and the reflected light is incident on the camera 110. The camera 110 converts the reflected light into an electrical signal and sends the electrical signal to the image processing unit 131. The image processing unit 131 performs image processing so that an infrared light image is displayed on the monitor 30, and sends an infrared light image signal to the monitor 30. Then, the monitor 30 displays an infrared light image of the face in addition to the frame 32 indicating the position and size of the face. The operator can move his arm up and down, up and down, and stretch so that his face is not off the frame 32 of the monitor 30, his face is too large to protrude from the frame of the monitor 30, and his face is too small. Further, the position of the folding cellular phone 10 or the rotating cellular phone 20 is adjusted by contracting.

  The image processing unit 131 sends an image signal including the face outline and the facial feature to the face authentication calculation unit 133. In the face authentication calculation unit 133, first, the outline of the face excluding the hairstyle is extracted. In addition, the positions of both eyes, the position of the nostril, the position of the mouth, and their positional relationship are calculated. Then, the feature portion of the captured face is grasped. Next, the face authentication calculation unit 133 accesses the face image file 135 and reads face image data stored in the face image file 135. Then, the read face image data is compared with the face contour and the facial feature portion as a result of the current calculation. The face authentication calculation unit 133 outputs a recognition result signal to the outside of the infrared face authentication device 100 after the comparison. As indicated by a dotted arrow from the face authentication calculation unit 133 to the monitor 30, the face authentication calculation unit 133 sends a recognition result signal to the monitor 30, and “recognizes the person” or “recognizes the person”. "I couldn't do it." Further, the state of face recognition may be notified to the operator by voice without displaying on the monitor 30.

  The infrared image of the face displayed on the monitor 30 is a single color and is an image close to a so-called black and white image. However, by irradiating the face with infrared light, the camera 110 picks up an image that has entered several millimeters from the surface of the facial skin into the inside instead of an image of the facial skin surface. For example, “freckle” and scratches blowing on the face surface are not imaged. Also, since makeup is not imaged even with dark makeup, even if another person makes makeup similar to the person, it is not mistakenly determined to be the person. In addition, in the infrared light image, even if face authentication of a person wearing glasses is hardly affected by the lens of the glasses, a high recognition rate can be obtained by face authentication even if the glasses are replaced. . Furthermore, even if the camera 110 takes a face photograph of the same size as the operator himself, the face photograph reflects infrared light as it is from the entire surface of the photograph with substantially the same reflectance. That is, since an infrared light image obtained by capturing a face photograph can only acquire an image that looks like a blank sheet under visible light, it is not authenticated as the same person. If the positions of both eyes, the position of the nostrils, the position of the mouth, and the positional relationship between them taken with infrared light are grasped, face authentication can be performed with a high recognition rate.

  The authentication rate of face recognition is high because it is not affected by disturbances by not using visible light. For example, when face authentication is attempted with visible light, it is affected by flickering of the fluorescent lamp under the fluorescent lamp. Also, unless flash photography or front illumination is performed at the time of face authentication, a shadow is generated beside or under the nose due to illumination attached to the roof or the like. For this reason, face recognition using visible light has a low recognition rate. On the other hand, since this embodiment irradiates infrared light, these problems do not occur.

<Camera configuration>
3 and 4 are configuration diagrams showing the basic configuration of the camera 110. Components having the same function are denoted by the same reference numerals. FIG. 3A shows a camera 110 -A including a visible light camera light receiving unit 120 and an infrared light camera light receiving unit 122. The visible light camera light receiving unit 120 transmits only visible light and collects a visible light filter 125 that blocks wavelengths of about 760 nm or more, a lens 129 that collects visible light that has passed through the visible light filter 125, and a lens 129. A photoelectric conversion element that converts the emitted light into an electric signal, for example, an area CCD (Charge Coupled Device) 121 is configured. On the other hand, the infrared camera light receiving unit 122 includes an infrared filter 127 that transmits only a wavelength of about 760 nm or more, a lens 129 that collects infrared light transmitted through the infrared filter 127, and light collected by the lens 129. And an area CCD 121 for converting the signal into an electric signal. The visible light filter 125 and the infrared filter 127 are arranged between the optical path between the operator's face and the lens 129, but may be arranged between the optical path between the lens 129 and the area CCD 121. If it is not necessary to photograph a landscape or the like with the visible light camera light receiving unit 120, only the infrared light camera light receiving unit 122 may be provided.

  The camera 110-A further includes an A / D converter 115 that converts the output of the area CCD 121 into a digital signal, and a camera control unit 116 that controls the entire camera 110. Based on the command signal from the image control unit 137, the camera control unit 116 separately drives each area CCD 121 of the visible light camera light receiving unit 120 and the infrared light camera light receiving unit 122, and the A / D converter 115. To convert an analog signal to a digital signal. Through these operations, a digital signal of an infrared light image or a visible light image is output from the camera 110-A. In the case of the foldable mobile phone 10, when performing face authentication as shown in FIG. 1A, it is more convenient that the infrared light receiving unit 122 is arranged on the monitor 30 side. On the other hand, when the user wants to photograph a landscape or another person, it is more convenient to arrange the visible light camera light receiving unit 120 on the back of the monitor 30 of the first housing 10. That is, although the size or thickness of the first housing 10 is increased, when considering the convenience of face authentication and the convenience of normal shooting, the visible light camera light receiving unit 120 and the infrared light camera light receiving unit 122 are provided. The provided camera 110-A is effective.

  FIG. 3B shows a camera 110 -B including a filter switching camera light receiving unit 123. The difference from the camera 110-A will be described, and the description of the same function will be omitted. The filter switching camera light receiving unit 123 has one area CCD 121 and one lens 129. Further, the filter switching camera light receiving unit 123 includes a mechanical mechanism for switching the visible light filter 125 and the infrared filter 127 in front of the lens 129 and a drive motor 114 for driving the mechanism, and which filter is used for the lens 129. And a sensor 113 for recognizing whether it is disposed in front. The camera control unit 116 receives a command signal indicating whether to output an infrared light image or a visible light image from the image control unit 137. If the command signal is a visible light image, a signal indicating which filter is in front of the lens 129 is received from the signal sensor 113, and driving is performed if the infrared filter 127 is disposed in front of the lens 129. The motor 114 is driven to move the visible light filter 125 in front of the lens 129, and the infrared filter 127 is retracted from the optical path. If the visible light filter 125 is a signal arranged in front of the lens 129, the operation proceeds to the next operation. By performing such an operation, the entire surface of the area CCD 121 is covered with the visible light filter 125, and a visible light image can be output from the area CCD 121. Since a visible light image and an infrared light image can be obtained with one area CCD 121 and one lens 129, space and cost can be reduced. In addition, since only one area CCD 121 is required, a high-performance CCD having large pixels can be used.

  FIG. 4A shows a camera 110-C including a camera light receiving unit 124 in which a filter is provided in the light receiving element. 4A is provided with a glass plate 128 that prevents dust and transmits a wide range of wavelengths. The switching CCD 117 is provided with a visible light filter 125 and an infrared filter 127 in front of the light receiving element. ing. FIG. 4B is an enlarged view of the light receiving element of the CCD 117. In FIG. 4B, the visible light filter 125 is shown as an R filter that transmits red, a G filter that transmits green, and a B filter that transmits blue. The switching CCD 117 includes a first visible light line 118 in which R filters and G filters are alternately arranged, an infrared light line 119 in which an Ir filter 127 that transmits infrared light is arranged, a G filter, and a B filter. The second visible light line 118 arranged alternately and the infrared light line 119 arranged with an Ir filter are composed of four lines. The arrangement of these four lines is sequentially repeated in the area of the CCD 117.

  In FIG. 4A, the camera control unit 116 receives a command signal indicating whether to output an infrared light image or a visible light image from the image control unit 137. If the command signal is a visible light image, the camera control unit 116 controls to output an image signal only from the visible light line 118. The image signal enters the A / D converter 115 and outputs a visible light image as a digital signal. If the command signal is an infrared light image, the camera control unit 116 controls to output an image signal only from the infrared light line 119. Since it can be switched electrically, the response is fast and the failure can be reduced.

  Although the camera 110 has been described with reference to FIGS. 3 and 4, the solid-state imaging device used in these is not limited to the CCD, but may be a CMOS (Complementary Metal-Oxide Semiconductor). Although the RGB filter is used in FIG. 4B, the visible light filter 125 may be configured by a magenta (Mg) filter, a cyan (Cy) filter, a yellow (Ye) filter, and a G filter.

FIG. 5 is a diagram showing spectral sensitivity characteristics of the area CCD 121 or the CCD 117. The horizontal axis represents wavelength (nm) and the vertical axis represents sensitivity (A / W).
Currently, mobile phones 10 and the like, which are examples of mobile terminals, have camera functions in many products. The CCD of these cameras is an inter transfer type CCD, and is abbreviated as IT-CCD. The IT-CCD includes a photodiode portion that converts light into electric charge in one pixel region, and a vertical transfer CCD and a horizontal transfer CCD that transmit the electric charge to an amplifier portion. For this reason, the IT-CCD has characteristics such as a reduced light receiving area. For example, the IT-CCD has characteristics such as the distribution IT-C in FIG. In the visible light region from 380 nm to 760 nm, the sensitivity is somewhat high, but for visible light and infrared light of about 720 nm or more, the sensitivity is 0.1 A / W or less.

  On the other hand, there is a frame transfer type CCD, which is described as FT-CCD. In the FT-CCD, an imaging area for generating electric charge and an accumulation area for storing it are separated. Since both the imaging area and the storage area can transfer charges, they act as a vertical transfer CCD. Then, charges can be sent to the amplifier using a horizontal transfer CCD. The FT-CCD has a large dynamic range because it can take a large area for generating electric charge, and has a high sensitivity even if an infrared filter is provided. For example, the FT-CCD has characteristics such as the distribution FT-C in FIG. Even if the infrared light region is 760 nm or more, the sensitivity is high, but the sensitivity is 0.25 A / W or less even for infrared light of about 900 nm. For example, in the infrared light region around 880 nm to 1020 nm, there is a sensitivity difference of about 10 times.

<Configuration of IrLED>
Next, the IrLED 60 will be described with reference to FIGS.
In order to authenticate the face of the operator himself / herself with the mobile phone 10 or the mobile phone 20 which is a mobile terminal, it is necessary to hold the mobile phone 10 or the mobile phone 20 with his / her hand and photograph his / her face. For this reason, in this embodiment using a mobile phone, it is assumed that the distance between the IrLED 60 or the camera 110 and the face ranges from 20 cm when the arm is bent to 80 cm when the arm is extended. The imaging distance for the best face authentication is assumed to be about 30 to 50 cm. If the arm is bent, the distance between the camera 110 and the face can be changed from 10 cm to 15 cm, but the lens 129 of the camera 110 must have a very wide angle. However, if a very wide-angle lens is used, when the distance between the camera 110 and the face is about 40 cm, the face may become too small to perform face authentication. Depending on the use of the portable terminal, the imaging distance for the best face authentication can be changed as appropriate. For example, when the portable terminal is a notebook computer with the infrared face authentication device 100 attached, the distance between the camera 110 and the face can be about 50 to 60 cm. In order to perform face authentication when entering a building or a room, when a security device is placed on the building entrance door or indoor door, the camera 110 and the face are connected so that face authentication can be performed without bringing the face close to the camera. The distance is preferably about 60 cm to 150 cm. When a security device is arranged in an automobile, the distance between the camera 110 and the face is assumed to be approximately 40 cm to 70 cm, assuming a state where the handle is grasped.

  FIG. 6 is an image diagram in which the face is irradiated with infrared light by the mobile phone 10 or the mobile phone 20. In FIG. 6, the mobile phone 10 or the mobile phone 20 is provided with an optical substrate 150 on which the IrLED 60 and the camera 110 are mounted. The IrLED 60 and the camera 110 are integrally manufactured for manufacturing cost and space saving. Since the monitor 30 is also arranged on the same plane as the IrLED 60 and the camera 110, the IrLED 60, the camera 110, and the monitor 30 may be manufactured integrally. Although two IrLEDs 60 are provided on the optical substrate 150 with the camera 110 interposed therebetween, various variations can be applied as shown in FIG. The distance between the IrLEDs 60 is about 15 mm to 40 mm. Not only IrLED60 but generally LED is manufactured so that directivity may become high. This time, an IrLED 60 having a visual angle V of about 30 to 40 degrees was used. In order to set the visual angle V to about 80 degrees, a scattering plate can be arranged in the vicinity of the light emission of the IrLED 60, but infrared light does not reach far.

  FIG. 7 is a data table 1 obtained by experimenting how much the IrLED 60 should be arranged on the mobile phone 10 or the mobile phone 20. FIG. 7 shows experimental data using an IT-CCD having the characteristics of the distribution IT-C shown in FIG. The distance between the face and the IrLED 60 was measured at intervals of 5 cm from 10 cm to 20 cm and from 60 cm to 80 cm, and at intervals of 10 cm from 20 cm to 60 cm. Further, the radiation intensity (mW / sr: milliwatt / steradian) of the IrLED 60 was changed in the radiation intensity of one IrLED 60 and the number of IrLEDs 60. The radiation intensity of the IrLED 60 shown in FIG. 7 is the radiation intensity when the voltage value is 5 V and the current value is 50 mA. In the combination cell of the distance and the irradiance intensity of the IrLED 60, “◯” indicates that face authentication has been performed 9 times or more out of 10 test results, and “Δ” indicates that from 6 out of 10 test results. “X” indicates that face authentication has been performed 8 times, and “X” indicates that face authentication has been performed only 5 times or less out of 10 test results. In addition, the current IrLED 60 emits infrared light in the wavelength range of 760 nm to 1200 nm. IrLEDs with various wavelengths are on the market, and particularly the IrLED with a wavelength of 800 nm to 1020 nm has a high authentication rate for face authentication.

  From the results shown in FIG. 7, it can be seen that when the distance between the IrLED 60 and the face is short, the IrLED 60 with strong radiation intensity tends to have a poor recognition rate due to uneven illumination on the face surface. Moreover, although it is difficult for unevenness in illuminance to occur on the face surface as the distance becomes longer, it can be read that the IrLED 60 having a weak radiation intensity tends not to reach infrared light sufficiently.

  If face authentication is performed with the mobile phone 10 or the mobile phone 20 so that the distance between the face and the IrLED 60 is about 30 cm, one IrLED 60 of 3 mW / sr is sufficient. When a plurality of IrLEDs 60 are used, power consumption increases. As a mobile phone that preferably consumes as little power as possible, a single 3 mW / sr IrLED 60 may be provided on the optical substrate 150. In order to be able to perform face authentication at an optimal face authentication distance of 30 cm to 50 cm, four IrLEDs 60 of 7 mW / sr are preferably arranged on the optical substrate 150.

  FIG. 8 is a data table 2 showing an experiment on how much the IrLED 60 should be arranged in the mobile phone 10 or the like. FIG. 8 shows experimental data using an FT-CCD having the characteristics of the distribution FT-C shown in FIG. The distance between the face and the IrLED 60 was measured at intervals of 5 cm from 10 cm to 20 cm and from 60 cm to 80 cm, and at intervals of 10 cm from 20 cm to 60 cm. The irradiance intensity of the IrLED 60 shown in FIG. 8 is the radiant intensity when the voltage value is 5 V and the current value is 10 mA. Further, “◯”, “Δ”, and “×” mean test results similar to those in FIG.

  Unlike FIG. 7, the radiation intensity of the IrLED 60 is about 1/5 to 1/10. However, since the sensitivity of the FT-CCD of 800 nm to 1020 nm differs by about 10 times, face authentication can be performed even with weak radiation intensity. From the results shown in FIG. 8, it can be seen that when the distance between the IrLED 60 and the face is short, the IrLED 60 having a high radiation intensity tends to have a poor recognition rate due to uneven illumination on the face surface. Moreover, although it is difficult for unevenness in illuminance to occur on the face surface as the distance becomes longer, it can be read that the IrLED 60 having a weak radiation intensity tends not to reach infrared light sufficiently.

  When a plurality of IrLEDs 60 are provided in the mobile phone 10 or the like, the IrLEDs 60 having the same wavelength are not necessarily required. As will be described later, it is also possible to provide a plurality of infrared wavelengths suitable for infrared face authentication.

<Infrared filter>
FIG. 9 is a graph showing the sunlight wavelength spectrum. The horizontal axis represents wavelength and the vertical axis represents radiation. The radiation amount OE outside the atmosphere has a peak in the visible light region, and the radiation amount is reduced to draw a clean curve up to 3000 nm infrared light.

  On the other hand, the radiation amount EE on the ground surface has a steep radiation amount drop region a1 in the vicinity of 680 nm to 760 nm in the visible light region. Also in the infrared light region, there is a steep radiant drop region a2 near 860 nm to 980 nm, a steep radiant drop region a3 near 1150 nm to 1350 nm, and a steep radiant amount around 1580 nm to 1750 nm. There is a depression area a4. The radiation amount drop region a1 in the visible light region is considered to be a phenomenon that occurs when visible light having a wavelength in the vicinity of 680 nm to 760 nm is absorbed by oxygen in the atmosphere. It is considered that the radiation amount drop regions a2 to a4 in the infrared light region are absorbed by the infrared light having the above wavelength by water vapor in the atmosphere.

FIG. 10 is a graph showing the relationship between the wavelength of the first IrLED 60-1 that is the first example of the IrLED 60 and the wavelength cut of the first infrared filter 127-1 that is the first example of the infrared filter 127.
As described so far, in the present invention, the infrared light from the IrLED 60 is irradiated to the face. In particular, the amount of radiation from the sun in midsummer is large, and the amount of infrared light is also large. For this reason, interference with infrared light components contained in sunlight may occur, and the authentication rate of face authentication in the outdoors in midsummer may deteriorate. Therefore, it is preferable to set the wavelength of the IrLED 60 and the infrared filter 127 so that the authentication rate of face authentication can be increased even in the outdoors in midsummer.

  FIG. 10 is an enlarged view of the radiation amount drop region a2 of FIG. In this 860 nm to 980 nm region, since the amount of infrared light emitted from the ground surface is small, an LED having a peak value of the first IrLED 60-1 in this wavelength region is prepared. In this way, interference with infrared light components contained in sunlight is reduced. The first infrared filter 127-1 is set to a filter that transmits 830 nm to 1040 nm. In the figure, the wavelength region FC-1 of 830 nm or less and the wavelength region FC-1 of 1040 nm or more are blocked by the first infrared filter 127-1. The first infrared filter 127-1 reduces interference with infrared light components contained in sunlight. Therefore, if both the first IrLED 60-1 and the first infrared filter 127-1 are set within the above wavelength range, the authentication rate for face authentication does not deteriorate even in the midsummer outdoors.

  FIG. 11 is a graph showing a sunlight wavelength spectrum having a wavelength longer than 650 nm in FIG. FIG. 11A is a graph showing the relationship between the wavelength of the second IrLED 60-2, which is the second example of the IrLED 60, and the wavelength cut of the second infrared filter 127-2, which is the second example of the infrared filter 127. FIG. 11B is a graph showing the relationship between the wavelength of the third IrLED 60-3, which is the third example of the IrLED 60, and the wavelength cut of the third infrared filter 127-3, which is the third example of the infrared filter 127.

  In FIG. 11A, the second infrared filter 127-2 cuts the wavelength region FC-2 of about 780 nm or less. That is, the second infrared filter 127-2 cuts all visible light. As the second IrLED 60-2, an IrLED 60-21 including many wavelengths in the vicinity of 880 nm to 980 nm and an IrLED 60-22 including many wavelengths in the vicinity of 1150 nm to 1350 nm are used. For this reason, even if it is the 2nd infrared filter 127-2 which cuts the wavelength hunting FC-2 below about 780 nm, in the fall area | region a2 and the fall area | region a3 (refer FIG. 9) of the radiation amount EE on the surface, 2nd IrLED60 Since the light quantity of -2 is large, it is difficult to receive interference even in midsummer sunlight.

  In FIG. 11B, the third IrLED 60-31 uses an IrLED 60 that includes many wavelengths in the vicinity of 900 nm to 1300 nm. That is, the third IrLED 60-31 emits a wide range of infrared light. On the other hand, the third infrared filter 127-3 cuts the wavelength region FC-3 other than about 940 nm to 1000 nm and about 1150 nm to 1320 nm. For this reason, even if it is 3rd IrLED60-3 which irradiates a wide range of infrared light, the light quantity of 3rd IrLED60-31 is large in the fall area | region a2 and the fall area | region a3 (refer FIG. 9) of the radiation amount EE of the ground surface. Therefore, even in midsummer sunlight, it is less susceptible to interference.

The third IrLED 60-32 uses an IrLED 60 having a wide wavelength range from 700 nm in the visible light region to 1500 nm in the infrared region. That is, the third IrLED 60-32 emits a wide range of infrared light. Thus, even if irradiation is performed with an IrLED partially including a visible light region, the amount of light of the third IrLED 60-32 is large in the drop region a2 and the drop region a3 (see FIG. 9) of the radiation dose EE on the ground surface. Even with sunlight, it is less susceptible to interference.
Although the radiation amount drop region a4 in FIG. 9 is not shown, the same effect can be obtained by setting the wavelength of the IrLED 60 and the transmission wavelength of the infrared filter 127 in the same manner.

<Flowchart of face authentication in portable terminal>
An operation of face authentication in the mobile phone 10 will be described as an example of the mobile terminal. FIG. 12 is a flowchart for performing face authentication when starting to use the mobile phone 10 in the first embodiment. The mobile phone 10 includes a lot of personal information or mail. For this reason, the mobile phone 10 cannot be used unless the face authentication is passed.

  In step S71 in FIG. 12, variables N and M used for face authentication are initialized. In step S72, face authentication is started. At this time, a frame 32 (see FIG. 2) indicating the position and size of the face may be displayed on the monitor 30. This is because, in order to increase the recognition rate of the face, the operator extends the arm left and right, up and down, and extends or contracts the arm so as to urge the operator so that the face is in an optimal position and size. The frame indicating the size of the face may be a vertically long ellipse, a rectangular frame, or a general outline of a human face.

  In step S73, the outline of the face and the feature part of the face are grasped. In response to the image processing speed of the image processing unit 131 shown in FIG. 2, the face authentication calculation unit 133 extracts the face outline and feature portion. If the face is too large or too small to grasp the predetermined contour and feature portion, the process proceeds to step S74 and step S75 until the threshold value S1 is reached until the face contour and the feature portion are grasped. Steps S72 to S75 are repeated. When the threshold value S1 is reached in step S74, the fact that face recognition could not be performed is displayed on the monitor 30 in step S76.

  In step S73, if the face outline and the facial feature portion can be grasped, the process proceeds to step S77 to determine whether or not the image matches the registered image stored in the face image file 135 shown in FIG. For example, even if the contour of the face and the feature portion of the face can be grasped in step S73, it is determined that they are not the same person because the face is inclined sideways. If it does not match the registered image, the process proceeds to step S78 and step S79. Then, through the step of grasping the face outline and the facial feature portion again, it is determined whether or not it matches the registered image. When the threshold value S2 is reached in step S78, it is displayed on the monitor 30 that face recognition could not be performed in step S76. If it matches the registered image in step S77, various operations of the mobile phone 10 are permitted.

  FIG. 13 is a flowchart for performing face authentication when performing a specific function, for example, money settlement, in the second embodiment. Although many functions are incorporated in the mobile phone 10, recently it has become possible to make a financial settlement. The mobile phone 10 can be used without using face authentication, but a specific function that is judged to be damaged by fraudulent use such as money settlement cannot be used unless the face authentication is passed. Because.

  The flowchart of FIG. 13 is almost the same as FIG. 12, but different steps are given different step numbers. In FIG. 12, when face authentication is not possible, the fact that face recognition could not be performed is displayed on the monitor 30 in step S76. In FIG. 13, when the photographing of the face is insufficient, that is, when the threshold value S1 is reached in step S74, “Please photograph so that the face falls within the frame” is displayed on the monitor 30 in step S81. If the image does not match the registered image, that is, if the threshold value S2 is reached in step S78, “does not match the registered image” is displayed on the monitor 30 in step S82. This is because the reason why face authentication cannot be performed is displayed so that the operator can recognize that face authentication cannot be performed.

  Although various embodiments have been described above, these embodiments are exemplifications, and various modifications can be made to combinations of the respective constituent elements, and such modifications are also within the scope of the present invention. It will be understood by those skilled in the art. For example, although the lens 129 has been described on the assumption of a fixed focus, it goes without saying that an autofocus function may be provided. Moreover, although the boundary between the visible light filter and the infrared filter has been described with a wavelength of about 760 nm, it may be about 780 nm or about 800 nm. Further, there may be a partially overlapping region so that the visible light filter transmits a wavelength of 800 nm or less and the infrared filter transmits light of about 760 nm or more.

  Furthermore, although the mobile phone has been mainly described in the above embodiment, the infrared face authentication apparatus 100 of the present invention may be incorporated in a place where security is required. For example, when the infrared face authentication device 100 is provided at the door to enter the building and when the infrared face authentication device 100 is provided at the door or the room of the automobile, the accuracy can be obtained even under the hot summer heat or in the dark. Good face recognition can be performed. In addition, if the security device is fixed, the recognition rate can be improved by adjusting the sitting position or standing position while confirming the size and position of the face displayed on the display unit.

In a security device that performs financial settlement such as an ATM or a safe deposit box, it is necessary to prevent money from being withdrawn illegally. By incorporating the infrared light face authentication device into these security devices, it is possible to deal with fraudulent drawers using facial photographs and the like.
Further, from the viewpoint of personal information protection or trade secret protection, there is a demand for means for preventing a suspicious person from entering or leaving the room or illegal copying or access. Unauthorized access can be dealt with by incorporating an infrared light face authentication device into a device that requires security, such as entrance / exit management or attendance management, a copy machine, or a personal computer.

A is a perspective view of the foldable mobile phone 10 including the IrLED 60, and B is a rear view of the rotary mobile phone 20 including the IrLED 60. 1 is a configuration diagram of an infrared face authentication device 100. FIG. A is a camera 110 -A including a visible light camera light receiving unit 120 and an infrared light camera light receiving unit 122, and B is a camera 110 -B including a filter switching camera light receiving unit 123. A is a camera 110-C including a camera light receiving unit 124 in which a filter is provided in the light receiving element. B is an enlarged view of the light receiving element of the CCD 117 of the camera light receiving unit 124. FIG. 5 is a sensitivity distribution characteristic diagram showing a relationship between wavelength and sensitivity in an inter-transfer type CCD and a frame transfer type CCD. It is an image figure which irradiated infrared light to the face with the mobile phone. It is the data table | surface which experimented how much IrLED60 should be arrange | positioned with CCD of an inter transfer system. It is the data table | surface which experimented how much IrLED60 should be arrange | positioned with CCD of a frame transfer system. It is a graph showing the radiation dose OE outside the atmosphere and the radiation dose EE on the ground surface with respect to the sunlight spectrum. It is the graph which showed the relationship between the wavelength of IrLED60, and the wavelength cut of the 1st example of the infrared filter 127. FIG. A is a graph showing the wavelength cut of the second example of the infrared filter 127, and B is a graph showing the wavelength cut of the third example of the infrared filter 127. It is a flowchart which performs face authentication when starting to use a mobile phone. It is a flowchart which performs face authentication when performing a financial settlement.

Explanation of symbols

30 ... Monitor 40 ... Input button 60 ... IrLED
100 ... Infrared face authentication device 110 ... Camera 117, 121 ... CCD
125 ... Visible light filter 127 ... Infrared filter 130 ... Face authentication unit 150 ... Optical substrate

Claims (13)

A light source that irradiates the face with infrared light having a wavelength of 760 nm or more;
An imaging unit that detects reflected light of the irradiated infrared light and outputs it as an infrared light image;
An authentication unit for performing face authentication using the infrared light image;
An infrared face authentication device comprising: 2. The infrared face authentication apparatus according to claim 1, wherein the authentication unit performs authentication by specifying an outline of the entire face from the infrared light image and further specifying positions of both eyes of the face. . The authentication unit performs authentication by specifying an outline of the entire face from the infrared light image, and further specifying a position of both eyes of the face, a position of a nostril, and a position of a mouth. The infrared face authentication apparatus according to claim 1. 4. The light source is one or more diodes, and a total radiation intensity of the one or more diodes is 0.3 mW / sr or more. 5. Infrared face authentication device described in 1. The light source is a plurality of diodes, and infrared light emitted from one of the plurality of diodes and infrared light emitted from another diode have different wavelengths. The infrared face authentication apparatus according to any one of claims 1 to 4. The imaging unit is a single photoelectric conversion element, and a visible light receiving element in which a visible light filter for receiving visible light is arranged and an infrared filter for receiving infrared light of 760 nm or more are arranged in the photoelectric conversion element. 6. The infrared ray according to claim 1, further comprising an element switching unit that is arranged to electrically switch between the visible light receiving element and the Ir light receiving element. Face recognition device. The imaging unit is a single photoelectric conversion element, and is disposed so as to cover the entire surface of the photoelectric conversion element, and is disposed so as to cover the entire surface of the photoelectric conversion element, and a visible light filter that transmits light having a wavelength of visible light. 6. The infrared face authentication apparatus according to claim 1, further comprising: a filter switching unit that mechanically switches an infrared filter that transmits infrared light having a wavelength longer than 760 nm. . A display unit for displaying an infrared light image output from the imaging unit;
The infrared face authentication apparatus according to any one of claims 1 to 7, wherein a surface of the imaging unit and a surface of the display unit are provided on the same plane. The infrared face authentication apparatus according to any one of claims 1 to 8, wherein the infrared filter is an infrared filter that transmits a wavelength of 760 nm or more. The infrared face authentication apparatus according to claim 9, wherein the infrared filter is an infrared filter that transmits a wavelength of a region where a radiation amount of infrared light of sunlight falls on a ground surface. 6. The infrared face authentication apparatus according to claim 1, wherein the light source includes a wavelength of a drop region of a radiation amount of infrared light of sunlight on a ground surface. A portable handheld device,
An infrared face authentication device according to any one of claims 1 to 11, comprising:
The authentication unit is activated at the start of use of the mobile terminal or at the start of money settlement. A security device attached to a moving or fixed object,
An infrared face authentication device according to any one of claims 1 to 11, comprising:
The security device, wherein the authentication unit authenticates a face of a person approaching the moving object or the fixed object.