JP7104940B2 - Palmprint authentication device and palmprint authentication method - Google Patents

Description

The present invention relates to a palmprint authentication device and a palmprint authentication method that perform authentication using palmprints.

In recent years, electronic personal authentication has been widely used in various daily situations such as electronic commerce and entrance/exit management. Conventionally, methods using IC cards, passwords, etc. have been used for personal authentication. So-called biometrics authentication, which confirms the identity of a person using personal characteristics and behavioral characteristics, has also been realized. Palm prints are one of the physical features used in this biometrics authentication. Palmprints can be used as biometric information to identify individuals in the same way as fingerprints, and they are less likely to fade due to aging or wear compared to fingerprints. 1).

For example, in Patent Document 1, an image including a palmprint is taken, and an image in a predetermined range is extracted as an authentication target image based on predetermined feature points from the image, and is compared with a preregistered palmprint matching image. A palm print authentication device for matching is described.

JP 2008-217307 A

However, since conventional palmprint authentication devices use a general CMOS camera, when the palm is imaged, the background of the palm is also reflected, and it is possible that something that interferes with the authentication may be reflected in the background. , there was a problem that it was difficult to detect the palm at the correct position and range. Backgrounds that interfere with authentication include, for example, wallpaper with a dark pattern, untidy luggage or furniture, or bright lighting. In palm print authentication, there is a considerable possibility that such a background will be reflected. Therefore, for example, it has been necessary to perform complicated image processing on captured images to recognize palms.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a palm print authentication device and a palm print authentication method that can easily recognize a palm.

A palmprint authentication device according to the present invention performs authentication using a palmprint, and includes near-infrared irradiation means for irradiating a near-infrared ray having a wavelength of 780 nm or more and 940 nm or less to the palm of a person to be authenticated; Short-wavelength light irradiation means for irradiating light with a wavelength of 380 nm or more and 570 nm or less, which is shorter than the near-infrared rays, imaging means for imaging the palm of the person to be authenticated, and first irradiation and short-wavelength light by the near-infrared irradiation means The second irradiation by the irradiation means is alternately performed, the first irradiation is performed at least once, and the imaging means captures a near-infrared image during the first irradiation and a short-wave light image during the second irradiation. Control means for controlling imaging; palm coordinate extraction means for extracting the coordinates of the palm image range used for authentication from the near-infrared image captured by the imaging means; and short-wavelength light image captured by the imaging means, A palm print image extracting means for extracting an image of a coordinate position obtained by the palm coordinate extracting means as an authentication target image, and a matching means for performing authentication using the authentication target image extracted by the palm print image extracting means. be.

A palmprint authentication method according to the present invention performs authentication using a palmprint, and near-infrared image capturing is performed by irradiating the palm of a person to be authenticated with near-infrared light having a wavelength of 780 nm or more and 940 nm or less to capture a near-infrared image. a palm coordinate extraction procedure for extracting the coordinates of the palm image range used for authentication from the near-infrared image captured in this near-infrared image capturing procedure; A short-wavelength light image capturing procedure for capturing a short-wavelength light image by irradiating light with a wavelength of 380 nm or more and 570 nm or less, which is shorter than the near-infrared light, and from the short-wavelength light image captured in this short-wavelength light image capturing procedure, It includes a palm print image extraction procedure for extracting an image of the coordinate position obtained by the palm coordinate extraction procedure as an authentication target image, and a verification procedure for performing authentication using the authentication target image extracted by the palm print image extraction procedure.

According to the present invention, a near-infrared image is captured by irradiating near-infrared rays, so the characteristics of the near-infrared image capturing means that an object near the imaging means is captured and an object far away is not captured are utilized. background can be easily removed and the position of the palm can be easily recognized. In addition, since light with a wavelength of 380 nm or more and 570 nm or less is emitted to capture a short-wavelength light image, the palm print can be clearly captured. Therefore, by extracting the coordinates of the image range of the palm used for authentication from the near-infrared image and extracting the image of the coordinate position from the short-wavelength light image, the image to be authenticated can be easily obtained. Therefore, complicated image processing for extracting the authentication target image of the palm from the captured image is not required, and the matching can be performed at high speed. Furthermore, since a short-wavelength light image is used, authentication can be performed with high accuracy.

1 is a configuration diagram of a palmprint authentication device according to an embodiment of the present invention; FIG. It is a figure showing an example of the near-infrared image of a palm. It is a figure showing an example of the short wavelength light image of a palm. FIG. 10 is a diagram for explaining a method of extracting the coordinates of the palm image range used for authentication in the palm coordinate extraction means; FIG. 10 is a diagram for explaining a method of extracting an image to be authenticated in a palm print image extracting means; FIG. 10 is a diagram for explaining a method of performing authentication using an authentication target image in a collating means; 2 is a flow chart showing procedures of a palm print authentication method according to the present embodiment;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the configuration of a palm print authentication device 10 according to the first embodiment. This palmprint authentication device 10 performs authentication using a palmprint, and includes near-infrared irradiation means 11 for irradiating the palm of the person to be authenticated with near-infrared rays having a wavelength of 780 nm or more and 940 nm or less. Short-wavelength light irradiation means 12 for irradiating light with a wavelength of 380 nm or more and 570 nm or less, which is shorter than infrared rays (hereinafter referred to as short-wavelength light), imaging means 13 for imaging the palm of the person to be authenticated, and these near-infrared rays. It is provided with irradiation means 11 , short-wavelength light irradiation means 12 , and control means 14 for controlling imaging means 13 . The near-infrared irradiation means 11, the short-wavelength light irradiation means 12, and the imaging means 13 are arranged, for example, on the surface of the housing 10A, and the control means 14 is arranged, for example, inside the housing 10A. ing. The near-infrared irradiation means 11, the short-wavelength light irradiation means 12, and the imaging means 13 are each connected to the control means 14, for example.

The near-infrared irradiation means 11 is composed of, for example, a near-infrared LED. In this palm print authentication device 10, the characteristics of the near-infrared image irradiated with near-infrared rays, particularly near-infrared rays with a wavelength of 780 nm to 940 nm Utilizing the characteristic that objects in the distance are not reflected, only the palm held near the imaging means 13 is projected by near-infrared rays, and the distant background is not projected and can be easily removed. It's becoming The wavelength range of the near-infrared rays irradiated by the near-infrared irradiation means 11 is, for example, among the near-infrared rays having a wavelength of 780 nm or more and 940 nm or less. Near infrared rays of 880 nm or less are more preferable. FIG. 2 shows an example of a near-infrared image captured by irradiating a palm with near-infrared rays having a wavelength of 780 nm or more and 940 nm or less.

The short-wavelength light irradiation means 12 is composed of, for example, a short-wavelength LED. The reason why short-wavelength light is used is that a palm print can be clearly imaged. The wavelength range of the light irradiated by the short-wavelength light irradiation means 12 is, for example, light with a wavelength of 450 nm or more and 495 nm or less, which is blue light that has little diffusion of light to the subcutaneous and has high sensitivity in a general-purpose CMOS image sensor. It is more preferable to have FIG. 3 shows an example of a short-wavelength light image captured by irradiating a palm with short-wavelength light. The imaging means 13 is composed of, for example, a CMOS camera, and is preferably capable of imaging both a near-infrared image irradiated with near-infrared rays and a short-wavelength light image irradiated with short-wavelength light.

For example, the control means 14 alternately performs the first irradiation by the near-infrared irradiation means 11 and the second irradiation by the short-wavelength light irradiation means 12 on the palm of the person to be authenticated, and the first irradiation is performed first, and then at least one irradiation is performed. It is configured to carry out each time, and to take a near-infrared image at the time of the first irradiation and a short-wave light image at the time of the second irradiation by the imaging means 13 . Note that the control means 14 alternately performs the first irradiation by the near-infrared irradiation means 11 and the second irradiation by the short-wavelength light irradiation means 12 until the near-infrared image and the short-wavelength light image can be acquired, and the near-infrared image and the short-wavelength light image are obtained. Preferably, it is arranged to repeat taking short wavelength light images. Further, the control unit 14 controls the timing of the first irradiation by the near-infrared irradiation unit 11 and the timing of capturing the near-infrared image by the imaging unit 13, and the timing of the second irradiation by the short-wavelength light irradiation unit 12 and the short-wave irradiation by the imaging unit 13. It is preferable to have a synchronizing means for synchronizing with the imaging timing of the wavelength light image. As the synchronizing means, for example, a signal indicating frame switching of the imaging means 13 or a signal prompting the light emission timing of the strobe is used as a synchronizing signal. It is preferable to configure so that the second irradiation by the wavelength light irradiation means 12 and the imaging by the imaging means 13 are performed.

This palm print authentication device 10 also includes palm coordinate extraction means 15 for extracting the coordinates of the palm image range used for authentication from the near-infrared image taken by the imaging means 13, and the short-wavelength light image taken by the imaging means 13. palm print image extracting means 16 for extracting the image of the coordinate position obtained by the palm coordinate extracting means 15 as an image to be authenticated, and collation means 17 for performing authentication using the authentication target image extracted by the palm print image extracting means 16. and

These palm coordinate extracting means 15, palm print image extracting means 16, and collating means 17 are arranged inside the housing 10A, for example. The palm coordinate extraction means 15 is connected to the imaging means 13, the control means 14, and the palm print image extraction means 16, for example. The palm print image extraction means 16 is connected to, for example, the imaging means 13, the control means 14, the palm coordinate extraction means 15, and the collation means 17, respectively. The collation means 17 is connected to the control part 14 and the palm print image extraction means 16, for example.

The palm coordinate extraction means 15 is configured, for example, to extract the coordinates of the palm image range used for authentication in the following manner. FIG. 4 explains the extraction method. The palm coordinate extraction means 15, for example, binarizes the near-infrared image, extracts a valley portion A between the bases of the index and middle fingers and a valley portion B between the bases of the ring finger and little finger, and extracts these two points A and B. , then draw a straight line X that is perpendicular to this straight line Y and passes through the centers of two points A and B; A parallel square region R with a center C separated from the straight line Y by a predetermined distance is defined as a palm image range, and its coordinates are extracted. Any extraction method may be used in the palm coordinate extraction means 15, and other methods may be used for extraction.

The palm print image extracting means 16 is configured, for example, as shown in FIG. 5, to extract an image of a portion corresponding to the region R specified by the palm coordinate extracting means 15 from the short wavelength light image as an authentication target image. ing.

The verification means 17 is configured to, for example, extract feature points from the authentication target image extracted by the palmprint image extraction means 16, and perform authentication by comparing the feature points with the feature points of the verification image of the registrant's palmprint registered in advance. preferably. For example, the matching means 17 is preferably configured to perform authentication by the phase-only correlation method. In the phase-only correlation method, a correlation function is calculated using only phase information obtained by Fourier transforming an image that has been converted into a digital signal.

As a specific configuration of the collation unit 17, for example, it has a storage unit 17A, a collation position specifying unit 17B, a correlation calculation unit 17C, a correction unit 17D, and a determination unit 17F. The storage unit 17A stores the verification image of the registrant's palmprint and the authentication target image extracted by the palmprint image extraction unit 16 . The matching position specifying unit 17B specifies matching positions for the matching image and the authentication target image, and is configured to specify, for example, positions (ranges) indicated by black circles in FIG. The correlation calculator 17C calculates a positional deviation amount and a correlation peak (similarity scale) with respect to the matching positions of the matching image and the authentication target image using the phase-only correlation method. The correction unit 17D corrects the matching position based on the positional deviation amount obtained by the correlation calculation unit 17C. The determination unit 17E determines that the person is the person when the correlation peak value obtained by the correlation calculation unit 17C is equal to or higher than a certain threshold, and determines that the person is not the person when the value is lower than the threshold. The collation means 17 sequentially performs the identification of the collation position by the collation position identification unit 17B, the calculation of the correlation function by the correlation calculation unit 17C, and the correction by the correction unit 17D, and makes a determination based on the obtained correlation peak value. It is preferably configured to be determined by the unit 17E.

This palm print authentication device 10 preferably further comprises, for example, authentication starting means 18 for starting authentication, and display means 19 . The authentication initiation means 18 and the display means 19 are arranged, for example, on the surface of the housing 10A and connected to the control means 14, respectively. The authentication start means 19 can be composed of, for example, a sensor that detects that the palm is held near the imaging means 13, or a switch that the person to be authenticated instructs to start authentication. The display unit 19 displays, for example, the result of authentication by the collation unit, and may display an image picked up by the imaging unit 14 at the time of authentication.

For example, the palm print authentication device 10 performs authentication as follows. FIG. 7 shows the procedure flow of the palmprint authentication method according to the present embodiment.

First, when the authentication starting means 18 instructs the start of authentication, the near-infrared irradiation means 11 first irradiates the palm of the person to be authenticated with near-infrared rays having a wavelength of 780 nm or more and 940 nm or less according to the instruction from the control means 14. (Step S101), the image capturing means 13 captures a near-infrared image at the time of the first irradiation (step S102). A near-infrared image captured by the imaging means 13 (see, for example, FIG. 2) is sent to the palm coordinate extraction means 15, and the palm coordinate extraction means 15 extracts the coordinates of the palm image range used for authentication from the near-infrared image. Extract (step S103).

Specifically, for example, as shown in FIG. 4, the near-infrared image is binarized, and the valley portion A between the base of the index finger and the middle finger and the valley portion B between the base of the ring finger and little finger are extracted, Draw a straight line Y connecting these two points A and B, then draw a straight line X perpendicular to this straight line Y and passing through the centers of the two points A and B, then have a center C on the straight line X, A square region R having one side parallel to the straight line X and having a center C separated from the straight line Y by a predetermined distance is set as a palm image range, and its coordinates are extracted. After extracting the coordinates of the palm image range, the palm coordinate extraction means 15 sends the coordinates to the palm print image extraction means 16 and also sends a signal to the control means 14 indicating that the coordinates of the palm image range have been extracted.

Further, the control means 14 instructs the near-infrared irradiation means 11 to perform the first near-infrared irradiation, instructs the imaging means 13 to perform imaging during the first irradiation, and then directs the short-wavelength light irradiation means 12 to perform the first short-wavelength light irradiation. In addition to instructing the second irradiation, the imaging means 13 is instructed to perform imaging during the second irradiation. As a result, the short-wavelength light irradiation means 12 secondly irradiates the palm of the person to be authenticated with the short-wavelength light (step S104), and the imaging means 13 captures the short-wavelength light image during the second irradiation (step S105). ). The short-wavelength light image (see, for example, FIG. 3) captured by the imaging means 13 is sent to the palmprint image extraction means 16, and the palmprint image extraction means 16 obtains the palm coordinate extraction means 15 from the short-wavelength light image. The image at the determined coordinate position is extracted as an image to be authenticated (step S106).

Specifically, for example, as shown in FIG. 5, an image of a portion corresponding to the region R specified by the palm coordinate extraction means 15 is extracted from the short-wavelength light image as the authentication target image. After extracting the authentication target image, the palm print image extracting means 16 sends the authentication target image to the matching means 17 and also sends a signal to the effect that the authentication target image has been extracted to the control means 14 .

Note that the control means 14 waits until it receives a signal indicating that the coordinates of the palm image range have been extracted from the palm coordinate extracting means 15 and a signal indicating that the authentication target image has been extracted from the palm print image extracting means 16. Instructions for first irradiation to the infrared irradiation means 11, instructions for imaging during the first irradiation for the imaging means 13, instructions for second irradiation for the short-wavelength light irradiation means 12, and during the second irradiation for the imaging means 13 , and instructions for imaging are alternately performed.

After that, the matching means 17 compares the feature points of the authentication target image and the matching image (step S107). Specifically, for example, as indicated by black circles in FIG. A positional deviation amount and a correlation peak are calculated by the method, and the matching position is corrected by the correction unit 17D, and these are repeated multiple times as necessary. Next, when the correlation peak value obtained by the correlation calculation unit 17C is equal to or greater than a certain threshold value by the judgment unit 17E (step S108; Y), the person is judged to be the person. (step S108; N), it is determined that the person is not the person himself/herself. The collation means 17 sends the judgment result to the control part 14 , and the control part 14 displays the result on the display means 19 . Further, the collation means 17 outputs the determination result to an external device (not shown) that uses the authentication result, for example.

As described above, according to the present embodiment, the near-infrared image is captured by irradiating the near-infrared rays, so that an object close to the near-infrared image capturing means 13 is captured and an object far away is not captured. The background can be easily removed and the position of the palm can be easily recognized by using the characteristic that there is no background. In addition, since the short-wavelength light is irradiated and the short-wavelength light image is captured, the palm print can be clearly captured. Therefore, by extracting the coordinates of the image range of the palm used for authentication from the near-infrared image and extracting the image of the coordinate position from the short-wavelength light image, the image to be authenticated can be easily obtained. Therefore, complicated image processing for extracting the authentication target image of the palm from the captured image is not required, and the matching can be performed at high speed. Furthermore, since a short-wavelength light image is used, authentication can be performed with high accuracy.

Although the present invention has been described with reference to the embodiments and examples, the present invention can be modified in various ways. For example, although the constituent elements of the present invention have been specifically described in the above embodiment, the specific configuration may be different. Further, it may not include all the components described in the above embodiments, or may include other components.

It can be used for palm print authentication.

DESCRIPTION OF SYMBOLS 10...Palmprint authentication apparatus, 10A...Housing, 11...Near-infrared irradiation means, 12...Short wavelength light irradiation means, 13...Imaging means, 14...Control means, 15...Palm coordinate extraction means, 16...Palmprint image extraction means, 17... Collation means, 17A... Storage unit, 17B... Feature point extraction unit, 17C... Comparison unit, 18... Authentication start means, 19... Display means

Claims (6)

A palmprint authentication device that performs authentication using a palmprint,
a near-infrared irradiation means for irradiating near-infrared rays having a wavelength of 780 nm or more and 940 nm or less to the palm of the person to be authenticated;
Short-wavelength light irradiation means for irradiating the palm of the person to be authenticated with light having a wavelength of 380 nm or more and 570 nm or less, which is shorter than that of near-infrared rays;
imaging means for imaging the palm of the person to be authenticated;
The first irradiation by the near-infrared irradiation means and the second irradiation by the short-wavelength light irradiation means are alternately performed, and the first irradiation is performed at least once each, and the imaging means performs the first irradiation near the time of the first irradiation. a control means for controlling to capture an infrared image and a short-wavelength light image during the second irradiation;
palm coordinate extraction means for extracting the coordinates of the palm image range used for authentication from the near-infrared image captured by the imaging means;
palm print image extracting means for extracting an image of the coordinate position obtained by the palm coordinate extracting means from the short-wavelength light image captured by the imaging means as an authentication target image;
A palmprint authentication device, comprising: a matching means for performing authentication using the authentication target image extracted by the palmprint image extraction means. The collation means extracts feature points from the image to be authenticated extracted by the palm print image extraction means, and performs authentication by comparing the feature points with the feature points of a pre-registered registrant's palm print image for collation. Item 1. The palmprint authentication device according to item 1. The imaging means includes timing of first irradiation by the near-infrared irradiation means and timing of capturing a near-infrared image by the imaging means, and timing of second irradiation by the short-wavelength light irradiation means and short-wavelength light by the imaging means. 3. The palmprint authentication device according to claim 1, further comprising synchronization means for synchronizing with the timing of image pickup. 2. The wavelength range of the near-infrared rays irradiated by the near-infrared irradiation means is 810 nm or more and 880 nm or less, and the wavelength range of the light irradiated by the short-wavelength light irradiation means is 450 nm or more and 495 nm or less. The palm print authentication device according to claim 3. A palmprint authentication method for authentication using a palmprint,
A near-infrared image capturing procedure for irradiating the palm of the person to be authenticated with near-infrared light having a wavelength of 780 nm or more and 940 nm or less, and capturing a near-infrared image;
A palm coordinate extraction procedure for extracting the coordinates of the palm image range used for authentication from the near-infrared image captured in the near-infrared image capturing procedure;
After the near-infrared image capturing procedure, a short-wavelength light image capturing procedure for capturing a short-wavelength light image by irradiating the palm of the person to be authenticated with light having a wavelength of 380 nm or more and 570 nm or less, which is shorter than the near-infrared light;
a palmprint image extraction procedure for extracting an image of the coordinate position obtained by the palm coordinate extraction procedure from the short wavelength light image captured in the short wavelength light image pickup procedure as an authentication target image;
A palmprint authentication method comprising: a matching procedure for performing authentication using the authentication target image extracted by the palmprint image extraction procedure. In the verification procedure, feature points are extracted from the image to be authenticated extracted by the palm print image extraction procedure, and authentication is performed by comparing the feature points with the feature points of a pre-registered registrant's palm print verification image. Item 6. The palmprint authentication method according to item 5.

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