JP3450675B2 - Pattern input device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern input device suitable for use in a device for personal recognition based on a biometric information pattern, such as a fingerprint collation device or a face image collation device.

[0002]

2. Description of the Related Art In recent years, in fields requiring personal recognition such as entry / exit control for computer rooms and important machine rooms, access control for computer terminals and bank financial terminals,
A fingerprint collation device and a face image collation device are being adopted in place of the personal identification number and the ID card used so far.

Japanese Unexamined Patent Publication No. 1-307886 discloses a "contact type fingerprint detecting device" for capturing a registered fingerprint or a collated fingerprint in a fingerprint collating device. This contact type fingerprint detection device aims to obtain a clear and wide fingerprint image irrespective of individual differences in sweating, and the time t1 from the brightness S of the input fingerprint image S1 to S2 (S2> S1) An input fingerprint image obtained after measurement and a predetermined time t2 corresponding to this time t1 is taken in as a registration / verification fingerprint.

That is, although a person whose sweating is relatively active has the brightness S of the fingerprint image over the brightness value S0 over a wide range,
For a person who sweats relatively slowly, the brightness S of the fingerprint image is the brightness value S0.
The range over is narrow. However, over time, the brightness of the fingerprint image exceeds S2 for everyone. Therefore, the time t from S1 to S2 is determined by setting S1 lower than S2.
If 1 is measured and the fingerprint image is captured after a predetermined time t2 corresponding to this time t1, the fingerprint image in a state where sweating is appropriate can be captured in any case.

[0005]

However, according to this contact type fingerprint detecting device, when the surrounding environment is low temperature and low humidity or in the case of a fingerprint image of an atopic person, its brightness S
May not reach S2. In this case, the fingerprint image cannot be captured because t1 cannot be measured. Even in such a case, it is necessary to make S1 and S2 considerably low in order to be able to capture the fingerprint image. However, if S1 and S2 are lowered,
In the normal case, the sweating is not sufficient and the fingerprint image is captured in a state of poor quality, which deteriorates the matching accuracy .

The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a pattern capable of quickly capturing a biometric information pattern image such as a fingerprint image or a face image with high quality. It is to provide an input device.

[0007]

In order to achieve such an object, the first invention (the invention according to claim 1) compares the image illuminance of an inputted biometric information pattern with a first threshold value. If the pattern image illuminance is equal to or higher than the first threshold, the first pattern image capturing means for immediately capturing the pattern image at that time, the image illuminance of the biometric information pattern to be input, and the first threshold If the pattern image illuminance is higher than the second threshold and lower than the first threshold for a predetermined time, the pattern image with the highest illuminance within the predetermined time is captured. The second pattern image capturing means is provided. According to the present invention, when the image illuminance of the input biometric information pattern becomes equal to or higher than the first threshold value, the pattern image is immediately captured. On the other hand, if the first threshold is not reached, the second
When the state of being equal to or more than the threshold value is maintained for a predetermined time, the pattern image with the highest illuminance within the predetermined time is captured.

The second invention (the invention according to claim 2) is the first invention.
In the invention, when the area value of the pattern image is equal to or less than the predetermined value and the variance value of the illuminance is equal to or more than the predetermined value, the removing means is provided for removing the pattern image from the image to be captured. According to the present invention, when the area value of the pattern image is equal to or smaller than the predetermined value and the variance value of the illuminance is equal to or larger than the predetermined value, the pattern image is excluded from the capture target images. A third invention (the invention according to claim 3) is provided with an operation instructing means for giving an operation instruction to appropriately input the pattern image again when the pattern image is removed from the capture target image in the second invention. It is a thing. According to the present invention, when the area value of the pattern image is equal to or less than the predetermined value and the variance value of the illuminance is equal to or more than the predetermined value, the pattern image is removed from the capture target image, and again appropriately. An operation instruction is given to input the pattern image.

[0009]

[0010]

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail based on embodiments. FIG. 2 is a block configuration diagram of a fingerprint collation device showing an embodiment of the present invention. In the figure, 10 is an operation unit, 20 is a control unit, and the operation unit 10 includes a ten-key 10-1, a display (LCD).
A fingerprint sensor 10-3 is provided together with 10-2.
The fingerprint sensor 10-3 includes a light source (LED) 10-31, a prism 10-32, and a CCD camera 10-33.

The control unit 20 includes a control unit 20-1 having a CPU, a ROM 20-2, and a RAM 20-.
3, a hard disk (HD) 20-4, a frame memory (FM) 20-5, and an external connection unit (I / F) 20-
6 and a Fourier transform unit (FFT) 20-7, and the ROM 20-2 stores a registration program and a collation program.

[ Embodiment ] [Capture of Fingerprint Image] In this fingerprint collating apparatus, a user's fingerprint is captured as follows. That is, when inputting the registered fingerprint or the collation fingerprint, the user inputs the ID number (identification number) assigned to himself / herself using the ten-key 10-1 and then inputs the finger on the prism 10-32 of the fingerprint sensor 10-3. Put.
Light is emitted from the light source 10-31 to the prism 10-32, and the valley portion of the fingerprint is dark and the ridge portion is bright, and a fingerprint fingerprint pattern with high contrast is collected. The collected fingerprint pattern is given to the control unit 20 by A / D conversion as a grayscale image (image data) of 512 × 512 pixels and 256 gradations.

The control unit 20-1 takes in the image data supplied from the operation unit 10 via the frame memory 20-5, and performs a reduction process on the taken-in image data. As a result, the image data of the input fingerprint is 128 ×
The image data is reduced to 128 pixels and 256 gradations (see FIG. 3). Then, the control unit 20-1 sets the center of the reduced image data of the input fingerprint (fingerprint image) to be the same as the center of the image data area A1 50 × 5.
The illuminance (average illuminance) of the 0 pixel local area A2 is obtained.

Then, the control unit 20-1 compares the illuminance of the local area A2 (hereinafter, this illuminance is referred to as relative area illuminance) Lx with a predetermined first threshold value L1 (see FIG. 1). Step 101) shown, and if Lx ≧ L1, the process proceeds to step 114.

In step 114, the control unit 20-1
Compares the area value Bx of the fingerprint image in the local area A2 with a predetermined value B1. That is,
The number Bx of pixels having a certain illuminance value or more in the local area A2 is compared with a predetermined value B1. Also, step 114
In, the control unit 20-1 compares the variance value Dx of the illuminance of the fingerprint image in the local area A2 with a predetermined value D1. The dispersion of the illuminance of the fingerprint image is described in detail in, for example, Japanese Patent Laid-Open No. 61-145686, so the description thereof will be omitted here.

The comparison result in step 114 is Bx ≦ B
When 1 and Dx ≧ D1, it is determined that the image is dirty or that the fingerprint image is too small, and a message to the operator “Please push a little more strongly” is displayed on the display 10-2. Ue (Step 11
5) Return to the fingerprint acquisition conditions. This prompts the operator to appropriately input the fingerprint image again, and the operator does not get confused. Also, YES in step 114 .
The determined fingerprint image is removed from the fingerprint image to be captured in step 102. The message in step 115 may be voiced. Further, steps 114 and 115 may be omitted.

The comparison result in step 114 is Bx> B
If 1 and Dx <D1, it is determined that there is no problem with the area value of the fingerprint image in the local area A2 that is a standard fingerprint, the fingerprint image at that time is immediately taken, and the RAM 20-3 (Step 102).
Then, if the timer in step 108 described later is operating, this timer is stopped (step 10
3) The procedure proceeds to registration / verification processing.

On the other hand, the comparison result in step 101 is Lx.
<L1, the process proceeds to step 104. In step 104, the control unit 20-1 determines the relative area illuminance L
x is compared with a predetermined second threshold value L2.
Here, the second threshold L2 is set lower than the first threshold L1. In this embodiment, it is set slightly higher than in the case of only the background without fingerprints.

If Lx <L2 in step 104, it is determined that only the background is in the state where no finger is placed, and the process returns to the fingerprint capture condition through NO in step 112.
If Lx ≧ L2 in step 104, it is determined that the fingerprint or the stain is present, and the process proceeds to step 105.

In step 105, the control unit 20-1
In the same manner as in step 114 above, the local area A2
The area value Bx of the fingerprint image in FIG. 4 is compared with a predetermined value B1, and the variance value Dx of the illuminance of the fingerprint image in the local area A2 is compared with a predetermined value D1.

The comparison result in step 105 is Bx ≦ B
When 1 and Dx ≧ D1, it is determined that the image is dirty or that the fingerprint image is too small, and a message to the operator “Please push a little more strongly” is displayed on the display 10-2. Ue (Step 10
6) Then, the process returns to the fingerprint acquisition condition through NO in step 112. This prompts the operator to appropriately input the fingerprint image again, and the operator does not get confused.
The fingerprint image determined as YES in step 105 is removed from the fingerprint image to be captured in step 113 described later. The message in step 106 may be voiced. Also, steps 105 and 1
06 may be omitted.

The comparison result in step 105 is Bx> B
If 1 and Dx <D1, it is determined that the image is a thin fingerprint image, and if NO in step 107, the process proceeds to step 108 to start a check timer (soft timer) for 1 second. Then, the section maximum value = 0 is set (step 109), and the relative area illuminance Lx is compared with the section maximum value (step 110). Where Lx ≧
If it is the section maximum value, Lx at this time is set as a new section maximum value, and the fingerprint image at this time is also updated and stored (step 111). In this case, since the section maximum value = 0, the Lx at the time when the relative area illuminance Lx exceeds the second threshold value L2 is the section maximum value. Further, the fingerprint image at this time is saved.

Then, the control section 20-1 executes step 10
It is confirmed whether or not the time counting of the timer started in 8 is finished (timer fire) (step 112), and Lx <L
If 1, then step 104 until timer fire
The operations of to 112 are repeated. As a result, if the state in which the relative area illuminance Lx is equal to or greater than the second threshold L2 and less than the first threshold L1 is maintained for 1 second, the highest value of the relative area illuminance Lx during the 1 second is set as the section maximum value. At this time, the control unit 20-1 proceeds to step 113 in response to YES in step 112, takes in the fingerprint image whose relative area illuminance Lx secured in step 111 is the maximum value in the section, and proceeds to registration / verification processing. And proceed.

FIG. 4A shows the time variation of the relative area illuminance Lx in the case of a normal fingerprint. In this case, after the relative area illuminance Lx becomes equal to or larger than the second threshold value L2 (t1 point),
Immediately (within 1 second), the first threshold value L1 or higher is reached (t2 point), so the time point t2 when the first threshold value L1 or higher is reached.
The fingerprint image of is captured immediately.

FIG. 4B shows the time variation of the relative area illuminance Lx in the case of a thin fingerprint. In this case, the relative area illuminance Lx is 1 or more after the second threshold L2 or more (t1 point) and then the second threshold L2 or more and less than the first threshold L1.
Hold for more than a second. Therefore, the relative area illuminance Lx is the second
When the relative area illuminance Lx is the highest value, the fingerprint image at the time point t2 is captured in the following 1 second after the threshold value L2 is equal to or more than the threshold value L2.

As described above, according to this embodiment, if the state in which the relative area illuminance Lx is equal to or greater than the second threshold value L2 and is less than the first threshold value L1 continues for 1 second, during that 1 second. The best quality fingerprint image will be captured, and even if the surrounding environment is low temperature and low humidity or the fingerprint image of a person with atopic disease, you can quickly capture a high quality fingerprint image and perform registration or matching. Will be able to.

Reference Example FIG. 5 is a time chart showing the timing of starting energization of the CCD camera 10-33 and the light source 10-31 and the timing of capturing a fingerprint image in the fingerprint collation device shown in FIG.

In this case, when inputting the registered fingerprint or the collation fingerprint, the user inputs the ID number (identification number) assigned to himself using the ten-key 10-1. For example,
Enter "123 #". Then, the control unit 20-1
In response to the input operation of the first number “1” of this ID number (input start operation of the identification number), energization of the CCD camera 10-33 is started (power-on) at the same time when this number “1” is input. (Point t1 shown in FIG. 5A). As a result, the output of the CCD camera 10-33 becomes unstable for 0.5 to 0.6 seconds after the power is turned on, but remains stable after that.

Subsequently, the user inputs the ID number numbers "2" and "3", and finally "#". Then, the control unit 20-1 responds to the input operation of the last number “#” of this ID number (input completion operation of the identification number), and simultaneously inputs the number “#” to the light source 10-31. Energization is started (power is turned on) (t2 shown in FIG. 5B)
point). As a result, the light source 10-31 emits light with almost no delay, and the light emission output of the light source 10-31 immediately maintains a stable state.

Here, the control section 20-1 controls the light source 10-3.
1 is started, that is, in a state where both the CCD camera 10-33 and the light source 10-31 are turned on, the capturing of the image of the finger placed on the prism 10-32 is started (FIG. 5 ( See c)). It should be noted that in this embodiment, the capture of the fingerprint image is started 1/60 seconds after the start of energization of the light source 10-31.
Then, the presence / absence of the fingerprint is determined every 60 msec,
If there is a fingerprint, registration or verification is performed.

As described above, according to this reference example , the fingerprint image is not captured during the rising time of the CCD camera 10-33, the fingerprint image can be captured with high quality, and the collation accuracy is deteriorated. Can be prevented. Further, according to this reference example , since the energization of the CCD camera 10-33 and the light source 10-31 is started in response to the input operation of the ID number, the waiting time is eliminated and the usability is improved for the user. .

As a conventional method, it is possible to turn on the light source 10-31 and the CCD camera 10-33 at the same time and wait for the rise time of the CCD camera 10-33 to capture the fingerprint image. But with this method,
The CCD camera 10-33 may wait unnecessarily for the rising time to elapse, which may delay the capture of the fingerprint image. On the other hand, in this reference example , a high-quality fingerprint image can be quickly captured without waiting more than necessary.

As a conventional method, it can be considered that the light source 10-31 and the CCD camera 10-33 are kept energized. However, this method has a problem in life and power consumption. On the other hand, in this reference example , the lives of the light source 10-31 and the CCD camera 10-33 can be extended, and the influence of the heat of the light source 10-31 on the device can be reduced.

In this reference example , the power supply to the light source 10-31 is started in response to the operation of completing the input of the identification number, but the operation of starting the input of the identification number is performed in the CCD camera 10-33. After the energization is started, the energization of the light source 10-31 may be started after waiting a predetermined time.

[0036]

As is apparent from the above description, according to the present invention, in the first invention, when the image illuminance of the biometric information pattern to be input becomes equal to or higher than the first threshold value, the pattern image is immediately captured. On the other hand, when the first threshold value is not reached, the pattern image with the highest illuminance within the predetermined time is captured when the state of being equal to or higher than the second threshold value is maintained for the predetermined time. An image of a biometric information pattern such as an image can be captured quickly and with high quality.

In the second invention, in the first invention, when the area value of the pattern image is equal to or less than the predetermined value and the variance value of the illuminance is equal to or more than the predetermined value, the pattern image is excluded from the capture target image. As a result, a dirty image or a pattern image that is too small is prevented from being captured as an image of the biometric information pattern. In the third invention, in the second invention, when the area value of the pattern image is equal to or smaller than a predetermined value and the variance value of the illuminance is equal to or larger than the predetermined value, the pattern image is excluded from the capture target image. Therefore, the operation instruction is given to input the pattern image properly again, and in addition to the effect of the second invention, it is urged to input the pattern image again properly, and the operator is not confused. I'm done.

[0038]

[Brief description of drawings]

FIG. 1 is a flowchart for explaining a fingerprint image capturing operation in a fingerprint collation device according to the present invention.

FIG. 2 is a block diagram of the fingerprint collation device.

FIG. 3 is a diagram showing a local area defined for a fingerprint image.

FIG. 4 is a diagram showing a temporal change in relative area illuminance Lx for a normal fingerprint and a thin fingerprint.

FIG. 5 is a time chart showing the timing of starting energization of a CCD camera and a light source and the timing of capturing a fingerprint image.

[Explanation of symbols]

10 ... Operation part, 20 ... Control part, 10-1 ... Numeric keypad, 10-2 ... Display (LCD), 10-3 ...
Fingerprint sensor, 10-31 ... Light source, 10-32, Prism, 10-33 ... CCD camera, 20-1 ... Control unit, 2
0-2 ... ROM, 20-3 ... RAM, 20-4 ... Hard disk (HD), 20-5 ... Frame memory (F
M), 20-6 ... External connection section (I / F), 20-7 ... Fourier transform section (FFT).

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-255481 (JP, A) JP-A-61-145686 (JP, A) JP-A-61-28175 (JP, A) JP-A-61- 43379 (JP, A) JP 61-59574 (JP, A) JP 1-259468 (JP, A) JP 3-180988 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G06T 1/00 A61B 5/117

Claims (3)

(57) [Claims] 1. An image illuminance of an input biometric information pattern is compared with a first threshold value, and if the pattern image illuminance is equal to or higher than a first threshold value, the pattern image at that time is immediately taken in. Comparing the image illuminance of the input biometric information pattern with the second threshold value lower than the first threshold value, and the pattern image illuminance is equal to or higher than the second threshold value and the first threshold value. A pattern input device comprising: a second pattern image capturing means for capturing a pattern image having the highest illuminance within the predetermined time if the state below is maintained for a predetermined time. 2. The removal according to claim 1, wherein when the area value of the pattern image is equal to or less than a predetermined value and the variance value of the illuminance is equal to or more than a predetermined value, the pattern image is removed from the image to be captured. A pattern input device comprising means. 3. The pattern input according to claim 2, further comprising operation instruction means for giving an operation instruction to appropriately input the pattern image again when the pattern image is removed from the image to be captured. apparatus.