JP3014552B2 - Window alignment type fingerprint collation method and device for positioning - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a registration window changing type fingerprint verification method and a fingerprint verification method using a verification window as a positioning window when positioning using a positioning window is difficult.

In recent years, with the introduction of computers into a wide range of social systems, there has been a need to maintain the security of such systems. For example, when entering a computer room or the like, or when using a terminal device, ID cards and passwords conventionally used as means for confirming whether or not the person is the user still have a problem in terms of ensuring security. For this reason, the use of a fingerprint collation device as a powerful alternative has been studied.
Fingerprint verification is used for fingerprints,
This is because it has two major characteristics, "lifelong immutability."

[0003]

2. Description of the Related Art Conventionally, fingerprint matching uses fingerprint feature points in order to effectively use the above-described features.
The characteristic point refers to a point (a branch point) at which a ridge formed of a series of convex portions of the fine irregularities formed on the fingertip is divided into two, or a dead end point (end point). These feature points form the two major features of the fingerprint.

[0004] In the fingerprint collation, it is possible to flexibly cope with a high speed of the fingerprint collation and a partial expansion and contraction of a fingerprint image due to a difference in how a force is applied at the time of inputting a fingerprint and moving with a finger on the glass. What can be done is an issue to be solved. To meet this demand, the present applicant has already proposed a fingerprint registration and collation method called the "moving window method". The outline of the fingerprint registration / collation method is as follows.

[0005] In the registration verification system of the fingerprint, one and aligning window position, the feature information storage unit and a plurality of matching windows that are obtained as around <br/> the alignment window in its registration To memorize. FIG. 4 shows an example in which the one alignment window and a plurality of collation windows are shown on an input fingerprint image.
Shown in To explain this with reference to FIG. 5, and stores the binarized fingerprint signal from the fingerprint sensor 2 0 in the binarization circuit 22 into binary memory 24. 2 of the fingerprint in the binarization memory 24
The value image is thinned by the feature extraction unit 28 to extract feature points. The extracted binary image near the predetermined number of feature points is cut out as a “window” by the window cutout unit 30 and the window is registered in the feature information storage unit 32.

At the time of registration, as registration information,
The binary image in the “window”, the relative positional relationship between the “window” and the “window”, the type of the feature point in the “window”, and the like are registered in the feature information storage unit 32, and these are registered. Select one stable window that is relatively close to the center of the fingerprint among the “windows”, and use it as the “registration registration window” and the rest as the “registration verification window”.
Define and register as

Next, in the "collation" process, the coordinates of the "registration registration window" registered in the characteristic information storage unit 32 are used by the main displacement amount changing unit 34, and the read address from the memory address specifying unit 38 is read out. Is output, and the “registration registration window” is read from the feature information storage unit 32. Pattern matching between the “registration registration window” and a corresponding window (hereinafter referred to as an input fingerprint image window) in the input fingerprint image written in the binarization memory 24 as described above is performed by pixel value comparing means. Performed at 40 (see S1 in FIG. 6),
The displacement amount indicating the difference between the input positions at the time of registration and at the time of collation is extracted. As shown in FIG. 6, the displacement amount is extracted until a candidate point is found in the comparison between the “registered registration window” and the input fingerprint image (see Yes in S2 in FIG. 6). By moving the position of the “registration registration window” by one or two dots (see S3 in FIG. 6), it is determined whether or not the movement is within a predetermined movement range (S4 in FIG. 6).
(See S1 in FIG. 6) to extract candidate points (see S2 in FIG. 6). In determining whether the movement is within a predetermined movement range,
If the input image is out of the range (No in S4 in FIG. 6), the fingerprint matching for the input image is rejected and the fingerprint matching is rejected (S5 in FIG. 6).

The displacement amount is used for collation between the registration collation window and the input fingerprint image window. That is, a comparison is made between the registration matching window moved by the displacement amount and the input fingerprint image window corresponding to the registration matching window. In the matching between each registration matching window and the corresponding input fingerprint image window, for each window,
In addition to providing the registration matching window with a displacement corresponding to the displacement amount of the registration matching window, a spiral shape in the pattern matching between the “registered registration window” and the corresponding registration window in the input fingerprint image. The movement is changed by the sub-displacement amount changing means 36.
The registration matching window is read out from the feature information storage unit 32 by the memory addressing means 38 in a state where the window is given to the registration matching window by using the register value matching window in the input image. This is performed by the comparing means 40 (S in FIG. 6).
6). This is because human fingers are very soft
This is for absorbing the partial expansion and contraction of the input fingerprint image due to the difference in the way of applying the force at the time of imprinting.

In the collation (pattern matching), the collation is obtained (passed) and the pixel value comparing means 4
When a pass signal is output from 0 (S7 in FIG. 6)
If the number of passes is greater than a predetermined threshold (see Yes in S8 of FIG. 6), a signal indicating that the identity of the user has been obtained is output from the pass window evaluation means 42 (see FIG. 6). See S11).

If the result is not acceptable (No in S7 in FIG. 6), or if the number of passes is less than the threshold (S8 in FIG. 6).
If the above processing has not been completed for all windows (see No in S9 of FIG. 6), the feature information storage unit 32
Using the coordinate information of the next registered collation window registered in (1) (see S10 in FIG. 6), the above-described processing for the collation window, that is, steps S6 to S9, is performed.

The above processing steps 6 to S8 have been performed for all windows. If the number of passes still does not reach the threshold value (see Yes in S9 of FIG. 6), the collation processing for the person to be collated is performed. Reject (see S12 in FIG. 6).

[0012]

[Problems to be Solved by the Invention]
The window method performs the fingerprint collation processing as described above. However, since there is only one registration registration window, if the collation fails, the collation is also performed for the subsequent collation windows. Can not do. From the standpoint of improving the matching rate, it still has problems.

SUMMARY OF THE INVENTION The present invention has been made in view of the above technical problem, and has a registration window changing type fingerprint verification method for improving a verification ratio by using a plurality of positioning windows for window positioning. Its purpose is to provide the device.

[0014]

SUMMARY OF THE INVENTION The invention according to claim 1, i.e. the invention of the window changes fingerprint verification method for positioning a registration position
The order in which the alignment window will be used as the registration
In accordance with a predetermined order, the registered registration window and the input fingerprint image are compared by matching the registered registration window with the registration window corresponding to the registered registration window in the input fingerprint image. A predetermined number of registration / collation windows and a registration / collation window for determining a displacement amount between the registration / registration window corresponding to the registration / registration window and a relative correction corresponding to the displacement amount for comparison. Between the windows for matching in the input fingerprint image corresponding to each of
When a predetermined number of registered matching windows in the order and matching of each matching window in the input fingerprint image corresponding to each of the registered matching windows are not obtained, the next order used as the registered position matching window. (Hereinafter referred to as a tentative registered position matching window) and a position matching window in the input fingerprint image corresponding to the tentative registered position matching window,
Determine the amount of displacement between the temporary registration positioning window and the registration window corresponding to the temporary registration registration window in the input fingerprint image, and perform a relative correction according to the displacement amount. A process of performing matching between a predetermined number of registration matching windows other than the registration matching window used as the temporary registration positioning window and a matching window in the input image corresponding to the registration matching window. It is characterized by repeating in that order.

As shown in FIG. 1, the invention according to claim 2, that is, the invention of a fingerprint matching device with a window changing type for registration, corresponds to a registration registration window and a registration registration window in an input fingerprint image. The amount of displacement with respect to the positioning window is determined, and a correction according to the amount of displacement is performed on a predetermined number of registration / verification windows, and the predetermined number of registration / verification windows and the registration in the input fingerprint image are determined. In a fingerprint matching device that performs matching with a matching window corresponding to each matching window, a registration position matching window storage means 2 and a predetermined number of registered matching windows are registered when registering the registration matching window. Window registration control means 4 for determining the order to be used as the positioning window and registering it in the registered positioning window storage means 2; the predetermined number of registration verification windows; and the registration verification window in the input fingerprint image The collation with the collation window corresponding to each of If not, the registration / registration window having the next rank in the determined order from the registration / registration window storage means 2 is used for matching with the verification window corresponding to the registration / verification window in the input fingerprint image. A window readout control means 8 for outputting as a registration position adjustment window; and a registration position adjustment window output from the window readout control means 8 for registering a position corresponding to the registration position adjustment window in the input fingerprint image. It is characterized in that it is used to determine the amount of displacement between the window and the window.

[0016]

According to the first aspect of the present invention, the registration registration is performed.
The order in which the window is used as the registration verification window is determined in advance,
If necessary, the order is stored in the window for registration registration
Remember. Then, the displacement amount between the registered registration window and the registration window in the input fingerprint image corresponding to the registered registration window is determined by comparing the registered registration window with the registration window.

After a relative correction according to the amount of displacement is made between a predetermined number of registration / verification windows and the verification window in the input fingerprint image corresponding to each of the registration / verification windows. , Matching between the two windows.

In the matching, when a predetermined number of registered matching windows cannot be matched with each matching window in the input fingerprint image corresponding to each of the registered matching windows, the following processing is performed. A registration / collation window in the next order used as a registration registration window (hereinafter referred to as a provisional registration registration window) and a registration in the input fingerprint image corresponding to the provisional registration registration window. After determining the amount of displacement between the temporary registration registration window and the registration window corresponding to the temporary registration registration window in the input fingerprint image by collation with the window, the displacement amount is determined. A predetermined number of registration matching windows other than the registration matching window used as the temporary registration positioning window and the matching in the input image corresponding to each of the registration matching windows are used. The process of performing matching between windows is repeated in this order. In this order, matching between a predetermined number of registered matching windows and each matching window in the input fingerprint image corresponding to each of the registered matching windows is performed. If available, confirm the identity of the fingerprint When not obtained, the same processing is repeated in the further next place.

As described above, the original purpose is to use the registration / collation window used for collation as the temporary registration / registration window as the registration / registration window. Therefore, even if the registration / registration window fails to collate. In this case, the collation processing for the fingerprint is not rejected by itself, thereby improving the fingerprint collation rate.

According to a second aspect of the present invention, when registering a registration / registration window, the order in which a predetermined number of registration / verification windows are used as a registration / positioning window is determined and stored in the registration / registration window storage means 2. register.

When a predetermined number of registered collation windows in the collating means 6 are not collated with the collation windows in the input fingerprint image corresponding to each of the registered collation windows, The window readout control means 8 determines whether the registration / registration window in the next order registered in the registration / registration window storage means 2 is to be compared with the verification window corresponding to the registration / verification window in the input fingerprint image. Read as a registered positioning window for position matching.

The registered position matching window is used for position matching with a matching window corresponding to the registered position matching window (a window originally used as a matching window) in the input fingerprint image. The amount of displacement between the windows is determined, and the amount of displacement is used for fingerprint matching by the moving window method.

According to a second aspect of the present invention, a difference between the first and second registration matching windows and the matching window in the input fingerprint image corresponding to each of the registration matching windows is compared with the first embodiment. Just by having, it is possible to obtain substantially the same effect as the invention according to claim 1.

[0024]

FIG. 2 shows an embodiment of the invention according to the first and second aspects. This embodiment is also a fingerprint collation device based on the Movink window method. In this figure, FIG.
Since the same reference numbers indicate the same components,
The details are omitted. In the embodiment shown in FIG. 2, the characteristic part of the invention according to claim 2 resides in an alignment window order determination unit 31 connected to the window cutout unit 30 and a characteristic information storage unit 33. The means 43 also constitutes a characteristic part. The pass window number evaluation means 43 outputs a registered position adjustment window change signal in addition to the output of the identity confirmation signal.

The personal characteristic information includes, for example,
Includes name, employee number, binary image information, window coordinate information, and the like. In addition, the personal characteristic information includes window use order information for positioning. The positioning window usage order information indicates the order in which the matching window is used as the positioning window in the positioning process, and the order indicates that the matching window is closer to the positioning window than the matching window. The order is determined from the order in which the correlation with the background image is low to the order in which the correlation with the background image is strong.

In FIG. 2, a feature information storage unit 33 corresponds to the registered position matching window storage unit 2 in FIG. 1, and a feature extracting unit 28, a window image cutout unit 30, and a positioning window use order determining unit 31 , Corresponds to the window registration control means 4 of FIG.
The main displacement amount changing means 34, the sub displacement amount changing means 36, the memory address specifying means 38, and the pixel value comparing means 41 correspond to the matching means 6 in FIG. FIG.
Corresponding to the window readout control means 8.

The operation of the apparatus having such a configuration will be described below with reference to FIGS. For convenience of illustration, step S2 in FIG. 3 represents step S8 in FIG. In the registration of the window information, the fingerprint signal read by the fingerprint sensor 20 is binarized by the binarization circuit 22 and stored in the binarization memory 24 as described in the section of [Prior Art]. . The input image is thinned by the feature extraction unit 26 and feature points are extracted. Window extraction is performed by the window image cutout unit 30 using the feature points. Extraction of that window,
That is, in extracting the registration position alignment window and the registration collation window, personal characteristic information is added to the window in the same manner as in the related art. Then, the positioning window use order determining unit 31 assigns a position matching window use order to each matching window.

The personal characteristic information for each of the registered position matching window and the registered collation window is registered in the characteristic information storage unit 33. In the fingerprint collation processing, the input image read out from the binarization memory 24 according to the conventional method and the first order specified by the main displacement amount changing unit 34 and the memory address specifying unit 38 from the feature information storage unit 33. pattern matching according to Figure 6 with the "registered alignment window" of is performed in the pixel value comparison unit 4 1.

In the pattern matching (comparison), when the position can be adjusted, the matching between the registration matching window and the corresponding matching window in the input fingerprint image is started as in the related art. Then, in the collation of the collation window, if the number of passes is larger than a predetermined threshold (Ye in step S8 in FIG. 6).
s), and confirm the person to be verified as the person in question.

The user cannot be identified (step S2 in FIG. 3).
No), if all of the matching windows ranked as alignment windows are not used for alignment (see No in step S3 in FIG. 3), the pixel value comparing unit 41 is used.
Is transferred to the number-of-passed-windows evaluation means 43.
The number-of-accepted-windows evaluation means 43 transfers the alignment window change signal to the characteristic information storage unit 33. As a result, the process shown in FIG. 6 is repeated with the collation window determined to be in the second rank as the registered positioning window or the next rank as the positioning window as the next positioning window. If the identity can be confirmed in the matching process in any of the alignment windows (see Yes in step S2 in FIG. 3), the person who is currently performing the matching process is identified as the identity. Conversely, if all of the matching windows ranked as alignment windows are used for alignment (see Yes in step S3 of FIG. 3), the identification processing cannot be performed and the matching process is rejected. I do. In the above-described embodiment, the case where all the matching windows are used has been described.However, when a predetermined number of matching windows used as alignment windows are used, it is determined that the identity cannot be confirmed. The collation processing may be rejected. The registration position adjustment window and / or the registration collation window and the input fingerprint image window may be relatively moved in response to the displacement amount.

[0031]

As described above, according to the present invention, since the matching window is also used as a positioning window, even if the imaged fingerprint has a flaw different from that at the time of registration, it can be used in the conventional method. Compared to using one alignment window,
The matching rate can be improved.

[Brief description of the drawings]

FIG. 1 is a principle block diagram of the invention according to claim 2;

FIG. 2 is a diagram showing one embodiment of the invention according to claims 1 and 2;

FIG. 3 is a diagram showing a processing flow of one embodiment of the invention according to claims 1 and 2;

FIG. 4 is an explanatory diagram of a known moving window method.

FIG. 5 is a configuration diagram of a conventional fingerprint matching device.

FIG. 6 is a diagram showing a processing flow of the apparatus in FIG. 5;

[Explanation of symbols]

2 Registered Positioning Window Storage Means 4 Window Registration Control Means 6 Matching Means 8 Window Readout Control Means 28 Feature Extraction Unit 30 Window Image Cutout Unit 31 Positioning Window Use Order Determination Unit 33 Feature Information Storage Unit 34 Main Displacement Change Unit 36 auxiliary displacement amount changing means 38 memory address specifying means 40, 41 pixel value comparing means 43 pass window number evaluating means

Continuation of front page (56) References JP-A-63-78286 (JP, A) JP-A-4-3244583 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G06T 7 / 00

Claims (2)

(57) [Claims] 1. A registration positioning window is used as a registration collation window.
The registered position matching window is determined in advance according to a predetermined order, and the registered position matching window is compared with a position matching window in the input fingerprint image corresponding to the registered position matching window. And a predetermined number of registration / collation windows for determining the amount of displacement between the input fingerprint image and the registration window corresponding to the registration position alignment window, and using a relative correction according to the displacement amount for comparison. And a matching window in the input fingerprint image corresponding to each of the registration matching windows to perform matching between the two windows. When the collation with each collation window in the input fingerprint image corresponding to each is not obtained, the registration collation window in the next order used as the registration registration window (hereinafter referred to as a temporary registration registration window) ) And the temporary registration positioning window. By matching the alignment window in the corresponding input fingerprint image,
Determine the amount of displacement between the temporary registration registration window and the registration window corresponding to the temporary registration registration window in the input fingerprint image, and perform relative correction according to the displacement. A process of performing matching between a predetermined number of registration matching windows other than the registration matching window used as the temporary registration positioning window and a matching window in the input image corresponding to the registration matching window. A positioning window changing type fingerprint matching method characterized by repeating in the order. 2. A method for determining a displacement amount between a registration positioning window and a registration window corresponding to the registration positioning window in an input fingerprint image, and correcting a predetermined number of registration verifications according to the displacement amount. A fingerprint matching device that is applied to the registration window and performs matching between the predetermined number of registration matching windows and matching windows corresponding to each of the registration matching windows in the input fingerprint image. The storage means (2) determines the order in which a predetermined number of registration verification windows are used as registration positioning windows when registering the registration verification window, and registers the order in the registration positioning window storage means (2). The window registration control means (4), and the matching means (6) obtains the matching between the predetermined number of registration matching windows and the matching windows corresponding to each of the registration matching windows in the input fingerprint image. When there is no such information, the registered position matching window storage means (2) Window readout control means (8) for outputting a registration / registration window having the next highest rank in the input fingerprint image as a registration / positioning window for matching with a verification window corresponding to the registration / verification window in the input fingerprint image; And using the registration position window output from the window readout control means (8) for determining the amount of displacement between the input fingerprint image and the registration window corresponding to the registration position window in the input fingerprint image. A window-changeable fingerprint collation device featuring a positioning feature.