KR101274260B1 - Apparatus of acquiring fingerprint image and method of acquiring fingerprint image - Google Patents

Abstract

The non-contact fingerprint image acquisition device includes a fingerprint image acquisition unit for obtaining a fingerprint image including at least one specimen inspection image through at least one window disposed in a virtual user's finger, and the fingerprint image from which the at least one specimen inspection image is obtained. It includes a fingerprint image suitability determination unit for checking whether or not the suitability of the.

Description

Non-contact fingerprint image acquisition device and method {APPARATUS OF ACQUIRING FINGERPRINT IMAGE AND METHOD OF ACQUIRING FINGERPRINT IMAGE}

The present invention relates to a non-contact fingerprint image acquisition technology, and more particularly, to obtain a fingerprint image including at least one sample inspection image through at least one window disposed in the virtual user finger, and obtained at least one sample By checking the suitability of the fingerprint image through the inspection image, it is possible to determine the suitability of the entire fingerprint image through at least one inspection process of focus and quality of a portion of the fingerprint image to obtain a high quality fingerprint image at a high processing speed. The present invention relates to a non-contact fingerprint image acquisition device and method.

In general, the fingerprint recognition system is widely used because it is superior in price and performance compared to other biometric systems, and the technology applied to the fingerprint recognition system can be largely classified into a contact and a contactless fingerprint recognition technology.

In this case, the contact fingerprint recognition technology may cause the user to feel rejection because the user's finger needs to be in contact with the flat panel touch sensor. In particular, the contact fingerprint recognition technology may deteriorate the performance of the fingerprint recognition due to distortion of the fingerprint image, which may be generated according to pressure applied to the sensor upon contact, finger movement, and skin condition of the user.

Various contactless fingerprint recognition techniques have been provided to overcome this problem. The following prior art provides techniques related to this.

Korean Patent No. 10-0895274 relates to a non-contact fingerprint image acquisition technology, and more specifically, a finger support in which a user's finger is inserted and supported so as to prevent a user's finger trembling and movement in up, down, left and right, and supported by the finger support. One camera for taking a continuous fingerprint image according to the amount of rotation of the finger in a state fixed to the lower portion of the finger to be fixed, installed between the finger and the camera supported by the finger support and light to the user's fingerprint area A lighting device for illuminating, a light diffuser for distributing the light emitted by the lighting device evenly on the finger, a finger rotation detecting means for measuring the amount of rotation of the finger inserted into the finger support, and operating the camera The fingerprint image inserted into the finger support The present invention relates to a non-contact continuous fingerprint image acquisition device including a controller for controlling a photographing time point of the camera according to a rotation amount of a finger measured by the finger rotation amount sensing means.

Korean Patent No. 10-0604267 relates to a non-contact fingerprint image detection technology, and more particularly, an activation sensor for detecting whether a user's finger approaches a photographing area of the photographing apparatus, and a fingerprint image detection by the activation sensor. As the device is activated, an illumination unit for irradiating light of the short wavelength band to the user fingerprint region, a short-wave pass filter for transmitting the image of the fingerprint region only to the short wavelength band and incident to the photographing apparatus, and to prevent the shaking of the user It relates to a non-contact fingerprint image detection device comprising a support for blocking the incident light to the imaging device.

In order to solve the above problems, the prior art discloses a configuration of photographing and synthesizing a continuous fingerprint image, an illumination configuration having a double structure, and a configuration of transmitting light of a short wavelength band.

In this situation, the non-contact fingerprint recognition technology acquires a fingerprint image through a photographing device (eg, a camera), so that even if the focus of the user's finger is not correct even if the configurations provided by the prior arts are included, a distinct ridge is included. A fingerprint image cannot be obtained. Specifically, when the auto focus function supported by the photographing apparatus is used, the time required to adjust the focus (about 1 s) is longer than the image acquisition time (about 40 ms), so that the fingerprint image obtained through the preprocessing process sharpens the ridge of the user. It is not shown.

Korean Patent Registration No. 10-0895274 Korea Patent Registration No. 10-0604267

The present invention obtains a fingerprint image including at least one sample inspection image through at least one window disposed in the virtual user's finger, and checks the suitability of the fingerprint image through the obtained at least one sample inspection image. Determine whether the entire fingerprint image is appropriate by checking at least one of the focus and quality of a part of the image, and whether a high-quality fingerprint image was obtained at a high processing speed even when using a photographing device with a slow processing speed of auto focus. It is an object of the present invention to provide an apparatus and method for obtaining a non-contact fingerprint image.

The present invention extracts a ridge pattern from at least one sample inspection image and checks whether a fingerprint image is suitable based on at least one of focus suitability and quality suitability determined based on the extracted ridge pattern, thereby providing a high quality fingerprint image. It is an object of the present invention to provide an apparatus and method for obtaining a non-contact fingerprint image, which can determine whether to obtain a fast processing speed.

In example embodiments, the non-contact fingerprint image acquisition device may include a fingerprint image acquisition unit for acquiring a fingerprint image including at least one sample inspection image through at least one window disposed in a virtual user finger, and the at least one sample inspection image. And a fingerprint image suitability determination unit configured to check whether the acquired fingerprint image can be guaranteed.

The display device may further include a display unit configured to display guide lines for the at least one window.

In an embodiment, the fingerprint image acquirer may apply an image enhancement filter associated with at least one of sharpness and contrast to each of the at least one sample inspection image.

In an embodiment, the apparatus may further include a ridge pattern extractor configured to extract a ridge pattern for each of the at least one sample inspection image.

The ridge pattern extracting unit may determine a ridge pattern including at least one ridge by extracting a unit direction component for each of the at least one sample inspection image.

In an example embodiment, the fingerprint image suitability determination unit may determine whether to focus on each of the at least one sample inspection image based on contrast between the ridge region and the non-ridge region included in the extracted ridge pattern. have.

In one embodiment, the fingerprint image suitability determination unit may determine whether the quality suitability for each of the at least one sample inspection image based on at least one of the area of the ridge area and the distance between the ridge area.

The fingerprint image suitability determination unit may determine whether the acquired fingerprint image is suitable based on at least one of focus suitability and quality suitability for each of the determined at least one sample inspection image.

In an embodiment, the fingerprint image suitability determination unit may ensure suitability of the acquired fingerprint image when the number of sample inspection images satisfying the focus suitability and quality suitability is greater than or equal to a preset number when there are a plurality of sample inspection images. Can be determined.

In embodiments, a method for obtaining a non-contact fingerprint image may include obtaining a fingerprint image including at least one sample inspection image through at least one window disposed in a virtual user finger, and wherein the at least one sample inspection image is obtained. Checking whether the suitability of the fingerprint image can be guaranteed.

In an embodiment, the acquiring of the fingerprint image may further include displaying guide lines for the at least one window.

In an embodiment, the acquiring of the fingerprint image may further include applying an image enhancement filter associated with at least one of sharpness and contrast to each of the at least one sample inspection image. .

In an embodiment, the checking whether the suitability of the obtained fingerprint image may be guaranteed may further include extracting a ridge pattern for each of the at least one sample inspection image.

In an embodiment, the extracting of the ridge pattern may further include determining a ridge pattern including at least one ridge by extracting a unit direction component for each of the at least one sample inspection image.

In an embodiment, the checking of whether the acquired fingerprint image can be guaranteed can be performed based on the contrast of the ridge region and the non-ridge region included in the extracted ridge pattern. The method may further include determining whether to focus on each sample inspection image.

In one embodiment, checking whether the suitability of the acquired fingerprint image can be ensured is based on at least one of the area of the ridge area and the distance between the ridge areas, the quality of each of the at least one sample inspection image. The method may further include determining suitability.

In one embodiment, checking whether the suitability of the obtained fingerprint image can be guaranteed can be determined based on at least one of focus suitability and quality suitability for each of the determined at least one sample inspection image. The method may further include determining whether the fingerprint image is suitable.

In an embodiment, the checking of whether the acquired fingerprint image may be guaranteed may be performed if the number of sample inspection images satisfying the focus suitability and quality suitability when the sample inspection image is plural. The method may further include determining that suitability of the obtained fingerprint image may be guaranteed.

An apparatus and method for obtaining a non-contact fingerprint image according to an embodiment of the present invention obtains a fingerprint image including at least one sample inspection image through at least one window disposed in a virtual user finger, and obtains at least one sample inspection By checking the suitability of the fingerprint image through the image, it is determined whether or not the entire fingerprint image is suitable through at least one inspection process of focus and quality of a part of the fingerprint image, so that the automatic focusing processing device is used. Even if it is possible to determine whether a high quality fingerprint image is obtained at a high processing speed.

The apparatus and method for obtaining a non-contact fingerprint image according to an embodiment of the present invention extracts a ridge pattern from at least one sample inspection image and based on at least one of focus fit and quality fit determined based on the extracted ridge pattern. By checking the suitability of the fingerprint image, it is possible to determine whether a high quality fingerprint image has been obtained at a high processing speed.

1 is a view for explaining a non-contact fingerprint image acquisition system according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating an apparatus for obtaining a contactless fingerprint image of FIG. 1.
3 is a flowchart illustrating a process of obtaining a contactless fingerprint image performed by the apparatus for obtaining a contactless fingerprint image.
4 is a flowchart illustrating a process of obtaining a contactless fingerprint image performed by the apparatus for obtaining a contactless fingerprint image according to an embodiment of the present invention.
5 is a view for explaining a non-contact fingerprint image acquisition process according to the present invention.
6 is a diagram illustrating a guideline for a window according to an embodiment of the present invention.
7 is a view for explaining a sample inspection image according to an embodiment of the present invention.

Description of the present invention is only an embodiment for structural or functional description, the scope of the present invention should not be construed as limited by the embodiments described in the text. That is, the embodiments are to be construed as being variously embodied and having various forms, so that the scope of the present invention should be understood to include equivalents capable of realizing technical ideas. Also, the purpose or effect of the present invention should not be construed as limiting the scope of the present invention, since it does not mean that a specific embodiment should include all or only such effect.

Meanwhile, the meaning of the terms described in the present application should be understood as follows.

The terms "first "," second ", and the like are intended to distinguish one element from another, and the scope of the right should not be limited by these terms. For example, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

It is to be understood that when an element is referred to as being "connected" to another element, it may be directly connected to the other element, but there may be other elements in between. On the other hand, when an element is referred to as being "directly connected" to another element, it should be understood that there are no other elements in between. On the other hand, other expressions describing the relationship between the components, such as "between" and "immediately between" or "neighboring to" and "directly neighboring to", should be interpreted as well.

It should be understood that the singular " include "or" have "are to be construed as including a stated feature, number, step, operation, component, It is to be understood that the combination is intended to specify that it does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

In each step, the identification code (e.g., a, b, c, etc.) is used for convenience of explanation, the identification code does not describe the order of each step, Unless otherwise stated, it may occur differently from the stated order. That is, each step may occur in the same order as described, may be performed substantially concurrently, or may be performed in reverse order.

The present invention can be embodied as computer-readable code on a computer-readable recording medium, and the computer-readable recording medium includes all kinds of recording devices for storing data that can be read by a computer system . Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and also implemented in the form of a carrier wave (for example, transmission over the Internet) . In addition, the computer-readable recording medium may be distributed over network-connected computer systems so that computer readable codes can be stored and executed in a distributed manner.

All terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. The terms defined in the commonly used dictionary should be interpreted to coincide with the meanings in the context of the related art, and should not be interpreted as having ideal or excessively formal meanings unless clearly defined in the present application.

1 is a view for explaining a non-contact fingerprint image acquisition system according to an embodiment of the present invention.

Referring to FIG. 1, the non-contact fingerprint image acquisition system 100 includes a non-contact fingerprint image acquisition device 120 that acquires an image of a fingerprint of a user's finger 110 in a non-contact manner.

In one embodiment, the user finger 110 may correspond to at least one of the plurality of fingers.

The contactless fingerprint image acquisition device 120 corresponds to a device capable of contactlessly recognizing a fingerprint of the user finger 110.

In an embodiment, the non-contact fingerprint image capturing apparatus 120 may include a photographing apparatus. Here, the photographing apparatus may include a lighting apparatus and a camera module.

In one embodiment, the contactless fingerprint image acquisition device 120 may include at least one infrared illumination device. For example, infrared light may correspond to an IR LED.

In an embodiment, the non-contact fingerprint image capturing apparatus 120 may include at least one filter that passes a predetermined wavelength band. For example, the non-contact fingerprint image capturing apparatus 120 may include a band pass filter (BPPF) that may pass a wavelength band of 750 to 950 nm.

In one embodiment, the contactless fingerprint image acquisition device 120 may be implemented as a mobile terminal. For example, the contactless fingerprint image acquisition device 120 may be implemented as a cellular phone, a smart phone, or a tablet personal computer.

Hereinafter, the non-contact fingerprint image acquisition device 120 will be described in detail with reference to FIG. 2.

FIG. 2 is a block diagram illustrating an apparatus for obtaining a contactless fingerprint image of FIG. 1.

Referring to FIG. 2, the non-contact fingerprint image acquisition device 120 includes a fingerprint image acquisition unit 210, a suitability determination unit 220, a ridge pattern extraction unit 230, a display unit 240, and a controller 250. do.

The fingerprint image acquisition unit 210 acquires a fingerprint image including at least one sample inspection image. Here, the fingerprint image acquisition unit 210 may acquire a fingerprint image including at least one sample inspection image through at least one window disposed in the virtual user's finger.

In one embodiment, when there are a plurality of windows disposed in the virtual user finger, the fingerprint image acquisition unit 210 may obtain a fingerprint image including a plurality of sample inspection images through the plurality of windows spaced apart from each other. . Here, each of the plurality of windows may have a specific area and be separated from each other independently.

More specifically, the fingerprint image acquisition unit 210 may acquire at least one sample inspection image corresponding to each of the at least one window through at least one window having a predetermined arrangement and area in the virtual user finger.

Here, the virtual user finger corresponds to a preset area among the area range that can be photographed by the photographing apparatus, and when there are a plurality of windows, each of the plurality of windows is located at a predetermined area spaced apart from the virtual user finger. This may be the case.

For example, in FIGS. 6 and 7, when an elliptic-shaped virtual user finger 610 and five square windows 620a to 620e are set within an area range of an image that can be photographed by the photographing apparatus, photographing. When the fingerprint image of the user finger 110 is generated by the device, five images included in each area of the windows 620a to 620e in the fingerprint image and the fingerprint image are obtained as the sample inspection images 710a to 710e. can do.

In an embodiment, the fingerprint image acquisition unit 210 may receive setting information associated with at least one of the area, location, shape, and number of windows, and obtain at least one sample inspection image based on the input setting information. have. Here, the setting information may be input by the administrator, and may include setting data for at least one of the area, position, shape, and number of windows. For example, the fingerprint image acquisition unit 210 prompts the setting input window for the area, position, shape, and number of windows through the display unit 240, and receives the setting data when the user inputs the setting data. Therefore, you can define the area, position, shape, and number of windows.

That is, in the process of acquiring the contactless fingerprint image according to the present invention, the manager may finally obtain at least one of the area, position, shape, and number of windows in consideration of at least one of the quality of the fingerprint image to be acquired and the processing speed of the non-contact fingerprint image acquisition device. Can be set.

In an embodiment, the fingerprint image acquisition unit 210 may display the guide line for at least one of the virtual user finger 610 and the at least one window 620 through the display unit 240. That is, the fingerprint image acquisition unit 210 may display a guideline in which the specimen inspection images may be photographed, thereby allowing the user to appropriately place his or her finger.

In one embodiment, the fingerprint image acquisition unit 210 may output a warning sound based on the position of the user's finger. For example, when the position of the user finger is outside the at least one region of the preset virtual user finger 610 and at least one window 620, by outputting a warning sound through the sound output device included in the contactless fingerprint image acquisition device In this case, the user can appropriately place his or her finger.

In one embodiment, the fingerprint image acquisition unit 210 may apply an image enhancement filter associated with at least one of sharpness and contrast to each of the at least one sample inspection image. For example, when the fingerprint image acquisition unit 210 acquires the plurality of sample inspection images 710a to 710e, in order to highlight the ridges and non-ridge areas included in each of the sample inspection images 710a to 710e. You can increase the sharpness or increase the contrast of black and white.

The suitability determination unit 220 checks the suitability of the fingerprint image based on the at least one sample inspection image acquired by the suitability determination unit 220. More specifically, the suitability determination unit 220 may check whether at least one sample inspection image including a part of the fingerprint of the user's finger can ensure the suitability of the fingerprint image with respect to the entire fingerprint of the user's finger. .

That is, in general, in order to overcome a performance degradation problem that may occur when the fingerprint recognition preprocessing process is performed with images whose focus is not accurate because the focusing time of the photographing apparatus is longer than the fingerprint image acquisition time, the suitability determination unit ( 220 may determine suitability of the fingerprint image based on some areas of the fingerprint image.

In one embodiment, the non-contact fingerprint image acquisition device 120 may further include a ridge pattern extractor 230. Here, the suitability determination unit 220 may determine the suitability of the fingerprint image based on the ridge pattern extracted by the ridge pattern extractor 230.

In one embodiment, the ridge pattern extractor 230 may extract the ridge pattern for each of the at least one sample inspection image. For example, in FIG. 7, the ridge pattern extractor 230 may extract a ridge pattern including at least one ridge from some images of fingerprints of a user's finger included in each of the sample inspection images 710a to 710e. Can be.

In one embodiment, the ridge pattern extractor 230 may determine a ridge pattern including at least one ridge by extracting a unit direction component for each of the at least one sample inspection image. Here, the ridge pattern extractor 230 may determine the unit direction component of the ridge through Local-Block Analysis. For example, the ridge pattern extractor 230 may divide the sample inspection image 710a into blocks of 16 * 16 and calculate a unit direction for each block.

In one embodiment, the ridge pattern extractor 230 may extract the ridge pattern for each of at least one sample inspection image to which the image enhancement filter is applied. That is, the ridge pattern extractor 230 applies the ridge pattern to each of the at least one sample inspection image to which the image enhancement filter associated with at least one of sharpness and contrast is applied by the fingerprint image acquisition unit 210. Can be extracted.

In one embodiment, the suitability determination unit 220 may determine whether the focus is appropriate for each of the at least one specimen inspection image based on the ridge pattern extracted by the ridge pattern extraction unit 230. Here, the suitability determination unit 220 may determine whether the focus is suitable based on the contrast (contrast) to the ridge and the non-ridge region included in the ridge pattern.

Referring to the single sample inspection image as an example, in FIG. 7, the suitability determination unit 220 may measure the contrast with respect to the ridges and non-ridge regions included in the sample inspection image 710a, and the measured contrast is It may be determined whether the predetermined threshold is exceeded. Here, the suitability determination unit 220 may determine that the focus of the sample inspection image 710a is appropriate when the measured contrast exceeds a predetermined threshold.

In one embodiment, the suitability determination unit 220 may determine whether the quality suitability for each of the at least one sample inspection image based on the ridge pattern extracted by the ridge pattern extractor 230. Herein, the suitability determination unit 220 may determine whether the quality is appropriate for each of the at least one sample inspection image based on at least one of the area of the ridge area and the interval between the ridge areas.

Referring to the single sample inspection image as an example, in FIG. 7, the suitability determination unit 220 sets a predetermined threshold (first threshold value) of an area (eg, the number of pixels) of the ridge area included in the sample inspection image 710a. Is exceeded (first condition) and whether the interval between the ridge areas is less than the predetermined threshold (second threshold) (second condition). Here, the suitability determination unit 220 may determine that the quality of the sample inspection image 710a is appropriate when the area of the ridge area exceeds the first threshold and the distance between the ridge areas is less than the second threshold. On the other hand, the first threshold value, the second threshold value and the conditions for the quality conformance (satisfied both the first condition and the second condition, satisfies the first condition or the second condition) are set according to the quality of the fingerprint image to be acquired Can be determined.

In one embodiment, the suitability determination unit 220 may determine whether the fingerprint image is suitable based on at least one of whether the focus fit and the quality suitability for each of the at least one sample inspection image. For example, the suitability determination unit 220 may determine that the fingerprint image is suitable when all the sample inspection images satisfy the focus fit and the quality fit.

In one embodiment, the suitability determination unit 220 may determine whether the fingerprint image is suitable based on at least one of whether the focus suitability and the quality suitability for the sample inspection image disposed in the predetermined area. For example, in FIG. 7, the suitability determination unit 220 is based on the focus and quality of the sample inspection images 710a and 710c disposed in the outer region of the finger, which may have a low brightness value during the contactless fingerprint recognition process. Suitability of the fingerprint image can be determined.

In one embodiment, when there are a plurality of sample inspection images, the suitability determination unit 220 may determine the suitability of the fingerprint image based on the number of sample inspection images satisfying the focus suitability and the quality suitability. For example, the suitability determination unit 220 may determine that the fingerprint image is suitable when the number of sample inspection images satisfying the focus suitability and the quality suitability exceeds a predetermined threshold (eg, three).

Meanwhile, the suitability condition of the fingerprint image, which may be composed of a combination of focus suitability and quality suitability of the plurality of sample inspection images, may be determined in the setting process according to the quality of the fingerprint image to be acquired.

In one embodiment, the suitability determination unit 220 may determine an optimal fingerprint image among a plurality of fingerprint images satisfying the suitability. For example, if a plurality of fingerprint images satisfying suitability according to the contactless fingerprint image acquisition process of the present invention among the fingerprint images acquired by the fingerprint image acquisition unit 210 correspond to, the suitability determination unit 220 Among the plurality of fingerprint images, the fingerprint image having the maximum number of sample inspection images satisfying the focus suitability and quality suitability may be determined.

The display unit 240 may display a guide line for at least one of the virtual user finger 610 and the at least one window 620. That is, the display unit 240 may display a guide line on which the specimen inspection image may be photographed, thereby allowing the user to appropriately place his or her finger.

The controller 250 controls the operation and data flow of the fingerprint image acquisition unit 210, the suitability determination unit 220, the ridge pattern extraction unit 230, and the display unit 240.

3 is a flowchart illustrating a process of obtaining a contactless fingerprint image performed by the apparatus for obtaining a contactless fingerprint image. 3 illustrates a case in which a plurality of windows spaced apart from each other in the process of obtaining a contactless fingerprint image and a plurality of sample inspection images acquired through the plurality of spaced windows are illustrated as an example. On the other hand, these examples are not intended to limit the scope of the invention. That is, in the process of acquiring the contactless fingerprint image according to the present invention, the manager may finally obtain at least one of the area, position, shape, and number of windows in consideration of at least one of the quality of the fingerprint image to be acquired and the processing speed of the non-contact fingerprint image acquisition device. Can be set.

The fingerprint image acquisition unit 210 acquires a fingerprint image including a plurality of sample inspection images (step S310). Here, the fingerprint image acquisition unit 210 may acquire a fingerprint image including a plurality of sample inspection images through a plurality of spaced windows disposed in the virtual user's finger.

More specifically, the fingerprint image acquisition unit 210 may acquire a plurality of sample inspection images corresponding to each of the plurality of windows through a plurality of windows having a predetermined arrangement and area in the virtual user's finger.

Here, the virtual user finger may correspond to a preset area among the range of areas that may be photographed by the photographing apparatus, and each of the plurality of windows may correspond to preset areas that are spaced apart from the virtual user finger.

The suitability determination unit 220 checks the suitability of the fingerprint image based on the plurality of sample inspection images acquired by the suitability determination unit 220 (step S320). More specifically, the suitability determination unit 220 may check whether a plurality of sample inspection images including a part of the fingerprint of the user's finger can guarantee the suitability of the fingerprint image with respect to the entire fingerprint of the user's finger.

That is, in general, in order to overcome a performance degradation problem that may occur when the fingerprint recognition preprocessing process is performed with images whose focus is not accurate because the focusing time of the photographing apparatus is longer than the fingerprint image acquisition time, the suitability determination unit ( 220 may determine suitability of the fingerprint image based on some areas of the fingerprint image.

4 is a flowchart illustrating a process of obtaining a contactless fingerprint image performed by the apparatus for obtaining a contactless fingerprint image according to an embodiment of the present invention. Hereinafter, FIG. 4 illustrates an example in which a plurality of windows spaced apart from each other in a process of obtaining a contactless fingerprint image and a plurality of sample inspection images acquired through a plurality of spaced windows are illustrated. On the other hand, these examples are not intended to limit the scope of the invention. That is, in the process of acquiring the contactless fingerprint image according to the present invention, the manager may finally obtain at least one of the area, position, shape, and number of windows in consideration of at least one of the quality of the fingerprint image to be acquired and the processing speed of the non-contact fingerprint image acquisition device. Can be set.

The fingerprint image acquisition unit 210 may display a guide line for at least one of the virtual user finger 610 and the plurality of spaced apart windows 620 through the display unit (step S410). That is, the fingerprint image acquisition unit 210 may display a guideline in which the specimen inspection images may be photographed, thereby allowing the user to appropriately place his or her finger.

The fingerprint image acquisition unit 210 acquires a fingerprint image including a plurality of sample inspection images (step S420). Here, the fingerprint image acquisition unit 210 may acquire a fingerprint image including a plurality of sample inspection images through a plurality of spaced windows disposed in the virtual user's finger.

The fingerprint image acquirer 210 may apply an image enhancement filter associated with at least one of sharpness and contrast to at least one of the plurality of sample inspection images (step S430). That is, when the fingerprint image acquisition unit 210 acquires the plurality of sample inspection images 710a to 710e, the sharpness of the ridges and non-ridges included in each of the sample inspection images 710a to 710e may be increased. You can increase or increase the contrast of black and white.

The ridge pattern extractor 230 may extract a unit direction component for each of the plurality of sample inspection images (step S440).

The ridge pattern extractor 230 may extract the ridge pattern for each of the plurality of sample inspection images (step S450). In one embodiment, the ridge pattern extractor 230 may extract the ridge pattern for a plurality of sample inspection images to which the image enhancement filter is applied.

The suitability determination unit 220 may determine whether to focus on each of the plurality of sample inspection images based on the ridge pattern extracted by the ridge pattern extraction unit 230 (step S460). Here, the suitability determination unit 220 may determine whether the focus is suitable based on the contrast (contrast) to the ridge and the non-ridge region included in the ridge pattern.

The suitability determination unit 220 may determine whether the quality is appropriate for each of the plurality of sample inspection images based on the ridge pattern extracted by the ridge pattern extraction unit 230 (step S470). Herein, the suitability determination unit 220 may determine whether the quality of each of the plurality of sample inspection images is appropriate based on at least one of the area of the ridge area and the interval between the ridge areas.

The suitability determination unit 220 may determine the suitability of the fingerprint image based on the plurality of sample inspection images (step S480).

In one embodiment, the suitability determination unit 220 may determine whether or not the fingerprint image is suitable based on at least one of whether the focus suitability and the quality suitability for each of the plurality of sample inspection images. For example, the suitability determination unit 220 may determine that the fingerprint image is suitable when all the sample inspection images satisfy the focus fit and the quality fit.

In one embodiment, the suitability determination unit 220 may determine whether the fingerprint image is suitable based on at least one of whether the focus suitability and the quality suitability for the sample inspection image disposed in the predetermined area. For example, in FIG. 7, the suitability determination unit 220 is based on the focus and quality of the sample inspection images 710a and 710c disposed in the outer region of the finger, which may have a low brightness value during the contactless fingerprint recognition process. Suitability of the fingerprint image can be determined.

In one embodiment, the suitability determination unit 220 may determine the suitability of the fingerprint image based on the number of sample inspection images satisfying the focus suitability and quality suitability. For example, the suitability determination unit 220 may determine that the fingerprint image is suitable when the number of sample inspection images satisfying the focus suitability and the quality suitability exceeds a predetermined threshold (eg, three).

Meanwhile, the suitability condition of the fingerprint image, which may be composed of a combination of focus suitability and quality suitability of the plurality of sample inspection images, may be determined in the setting process according to the quality of the fingerprint image to be acquired.

In one embodiment, the suitability determination unit 220 may determine an optimal fingerprint image among a plurality of fingerprint images satisfying the suitability. For example, if a plurality of fingerprint images satisfying suitability according to the contactless fingerprint image acquisition process of the present invention among the fingerprint images acquired by the fingerprint image acquisition unit 210 correspond to, the suitability determination unit 220 Among the plurality of fingerprint images, the fingerprint image having the maximum number of sample inspection images satisfying the focus suitability and quality suitability may be determined.

5 is a view for explaining a non-contact fingerprint image acquisition process according to the present invention.

More specifically, FIG. 5A corresponds to a diagram illustrating a fingerprint image generated after a preprocessing process on a fingerprint image photographed in a state in which focus is appropriate using an autofocus function of the photographing apparatus, and FIG. Corresponding to the drawing illustrating a fingerprint image generated after a preprocessing process for a fingerprint image photographed in an unstable focus using an auto focus function.

In general, unlike the contact-type fingerprint recognition device, the non-contact fingerprint recognition device is difficult to obtain a high quality fingerprint image as shown in FIG. 5A due to focal instability such as minute movement, rotation, and shaking of a user's finger. That is, the fingerprint image acquired in an unstable focus may not clearly show the ridge of the fingerprint of the user's finger as shown in FIG. 5B and may deteriorate the fingerprint recognition performance.

In this case, when the auto focus function of the photographing apparatus is utilized, the general focusing time is in [sec] units, and a delay of approximately 20 times or more for focusing is compared with [several ms], which is a general fingerprint image acquisition time. Inefficient

As described above, it is possible to quickly determine whether a high quality fingerprint image is obtained through the non-contact fingerprint image acquisition process according to the present invention.

6 is a diagram illustrating a guideline for a window according to an embodiment of the present invention.

In FIG. 6, when an elliptic-shaped virtual user finger 610 and five square windows 620a to 620e are set within an area range of an image that may be photographed by the photographing apparatus, the fingerprint image obtaining unit 210 may be configured. A guide line for at least one of the virtual user finger 610 and the plurality of spaced windows 620 may be displayed through the display unit. That is, the fingerprint image acquisition unit 210 may display a guideline in which the specimen inspection images may be photographed, thereby allowing the user to appropriately place his or her finger.

7 is a view for explaining a sample inspection image according to an embodiment of the present invention.

In FIG. 7, when five square windows 620a to 620e are set in an area range of an image that can be photographed by the photographing apparatus, a fingerprint image of the user finger 110 is generated by the photographing apparatus. The image acquirer 210 may acquire five images included in each area of the windows 620a through 620e as the sample inspection images 710a through 710e in the fingerprint image.

Although described above with reference to a preferred embodiment of the present application, those skilled in the art will be variously modified and changed within the scope of the present invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

100: contactless fingerprint image acquisition system
110: user finger 120: contactless fingerprint image acquisition device
210: fingerprint image acquisition unit 220: conformity determination unit
230: ridge pattern extraction unit 240: display unit
250:
610: virtual user finger 620: Windows
710: sample inspection image

Claims (18)

A fingerprint image obtaining unit obtaining a fingerprint image including at least one sample inspection image through at least one window disposed in the virtual user finger; And
And a fingerprint image suitability determining unit configured to check whether the at least one sample inspection image can guarantee the suitability of the acquired fingerprint image.
The method of claim 1,
And a display unit for displaying guide lines for the at least one window.
The method of claim 1, wherein the fingerprint image acquisition unit
And applying an image enhancement filter associated with at least one of sharpness and contrast to each of the at least one sample inspection image.
The method of claim 1,
And a ridge pattern extractor for extracting a ridge pattern for each of the at least one sample inspection image.
The method of claim 4, wherein the ridge pattern extraction unit
And extracting a unit direction component for each of the at least one specimen inspection image to determine a ridge pattern including at least one ridge.
The method of claim 5, wherein the fingerprint image suitability determination unit
And determining whether the focus is appropriate for each of the at least one specimen inspection image based on contrast between the ridge region and the non-ridge region included in the extracted ridge pattern.
The method of claim 6, wherein the fingerprint image suitability determination unit
And determining whether quality is appropriate for each of the at least one sampled inspection image based on at least one of an area of the ridge area and a distance between the ridge areas.
The method of claim 7, wherein the fingerprint image suitability determination unit
And determining whether the acquired fingerprint image is suitable based on at least one of focus fit and quality suitability for each of the determined at least one sample inspection image.
The method of claim 8, wherein the fingerprint image suitability determination unit
In the case where there are a plurality of sample inspection images, if the number of sample inspection images satisfying the focus suitability and the quality suitability is more than a predetermined number, it is determined that the suitability of the acquired fingerprint image can be guaranteed. Device.
Obtaining a fingerprint image comprising at least one sample inspection image through at least one window disposed within the virtual user finger; And
And checking whether the at least one sample inspection image can ensure suitability of the acquired fingerprint image.
The method of claim 10, wherein obtaining the fingerprint image
The method of claim 1, further comprising displaying a guide line for the at least one window.
The method of claim 10, wherein obtaining the fingerprint image
And applying an image enhancement filter associated with at least one of sharpness and contrast to each of the at least one sample inspection image.
The method of claim 10, wherein checking whether the acquired fingerprint image can be guaranteed suitability
And extracting a ridge pattern for each of the at least one sample inspection image.
The method of claim 13, wherein the extracting the ridge pattern is
And extracting a unit direction component for each of the at least one specimen inspection image to determine a ridge pattern including at least one ridge.
The method of claim 14, wherein the checking whether the conformity of the obtained fingerprint image can be guaranteed
And determining whether the focus is appropriate for each of the at least one specimen inspection image based on contrast between the ridge region and the non-ridge region included in the extracted ridge pattern. Image Acquisition Method.
The method of claim 15, wherein checking whether the acquired fingerprint image can be guaranteed suitability
And determining whether quality is appropriate for each of the at least one sampled inspection image based on at least one of an area of the ridge area and a distance between the ridge areas.
17. The method of claim 16, wherein checking whether the suitability of the obtained fingerprint image can be guaranteed
And determining whether the obtained fingerprint image is suitable based on at least one of focus fit and quality suitability for each of the determined at least one sample inspection image. .
18. The method of claim 17, wherein checking whether the suitability of the obtained fingerprint image can be guaranteed
If there are a plurality of sample inspection images, if the number of sample inspection images that satisfies the focus suitability and quality suitability further comprises the step of determining that the suitability of the obtained fingerprint image can be guaranteed Non-contact fingerprint image acquisition method.

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