TWI421782B - Fingerprint anti-spoof apparatus and method thereof - Google Patents

Description

Fingerprint anti-counterfeiting device and method thereof

The invention relates to a fingerprint anti-counterfeiting device and a method thereof, in particular to a fingerprint anti-counterfeiting device and a method for performing fingerprint anti-counterfeiting using different true and false finger elasticity.

For fingerprint biometric applications, the identification of fake fingers has been an important research for a long time. At present, there are many methods of optical detection, such as infrared technology to detect the biological characteristics of subcutaneous tissue (such as blood oxygen concentration or blood flow rate), and then the identification of true and false fingers. However, this type of method requires a complicated infrared optical machine, which is relatively high in cost; and because such a complicated optical system is not easy to reduce the size of the sensing element, it is required for a portable electronic system such as a light and thin one. In the case of a mobile phone or a notebook computer, it is not easy to meet the needs of its users.

In recent years, a fingerprint sensing device that can meet the requirements of light and thin has been successfully developed and applied to the above-mentioned portable electronic device. The main sensing principle is that it is not optically sensed, but is fabricated by using a semiconductor. The tiny electrode matrix, and measuring the capacitance value of the corresponding area of each electrode and the finger by the conductive property of the human body; the corresponding method of detecting the fake finger is also based on the basic principle, through the skin impedance Measure to identify differences in true skin and fake finger materials.

However, due to the variety of fake finger materials, there are currently materials that can almost perfectly simulate the conductive properties of real fingers. For example, a gummy finger made of jelly glue has a similar impedance characteristic to human skin, so that the sensing device cannot effectively recognize the true and false fingers. Therefore, this method of measuring the true and false fingers by measuring the conductive properties of the finger skin is problematic.

To this end, the present invention will employ another three-dimensional spatial image analysis method to solve the above problems.

In view of the above-mentioned problems of the prior art, the object of the present invention is to provide a fingerprint anti-counterfeiting device and a method thereof for solving the conventional fingerprint anti-counterfeiting method because the humidity and the resistance value overlap range of the true and false fingers are too large to effectively perform fingerprint anti-counterfeiting. .

According to an object of the present invention, a fingerprint anti-counterfeiting device is provided, which comprises a fingerprint capturing unit and a processing unit. The fingerprint capture unit continuously captures one fingerprint of one finger and provides a plurality of fingerprint images according to the fingerprint. The processing unit determines an elasticity value according to the deformation state of any two neighbors of the fingerprint image. When the elasticity value conforms to a predetermined elastic value range, the processing unit determines that the finger is a forged finger.

Wherein, when the elasticity value does not meet the preset elastic value range, the processing unit determines that the finger is a real finger.

Wherein, the fingerprint capturing unit further has a bump, the bump is attached to the finger to produce deformation, and the processing unit analyzes the deformation recovery state of the depressed portion generated by the finger after the bump passes to determine the elastic value.

Wherein, the processing unit determines that one of the depressed portions generated by the finger after the bump passes is deformed relative to the finger without being bumped to determine the elasticity value.

The processing unit is configured to recognize a singular point of the fingerprint image, and expand a region range around the singular point, and the processing unit further analyzes the deformation of the fingerprint image in the region to determine the elasticity value.

According to the purpose of the present invention, a fingerprint anti-counterfeiting method is further applied to a fingerprint anti-counterfeiting device, and the fingerprint anti-counterfeiting device comprises a fingerprint capturing unit and a processing unit. The fingerprint anti-counterfeiting method comprises: continuously capturing one fingerprint of one finger by the fingerprint capturing unit and providing a plurality of fingerprint images according to the fingerprint, and then determining, by the processing unit, according to the deformation state of any two neighbors of the fingerprint image. The elastic value, when the elastic value meets a predetermined elastic value range, the processing unit determines that the finger is a fake finger.

Wherein, when the elasticity value does not meet the preset elastic value range, the processing unit determines that the finger is a real finger.

Wherein, the fingerprint capturing unit further has a bump, the bump is attached to the finger to produce deformation, and the processing unit analyzes the deformation recovery state of the depressed portion generated by the finger after the bump passes to determine the elastic value.

Wherein, the processing unit determines that one of the depressed portions generated by the finger after the bump passes is deformed relative to the finger without being bumped to determine the elasticity value.

The processing unit is configured to recognize a singular point of the fingerprint image, and expand a region range around the singular point, and the processing unit further analyzes the deformation of the fingerprint image in the region to determine the elasticity value.

According to the above, the fingerprint anti-counterfeiting device and the method thereof can have one or more The following advantages:

(1) The fingerprint anti-counterfeiting device and the method thereof can perform fingerprint anti-counterfeiting by analyzing the deformation state of the finger when sliding over the fingerprint capturing module, thereby improving the correctness of the fingerprint anti-counterfeiting.

(2) The fingerprint anti-counterfeiting device and the method thereof can perform fingerprint anti-counterfeiting by analyzing deformation from a singular point of the fingerprint image to a surrounding area, thereby effectively improving the efficiency of fingerprint recognition and anti-counterfeiting.

1‧‧‧Finger anti-counterfeiting device

10‧‧‧Finger capture unit

100‧‧‧ bumps

11‧‧‧Processing unit

2‧‧‧ fingers

20‧‧‧ Fingerprint

200, 201, 202‧ ‧ fingerprint images

203‧‧‧Fake finger fingerprint image

204‧‧‧ true finger fingerprint image

21‧‧‧Depression

3‧‧‧Flexible value

4‧‧‧Preset elastic value range

5‧‧‧Singularity

6‧‧‧Scope

S10~S40‧‧‧Steps

1 is a block diagram of a fingerprint anti-counterfeiting device of the present invention; FIG. 2A is a schematic view of a first embodiment of a fingerprint anti-counterfeiting device of the present invention; and FIG. 2B is a first embodiment of a fingerprint anti-counterfeiting device of the present invention; 3 is a schematic diagram of a second embodiment of the fingerprint anti-counterfeiting device of the present invention; FIG. 4 is a schematic view of a third embodiment of the fingerprint anti-counterfeiting device of the present invention; A flowchart of the fingerprint anti-counterfeiting method of the present invention; and FIG. 6 is another flow chart of the fingerprint anti-counterfeiting method of the present invention.

Please refer to FIG. 1 , which is a block diagram of the fingerprint anti-counterfeiting device of the present invention. As shown in the figure, the fingerprint anti-counterfeiting device 1 of the present invention comprises a fingerprint capturing unit 10 and a processing unit 11. The fingerprint capture unit 10 continuously captures one fingerprint 20 of one finger 2 and provides a plurality of fingerprint images 200, 201, 202 according to the fingerprint 20. The processing unit 11 determines one according to the deformation state of any two adjacent fingerprint images 200, 201, and 202. The elasticity value is 3. When the elasticity value 3 meets a predetermined elastic value range of 4, the processing unit 11 determines that the finger 2 is a forged finger. In addition, when the elasticity value 3 does not meet the preset elastic value range 4, the processing unit 11 determines that the finger 2 is a real finger.

Please refer to FIG. 2A, which is a schematic diagram of a first embodiment of the fingerprint anti-counterfeiting device of the present invention. As shown in the figure, the fingerprint capture unit 10 is an elongated sensor, and the finger 2 of the user to be authenticated slides over the fingerprint capture unit 10 in a sliding manner. The fingerprint capturing unit 10 is further provided with a bump 100 for making deformation on the finger 2, so that the processing unit can more easily analyze the deformation state of the finger 2. Since the figure is only a schematic view, a depressed portion 21 generated when the finger 2 passes the bump 100 is represented in a blank manner on the drawing, and the fingerprint deformation of the depressed portion 21 is further indicated by a broken line. The type of response. When the user presses the finger 2 on the fingerprint capturing unit 10 and starts to slide, the processing unit then analyzes the deformation recovery state of the depressed portion 21 generated by the finger 2 after passing through the bump 100 to determine the elasticity value 3; the processing unit can also analyze After the finger 2 passes the bump 100, a portion of the depressed portion 21 that has not passed through the bump 100 with respect to the finger 2 is deformed to determine the elastic value 3.

Please refer to FIG. 2B , which is an actual pattern of different true and false fingerprint deformations of the first embodiment of the fingerprint anti-counterfeiting device of the present invention. As shown on the left side of the figure, it is a fake finger fingerprint image 203. Since the elastic value of the fake finger is relatively simple, the recovery of the deformation (recovery condition of the depressed portion 21) is also uniform; in contrast, the figure is right. Since the true finger fingerprint image 204 of the square is different in the elasticity value of the real finger, it can be found that the recovery state of the true finger fingerprint image 204 after passing the bump is also uneven. Therefore, according to the deformation mode and the shape variable, the present invention can determine whether the fingerprint image captured by the fingerprint capture unit is captured by a real finger. In addition, in the fingerprint registration, in addition to the storage of the feature information, the information of the anti-fake finger is also stored, and the information of the anti-fake finger (ie, the elastic value of various possible fake finger materials) constitutes a pre-preparation. The scope of the setting. Since the material characteristics of a gummy finger are relatively simple, the change of the shape variable will fall within a certain range; on the contrary, the deformation of the real finger varies from person to person, and the change of the shape variable cannot be The specific scope is defined.

Please refer to FIG. 3, which is a schematic diagram of a second embodiment of the fingerprint anti-counterfeiting device of the present invention. As shown in the figure, the maximum difference between the embodiment and the first embodiment is that the fingerprint capturing unit 10 is not provided with a bump. Therefore, the embodiment is based on analyzing the change of the shape variable on the fingerprint image. The finger 2 of the fingerprint capturing unit 10 is pressed to have different elasticity values, and each of the two (or more) fingerprint images calculates an elasticity value. When the processing unit finds that the elasticity value corresponding to any two (or more) adjacent (or consecutive) fingerprint images falls within a specific range (ie, the preset elastic value range of FIG. 1 is 4, or as in the previous implementation When the information of the fake finger is input in advance, the processing unit determines that the finger 2 pressed on the fingerprint capturing unit 10 is a fake finger; when the processing unit finds that the elasticity value does not fall within a specific range (ie, When the preset elastic value range of FIG. 1 is 4), the processing unit determines that the finger 2 pressed on the fingerprint capturing unit 10 is a real finger. At this time, after determining that the finger 2 pressed on the fingerprint capturing unit 10 is a real finger, the processing unit may further use other mechanisms to confirm whether it is a real finger, for example, temperature or conductivity.

In addition, the anti-fake finger method adopted by the present invention converts the three-dimensional geometric physical information (ie, deformation) of the fingerprint path into a voltage information that can be measured and calculated. For example, in the fingerprint registration, in addition to the storage of the feature information, the information of the anti-fake finger is also stored, and the information of the anti-fake finger is calculated through a fixed area. The shape variable of the sampled fingerprint image (representing the vertical space information of the fingerprint), and the selection of "a fixed area" is also a major feature of the present invention, since the fingerprint line density in each direction and region is different, If a specific area and a fixed area are not selected, the results obtained will vary greatly.

Please refer to FIG. 4, which is a schematic diagram of a third embodiment of the fingerprint anti-counterfeiting device of the present invention. As shown in the figure, the maximum difference between the present embodiment and the first two embodiments is that the processing unit expands an area around the singular point 5 after identifying one of the singular points 5 of the fingerprint image 200. In the range 6 (i.e., a specific area), the processing unit reanalyzes the deformation of the fingerprint image 200 within the area range 6 to determine the elasticity value 3. Wherein, the shape outside the range may be a circle, an ellipse or a polygon, and in this embodiment, it is a square. Since the fingerprint capture unit 10 captures the fingerprint 20 in a continuous capture manner and provides the fingerprint image 200, if the processing unit does not find that the fingerprint image 200 has the singular point 5, the calculation of the elasticity value is not performed and the finger is determined. The authenticity of 2; only when the processing unit finds that the fingerprint image 200 contains the singular point 5, the region range 6 is expanded according to the singular point 5, and the elasticity value is calculated within the region range 6, and then the judgment finger 2 is performed. The authenticity of the present invention can effectively and greatly improve the efficiency of fingerprint anti-counterfeiting and save system resources.

As for the selection of the singular point, it is briefly described as follows: after obtaining an original fingerprint image, the fingerprint image value is re-allocated to 0 to 255 after normalization of the fingerprint image. For example, the gray-scale distribution of 8bits is processed by the normalized fingerprint and then by putty (for the average value of one image calculated by using 3x3 nine-square grid), and finally, according to the regular fingerprint image after the putty, the nine-square grid is calculated by using the 3x3 nine-square grid. The average gradient value is obtained, and the average angle value is obtained, and then the singular point is calculated by the difference of the vector angle map (when the adjacent angle difference is greater than a preset angle) Singular point).

Although the concept of the fingerprint anti-counterfeiting method of the present invention has been simultaneously described in the foregoing description of the fingerprint anti-counterfeiting device of the present invention, for the sake of clarity, a detailed description of the flowchart will be further described below.

Please refer to FIG. 5, which is a flow chart of the fingerprint anti-counterfeiting method of the present invention. The fingerprint anti-counterfeiting method of the present invention is applicable to a fingerprint anti-counterfeiting device, and the fingerprint anti-counterfeiting device comprises a fingerprint capturing unit and a processing unit. As shown in the figure, the fingerprint anti-counterfeiting method comprises the following steps: (S10) continuously capturing one fingerprint of one finger by the fingerprint capturing unit and providing a plurality of fingerprint images according to the fingerprint; (S20) according to the fingerprint image by the processing unit Determining an elastic value of any two neighbors and determining whether the elastic value conforms to a predetermined elastic value range; (S30) when the elastic value conforms to the preset elastic value range, the processing unit determines that the finger is a fake finger And (S40) when the elasticity value does not meet the preset elastic value range, the processing unit determines that the finger is a real finger.

Please refer to FIG. 6, which is another flow chart of the fingerprint anti-counterfeiting method of the present invention. In some preferred embodiments, after the step (S10), the following steps may be further included: (S11) after the processing unit recognizes one of the singular points of the fingerprint image, and circumscribes the singular point to the periphery Expanding a range of regions; and (S12) treating the unit according to any two neighbors of the fingerprint image within the region, An elastic value is determined in the deformation state in the region, and it is determined whether the elastic value conforms to a predetermined elastic value range.

Next, step (S30) or (S40) is performed after the step (S12).

The details of the fingerprint anti-counterfeiting method of the present invention have been described in detail in the foregoing description of the fingerprint anti-counterfeiting device of the present invention, and will not be described herein.

In summary, the fingerprint anti-counterfeiting device and the method thereof can perform fingerprint anti-counterfeiting by analyzing the deformation state of the finger when sliding over the fingerprint capturing module, thereby effectively improving the correctness of the fingerprint anti-counterfeiting; The fingerprint is anti-counterfeiting by analyzing the deformation from a singular point of the fingerprint image to the periphery of the fingerprint image, thereby greatly improving the efficiency of fingerprint recognition and anti-counterfeiting.

The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.

S10~S40‧‧‧Steps

Claims (8)

A fingerprint anti-counterfeiting device comprising: a fingerprint capturing unit, wherein a bump is arranged on a sliding path of a finger to make a deformation on the finger through the bump, and the fingerprint capturing unit continuously captures the a fingerprint of one of the fingers, and providing a plurality of fingerprint images according to the fingerprint; and a processing unit, the processing unit is configured to perform a depression according to the bump of the finger of any two adjacent ones of the plurality of fingerprint images The deformation recovery state determines an elasticity value, and when the elasticity value conforms to a predetermined elastic value range, the processing unit determines that the finger is a forged finger. The fingerprint anti-counterfeiting device of claim 1, wherein the processing unit determines that the finger is a real finger when the elastic value does not meet the preset elastic value range. The fingerprint anti-counterfeiting device according to claim 1, wherein the processing unit determines that the concave value of the finger after the finger passes through the bump is determined by the deformation of the finger without passing through the bump. The fingerprint anti-counterfeiting device according to claim 1, wherein the processing unit is configured to recognize a singular point of the fingerprint image, and expand a region range around the singular point, the processing unit The deformation of the fingerprint image in the region is further analyzed to determine the elasticity value. A fingerprint anti-counterfeiting method is applicable to a fingerprint anti-counterfeiting device. The fingerprint anti-counterfeiting device comprises a fingerprint capturing unit and a processing unit. The fingerprint anti-counterfeiting method comprises the following steps: The fingerprint capture unit is provided with a bump on a sliding path of a finger, and the bump is formed on the finger to form a deformation, so as to continuously capture a fingerprint of one finger and provide a plurality of fingerprint images according to the fingerprint. And determining, by the processing unit, an elastic value according to a deformation recovery state of the depressed portion generated by the finger of the two adjacent ones of the plurality of fingerprint images after the bump passes, and when the elastic value meets a pre-determination When the elastic value range is set, the processing unit determines that the finger is a fake finger. The fingerprint anti-counterfeiting method of claim 5, wherein the processing unit determines that the finger is a real finger when the elastic value does not meet a predetermined elastic value range. The fingerprint anti-counterfeiting method according to claim 5, wherein the processing unit determines that the concave value of the finger after the finger passes through the bump is determined by the deformation of the finger without passing through the bump. The fingerprint anti-counterfeiting method according to claim 5, wherein the processing unit is configured to recognize a singular point of the fingerprint image, and expand a region range around the singular point, the processing unit The deformation of the fingerprint image in the region is further analyzed to determine the elasticity value.