Method and device for locating upper and lower boundaries of banknote serial number based on magnetic signals

Abstract

The present invention provides a method and device for locating the upper and lower boundaries of a banknote serial number based on magnetic signals. The method comprises: determining a target area C, a unit scanning height D, and multiple target channels U based on the width A, height B, and type of the banknote to be tested; determining a magnetic signal base value P and a magnetic signal threshold Q based on a large number of sample banknotes of the same type as the banknote to be tested; sequentially collecting data from top to bottom of the banknote to be tested on each U in C based on a sliding window N to obtain a magnetic signal value X for each data point, where the width of N is the width of a single U and the height is the unit scanning height D; confirming the number S of valid magnetic signal points in each N based on P, Q, and the magnetic signal value X of each data point; and combining the N with the largest number of S on each target channel U to locate the upper and lower boundaries of the serial number. The present application collects and determines magnetic signals on the target channels based on the sliding window N, and can obtain more accurate upper and lower boundaries of the serial number.

Description

Technical Field

[0001] The present invention relates to the field of image recognition technology, and in particular to a method and device for locating the upper and lower boundaries of a banknote serial number based on magnetic signals. Background Art

[0002] Magnetic detection is a crucial part of banknote authentication. For typical banknotes, only the serial number area has magnetic characteristics. Therefore, simply detecting the presence of magnetic signals can confirm the serial number area and its boundaries. However, for special banknotes, not only does the serial number area have magnetic characteristics, but irregular magnetic signals may also be present in other areas of the banknote, making it difficult to locate the serial number boundary.

[0003] The current existing technology is to search for the magnetic signal of the banknote from top to bottom. When encountering a point with a strong magnetic signal, it is regarded as the upper boundary of the serial number area. Then the scan continues downward. When encountering a point with a weak magnetic signal, it is regarded as the lower boundary of the serial number area. Since the amplitude of the magnetic signal in the serial number area of ​​some special banknotes is relatively small, it is easy to be filtered out as an interference signal. Therefore, this technology still cannot accurately locate the upper and lower boundaries of the banknote serial number. Summary of the Invention

[0004] Based on this, the purpose of the present invention is to provide a method and device for locating the upper and lower boundaries of the banknote serial number based on magnetic signals. By sliding the window N to collect and judge the magnetic signals on the target channel, more accurate upper and lower boundaries of the serial number can be obtained.

[0005] In a first aspect, this embodiment provides a method for locating the upper and lower boundaries of a banknote serial number based on a magnetic signal, including: step S1: determining a target area C, a unit scanning height D, and multiple target channels U based on the width A, height B, and type of the banknote to be tested; step S2: determining a magnetic signal base value P and a magnetic signal threshold Q based on a large number of sample banknotes of the same type as the banknote to be tested; step S3: sequentially collecting data from the top to the bottom of the banknote to be tested on each target channel U in the target area C based on a sliding window N to obtain a magnetic signal value X for each data point, wherein the width of the sliding window N is the width of a single target channel U, and the height is the unit scanning height D; step S4: confirming the number S of valid magnetic signal points in each sliding window N based on the magnetic signal base value P, the magnetic signal threshold Q, and the magnetic signal value X of each data point; and step S5: combining the sliding windows N with the largest number S of valid magnetic signal points on each target channel U to locate the upper and lower boundaries of the serial number.

[0006] Furthermore, S1 includes: S11: determining the width E and height F of the target area C according to the width A, height B and type of the banknote to be tested; S12: determining the unit scanning height D and multiple target channels U according to the type of the banknote to be tested, wherein the unit scanning height D is the height of the serial number of the banknote to be tested.

[0007] Furthermore, S11 includes: for a 5000 ruble banknote, the target area C is the upper right corner of the banknote, and the width E of the target area C is 1 / 3A; the height F is 1 / 2B.

[0008] Furthermore, S12 includes: for a banknote to be tested of 5,000 rubles, the target channels U are the second channel U2, the third channel U3, the fourth channel U4, and the fifth channel U5; and the unit scanning height D is 25 data points.

[0009] Furthermore, the width A slightly larger than the banknote to be tested is divided into 18 equal parts, corresponding to 18 channels. The banknotes to be tested are U1-U18 from right to left.

[0010] Furthermore, S2 includes: S21: scanning each data point in the stable area of ​​a large number of sample banknotes of the same type as the banknotes to be tested, and obtaining the magnetic signal value X1 of each data point in the stable area, wherein the stable area is a preset area; S22: averaging the magnetic signal value X1 in the stable area to obtain the magnetic signal base value P; S23: scanning each data point in the interference area of ​​a large number of sample banknotes of the same type as the banknotes to be tested, and obtaining the magnetic signal value X2 of each data point in the interference area, wherein the interference area is a preset area; S24: averaging the absolute value I of the difference between the magnetic signal value X2 of each data point in the interference area and the magnetic signal base value P to obtain the magnetic signal threshold Q.

[0011] Furthermore, S3 includes: a sliding window N scans each target channel U and height F data point by data point; each target channel U is set with 400 data points.

[0012] Further, S4 includes: S41: comparing the absolute value J of the difference between the magnetic signal value X of each data point collected by each sliding window N and the magnetic signal base value P with the magnetic signal threshold Q; if the absolute value of the difference J is greater than or equal to the magnetic signal threshold Q, the data point is regarded as a valid magnetic signal point; S42: counting the number S of valid magnetic signal points in each sliding window N.

[0013] Furthermore, S5 includes: S51: taking the sliding window N with the largest number of valid magnetic signal points S as the target sliding window N'; S52: selecting one target sliding window N' in each target channel U; S53: combining multiple target sliding windows N' to obtain the serial number area, thereby locating the upper and lower boundaries of the banknote serial number.

[0014] In a second aspect, an embodiment of the present application provides a device for locating the upper and lower boundaries of a banknote serial number based on a magnetic signal, the positioning device being used to execute the above-mentioned positioning method, the positioning device comprising: a data confirmation module for determining a target area C, a unit scanning height D and multiple target channels U based on the width A, height B and type of the banknote to be tested; a threshold confirmation module for determining a magnetic signal base value P and a magnetic signal threshold Q based on a large number of sample banknotes of the same type as the banknote to be tested; a magnetic signal acquisition module for sequentially collecting data from the banknote to be tested on each target channel U in the target area C based on a sliding window N from top to bottom to obtain a magnetic signal value X for each data point, wherein the width of the sliding window N is the width of a single target channel U and the height is the unit scanning height D; a valid data confirmation module for confirming the number S of valid magnetic signal points in each sliding window N based on the magnetic signal base value P, the magnetic signal threshold Q and the magnetic signal value X of each data point; and a boundary confirmation module for combining the sliding windows N with the largest number S of valid magnetic signal points on each target channel U to locate the upper and lower boundaries of the serial number.

[0015] The beneficial effects of the embodiments of the present invention are as follows:

[0016] The present invention provides a method and device for locating the upper and lower boundaries of a banknote serial number based on magnetic signals. The method comprises: determining a target area C, a unit scanning height D, and multiple target channels U based on the width A, height B, and type of the banknote to be tested; determining a magnetic signal base value P and a magnetic signal threshold Q based on a large number of sample banknotes of the same type as the banknote to be tested; sequentially collecting data from top to bottom of the banknote to be tested on each U in C based on a sliding window N to obtain a magnetic signal value X for each data point, where the width of N is the width of a single U and the height is the unit scanning height D; confirming the number S of valid magnetic signal points in each N based on P, Q, and the magnetic signal value X of each data point; and combining the N with the largest number of S on each target channel U to locate the upper and lower boundaries of the serial number. The present application collects and determines magnetic signals on the target channels based on the sliding window N, and can obtain more accurate upper and lower boundaries of the serial number.

[0017] Other features and advantages of the present invention will be set forth in the following description, or some features and advantages may be inferred or unambiguously determined from the description, or may be learned by implementing the above-mentioned technology of the present invention.

[0018] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are specifically listed below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 A flowchart of a method for locating the upper and lower boundaries of a banknote serial number based on magnetic signals provided by an embodiment of the present invention;

[0021] Figure 2 A schematic diagram of a banknote image to be tested and a target area provided by an embodiment of the present invention;

[0022] Figure 3 A schematic diagram of the corresponding relationship between a magnetic signal and a banknote provided by an embodiment of the present invention;

[0023] Figure 4 A schematic diagram of a sliding window provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0025] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention. Example

[0026] like Figure 1 As shown, this embodiment provides a method for locating the upper and lower boundaries of a banknote serial number based on magnetic signals, including:

[0027] S1: Determine the target area C, unit scanning height D and multiple target channels U according to the width A, height B and type of the banknote to be tested.

[0028] Specifically, it includes:

[0029] S11: Determine the width E and height F of the target area C according to the width A, height B and type of the banknote to be tested.

[0030] Specifically, for a 5000 ruble note, the target area C is Figure 2 The area of ​​the upper right corner, that is, the width E≈1 / 3A; the height F≈1 / 2B, such as Figure 2 shown.

[0031] This setting can roughly locate the scanning area and reduce the amount of calculation.

[0032] S12: Determine a unit scanning height D and a plurality of target channels U according to the type of the banknote to be tested, wherein the unit scanning height D is the height of the serial number of the banknote to be tested.

[0033] Specifically, for a 5000 ruble banknote, we know in advance the actual height of the serial number characters. Here, the actual height of the serial number characters is defined as the scanning height D.

[0034] Furthermore, the location of the serial number on a particular type of banknote can be pre-determined, and based on this, the target channel can be determined. Specifically, for a 5,000-ruble banknote, it can be roughly predicted that its serial number will be in channels 2 through 4. Therefore, the second channel U2, the third channel U3, the fourth channel U4, and the fifth channel U5 are defined as target channels U.

[0035] In this embodiment, the width A of the banknote to be tested is divided into 18 equal parts, that is, 18 channels. The banknotes are U1-U18 from right to left. Figure 3 As shown. For the same magnetic signal collector (also called sensor), the total number of channels is fixed. In this embodiment, each channel is set with 400 data points. The magnetic signal data collected by the sensor is shown in the figure Figure 3 As shown, from Figure 3 It can be seen that the magnetic signals of the 18 channels of banknotes correspond to the signal fluctuation diagram on the left (18 lines).

[0036] S2: Determine the magnetic signal base value P and the magnetic signal threshold value Q based on a large number of sample banknotes of the same type as the banknotes to be tested.

[0037] S2 includes:

[0038] S21: Scan each data point in the stable region of a large number of sample banknotes of the same type as the banknotes to be tested to obtain a magnetic signal value X1 of each data point in the stable region, wherein the stable region is a preset region.

[0039] S22: Average the magnetic signal value X1 in the stable area to obtain a magnetic signal base value P.

[0040] S23: Scan each data point in the interference area of ​​a large number of sample banknotes of the same type as the banknote to be tested to obtain a magnetic signal value X2 of each data point in the interference area, wherein the interference area is a preset area.

[0041] S24: Average the absolute value I of the difference between the magnetic signal value X2 of each data point in the interference area and the magnetic signal base value P to obtain the magnetic signal threshold Q.

[0042] S3: Collect data from the top to the bottom of the banknote to be tested on each target channel U in the target area C in turn based on the sliding window N to obtain the magnetic signal value X of each data point, where the width of the sliding window N is the width of a single target channel U, and the height is the unit scanning height D.

[0043] Specifically, Figure 3 Enlarge the picture in the box and get Figure 4 .

[0044] In S3, specifically, the sliding window N scans each target channel U and height F data point by data point. Figure 2 and Figure 4 The direction is inconsistent. Figure 2 The high is Figure 4 The corresponding relationship is shown in Figure 3 Therefore, when the sensor scans the banknote from top to bottom, the result is Figure 4 Magnetic signal diagram from left to right.

[0045] In this embodiment, there are 400 data points on each target channel U (corresponding to the banknote height B, i.e., there are 400 sampling points on B). Generally, only the first 200 are collected (the height F of the target area C is ≈ 1 / 2B). Therefore, the number of sliding windows N obtained on any of the 18 channels is 200-25+1. Figure 4 As shown, the number of data points corresponding to the width of each sliding window N is 25, that is, the number of data points occupied by the height of the serial number of the version and denomination, that is, the unit scanning height D; the height of the sliding window N is the width of any channel (the width of any channel from U1 to U18), that is, Figure 4 Each box shown represents a sliding window N, Figure 4 All boxes in are equal in size.

[0046] S4: Determine the number S of valid magnetic signal points in each sliding window N according to the magnetic signal base value P, the magnetic signal threshold Q, and the magnetic signal value X of each data point.

[0047] S41: Compare the absolute value J of the difference between the magnetic signal value X and the magnetic signal base value P of each data point collected by each sliding window N with the magnetic signal threshold Q. If the absolute value J of the difference is greater than or equal to the magnetic signal threshold Q, the data point is regarded as a valid magnetic signal point.

[0048] S42: Count the number S of valid magnetic signal points in each sliding window N.

[0049] S5: Combine the sliding windows N with the largest number S of valid magnetic signal points on each target channel U to locate the upper and lower boundaries of the prefix number.

[0050] S51: The sliding window N with the largest number of valid magnetic signal points S is used as the target sliding window N'.

[0051] S52: Select a target sliding window N' in each target channel.

[0052] S53: combining multiple target sliding windows N' to obtain a serial number area, thereby locating the upper and lower boundaries of the banknote serial number.

[0053] In this embodiment, one window is selected from each of the second channel U2, the third channel U3, the fourth channel U4, and the fifth channel U5, and then the four selected windows are combined, as shown in FIG. Figure 4 The four boxes shown are used to obtain the serial number area, and the upper and lower boundaries of the area can be accurately located.

[0054] In this embodiment, by defining the width of the sliding window N in advance (that is, defining it as the height D of the serial number), the upper and lower boundaries of the serial number can be accurately located. Example

[0055] This embodiment provides a device for locating the upper and lower boundaries of a banknote serial number based on magnetic signals. The device is used to perform the above-mentioned positioning method. The device includes:

[0056] The data confirmation module is used to determine the target area C, the unit scanning height D and multiple target channels U according to the width A, height B and type of the banknote to be tested.

[0057] The threshold value confirmation module is used to determine the magnetic signal base value P and the magnetic signal threshold value Q based on a large number of sample banknotes of the same type as the banknotes to be tested.

[0058] The magnetic signal acquisition module is used to collect data from the top to the bottom of the banknote to be tested on each target channel U in the target area C in turn based on the sliding window N to obtain the magnetic signal value X of each data point, where the width of the sliding window N is the width of a single target channel U and the height is the unit scanning height D.

[0059] The valid data confirmation module is used to confirm the number S of valid magnetic signal points in each sliding window N according to the magnetic signal base value P, the magnetic signal threshold Q and the magnetic signal value X of each data point.

[0060] The boundary confirmation module is used to combine the sliding windows N with the largest number S of valid magnetic signal points on each target channel U to locate the upper and lower boundaries of the serial number.

[0061] The device for positioning the upper and lower boundaries of the banknote serial number based on magnetic signals provided in the embodiment of the present invention has the same implementation principle and technical effects as the aforementioned method embodiment for positioning the upper and lower boundaries of the banknote serial number based on magnetic signals. For the sake of brief description, for matters not mentioned in the device embodiment, please refer to the corresponding content in the aforementioned method embodiment.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for locating the upper and lower boundaries of a banknote serial number based on magnetic signals, characterized by: S1: Determine the target area C, unit scanning height D and multiple target channels U according to the width A, height B and type of the banknote to be tested; S2: Determine the magnetic signal base value P and the magnetic signal threshold value Q based on a large number of sample banknotes of the same type as the banknote to be tested; S3: Collect data from the top to the bottom of the banknote in each target channel U of the target area C in turn based on a sliding window N to obtain the magnetic signal value X of each data point, where the width of the sliding window N is the width of a single target channel U and the height is the unit scanning height D; S4: Determine the number S of valid magnetic signal points in each sliding window N based on the magnetic signal base value P, the magnetic signal threshold Q and the magnetic signal value X of each data point; S5: Combine the sliding windows N with the largest number S of valid magnetic signal points on each target channel U to locate the upper and lower boundaries of the prefix number; S2 includes: S21: Scan each data point in the stable region of a large number of sample banknotes of the same type as the banknotes to be tested to obtain a magnetic signal value X1 of each data point in the stable region, wherein the stable region is a preset region; S22: averaging the magnetic signal values ​​X1 in the stable region to obtain a magnetic signal base value P; S23: Scan each data point in the interference area of ​​a large number of sample banknotes of the same type as the banknotes to be tested to obtain a magnetic signal value X2 of each data point in the interference area, wherein the interference area is a preset area; S24: Average the absolute value I of the difference between the magnetic signal value X2 of each data point in the interference area and the magnetic signal base value P to obtain the magnetic signal threshold Q.

2. The method for locating the upper and lower boundaries of a banknote serial number based on magnetic signals according to claim 1, characterized in that: S1 includes: S11: Determine the width E and height F of the target area C according to the width A, height B and type of the banknote to be tested; S12: Determine a unit scanning height D and a plurality of target channels U according to the type of the banknote to be tested, wherein the unit scanning height D is the height of the serial number of the banknote to be tested.

3. The method for locating the upper and lower boundaries of a banknote serial number based on magnetic signals according to claim 2, characterized in that: The S11 includes: For a 5000 ruble banknote, the target area C is the upper right corner of the banknote. The width E of the target area C is 1 / 3A, and the height F is 1 / 2B.

4. The method for locating the upper and lower boundaries of a banknote serial number based on magnetic signals according to claim 3, characterized in that: S12 includes: For a 5000 ruble banknote, the target channels U are the second channel U2, the third channel U3, the fourth channel U4, and the fifth channel U5. The unit scanning height D is 25 data points.

5. The method for locating the upper and lower boundaries of a banknote serial number based on magnetic signals according to claim 4, characterized in that: Divide the width A, which is slightly larger than the banknote to be tested, into 18 equal parts, corresponding to 18 channels. The banknotes to be tested are U1-U18 from right to left.

6. The method for locating the upper and lower boundaries of a banknote serial number based on magnetic signals according to claim 5, characterized in that: S3 includes: The sliding window N scans each target channel U and height F data point by data point; Each target channel U is set with 400 data points.

7. The method for locating the upper and lower boundaries of a banknote serial number based on magnetic signals according to claim 6, characterized in that S4 include: S41: Compare the absolute value J of the difference between the magnetic signal value X and the magnetic signal base value P of each data point collected in each sliding window N with the magnetic signal threshold Q. If the absolute value J of the difference is greater than or equal to the magnetic signal threshold Q, then the data point is regarded as a valid magnetic signal point. S42: Count the number S of valid magnetic signal points in each sliding window N.

8. The method for locating the upper and lower boundaries of a banknote serial number based on magnetic signals according to claim 1, wherein S5 include: S51: taking the sliding window N with the largest number of valid magnetic signal points S as the target sliding window N'; S52: Select a target sliding window N' in each target channel U; S53: combining multiple target sliding windows N' to obtain a serial number area, thereby locating the upper and lower boundaries of the banknote serial number.

9. A device for locating the upper and lower boundaries of a banknote serial number based on magnetic signals, characterized in that: The positioning device is used to perform the positioning method according to any one of claims 1 to 8, and the positioning device includes: A data confirmation module is used to determine a target area C, a unit scanning height D, and multiple target channels U based on the width A, height B, and type of the banknote to be tested; A threshold value confirmation module is used to determine a magnetic signal base value P and a magnetic signal threshold value Q based on a large number of sample banknotes of the same type as the banknotes to be tested; A magnetic signal acquisition module is configured to sequentially acquire data from each target channel U in the target area C from top to bottom of the banknote to be tested based on a sliding window N to obtain a magnetic signal value X for each data point, wherein the width of the sliding window N is the width of a single target channel U, and the height is the unit scanning height D; A valid data confirmation module is used to confirm the number S of valid magnetic signal points in each sliding window N based on the magnetic signal base value P, the magnetic signal threshold Q and the magnetic signal value X of each data point; The boundary confirmation module is used to combine the sliding windows N with the largest number S of valid magnetic signal points on each target channel U to locate the upper and lower boundaries of the serial number; The threshold confirmation module is also used to scan each data point in the stable area of ​​a large number of sample banknotes of the same type as the banknotes to be tested, to obtain the magnetic signal value X1 of each data point in the stable area, wherein the stable area is a preset area; average the magnetic signal value X1 of the stable area to obtain the magnetic signal base value P; scan each data point in the interference area of ​​a large number of sample banknotes of the same type as the banknotes to be tested, to obtain the magnetic signal value X2 of each data point in the interference area, wherein the interference area is a preset area; average the absolute value I of the difference between the magnetic signal value X2 of each data point in the interference area and the magnetic signal base value P to obtain the magnetic signal threshold Q.

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