WO2015066978A1

WO2015066978A1 - High-speed banknote recognition device and foreign matter detection method thereof

Info

Publication number: WO2015066978A1
Application number: PCT/CN2014/071198
Authority: WO
Inventors: 刘思伟; 梁添才; 陈定喜; 崔莹
Original assignee: 广州广电运通信息科技有限公司
Priority date: 2013-11-08
Filing date: 2014-01-23
Publication date: 2015-05-14
Also published as: CN103593907A; CN103593907B

Abstract

A high-speed banknote recognition device and foreign matter detection method thereof, the device comprising a transmission channel, an image sensor, a magnetic sensor and a group of bijection sensors. On the premise of maintaining the banknote detecting speed and precision of the high-speed banknote recognition device, an image sensor group is used to perform the main functions of the reduced two groups of bijection sensors to inspect for foreign matter inside the device, thus increasing accuracy of foreign matter detection; two groups of the bijection sensors are reduced, thus lowering complexity of the circuit board design and components layout, simplifying the device structure, and reducing the size of the high-speed banknote recognition device and the manufacturing cost.

Description

High-speed identification device for banknotes and method for detecting foreign matter The present application claims to be filed on November 8, 2013 with the Chinese Patent Office, application number 201310553957.4, and the invention titled "a high-speed identification device for banknotes and a method for detecting foreign matter" Priority of the application, the entire contents of which are incorporated herein by reference.

Technical field

The present invention relates to the field of banknote recognition technology systems, and more particularly to a banknote high speed identification device and a method for detecting foreign matter.

1 is a bill identifying device that is currently used. As shown in FIG. 1, a pair of the pair of optical sensors 20 and an image sensor group 120 are disposed at the front end of the image sensor group 110. The front end is provided with a pair of optical sensors 22, whereby banknote recognition is achieved. An important function of the on-beam optical sensor is to detect if the device has foreign matter remaining.

However, due to too many pairs of sensors, the corresponding control circuit, communication cable, power supply cable and other elements are complex and numerous, which makes the design layout of the device redundant, and the device is relatively large, which increases the manufacturing cost. , more and more can not meet the refined development trend of financial equipment products, that is, small size, processing speed block, large capacity, high precision.

Summary of the invention

In view of the above, the present invention provides a high speed identification device for banknotes and a method for detecting foreign matter thereof to solve the above series of problems.

A high-speed identification device for banknotes, comprising: a transmission channel, an image sensor group, a magnetic sensor, and a set of radiation sensors;

The image sensor group is configured to identify initial information of the banknote and identify image authenticity information of the paper currency according to the initial information, and detect whether the device has foreign matter;

The magnetic sensor is configured to identify magnetic authenticity information of the banknote according to the initial information;

The radiation sensor is used to detect the moment when the banknote enters it.

Preferably, the image sensor group includes: a first image sensor and a second image sensor; the first image sensor identifies initial information of the banknote, and detects whether the device has foreign matter; the second image sensor is based on the initial information , identifying the authenticity of the image of the banknote, and The device is tested for the presence of foreign matter.

A method for detecting foreign matter, based on a high-speed banknote identification device, the device comprising: a transmission channel, an image sensor group, a magnetic sensor, and a set of radiation sensors;

The method includes:

The banknote high-speed identification device enters the foreign object detection mode, triggers the image sensor group n times, acquires n lines of signals, forms an array signal, and the n is a positive integer;

Detecting the connected domain in the array signal, and selecting the connected domain with the largest area;

The height of the connected domain having the largest area is calculated. If the height is greater than the threshold, it is judged that the foreign matter is detected, otherwise, it is judged that the foreign matter is not detected.

Preferably, the n is greater than 1, and the array signal is a two-dimensional array signal.

Preferably, before detecting the connected domain in the array signal, the method further includes:

The high frequency filtering is used to remove random noise in the two-dimensional array signal.

Preferably, the n is 1 and the array signal is a one-dimensional array signal.

The method includes:

51. The banknote high-speed identification device enters the foreign object detection mode, triggers the image sensor group n times, acquires n lines of signals, forms an array signal, and the n is a positive integer;

52. Detect the connected domain in the array signal, calculate the height of the connected domain; if the height is less than the threshold, continue to detect and calculate the height of other connected domains in the array signal until the connected domain in the array signal is detected, then determine No foreign matter is detected. Otherwise, if the height is greater than the threshold, it is judged that foreign matter is detected and stopped.

Preferably, the S2 is:

Al, a row of signals in the selected array signal;

A2. Detect non-zero points from left to right, and use them as the starting point of the connected domain to calculate the height of the connected domain. If the height is not 0, execute A3. If no non-zero point is detected, continue to detect from the next line. Execute A2 until all lines have been detected;

A3. Check if the point below the current point is 0. If it is not 0, set the lower point to the current point. Increase the height by 1 and re-enter step A3. If it is 0, execute A4;

A4. Check if the point to the right of the current point is 0. If it is not 0, set the right point to the current point, execute A3, if it is 0, execute A5;

A5. If the height is greater than the threshold, it is judged that the foreign object is detected; if the height is less than the threshold, the starting point of the other connected domains is continuously searched, and A2 is executed.

Preferably, the n is 1 and the array signal is a one-dimensional array signal.

According to the method for detecting high-speed banknotes and the method for detecting foreign objects provided by the present invention, the image sensor group is used instead of the main functions of the two sets of opposite-shooting sensors under the premise of maintaining the banknote recognition speed and accuracy of the banknote high-speed identification device, and the device Internal foreign object detection enhances the accuracy of foreign object detection; reduces the two pairs of radiation sensors, which reduces the complexity of circuit board design and component layout, simplifies device structure, reduces device size, and reduces manufacturing costs.

DRAWINGS

Figure 1 is a schematic structural view of a banknote identification device currently in use;

2 is a schematic diagram of a preferred structure of a banknote high-speed identification device according to an embodiment of the present invention; FIG. 3 is a schematic diagram of an original signal obtained by a sensor for scanning a banknote according to an embodiment of the present invention; FIG. 4 is a scanning motion of an image sensor group according to an embodiment of the present invention; FIG. 5 is a schematic diagram of an image signal obtained by an image sensor group according to an embodiment of the present invention; FIG. 6 is a flowchart of detecting a foreign object according to an embodiment of the present invention;

FIG. 7 is a flowchart of detecting a foreign object according to an embodiment of the present invention; FIG.

Figure 8 is a flow chart of a preferred method disclosed in the practice of the present invention;

9a is a schematic diagram of no foreign matter in the device disclosed in the embodiment of the present invention;

Figure 9b is a signal image obtained by the image sensor group of Figure 9a according to an embodiment of the present invention; Figure 9c is a signal image obtained by filtering the Figure 9b according to an embodiment of the present invention;

FIG. 9 is a connected domain with the largest area obtained according to an embodiment of the present invention;

10a is a schematic view of a residual banknote in a device according to an embodiment of the present invention;

Figure 10b is a signal image obtained by the image sensor group of Figure 10a according to an embodiment of the present invention; Figure 10c is a signal image obtained by filtering the image of Figure 10b according to an embodiment of the present invention;

FIG. 10 is a schematic diagram of a connected domain having the largest area and a height image thereof according to an embodiment of the present invention; FIG. 11 a is a schematic diagram of a residual piece of paper in the device disclosed in the embodiment of the present invention; FIG. 1 is a signal image obtained by the image sensor group of FIG. 11A according to an embodiment of the present invention; FIG. 11c is a signal image obtained by filtering the image of FIG.

FIG. 1 is a connected domain with the largest area and a height image thereof according to an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is a partial embodiment of the invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

Embodiments of the present invention provide a high-speed banknote identification device and a method for detecting foreign matter based on a banknote high-speed identification device.

The high-speed banknote identification device disclosed in the embodiment of the invention comprises: a transmission channel, an image sensor group, a magnetic sensor, and a set of radiation sensors;

The image sensor group is for identifying the initial information of the banknote, and based on the initial information, identifying the image authenticity information of the banknote, and detecting whether the device has foreign matter. The initial information includes currency, face value, and face-to-face information of the banknote, and the image authenticity information includes information such as a surface image of the banknote and a transmission image. The magnetic sensor is used to identify the magnetic authenticity information of the banknote based on the initial information, and the magnetic authenticity information includes magnetic ink information on the surface of the banknote and metal security line coding information. A set of illuminating sensors are located at the front end of the image sensor group to detect when the banknotes enter the illuminating sensor.

2 is a preferred embodiment of the present disclosure. Referring to FIG. 2, the image sensor group includes: a first image sensor and a second image sensor;

The first image sensor first identifies the initial information of the banknote, and determines the currency, face value, orientation, and the like of the banknote. The magnetic sensor specifically identifies the magnetic ink information on the surface of the banknote and the metal security line code information based on the initial information. The second image sensor image specifically identifies the surface image of the paper currency, the transmission image, and the like based on the initial information. Since the first image sensor first determines the initial information of the currency, the face value, the orientation of the banknote, the magnetic sensor and the second image sensor take in the specific anti-counterfeit identification information according to the initial information, and thus the corresponding authenticity information can be effectively identified.

The invention improves the accuracy of the foreign object detection by using the image sensor group instead of the reduced main functions of the two pairs of radiation sensors while maintaining the speed and accuracy of the banknote recognition of the device. First, the banknote recognition principle of the apparatus of the present invention is: In the first case, the movement speed of the banknote in the passage of the apparatus is stable. Since the layout of devices such as sensors inside the device is fixed, the distance between the radiation sensor and the image sensor group and the magnetic sensor is fixed. When the radiation sensor detects that the banknote has entered the detection range, the speed at which the banknote is transported is known, and the time when the banknote enters the image sensor group and the magnetic sensor can be obtained by calculation. Therefore, the start timing of each sensor can be obtained.

In the second case, for special reasons, such as the structural design of the device, including the design of the motor, bearing, hub, etc., the banknote cannot be stably moved in the passage of the device. The time when the radiation sensor detects the entry of the banknote into its detection range, and then the time when the banknote enters the first image sensor. The first image sensor obtains the exact time at which the banknote enters its detection range based on the sudden change in the signal when the banknote is detected, and then calculates the time at which the banknote enters the magnetic sensor. The magnetic sensor obtains the exact time when the banknote enters its detection range according to the sudden change of the signal when the banknote is detected, and then calculates the time when the banknote enters the second image sensor. The exact time principle of the banknote entering the sensor is determined by detecting a sudden change in the signal generated when the sensor recognizes the banknote. As shown in Fig. 3, the marked position is the time when the banknote enters.

Secondly, the principle of detecting the foreign matter in the channel by the device of the invention is as follows: the image sensor group is used to replace the reduced foreign object detection function of the two pairs of radiation sensors, and the image sensor group is used to acquire the line signal in the mechanical static state, and the characteristics of the line signal are used to judge Whether there is foreign matter in the device. A set of opposite sensors is composed of several sensors with a certain distance between them, and the image sensor is composed of continuous photosensitive elements, and the interval of the photosensitive elements is negligible if the foreign matter is smaller than each of the set of opposing sensors. The spacing between the sensors, the sensor is likely to be unable to detect foreign objects, then the image sensor detects the foreign object more accurately than the sensor.

The principle of image sensor acquiring image signal: The image sensor triggers to collect one line of image information at a time. The banknote moves in the device channel, the image sensor triggers at a certain frequency, and collects multiple lines of signals to obtain a complete banknote image signal with a certain resolution.

As shown in Figure 4, the image sensor is triggered by the frequency f (Hz), the line signal is collected, and the banknote moves linearly at a constant velocity V (m/s). The vertical resolution of the image is 0.025f/v (dpi) (scans per inch) Points). The image signals collected by the image sensor group are shown in Figure 5.

The invention adopts the image sensor group to replace the main functions of the two sets of the opposite radiation sensors while maintaining the speed and accuracy of the banknote recognition speed of the banknote high-speed identification device, and detects the foreign matter inside the device, thereby improving the accuracy of the foreign object detection; The number of sensors, which in turn reduces board design, The complexity of the device layout reduces the volume of the banknote high-speed identification device and reduces the manufacturing cost of the device. Based on the above-mentioned high-speed identification device for banknotes, an embodiment of the present invention discloses a method for detecting a foreign object. Referring to FIG. 6, the method includes:

Sl, the banknote high-speed identification device enters the foreign object detection mode, triggers the image sensor group n times, acquires n lines of signals, forms an array signal, and the n is a positive integer;

When there is a foreign matter in the detecting device, the banknote high-speed recognition device enters the foreign matter detecting mode, triggers the image sensor group n times, acquires n lines of signals, and forms an array signal. The image sensor group is preferably: a first image sensor and a second image sensor, thus forming two sets of array signals.

When n is 1, the image sensor only collects one line of signals, forming a one-dimensional array signal. The process of determining foreign matter is relatively simple, but the signal acquisition process may be caused by the influence of the system environment (such as electric field, magnetic field, mechanical motion). The noise, as shown in Figure 10, results in a false positive.

In order to improve the accuracy of detection, the image sensor needs to collect more signals. When n is greater than 1, the image sensor collects n lines of signals to form a two-dimensional array signal. At this time, high-frequency filtering is used to remove random signals in the two-dimensional array. .

52. Detect a connected domain in the array signal, and select a connected domain with the largest area;

When n is 1, the set of points larger than 0 in the one-dimensional array signal is detected, and the connected domain with the largest area is selected. When n is greater than 1, the connected domain in the two-dimensional array signal is detected, and the connected domain having the largest area is selected.

53. Calculate the height of the connected domain with the largest area. If the height is greater than the threshold, it is determined that the foreign object is detected. Otherwise, it is determined that no foreign object is detected.

When n is 1, it is judged whether or not the one-dimensional array signal has a set of consecutive points other than 0, and if not, it is judged that no foreign matter is detected, and if so, it is judged that the foreign matter is detected.

When n is greater than 1, the height h of the largest connected domain is calculated. If the height h is greater than the threshold H (for example, the threshold is set to 10), the judging device detects the foreign matter, otherwise, it determines that no foreign matter is detected. Also based on the above-described banknote high speed identification device, the embodiment of the present invention discloses another method of detecting foreign matter;

Referring to Figure 7, the method includes:

Sl, the banknote high-speed identification device enters the foreign object detection mode, triggers the image sensor group n times, and acquires n rows of signals, forming an array signal, wherein n is a positive integer;

When n is 1, the image sensor is triggered only once, and a line of signals is acquired to form a one-dimensional array signal. When n is greater than 1, the image sensor is triggered n times, and n rows of signals are acquired to form a two-dimensional array signal. At this time, a high frequency filtering method is used to remove random signals in the two-dimensional array.

S2: detecting a connected domain in the array signal, calculating a height of the connected domain; if the height is less than the threshold, continuing to detect and calculate the height of other connected domains in the array signal until the connected domain in the array signal is detected, then determining No foreign matter is detected. Otherwise, if the height is greater than the threshold, it is judged that the foreign matter is detected, and the flow is ended.

When n is 1, a set of consecutive points having a value other than 0 in the one-dimensional array signal is detected, and if so, it is judged that foreign matter is detected, and if not, it is judged that no foreign matter is detected.

When n is greater than 1, refer to Figure 8, Al, a row of signals in the selected array signal;

A3. Detect whether the point below the current point (y coordinate plus 1) is 0. If it is not 0, set the lower point to the current point, increase the height by 1 and re-enter step A3. If it is 0, execute A4.

A4. Check whether the point on the right side of the current point (X coordinate plus 1) is 0. If it is not 0, set the right point to the current point, execute A3, if it is 0, execute A5;

Because the signal scanned by the image sensor is relatively stable, in practice, only the first 10 lines of signals need to be searched, which can satisfy the accuracy of foreign object detection. Below, a process simulation of three typical cases of the above-described foreign matter detecting method is listed:

As shown in Fig. 9, in the first case, the detection of no foreign matter is simulated.

As shown in a, there is no foreign matter in the device, b is the signal image obtained by the image sensor group when there is no foreign matter, c is the signal image obtained by filtering the signal image obtained by the image sensor group when there is no foreign matter, and d is the communication with the largest area in c. area. The largest connected domain is caused by noise, its area is small, the height does not satisfy the condition, and no foreign matter is judged. As shown in Fig. 10, in the second case, banknotes are left in the apparatus, and most of the banknotes are attached to the image sensor.

As shown in a, the banknotes remain in the device, most of the banknotes are attached to the image sensor, b is the signal image obtained by the image sensor when most of the banknotes are attached to the image sensor, and c is the signal image obtained by filtering the signal image, d In order to obtain the largest connected area and its height image. The connected field in the scanned image is a rectangular area having a wide width, and the height satisfies the condition, and it is judged that there is a foreign object.

As shown in Fig. 11, in the third case, there is a small foreign matter in the device, such as paper dust, which is less attached to the image sensor.

Figure a is a picture showing a small piece of paper remaining in the device, which is less attached to the image sensor. b is a signal image obtained when the image sensor has a small piece of paper remaining in the device, and c is obtained by b filtering. The signal image, d is the connected domain with the largest area and its height image. The connected area in the scanned image is a rectangular area having a narrow width, and the height thereof also satisfies the condition, and it is judged that the foreign object is detected.

The related technology of image sensor has been more maturely applied to the current device. The improved method proposed in this paper can directly use the existing technology to upgrade on the basis of its core, without changing the design scheme of the software and hardware architecture of the signal image sensor system. The part of the detection algorithm needs to be modified to greatly save design and development costs.

The invention provides a banknote high-speed identification device and a foreign matter detecting method thereof, which simplifies two sets of radiation sensors, detects an internal moving banknote (other medium) by using an existing image sensor, and performs static foreign object detection inside the device. Thereby, the banknote recognition speed and accuracy of the existing device are maintained, and the accuracy of foreign matter detection is enhanced. After streamlining the two sets of radiation sensors, the structure of the identification device is simplified and the volume of the device is reduced. In practical applications, the length and height of the device design are reduced by 1/5 compared with the existing solutions, and the manufacturing cost is significantly reduced.

Finally, it should also be noted that in this context, relational terms such as first and second are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply these entities. There is any such actual relationship or order between operations. Furthermore, the terms "including", "comprising" or "comprising" or "comprising" are intended to encompass a non-exclusive inclusion, such that a process, method, article, or device that includes a plurality of elements includes not only those elements but also Other elements, or elements that are inherent to such a process, method, item, or device. In the absence of more restrictions, the elements defined by the statement "includes one..." are not There are additional identical elements that are excluded from the process, method, article, or device that includes the described elements. The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments are obvious to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but the scope of the inventions

Claims

Rights request

1. A high-speed banknote recognition device, characterized in that it includes: a transmission channel, an image sensor group, a magnetic sensor, and a group of through-beam sensors;

The image sensor group is used to identify the initial information of banknotes and identify the image authenticity information of banknotes based on the initial information, and detect whether there is foreign matter in the device;

The magnetic sensor is used to identify the magnetic authenticity information of banknotes based on the initial information;

The through-beam sensor is used to detect the moment when banknotes enter the sensor.

2. The device according to claim 1, wherein the image sensor group includes: a first image sensor and a second image sensor;

The first image sensor identifies the initial information of banknotes and detects whether foreign matter is present in the device; the second image sensor identifies the authenticity information of the image of banknotes based on the initial information, and detects whether foreign matter is present in the device.

3. A method for detecting foreign matter, characterized in that it is based on a high-speed banknote recognition device, and the device includes: a transmission channel, an image sensor group, a magnetic sensor, and a set of through-beam sensors;

The methods include:

The high-speed banknote recognition device enters the foreign object detection mode, triggers the image sensor group n times, acquires n rows of signals, and forms an array signal, where n is a positive integer;

Detect the connected domains in the array signal and select the connected domain with the largest area;

Calculate the height of the connected domain with the largest area. If the height is greater than the threshold, it is judged that a foreign object has been detected. Otherwise, it is judged that no foreign object has been detected.

4. The method according to claim 3, wherein n is greater than 1, and the array signal is a two-dimensional array signal.

5. The method according to claim 4, characterized in that, before detecting the connected domain in the array signal, it further includes:

Use high-frequency filtering to remove random noise in the two-dimensional array signal.

6. The method according to claim 3, wherein n is 1 and the array signal is a one-dimensional array signal.

7. A method for detecting foreign matter, characterized in that it is based on a high-speed banknote identification device, and the device Includes: transmission channel, image sensor group, magnetic sensor, and a set of through-beam sensors;

The methods include:

Sl. The banknote high-speed identification device enters the foreign object detection mode, triggers the image sensor group n times, acquires n rows of signals, and forms an array signal, where n is a positive integer;

S2. Detect the connected domain in the array signal and calculate the height of the connected domain; if the height is less than the threshold, continue to detect and calculate the heights of other connected domains in the array signal until the connected domain in the array signal is detected, then determine No foreign object is detected. Otherwise, if the height is greater than the threshold, it is judged that a foreign object is detected and the process ends.

8. The method according to claim 7, wherein n is greater than 1, and the array signal is a two-dimensional array signal.

9. The method according to claim 8, characterized in that, the S2 is:

Al. Select a row of signals in the array signal;

A2. Detect non-zero points from left to right, use them as the starting point of the connected domain, and calculate the height of the connected domain. If the height is non-zero, execute A3; if no non-zero point is detected, continue to detect from the next line of signals. Execute A2 until all lines have been detected;

A3. Check whether the point below the current point is 0. If it is not 0, set the point below as the current point, increase the height by 1, and re-enter step A3. If it is 0, execute A4;

A4. Check whether the point to the right of the current point is 0. If it is not 0, set the point to the right as the current point and execute A3. If it is 0, execute A5;

A5. If the height is greater than the threshold, it is judged that a foreign object has been detected; if the height is less than the threshold, continue to find the starting points of other connected domains and execute A2.

10. The method according to claim 7, wherein n is 1 and the array signal is a one-dimensional array signal.