A system and method for detecting object entry and exit based on polarization reconfigurable antenna

Abstract

The present invention relates to an article entry and exit detection system and method based on a polarization reconfigurable antenna, and belongs to the field of radio frequency identification technology. It includes: a detection device, the detection device includes a detection channel, and the detection channel is used for the entry and exit of articles carrying radio frequency identification tags; a first polarization reconfigurable antenna is installed on an inner wall of one side of the detection channel; a radio frequency identification reader, connected to the first polarization reconfigurable antenna, is used to obtain the left and right rotation channel signal strength indication value of the first polarization reconfigurable antenna; a host computer, connected to the radio frequency identification reader, is used to calculate the difference between the left and right rotation channel signal strength indication values; obtain the entry and exit direction of the article carrying the radio frequency identification tag according to the internal difference. The present invention reduces the probability of missing the tag, can flexibly adjust the antenna height, does not require additional space resources, and simplifies the identification process.

Description

Technical Field

[0001] The present invention relates to the field of radio frequency identification technology, and in particular to an article access detection system and method based on a polarization reconfigurable antenna. Background Art

[0002] Radio Frequency Identification (RFID) technology has developed rapidly in recent years due to its easy deployment and suitability for low-power systems, and has been widely used in many fields such as indoor positioning, item management, and smart parking. In particular, the application of RFID technology is particularly important in warehouse management. It can achieve efficient item tracking and management by determining the entry and exit status of items with RFID tags when passing through the door. In this application scenario, it is usually not necessary to achieve high-precision positioning, but only to determine the movement direction of the RFID tag.

[0003] In terms of judging the moving direction of RFID tags, researchers have proposed a variety of methods. For example, the first method uses the moving direction detection method of the active RFID system, which is based on the direction estimated by the RFID system and the individual information for automatic selection; the second method uses the time difference of the dual antenna, each data reading time is weighted by the read count n or the received power Pr, and the tag direction is calculated by the difference between the two weighted centers of the two antennas, and the time when the tag is closest to the reader antenna is estimated, so as to judge the moving direction of the tag; the third method uses multiple directional antenna reading and writing devices to form multiple reading areas, and realizes the judgment of the moving direction by extracting the events of the tag in each area and analyzing the logical sequence of the events; the fourth method is based on the electromagnetic environment model for evaluating the RFID door system, using the read count as a means to evaluate the accuracy of these methods, and using these models to evaluate the moving direction of the passive RFID tags in the door system; the fifth method uses the phase change trend of the signals received by the two antennas, and determines whether the tagged object is approaching or leaving the monitored area by checking the phase difference score sign.

[0004] However, although the above methods improve the accuracy of identifying the entry and exit status of objects, they also face some limitations. Specifically, when objects carrying tags enter and exit the access control system, due to the different polarization modes of the RFID tags and the antennas, there is a polarization mismatch between the two, which will cause the RFID system to miss read. The existence of the missed read phenomenon makes it impossible to accurately determine the direction of movement of the object. At present, the installation position of the antenna is usually fixed directly above the middle of the door, which can neither flexibly adjust the height nor occupy additional space resources. In addition, the use of machine learning and other methods to determine the direction of movement requires training the model first, and the recognition process is relatively complicated, which increases the complexity of the system and the difficulty of implementation. Summary of the invention

[0005] To this end, the technical problem to be solved by the present invention is to overcome the problems in the prior art such as tag missed reading, inability to flexibly adjust height, additional space resources occupied, and complicated identification process caused by the different polarization modes of the RFID tag and the antenna.

[0006] In a first aspect, in order to solve the above technical problems, the present invention provides an object access detection system based on a polarization reconfigurable antenna, comprising:

[0007] A detection device, the detection device comprising a detection channel, the detection channel is used for the entry and exit of objects carrying radio frequency identification tags;

[0008] The first polarization reconfigurable antenna is installed on an inner wall of one side of the detection channel;

[0009] a radio frequency identification reader, connected to the first polarization reconfigurable antenna, for obtaining a first received signal strength indicator value of the first polarization reconfigurable antenna;

[0010] The host computer is connected to the radio frequency identification reader and is used to calculate a first internal difference of the first received signal strength indicator value; according to the first internal difference, the entry and exit direction of the item carrying the radio frequency identification tag is obtained; wherein the first internal difference is the difference between the indicator values ​​of the left-hand circular polarization port and the right-hand circular polarization port of the first polarization reconfigurable antenna.

[0011] In one embodiment of the present invention, the left-hand circular polarization port and the right-hand circular polarization port in the first polarization reconfigurable antenna are connected to the radio frequency identification reader using coaxial cables of equal length.

[0012] In one embodiment of the present invention, it also includes a second polarization reconfigurable antenna, which is installed on the inner wall of the detection channel and has a different installation position from the first polarization reconfigurable antenna; the second polarization reconfigurable antenna is connected to the radio frequency identification reader.

[0013] In one embodiment of the present invention, the first polarization reconfigurable antenna and the second polarization reconfigurable antenna both include a left-hand circular polarization port and a right-hand circular polarization port, and the left-hand circular polarization port and the right-hand circular polarization port are switched with each other.

[0014] In one embodiment of the present invention, the detection channel includes two support arms, and the radio frequency identification reader is embedded in one of the support arms.

[0015] In one embodiment of the present invention, the connection mode between the host computer and the radio frequency identification reader includes: serial communication, USB communication and Ethernet communication.

[0016] In a second aspect, in order to solve the above technical problems, the present invention provides an object entry and exit detection method based on a polarization reconfigurable antenna, comprising:

[0017] Installing a first polarization reconfigurable antenna on an inner wall of one side of the detection channel;

[0018] Obtaining a first received signal strength indicator value of the first polarization reconfigurable antenna;

[0019] Calculating a first internal difference of the first received signal strength indicator value, and determining the direction of the RFID tag entering or leaving the door according to the trend of the first internal difference along the movement path of the RFID tag;

[0020] The first internal difference is the difference between the indication values ​​of the left-hand circular polarization port and the right-hand circular polarization port of the first polarization reconfigurable antenna.

[0021] In one embodiment of the present invention, the first received signal strength indication value includes a first left-hand port indication value and a first right-hand port indication value.

[0022] In one embodiment of the present invention, the method for obtaining the first internal difference of the first received signal strength indication value is to subtract the first right-hand port indication value from the first left-hand port indication value or to subtract the first right-hand port indication value from the first left-hand port indication value; when the first left-hand port indication value is subtracted from the first right-hand port indication value, if the first internal difference shows a downward trend along the travel path, the radio frequency identification tag is judged to be in the entry state; if the first internal difference shows an upward trend along the travel path, the radio frequency identification tag is judged to be in the exit state; when the first right-hand port indication value is subtracted from the first left-hand port indication value, if the first internal difference shows an upward trend along the travel path, the radio frequency identification tag is judged to be in the entry state; if the first internal difference shows a downward trend along the travel path, the radio frequency identification tag is judged to be in the exit state.

[0023] In a third aspect, in order to solve the above technical problem, the present invention provides an electronic device, including the above-mentioned object entry and exit detection system based on polarization reconfigurable antenna.

[0024] The above technical solution of the present invention has the following beneficial effects compared with the prior art:

[0025] The object entry and exit detection system and method based on a polarization reconfigurable antenna described in the present invention can accurately determine the entry and exit direction of the tagged object by using an RFID reader, a polarization reconfigurable antenna, an RFID tag, and a host computer, thereby avoiding the missed reading of the tag due to the different polarization modes of the RFID tag and the antenna. The first polarization reconfigurable antenna is installed on the inner wall of one side of the detection channel, and the detection blind area can be eliminated without adjusting the antenna angle, which simplifies the detection process, enhances the versatility and cost-effectiveness of the system, and saves space resources. In addition, the present invention compares the signal strength indication values ​​received by the left-handed and right-handed circularly polarized ports of the antenna, and calculates the difference between the two, and determines the entry and exit direction of the object according to the change trend of the difference along the movement path of the object, thereby avoiding the need for complex algorithms and training models, and achieving accurate judgment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0027] Figure 1 It is a schematic diagram of an access detection system in the prior art;

[0028] Figure 2 This is a structural diagram of an article access detection system based on a polarization reconfigurable antenna in a preferred embodiment of the present invention;

[0029] Figure 3 A schematic diagram of an object access detection system based on a polarization reconfigurable antenna in a preferred embodiment of the present invention;

[0030] Figure 4 It is a trend diagram of the difference between the RSSI of the left-handed port and the right-handed port when the first antenna enters the door when the tag is at 45° polarization in the preferred embodiment of the present invention;

[0031] Figure 5 It is a trend diagram of the difference between the RSSI of the left-handed port and the right-handed port when the first antenna goes out when the tag is at 45° polarization in the preferred embodiment of the present invention;

[0032] Figure 6 It is a trend diagram of the difference of RSSI of the left-handed port minus the right-handed port when the second antenna enters the door in the preferred embodiment of the present invention when the tag is in horizontal polarization;

[0033] Figure 7 It is a trend diagram of the difference of RSSI of the left-hand port minus the right-hand port when the second antenna goes out when the tag is in horizontal polarization in the preferred embodiment of the present invention;

[0034] Figure 8The present invention is a flowchart of a method for detecting the entry and exit of objects based on a polarization reconfigurable antenna in a preferred embodiment of the present invention.

[0035] Explanation of the reference numerals in the specification: 1. left-hand circular polarization port; 2. right-hand circular polarization port; 3. RFID tag; 4. coaxial cable; 5. RFID reader; 6. host computer; 7. object; 8. first polarization reconfigurable antenna; 9. second polarization reconfigurable antenna. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0037] Reference Figure 1 As shown in the figure, the detection area of ​​the existing detection system mainly covers the inner and outer sides of the door. This layout may cause the tag to be missed when it passes through the side of the door. To solve this problem, it is usually necessary to adjust the angle of the antenna to eliminate the detection blind area and ensure that the tag can be successfully detected. However, this method may increase the complexity of the system and the difficulty of operation.

[0038] In contrast, the detection system proposed in the present invention achieves comprehensive coverage of all paths that a tag may pass through. The advantage of this design is that it can effectively detect passing tags without changing the placement and angle of the antenna. This design not only simplifies the detection process and reduces the complexity of operation, but also significantly improves the detection accuracy and reliability of the system. By eliminating the detection blind spot, the present invention ensures that all tags passing through the access control are monitored without omission, thereby enhancing the overall security performance and efficiency.

[0039] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods. Embodiment 1

[0040] Reference Figure 2 As shown, an embodiment of the present invention provides an object entry and exit detection system based on a polarization reconfigurable antenna, comprising:

[0041] A detection device, the detection device includes a detection channel, and the detection channel is used for the entry and exit of the object 7 carrying the radio frequency identification tag;

[0042] The first polarization reconfigurable antenna 8 is installed on an inner wall of one side of the detection channel;

[0043] The radio frequency identification reader 5 is connected to the first polarization reconfigurable antenna 8 and is used to obtain a first received signal strength indicator value of the first polarization reconfigurable antenna 8;

[0044] The host computer 6 is connected to the radio frequency identification reader 5 and is used to calculate the first internal difference of the first received signal strength indication value; according to the first internal difference, the entry and exit direction of the object 7 carrying the radio frequency identification tag is obtained; wherein the first internal difference is the difference between the indication values ​​of the left-hand circular polarization port 1 and the right-hand circular polarization port 2 of the first polarization reconfigurable antenna 8.

[0045] The embodiment of the present invention provides an article entry and exit detection system based on a polarization reconfigurable antenna. By using a radio frequency identification reader 5, a first polarization reconfigurable antenna 8, a radio frequency identification tag 3 and a host computer 6, the direction of the article 7 carrying the tag entering and exiting the door can be accurately judged, thereby avoiding the tag missing reading caused by the different polarization modes of the radio frequency identification tag 3 and the antenna. The first polarization reconfigurable antenna 8 is installed on the inner wall of one side of the detection channel. There is no need to eliminate the detection blind area by modifying the placement angle of the antenna. The detection process is simple and convenient, more universal, and does not require additional space, which is conducive to reducing costs. In addition, by comparing the indication values ​​received by the left-handed circular polarization port 1 and the right-handed circular polarization port 2, and subtracting them to obtain the difference, the direction of the tag entering and exiting the door is judged according to the change trend of the difference along the movement path of the radio frequency identification tag 3. Such a design can accurately judge the entry and exit of the tag without complex algorithms and training models. The embodiment of the present invention greatly reduces the missed reading rate of the article 7 carrying the radio frequency identification tag 3 when passing through the entry and exit detection system, and can more accurately judge the movement direction of the article, providing a new and more efficient entrance and exit discrimination scheme for the entry and exit detection system.

[0046] Specifically, the article entry and exit detection system provided by the embodiment of the present invention includes a detection device, a host computer 6, a radio frequency identification reader 5 (hereinafter referred to as RFID reader 5), a reconfigurable antenna that can switch between left-handed and right-handed polarization (i.e., a first polarization reconfigurable antenna 8), and an article 7 with a radio frequency identification tag 3 (hereinafter referred to as RFID tag 3). The connection between the RFID reader 5 and the host computer 6 can be achieved in a variety of ways, including: serial communication, USB communication, and Ethernet communication. The host computer 6 is responsible for controlling the RFID reader 5, and the radio frequency signal output port of the RFID reader 5 is connected to the first polarization reconfigurable antenna 8.

[0047] In practical applications, only one polarization reconfigurable antenna is needed to achieve a good judgment effect. However, in order to further expand the radio frequency identification range and verify the judgment results to improve accuracy, the object entry and exit detection system in this embodiment also introduces a second polarization reconfigurable antenna 9. The second polarization reconfigurable antenna 9 is installed on the inner wall of the detection channel, and is installed at a different position from the first polarization reconfigurable antenna 8, and is connected to the RFID reader 5. Both the first polarization reconfigurable antenna 8 and the second polarization reconfigurable antenna 9 have the function of switching between left-handed and right-handed circular polarization modes, and can be symmetrically installed on the inner walls on both sides of the detection channel. For specific arrangements, please refer to Figure 3 It should be noted that the heights of the first polarization reconfigurable antenna 8 and the second polarization reconfigurable antenna 9 are not required to be consistent, and they only need to be located on both sides of the detection channel. In addition, the two polarization ports of each antenna are connected to the RFID reader 5 through coaxial cables 4 of equal length to ensure the consistency of signal transmission.

[0048] In this embodiment, the detection device includes a detection channel, such as a detection door in a security check, which includes two support arms, and the RFID reader 5 is embedded in one of the support arms. This design not only saves space, but also improves the stability and concealment of the overall structure, making the detection process more efficient and reliable. In addition, the detection device is also equipped with auxiliary components such as multiple sensors and indicator lights, which further enhances the functionality and practicality of the system.

[0049] Specifically, during the detection process of the object entry and exit detection system, the object 7 with the radio frequency identification tag 3 passes through the detection channel at a uniform speed and moves from one side to the other. In order to accurately capture the movement information of the object 7, the detection system sets equally spaced detection points on the object movement path. These detection points are mainly used to verify the entry and exit process of the object in the detection system. The accuracy of the object entry and exit detection system is judged by comparing the data obtained at the detection point with the data read from the radio frequency identification tag 3 by the two polarization reconfigurable antennas. Whenever the object 7 passes through these preset detection points, the two polarization reconfigurable antennas installed on both sides of the detection channel will read the data sent by the radio frequency identification tag 3 from their different polarization ports respectively. This process ensures continuous monitoring of the movement status of the object. Once the object completes its movement in the detection channel, the detection system will automatically save all the data collected at each detection point. In addition, according to the needs of the actual application and the specific conditions of the detection channel, the number of detection points can be flexibly set to achieve the best detection effect and system performance.

[0050] Furthermore, this embodiment can determine the moving direction of the object by analyzing the difference in the received signal strength indicator (RSSI) values ​​received by the left-hand and right-hand ports of each antenna. Taking the first polarization reconfigurable antenna 8 as an example, the first received signal strength indicator value received by the first polarization reconfigurable antenna 8 includes the RSSI value received by the left-hand circular polarization port 1 and the RSSI value received by the right-hand circular polarization port 2, and the RSSI value received by the left-hand circular polarization port 1 minus the RSSI value received by the right-hand circular polarization port 2 (or vice versa), and the change trend of the difference is used to determine whether the object is entering or leaving the door.

[0051] For example, when the difference between the antenna (the door antenna on the right when entering the door) shows a downward trend as the item moves along its path, it can be determined that the tag is in the state of entering the door; if the difference shows an upward trend, it can be determined that the tag is in the state of leaving the door. On the contrary, if the RSSI value of the right-handed port minus the left-handed port is used for analysis, the trend of the difference will be opposite to the state of the item entering or leaving the door.

[0052] In practical applications, due to the limited detection range of a single antenna, using two antennas can better cover the area near the door frame, which not only reduces the tag's missed reading rate, but also improves the accuracy of the system's detection results. Since the second polarization reconfigurable antenna 9 is in the opposite direction to the first polarization reconfigurable antenna 8, when the RSSI difference between the different polarization ports of the second polarization reconfigurable antenna 9 (the door antenna on the left when entering the door) shows an upward trend along the travel path, it can be judged that the tag is in the state of entering the door; if the difference shows a downward trend, it can be judged that the tag is in the state of leaving the door.

[0053] In order to further verify the effectiveness of the access detection system provided by the embodiment of the present invention, a simulation experiment is designed for verification. The specific experimental steps are as follows:

[0054] Step 1: Install two polarization reconfigurable antennas on the inner side of the door frame, set the height to 1.1 m, and connect the antennas, RFID reader 5 and host computer 6 system in sequence.

[0055] Step 2: Before the test begins, the RFID reader 5 is configured through the host computer 6. The type of the RFID reader 5 is selected as 4 antennas, and the transmission power is set to 30 dBm. In this simulation experiment, the host computer 6 is a PC.

[0056] Step 3: During the test, the RFID reader 5 emits a radio frequency signal. At the same time, the test item carrying the radio frequency identification tag 3 moves at a constant speed from one side of the door to the other side of the door, passing through the center of the door frame until it reaches the other side, completing the driving process. During the movement of the item, 13 equidistant detection points are set on the door frame. Whenever an item passes a detection point, the system reads the RSSI data from the four polarization ports of each antenna, and each reading lasts 0.2 seconds. Every 0.1 seconds, the system switches the four polarization ports in turn and records the RSSI value received at each port. Compare the RSSI values ​​received at the left and right ports of each antenna, and calculate the difference between the two (left-hand RSSI value minus right-hand RSSI value). Analyze the changing trend of these differences to determine the direction of movement of the tag. The specific judgment process is as follows:

[0057] (1) When the difference value of the first antenna (the right door antenna when entering the door) gradually decreases from a positive value to a negative value, and the difference value of the second antenna (the left door antenna when entering the door) gradually increases from a negative value to a positive value, it indicates that the tag is entering the door.

[0058] (2) When the difference of the first antenna gradually increases from negative to positive, and the difference of the second antenna gradually decreases from positive to negative, it indicates that the tag is leaving.

[0059] Step 4: Change the placement and polarization of the tag and repeat step 3. Usually, changing the placement and polarization of the tag will result in different RSSI values ​​for each port test, but in this experiment, the difference trend of the left and right ports remains consistent. This result strongly verifies the effectiveness of this design.

[0060] Combined with the above steps 1 to 4, the specific analysis results are as follows:

[0061] When the distance between the tag and the door is positive, it indicates that the tag is outside the door; when the distance between the tag and the door is negative, it indicates that the tag is inside the door. From the test results, it can be seen that at the first antenna detection end, when the item carrying the tag enters the door, the difference between the left-hand rotation and the right-hand rotation gradually decreases and changes from a positive value to a negative value; when leaving the door, the difference between the left-hand rotation and the right-hand rotation gradually increases and changes from a negative value to a positive value. For the second antenna detection end, when the item carrying the tag enters the door, the difference between the left-hand rotation and the right-hand rotation gradually increases and changes from a negative value to a positive value; when leaving the door, the difference between the left-hand rotation and the right-hand rotation gradually decreases and changes from a positive value to a negative value. The second antenna is in the opposite direction to the first antenna, so the change trends measured by the two antennas are opposite, which can double guarantee the accuracy of the judgment results.

[0062] Further, refer to Figure 4 and Figure 5 , shows the change trend of the RSSI difference between the left-handed port and the right-handed port of the first antenna when the tag is at 45° polarization during the process of entering and leaving the door. Figure 6 and Figure 7 , shows the change trend of the RSSI difference between the left-hand port and the right-hand port of the second antenna when the tag is in horizontal polarization during the process of entering and leaving the door. It should be noted that for the sake of simplicity, Figure 4 and Figure 5 The vertical coordinate in represents the first antenna with "antenna 1"; similarly, Figure 6 and Figure 7 The vertical axis in denoted by “antenna 2” represents the second antenna.

[0063] The above results show that the object entry and exit detection system provided by the embodiment of the present invention can accurately determine the entry and exit direction of the object, and has good adaptability to different test conditions, verifying the effectiveness and practicality of its design. When the object carrying the tag passes through the entry and exit detection system provided by the embodiment of the present invention, the system can accurately determine the movement direction and the state of the object entering and leaving the door, thereby providing an efficient and reliable solution for the automated management of the access control system. Embodiment 2

[0064] Based on the same inventive concept, this embodiment provides an object entry and exit detection method based on a polarization reconfigurable antenna. The principle of solving the problem is similar to that of an object entry and exit detection system based on a polarization reconfigurable antenna provided in Example 1, and the repeated parts will not be repeated.

[0065] refer to Figure 8 This embodiment provides an object entry and exit detection method based on a polarization reconfigurable antenna, comprising:

[0066] Installing the first polarization reconfigurable antenna 8 on an inner wall of one side of the detection channel;

[0067] Obtaining a first received signal strength indicator value of the first polarization reconfigurable antenna 8;

[0068] Calculate a first internal difference of the first received signal strength indicator value, and determine the direction of the RFID tag 3 entering or leaving the door according to the trend of the first internal difference along the movement path of the RFID tag 3;

[0069] The first internal difference is the difference between the indication values ​​of the left-hand circular polarization port 1 and the right-hand circular polarization port 2 of the first polarization reconfigurable antenna 8 .

[0070] The object entry and exit detection method proposed in this embodiment obtains the received signal strength indicator (RSSI) of the antenna and calculates its internal difference, that is, the difference between the indicator values ​​of the left-hand circular polarization port and the right-hand circular polarization port. According to the changing trend of these differences along the movement path of the RFID tag 3, the direction of the tag entering and leaving the door can be accurately determined. This design simplifies the installation and configuration process, and avoids the tag missing due to the different polarization mode of the RFID tag 3 and the antenna.

[0071] Specifically, the first received signal strength indication value includes a first left-hand port indication value and a first right-hand port indication value.

[0072] Further, the method for obtaining the first internal difference of the first received signal strength indication value is to subtract the first right-hand port indication value from the first left-hand port indication value or to subtract the first right-hand port indication value from the first left-hand port indication value; when the first left-hand port indication value is subtracted from the first right-hand port indication value, the first internal difference shows a downward trend along the travel path, and it is judged that the radio frequency identification tag 3 is in the entry state; the first internal difference shows an upward trend along the travel path, and it is judged that the radio frequency identification tag 3 is in the exit state; when the first right-hand port indication value is subtracted from the first left-hand port indication value, the first internal difference shows an upward trend along the travel path, and it is judged that the radio frequency identification tag 3 is in the entry state; the first internal difference shows a downward trend along the travel path, and it is judged that the radio frequency identification tag 3 is in the exit state. Embodiment 3

[0073] This embodiment provides an electronic device, including the object entry and exit detection system based on the polarization reconfigurable antenna described in the first embodiment.

[0074] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0075] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0076] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0077] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0078] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. An object access detection system based on a polarization reconfigurable antenna, characterized in that: include: A detection device, the detection device comprising a detection channel, the detection channel is used for the entry and exit of objects carrying radio frequency identification tags; The first polarization reconfigurable antenna is installed on an inner wall of one side of the detection channel; a radio frequency identification reader, connected to the first polarization reconfigurable antenna, for obtaining a first received signal strength indicator value of the first polarization reconfigurable antenna; A host computer connected to the RFID reader, used to calculate a first internal difference of the first received signal strength indicator value; and obtain the entry and exit direction of the article carrying the RFID tag according to the first internal difference; The first internal difference is the difference between the indication values ​​of the left-hand circular polarization port and the right-hand circular polarization port of the first polarization reconfigurable antenna; When the indication value of the left-hand circular polarization port is subtracted from the indication value of the right-hand circular polarization port, and the first internal difference shows a downward trend along the travel path, it is judged that the radio frequency identification tag is in the entry state; when the first internal difference shows an upward trend along the travel path, it is judged that the radio frequency identification tag is in the exit state; when the indication value of the right-hand circular polarization port is subtracted from the indication value of the left-hand circular polarization port, and the first internal difference shows an upward trend along the travel path, it is judged that the radio frequency identification tag is in the entry state; when the first internal difference shows a downward trend along the travel path, it is judged that the radio frequency identification tag is in the exit state.

2. According to claim 1, the object access detection system based on polarization reconfigurable antenna is characterized in that: The left-hand circular polarization port and the right-hand circular polarization port in the first polarization reconfigurable antenna are connected to the radio frequency identification reader by using coaxial cables of equal length.

3. The object access detection system based on polarization reconfigurable antenna according to claim 1, characterized in that: It also includes a second polarization reconfigurable antenna, which is installed on the inner wall of the detection channel and has a different installation position from the first polarization reconfigurable antenna; the second polarization reconfigurable antenna is connected to the radio frequency identification reader.

4. The object access detection system based on polarization reconfigurable antenna according to claim 3 is characterized in that: The first polarization reconfigurable antenna and the second polarization reconfigurable antenna both include a left-hand circular polarization port and a right-hand circular polarization port, and the left-hand circular polarization port and the right-hand circular polarization port are switched with each other.

5. The object access detection system based on polarization reconfigurable antenna according to claim 1, characterized in that: The detection channel includes two support arms, and the radio frequency identification reader is embedded in one of the support arms.

6. The object access detection system based on polarization reconfigurable antenna according to claim 1, characterized in that: The connection modes between the host computer and the radio frequency identification reader include: serial communication, USB communication and Ethernet communication.

7. A method for detecting the entry and exit of objects based on a polarization reconfigurable antenna, characterized in that: include: Installing a first polarization reconfigurable antenna on an inner wall of one side of the detection channel; Obtaining a first received signal strength indicator value of the first polarization reconfigurable antenna; Calculate a first internal difference of the first received signal strength indicator value, and judge the direction of the RFID tag entering or leaving the door according to the trend of the first internal difference along the movement path of the RFID tag; wherein the first received signal strength indicator value includes a first left-handed port indicator value and a first right-handed port indicator value; the first internal difference is obtained by: subtracting the first right-handed port indicator value from the first left-handed port indicator value or subtracting the first left-handed port indicator value from the first right-handed port indicator value; when the first left-handed port indicator value is subtracted from the first right-handed port indicator value, if the first internal difference shows a decreasing trend along the travel path, it is judged that the RFID tag is in the door entry state; if the first internal difference shows an increasing trend along the travel path, it is judged that the RFID tag is in the door exit state; when the first right-handed port indicator value is subtracted from the first left-handed port indicator value, if the first internal difference shows an increasing trend along the travel path, it is judged that the RFID tag is in the door entry state; if the first internal difference shows a decreasing trend along the travel path, it is judged that the RFID tag is in the door exit state; The first internal difference is the difference between the indication values ​​of the left-hand circular polarization port and the right-hand circular polarization port of the first polarization reconfigurable antenna.

8. An electronic device, characterized in that: An object entry and exit detection system based on a polarization reconfigurable antenna as described in any one of claims 1 to 6.

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