Article identification device and article identification method

Abstract

To provide an article identification device that takes measures to reduce the probability of incorrectly identifying an article that is not subject to identification as an article to be identified.SOLUTION: An article identification device according to the embodiment includes a placing table, an antenna, selection means, and identification means. The placing table has a placing surface on which an article with a radio tag attached is placed. The antenna has a receiving surface for receiving radio waves, and is arranged so that at least a part of the receiving surface is positioned directly below an area outside a placing area on the placing surface on which the article is placed. The selection means selects a radio tag located within the placing area from among radio tags that emitted the radio waves received by the antenna. The identification means identifies an article with a radio tag selected by the selection means as an article placed within the placing area.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] Embodiments of the present invention relate to an article identification device and an article identification method.

Background Art

[0002] An article identification device that identifies an article to be identified based on radio waves radiated from a radio tag attached to the article is known. In this type of article identification device, it is necessary to prevent misidentifying an article as the article to be identified based on radio waves from radio tags attached to articles other than the article to be identified that exist around the article to be identified. Under such circumstances, it has been desired to take measures to reduce the probability of misidentifying an article other than the article to be identified as the article to be identified.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem to be solved by the present invention is to provide an article identification device and an article identification method that take measures to reduce the probability of misidentifying an article other than the article to be identified as the article to be identified.

Means for Solving the Problems

[0005] The article recognition device according to the embodiment includes a mounting table, an antenna, a selection means, and an identification means. The mounting table has a mounting surface for mounting an article with a radio tag attached thereto. The antenna has a receiving surface for receiving radio waves, and at least a part of the receiving surface is arranged in a state of being located directly below the outside of the mounting area where the article is mounted on the mounting surface. The selection means selects a radio tag located within the mounting area from the radio tags that have emitted the radio waves received by the antenna. The identification means identifies the article with the radio tag selected by the selection means as the article mounted within the mounting area.

Brief Description of the Drawings

[0006]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Modes for Carrying Out the Invention

[0007] Hereinafter, the article identification device according to the embodiment will be described with reference to the drawings. FIG. 1 is a top view showing the appearance of the article identification device 1 according to the present embodiment. Note that each drawing used in the following description of the embodiment may not accurately represent the scale and position of each part. The article identification device 1 includes a mounting table 100. The mounting table 100 has a substantially horizontal top surface, which serves as a mounting surface 101 for mounting an article to be identified. On the mounting surface 101, marks MAA, MAB, MAC, and MAD representing the outer edges of the mounting area REA where the article is to be mounted are formed so as to be visible to humans. Note that the dashed line representing the mounting area REA is for illustrative convenience and is not formed to be visible. Then, the article identification device 1 identifies the corresponding article based on the radio wave radiated from the wireless tag 3 attached to the article 2 placed within the mounting area REA of the mounting surface 101. Although only one article 2 is shown in FIG. 1, a plurality of articles 2 may be placed on the mounting surface 101 at the same time. Also, the article 2 may be placed directly on the mounting surface 101, or may be placed on top of another article 2. Further, the article 2 may be placed on the mounting surface 101 while being placed in a basket. That is, the article 2 to be identified is located in the space above the mounting area REA.

[0008] The wireless tag 3 is typically an RFID (radio frequency identification) tag. The wireless tag 3 may be a different type of wireless tag from RFID. The wireless tag 3 is a passive wireless communication device that operates using the radio wave (hereinafter referred to as the transmission wave) radiated from the antenna 200 as an energy source. The wireless tag 3 performs backscatter modulation on the unmodulated wave included in the transmission wave, and radiates a radio wave (hereinafter referred to as the response wave) including the information stored in the wireless tag 3 (hereinafter referred to as the tag information). The tag information includes a tag code. The tag code is an identifier that can uniquely identify the wireless tag 3, or an identifier of the article 2 to which the wireless tag 3 is attached.

[0009] FIG. 2 is a block diagram showing the electrical schematic configuration of the article identification device 1. The article identification device 1 includes two antennas 200, a drive unit 300, a reading unit 400, and an inference unit 500. These antennas 200, drive unit 300, reading unit 400, and inference unit 500 are mainly housed in a housing space formed inside the mounting table 100. That is, the mounting table 100 is also the housing of the article identification device 1. However, at least one of the reading unit 400 and the inference unit 500 may be provided outside the mounting table 100. Furthermore, both the reading unit 400 and the inference unit 500 may be provided outside the mounting table 100.

[0010] The antenna 200 radiates a transmission wave corresponding to an electrical signal (hereinafter referred to as a transmission signal) supplied from the reading unit 400. The antenna 200 receives the response wave radiated from the wireless tag 3 and gives a corresponding electrical signal (hereinafter referred to as a reception signal) to the reading unit 400. The antenna 200 is disposed below the mounting surface 101 in a posture where the reception surface for receiving radio waves faces the mounting area REA.

[0011] The drive unit 300 includes a mechanism for moving the two antennas 200 along the mounting surface 101 respectively. That is, the drive unit 300 is an example of a moving mechanism. The reading unit 400 sends a transmission wave for calling to the wireless tag 3 attached to the article 2 placed in the mounting area REA of the mounting surface 101 via the antenna 200. The reading unit 400 receives the response wave radiated from the wireless tag 3 in response to this transmission wave via the antenna 200. Then, the reading unit 400 identifies the article 2 based on the received response wave.

[0012] The inference unit 500 selects, by inference using a learned model based on the reception status of response waves sequentially received at a plurality of positions by the antenna 200 while being moved by the drive unit 300, the response wave radiated from the wireless tag 3 located within the mounting area REA among the response waves received by the antenna 200.

[0013] FIG. 3 is a diagram showing the configuration of the drive unit 300. The drive unit 300 includes a stage 310, a movement mechanism 320, and a control unit 330. Note that FIG. 3 includes a perspective view showing the structure of the stage 310 and the movement mechanism 320, and a block diagram showing the main circuit configuration of the control unit 330.

[0014] In addition, the perspective view included in FIG. 3 shows, in addition to the drive unit 300, a part of the top surface of the mounting table 100, that is, a part of the mounting surface 101, the antenna 200, and the shopping basket BAA placed on the mounting surface. The article identification device 1 is used, for example, for identifying transaction goods in a store. And in this case, for example, as shown in FIG. 3, the transaction goods placed in the shopping basket BAA placed on the mounting surface 101 become the article 2 to be identified.

[0015] The stage 310 holds the two antennas 200 so that their receiving surfaces face each other. Further, the stage 310 holds the two antennas 200 in a posture such that the axes of their respective pointing directions are perpendicular to the movement axis by the movement mechanism 320. The stage 310 includes a base plate 311 and columns 312, 313. The base plate 311 is held horizontally by the movement mechanism 320. The columns 312, 313 are erected above the base plate 311. The columns 312, 313 hold the two antennas 200 in a posture such that the axes of their respective pointing directions face the space above the mounting area REA.

[0016] The moving mechanism 320 includes a guide rail 321 and a motor 322. The guide rail 321 holds the stage 310 so that it can move linearly. The axial direction of the guide rail 321 is parallel to the placement surface 101. The axial direction of the guide rail 321 intersects, and more preferably is orthogonal to, the arrangement direction of the two antennas 200. For example, the guide rail 321 has a ball screw nut structure inside. The nut of the ball screw nut structure holds the stage 310. The motor 322 generates power to move the stage 310 along the guide rail 321. For example, the motor 322 rotates the screw shaft of the ball screw nut structure. The rotational movement of the screw shaft of the ball screw nut structure is converted into the linear movement of the nut of the ball screw nut structure. As the motor 322, for example, a stepping motor is used.

[0017] Therefore, by rotating the motor 322, the stage 310 is linearly moved in the axial direction of the guide rail 321. The motor 322 can rotate forward and backward, and the moving direction of the stage 310 also becomes opposite according to the rotation direction. That is, the moving mechanism 320 can reciprocate the stage 310 in the moving axis direction.

[0018] The control unit 330 controls the moving mechanism 320. The control unit 330 includes a processor 331, a ROM (read-only memory) 332, a RAM (random-access memory) 333, a motor drive unit 334, a position sensor 335, an interface unit 336, and a transmission path 337. The processor 331, the ROM 332, and the RAM 333 are connected by the transmission path 337 to constitute a computer for controlling the moving mechanism 320.

[0019] Processor 331 corresponds to the central part of the computer. Processor 331 expands various information processing programs stored in ROM 332 into RAM 333. Based on the information processing program expanded in RAM 333, Processor 331 executes information processing for controlling the movement mechanism 320. Processor 331 is a CPU (central processing unit), MPU (micro processing unit), SoC (system on a chip), DSP (digital signal processor), GPU (graphics processing unit), ASIC (application specific integrated circuit), PLD (programmable logic device), FPGA (field-programmable gate array), or the like. Processor 331 may be a combination of a plurality of these.

[0020] ROM 332 corresponds to the main storage device of the computer centered on Processor 331. ROM 332 stores an information processing program for Processor 331. ROM 332 stores data predetermined to be used when Processor 331 performs various processes. Processor 331 stores various setting values and the like predetermined to be referred to when Processor 331 performs various processes.

[0021] RAM 333 corresponds to the main storage device of the computer centered on Processor 331. RAM 333 is a memory for expanding an information processing program for execution by Processor 331. RAM 333 is used as a work area for temporarily storing data used when Processor 331 performs various processes.

[0022] When the motor drive unit 334 is to rotate the motor 322, it generates a drive signal and supplies the drive signal to the motor 322. The position sensor 335 detects the stage 310 at a predetermined detection position. In this embodiment, the position sensor 335 uses a predetermined home position as the detection position. The position sensor 335 may also detect the stage 310 with respect to a plurality of detection positions.

[0023] The interface unit 336 performs communication processing for communicating with the reading unit 400. The transmission path 337 includes a control bus, an address bus, a data bus, and the like. The transmission path 337 transmits data and signals exchanged among the respective parts of the control unit 330.

[0024] FIG. 4 is a block diagram showing the main circuit configuration of the reading unit 400. The reading unit 400 includes a processor 401, a ROM 402, a RAM 403, an amplitude modulation unit 404, a DA (digital to analog) conversion unit 405, a front-end unit 406, an AD (analog to digital) conversion unit 407, a demodulation unit 408, interface units 409, 410, 411, and a transmission path 412.

[0025] The processor 401, the ROM 402, and the RAM 403 are connected by the transmission path 412 to constitute a computer for realizing the functions of the reading unit 400. The processor 401 corresponds to the central part of the computer. The processor 401 expands various information processing programs stored in the ROM 402 into the RAM 403. The processor 401 executes information processing for identifying the article 2 based on the information processing programs expanded in the RAM 403. The processor 401 is a CPU, an MPU, an SoC, a DSP, a GPU, an ASIC, a PLD, an FPGA, or the like. The processor 401 may be a combination of a plurality of these.

[0026] The ROM 402 corresponds to the main memory device of a computer centered around the processor 401. The ROM 402 stores an information processing program for the processor 401. The ROM 402 stores various preset setting values and the like that are to be referred to when the processor 401 performs various processes.

[0027] The RAM 403 corresponds to the main memory device of a computer centered around the processor 401. The RAM 403 is a memory for expanding the information processing program to be executed by the processor 401. The RAM 403 is used as a work area for temporarily storing data used by the processor 401 when performing various processes.

[0028] The amplitude modulation unit 404 generates a baseband transmission signal that is amplitude-modulated in a digital state according to the transmission data to be transmitted to the wireless tag 3. The DA conversion unit 405 converts the digital-state transmission signal generated by the amplitude modulation unit 404 into an analog signal.

[0029] The front-end unit 406 modulates a high-frequency carrier signal with the transmission signal that has been converted into an analog signal by the DA conversion unit 405 to convert it into a high-frequency transmission signal. The front-end unit 406 supplies the high-frequency transmission signal to each of the two antennas 200. High-frequency received signals obtained by the two antennas 200 respectively are input to the front-end unit 406. The front-end unit 406 removes the carrier component from the input received signal and converts it into an analog-state and baseband received signal containing the information transmitted from the wireless tag 3. The front-end unit 406 measures the phase of the received wave and the received electric field strength (RSSI: received signal strength indicator) based on each of the two input received signals.

[0030] The AD conversion unit 407 digitizes the analog-state received signal obtained by the front-end unit 406. The demodulation unit 408 extracts the information transmitted from the wireless tag 3 from the received signal in analog state obtained by the AD conversion unit 407.

[0031] The interface unit 409 performs communication processing for communication with the drive unit 300. The interface unit 410 performs communication processing for communication with the inference unit 500. The interface unit 411 performs communication processing for communication with an arbitrary external terminal that performs information processing using the identification result at the article identification device 1. The transmission path 412 includes a control bus, an address bus, a data bus, etc. The transmission path 412 transmits data and signals exchanged among the respective parts of the reading unit 400.

[0032] FIG. 5 is a block diagram showing the main circuit configuration of the inference unit 500. The inference unit 500 includes a processor 501, a ROM 502, a RAM 503, an auxiliary storage unit 504, an interface unit 505, and a transmission path 506.

[0033] The processor 501, the ROM 502, and the RAM 503 are connected by the transmission path 506 to constitute a computer for realizing the functions as the inference unit 500. The processor 501 corresponds to the central part of the computer. The processor 501 expands various information processing programs stored in the ROM 502 into the RAM 503. The processor 501 executes information processing for determining the article 2 placed in the placement area REA among the articles 2 identified by the reading unit 400 based on the information processing program expanded in the RAM 503. The processor 501 is a CPU, an MPU, an SoC, a DSP, a GPU, an ASIC, a PLD, an FPGA, or the like. The processor 501 may be a combination of a plurality of these.

[0034] The ROM 502 corresponds to the main memory device of a computer centered around the processor 501. The ROM 502 stores an information processing program for the processor 501. The ROM 502 stores various preset setting values and the like that are to be referred to when the processor 501 performs various processes.

[0035] The RAM 503 corresponds to the main memory device of a computer centered around the processor 501. The RAM 503 is a memory for expanding the information processing program to be executed by the processor 501. The RAM 503 is used as a work area for temporarily storing data used by the processor 501 when performing various processes.

[0036] The auxiliary storage unit 504 includes well-known storage devices such as, for example, EEPROM (electric erasable programmable read-only memory), HDD (hard disc drive), and SSD (solid state drive). The auxiliary storage unit 504 stores data used by the processor 501 when performing various processes. The auxiliary storage unit 504 stores, for example, measurement data DAA and the learned model MOA.

[0037] The measurement data DAA is data collected by associating the phase and received electric field strength measured for each of the two antennas 200 in the front-end unit 406 with the positions of the antennas 200. The learned model MOA has learned the tendency of the phase and received electric field strength measured by the front-end unit 406 while moving the two antennas 200 with respect to the response waves from the wireless tags 3 placed at various positions within and around the placement area REA. The learned model MOA is an inference model for determining whether or not the wireless tag 3 is located within the placement area REA based on the tendency of the phase and received electric field strength measured by the front-end unit 406 while newly moving the two antennas 200.

[0038] The interface unit 505 performs communication processing for communication with the reading unit 400. The transmission path 506 includes a control bus, an address bus, a data bus, and the like. The transmission path 506 transmits data and signals exchanged among the respective parts of the inference unit 500. Note that, as the hardware of the inference unit 500, for example, an existing general-purpose computer device can be used.

[0039] Next, the operation of the article identification device 1 configured as described above will be described. Note that the content of the processes described below is an example, and it is possible to appropriately change the order of some processes, omit some processes, or add other processes.

[0040] When identifying the article 2, the article 2 to be identified is placed in the placement area REA whose outer edge is represented by the marks MAA, MAB, MAC, and MAD on the placement surface 101. Note that if the article identification device 1 is used for identifying trading goods in a store as described above, as an example, a shopping basket BAA containing the article 2 as a trading good is placed on the placement surface 101 and inside the marks MAA, MAB, MAC, and MAD as shown in FIG. 3. Then, when a predetermined event occurs as a start trigger, the processor 401 in the reading unit 400 starts control processing for article identification. That is, the processor 401 expands the information processing program for this control processing from the ROM 402 to the RAM 403, and then executes information processing according to the information processing program expanded in this RAM 403. Note that the start trigger is, for example, a command for starting identification from an external terminal. However, the start trigger may be appropriately determined according to the use of the article identification device 1 or the like.

[0041] FIG. 6 is a flowchart of the control processing by the processor 401. As ACT11, the processor 401 starts a reading process for executing a predetermined sequence for reading the wireless tag 3. Note that the processor 401 executes this reading process in parallel with the control process shown in FIG. 6.

[0042] In the reading process, the processor 401 supplies predetermined transmission data for causing the antenna 200 to radiate a transmission wave for reading tag information from one wireless tag 3 according to a predetermined protocol to the amplitude modulation unit 404. As a result, a high-frequency transmission signal is supplied to the antenna 200 by the amplitude modulation unit 404, the DA conversion unit 405, and the front-end unit 406, and a transmission wave corresponding to the transmission data is radiated. As the above protocol, a well-known protocol such as a protocol compliant with ISO / IEC 18000 can be adopted. As the above protocol, any protocol other than the well-known protocol may be adopted. In the reading process, the processor 401 repeatedly executes a protocol for reading tag information from the wireless tag 3.

[0043] As ACT12, the processor 401 commands the drive unit 300 to start moving. For example, the processor 401 outputs a predetermined command for the movement start command from the interface unit 409. When this command is transmitted to the drive unit 300, it is received by the interface unit 336 and taken into the control unit 330. Then, when the processor 331 in the control unit receives the movement start command in this way, it starts the movement of the antenna 200.

[0044] FIG. 7 is a diagram showing the positional relationship between the antenna 200 when moved by the drive unit 300, the placement surface 101, and the marks MAA, MAB, MAC, and MAD. In FIG. 7, the position of the antenna 200 represented by the solid line is defined as the home position PA. When the processor 401 is waiting for a command to start movement, the antenna 200 is positioned at the home position PA. When the antenna 200 is at this home position PA, the position sensor 335 is turned on. That is, the processor 401 maintains the state in which the position sensor 335 is on. In this embodiment, the home position PA is set near one end within the range where the drive unit 300 can reciprocate the antenna 200. And in this embodiment, when located at the home position PA, the antenna 200 is out of the placement area REA from below.

[0045] When the processor 331 receives a command to start movement, it instructs the motor drive unit 334 to start forward rotation. In response to this instruction, the motor drive unit 334 starts driving the motor 322 to rotate forward. Note that the motor drive unit 334 may rotate the motor 322 continuously or intermittently for each fixed amount of rotation. In response to this, the stage 310 moves linearly in the axial direction of the guide rail 321, that is, in the direction indicated by the arrow in FIG. 7, and similarly the antenna 200 also moves. And both of the two antennas 200 can move to the end position PB on the opposite side of the home position PA across the placement area REA while a part of their reception surfaces passes directly below the outside of the placement area REA. In FIG. 7, the states of the antenna 200 and the stage 310 when located at the end position PB are represented by a dashed line.

[0046] Note that the movement trajectory TR of each antenna 200 when being moved by the drive unit 300 as described above is not limited to the state shown in FIG. 7, and may be set at a position shifted in the vertical direction in FIG. 7. However, in any position state, at least a part of the reception surface of each antenna 200 shall be located directly below the outside of the placement area REA. That is, all of the reception surfaces of each antenna 200 shall not always be in a state of being located directly below the placement area REA. In the movement trajectory TR of the antenna 200, all of the reception surfaces of the antenna 200 may be temporarily located directly below the placement area REA. While the movement of the antenna 200 thus started is in progress, the protocol for reading tag information from the wireless tag 3 as described above is repeated.

[0047] When the wireless tag 3 emits a response wave and this is received by the antenna 200, the tag information is demodulated from the response wave by the front-end unit 406, the AD conversion unit 407, and the demodulation unit 408. When the response wave emitted by one wireless tag 3 is received by two antennas 200 respectively, the tag information is demodulated for each of the received signals output from each antenna 200.

[0048] Here, the rotation speed of the motor 322 is determined such that the time for moving the antenna 200 over a specified distance is sufficiently longer than the time for executing the protocol for reading tag information from one wireless tag 3. Therefore, while the antenna 200 is being moved over a specified distance, the protocol for reading tag information is repeatedly executed a plurality of times. Thereby, when the antenna 200 is at a certain position, it is possible to read tag information from a plurality of wireless tags 3. Furthermore, while changing the relative positional relationship between the antenna 200 and the wireless tag 3, the tag information of the same wireless tag 3 is read a plurality of times.

[0049] Note that, the longer the time for moving the antenna 200 over a specified distance, the more tag information can be read from the wireless tags 3 as the number of protocol repetitions when the antenna 200 is at a certain position increases. However, the longer this time, the longer the execution time of the control process and the longer the time required for one control process. Therefore, the rotation speed of the motor 322 is appropriately determined by, for example, the designer of the article identification device 1 while considering the above circumstances.

[0050] As described above, in the situation where tag information is being read while moving the antenna 200, the processor 401 transitions to the waiting states of ACT13 and ACT14 in FIG. 6. As ACT13, the processor 401 checks whether it has obtained a tag code. If the processor 401 cannot confirm the corresponding event, it determines NO and proceeds to ACT14. As ACT14, the processor 401 waits for the movement of the antenna 200 to complete. If the processor 401 cannot confirm the corresponding event, it determines NO and returns to ACT13. Thus, as the waiting states of ACT13 and ACT14, the processor 401 waits for the acquisition of the tag code or the completion of the movement.

[0051] If the processor 401 can confirm that the tag information demodulated as described above contains a tag code, it determines YES at ACT13, assuming that it has obtained the tag code, and proceeds to ACT15. As ACT15, the processor 401 updates the reading list. The reading list is list data representing the history of tag information reading. The reading list is a set of data records respectively associated with each reading notification. When the processor 401 first executes ACT15 after starting the reading process, it generates a new data record and generates a new reading list containing only this one data record. When the processor 401 executes ACT15 for the second time and later, it generates a new data record and updates the existing reading list by adding this data record. Note that the processor 401 stores the reading list in the RAM 403.

[0052] FIG. 8 is a diagram schematically showing the configuration of one data record DRA constituting the reading list. The data record DRA includes fields FAA, FAB, FAC, FAD, FAE. The processor 401 sets the tag code included in the currently demodulated tag information in the field FAA. The processor 401 sets the antenna code for identifying which of the two antennas is the antenna 200 that received the response wave (herein referred to as the wave to be processed) from which the tag information including the tag code set in the field FAA was demodulated. The processor 401 sets the position of the antenna 200 when the wave to be processed is received in the field FAC. In this embodiment, the position of the antenna 200 is represented by the moving distance from the home position PA. Also in this embodiment, the moving distance of the antenna 200 is managed by multiples of the unit distance DI. Thus, the position is represented as, for example, 0, DI, 2·DI, 3·DI,... X·DI. The processor 401 sets the phase measured by the front-end unit 406 for the wave to be processed in the field FAD. The processor 401 sets the received electric field strength measured by the front-end unit 406 for the wave to be processed in the field FAE.

[0053] Note that, instead of the moving distance, any information that can identify the position of the antenna 200 may be used, such as the elapsed time since the start of the movement of the antenna 200 or the number of drive steps of the motor 322. Also, the position sensor 335 may be configured to detect the stage 310 with respect to a plurality of detection positions, and the output value of the position sensor 335 may be used as information on the position of the antenna 200.

[0054] When the processor 401 finishes updating the read list, it returns to the waiting states of ACT13 and ACT14. Thus, each time the processor 401 newly acquires tag information, it records the antenna code, position, phase, and received electric field strength in association with the tag code included in the tag information.

[0055] When the antenna 200 moves to the end position PB by the drive unit 300, the processor 331 stops the motor 322 and notifies the reading unit 400 of the completion of the movement. For example, the processor 331 sends a predetermined command for notifying the completion of the movement from the interface unit 336 to the reading unit 400.

[0056] Note that the processor 331 determines the moving distance of the antenna 200 based on, for example, the time during which the motor 322 is rotating or the total rotation amount of the motor 322, and determines that the antenna 200 has moved to the end position PB when this moving distance reaches the distance between the home position PA and the end position PB. Alternatively, a position sensor that turns on when the antenna 200 is located at the end position PB may be provided, and the processor 331 may determine that the antenna 200 has moved to the end position PB when this position sensor turns on. Note that the drive unit 300 may also end the movement of the antenna 200 in response to a stop command from the processor 401.

[0057] The processor 331 then reverses the motor 322 to return the antenna 200 to the home position PA. However, the processor 331 may leave the antenna 200 waiting at the end position PB and move the antenna 200 from the end position PB to the home position PA in the next control process.

[0058] When a command for notifying the completion of movement is transmitted to the reading unit 400, the command is received by the interface unit 409 and taken into the reading unit 400. Then, the processor 401 determines YES at ACT14 accordingly and proceeds to ACT16. As ACT16, the processor 401 ends the reading process that started at ACT11 and was executed in parallel with the control process. Thereby, the emission of the transmission wave and the reception process of the response wave are stopped.

[0059] As ACT17, the processor 401 generates measurement data DAA regarding the reading result in this reading process. FIG. 9 is a diagram schematically showing the configuration of the measurement data DAA. Data that describes the phase and the received electric field strength measured at each position of the antenna 200 moved by the drive unit 300 in association with the combination of each tag code included in the reading list and each antenna code of the two antennas 200.

[0060] The processor 401 extracts data records DRA included in the reading list, where the tag codes and antenna codes set in fields FAA and FAB are the same, and arranges the phases and received electric field strengths set in fields FAD and FAE of these data records DRA as measurement results at the positions set in field FAC of the same data records DRA. Note that since there is no guarantee that tag codes are obtained at all positions, for positions where phases and received electric field strengths are not measured, blanks are used, or predetermined values indicating non-measurement are set. Then, the processor 401 performs this process for all combinations of the tag codes and antenna codes set in fields FAA and FAB, thereby generating measurement data DAA having a structure as shown in FIG. 9. However, as long as the information shown in FIG. 9 can be grasped, the structure of the measurement data DAA may be determined as appropriate.

[0061] As ACT18 in FIG. 6, the processor 401 requests the inference unit 500 to execute inference, accompanied by notification of the generated measurement data DAA. The processor 401 outputs, for example, a predetermined command for requesting execution of inference from the interface unit 410. When this command is transmitted to the inference unit 500, it is received by the interface unit 505 and taken into the inference unit 500. The processor 501 is waiting for an inference request. Then, when receiving the inference request as described above, the processor 501 outputs a command for requesting the measurement data DAA from the reading unit 400 from the interface unit 505. When this command is transmitted to the reading unit 400, it is received by the interface unit 410 and taken into the reading unit 400. In response, the processor 401 outputs the measurement data DAA generated in ACT17 from the interface unit 410. This measurement data DAA is received by the interface unit 505 and stored in the auxiliary storage unit 504 under the control of the processor 501.

[0062] The processor 501 provides the learned model MOA with the phase sequence and received electric field strength sequence described in the measurement data DAA in association with one tag code as input data for determination, thereby obtaining a determination result as to whether the wireless tag 3 identified by the corresponding tag code is located within the placement area REA. Then, the processor 501 similarly obtains a determination result for each of the tag codes included in the measurement data DAA. Then, the processor 501 generates a list of tag codes for which a determination result that they are located within the placement area REA is obtained, and notifies this list to the reading unit 400 as an inference result. The processor 501 outputs, for example, a data file represented in a predetermined file format representing the list from the interface unit 505 as a response to the inference request. Thus, the computer having the processor 501 as the central part functions as a selection means by executing information processing.

[0063] Note that the phase and received electric field strength regarding the response wave radiated from a certain wireless tag 3 vary in various ways depending on the relationship between the position of the corresponding wireless tag and the position of the antenna 200 that received it. For this reason, by sequentially receiving the response wave from the corresponding wireless tag 3 while changing the position of the antenna 200, the phase and received electric field strength when the response wave is received by the antenna 200 change, but the change shows a tendency corresponding to the position of the wireless tag 3. Therefore, the inference unit 500 uses a learned model that has learned such a change tendency to infer whether the wireless tag 3 is placed within the placement area REA based on the tendency of the change in the actually measured phase and received electric field strength.

[0064] In the reading unit 400, after the processor 401 requests an inference in ACT18, it proceeds to ACT19. As ACT19, the processor 401 waits for notification of the inference result. Then, if the inference result is notified from the inference unit 500 as described above, the processor 401 determines YES and proceeds to ACT20. As ACT20, based on each of the tag codes included in the list notified from the inference unit 500, the processor 401 identifies the article 2 with the wireless tag 3 identified by the tag code, and generates an article list as a list of identifiers of those articles 2. Thus, the processor 401 functions as an identification means by executing information processing.

[0065] As ACT21, the processor 401 outputs the generated article list to a predetermined output destination. The output destination is, for example, an external terminal. When the external terminal is determined as the output destination, for example, the processor 401 outputs a data file representing the article list in a predetermined file format from the interface unit 411. Note that the processor 401 may save the corresponding data file in a storage device (not shown) externally attached or built into the reading unit 400. Also, the processor 401 may print an image representing the article list by a printing device (not shown) externally attached or built into the reading unit 400. Then, after finishing ACT21, the processor 401 ends the current control process.

[0066] As described above, the article identification device 1 identifies the article 2 placed in the placement area REA based on the reception status near the edge of the placement area REA of the response wave from the wireless tag 3. Thereby, the commodity placed in the placement area REA can improve the accuracy of distinguishing the article 2 located outside the placement area REA on the opposite side of the placement area REA across the placement area REA from the antenna 200, and can reduce the probability of misidentifying such an article 2 as an article 2 placed in the placement area REA.

[0067] Then, the article identification device 1 identifies the article 2 placed in the placement area REA based on the reception status of the response waves at each of the two antennas 200 arranged with the placement area REA therebetween. As a result, it is possible to improve the accuracy of distinguishing the article 2 located outside both side edges where the two antennas 200 are respectively positioned, and it is possible to reduce the probability of misidentifying such an article 2 as the article 2 placed in the placement area REA.

[0068] Since the article identification device 1 identifies the article 2 placed in the placement area REA as described above, it is necessary to place the article 2 to be identified in the placement area REA. Therefore, since the article identification device 1 makes the placement area REA easily recognizable by the marks MAA, MAB, MAC, and MAD on the placement surface 101, the operator can correctly place the article 2 in the placement area REA.

[0069] Since the article identification device 1 determines the position of the wireless tag 3 that emitted the response wave based on the reception status of the response wave as described above, it is acceptable for the response wave emitted from the wireless tag 3 located outside the placement area REA to be received. Therefore, there is no need to provide a shielding plate or the like for shielding the response wave from such a wireless tag 3.

[0070] The article identification device 1 has the antennas 200 in a posture tilted so that the axis in the direction of their orientation faces the space above the placement area REA. For this reason, with respect to the area outside the placement area REA from the edge on the side where the antennas 200 are located, it greatly deviates from the orientation direction of the antennas 200, and the sensitivity to the response wave emitted from the wireless tag 3 located in this area becomes low. As a result, the reception status of the response wave from the wireless tag 3 outside the identification target is significantly different from the reception status of the response wave from the wireless tag 3 located in the placement area REA, and the accuracy of distinguishing the two wireless tags 3 is improved.

[0071] This embodiment can be variously modified as follows. If the operator placing the article 2 to be identified on the placement surface can recognize the placement area REA, the marks MAA, MAB, MAC, and MAD may be appropriately changed to other marks. FIG. 10 is a diagram showing a first modification example of the mark. In FIG. 10, linear marks MBA, MBB, MBC, and MBD are formed at the center of each of the four edges of the placement area REA. FIG. 11 is a diagram showing a second modification example of the mark. In FIG. 11, cross-shaped marks MCA, MCB, MCC, and MCD are formed by aligning the intersections at the four corners of the placement area REA. FIG. 12 is a diagram showing a third modification example of the mark. In FIG. 12, a mark MDA is formed by coloring the entire area of the placement area REA with a color different from that of other areas. In FIG. 12, the mark MDA is represented by hatching for the sake of convenience to show the color difference.

[0072] There may be only one antenna 200.

[0073] One antenna 200 may be two-dimensionally moved along the edge of the placement area REA or along a circular or elliptical movement trajectory.

[0074] A plurality of antennas 200 may be fixedly arranged along the movement trajectory TR shown in FIG. 7.

[0075] The processor 401 in the reading unit 400 may execute the processing by the inference unit 500 without using the inference unit 500.

[0076] The inference unit 500 may notify the reading unit 400 of the result of determining whether each of the tag codes included in the measurement data DAA is within the placement area REA. In this case, the processor 401 extracts the tag code related to the wireless tag 3 located within the placement area REA based on the determination result in the inference unit 500, and generates an item list based on the tag code. In this case, the processor 401 will function as a selection means.

[0077] The posture of the antenna 200 is not limited to the posture shown in FIG. 3, and may be appropriately changed, for example, such that the receiving surface is parallel to the placement surface.

[0078] The inference of the position of the antenna 200 may be performed based on only one of the phase or the received electric field strength.

[0079] The inference of the position of the antenna 200 is not based on a learned model, and various other well-known inference methods may be applied.

[0080] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and its equivalent scope.

Explanation of Reference Numerals

[0081] 1... Article identification device, 2... Article, 3... Wireless tag, 100... Mounting table, 101... Mounting surface, 200... Antenna, 300... Driving unit, 310... Stage, 311... Base plate, 312... Support column, 313... Support column, 320... Moving mechanism, 321... Guide rail, 322... Motor, 330... Control unit, 331... Processor, 332... ROM, 333... RAM, 334... Motor drive unit, 335... Position sensor, 336... Interface unit, 337... Transmission path, 400... Reading unit, 401... Processor, 402... ROM, 403... RAM, 404... Amplitude modulation unit, 405... DA conversion unit, 406... Front-end unit, 407... AD conversion unit, 408... Demodulation unit, 409, 410, 411... Interface unit, 412... Transmission path, 500... Inference unit, 501... Processor, 502... ROM, 503... RAM, 504... Auxiliary storage unit, 505... Interface unit, 506... Transmission path.

Claims

1. A mounting table having a mounting surface for mounting an article with a wireless tag attached thereto, An antenna having a receiving surface for receiving radio waves, and at least a part of the receiving surface is arranged in a state of being located directly below the outside of the mounting area where the article is mounted on the mounting surface, Selection means for selecting a wireless tag located within the mounting area from the wireless tags that have emitted radio waves received by the antenna, Identification means for identifying an article with a wireless tag selected by the selection means as an article mounted within the mounting area, An article identification device comprising:

2. The mounting table has a mark representing the mounting area formed on the mounting surface, The article identification device according to Claim 1.

3. The apparatus further comprises a moving mechanism for moving the antenna in a state where at least a part of the receiving surface is located directly below the outside of the mounting area, The selection means selects radio waves from wireless tags located within the mounting area based on radio waves received by the antenna at a plurality of positions in response to the movement by the moving mechanism, The article identification device according to Claim 1.

4. Two antennas are provided, The moving mechanism moves the two antennas along two parallel straight lines sandwiching the mounting area respectively, The article identification device according to Claim 3.

5. The two antennas are provided in a posture in which the receiving surfaces are inclined with respect to the mounting surface so that the respective receiving surfaces face the inside of the mounting area, The article identification device according to Claim 4.

6. A mounting table having a mounting surface for mounting an article with a wireless tag attached thereto, An antenna having a receiving surface for receiving radio waves, and at least a part of the receiving surface is arranged in a state of being located directly below the outside of the mounting area where the article is mounted on the mounting surface, An article identification method in an article identification device comprising: Selecting a wireless tag located within the mounting area from the wireless tags that have emitted radio waves received by the antenna, Identifying an article with a selected wireless tag as an article mounted within the mounting area, An article identification method.

Images