JP7510065B2 - Inventory Management System - Google Patents

Description

It relates to an inventory management system that manages inventory.

There are cases where items with wireless tags attached are managed. For example, at airports, items with wireless tags attached are managed to shorten the time required for baggage unloading. In this case, the items are baggage. Patent Document 1 discloses a technology for managing baggage by associating an image of the baggage with an ID stored in the wireless tag attached to the baggage.

Patent document 2 discloses a technology that determines the location of a wireless tag based on the received signal strength (RSSI: Received Signal Strength Indicator) of the radio waves received from the wireless tag.

JP 2020-55691 A International Publication No. 2009/001408

It is assumed that baggage moving on a conveyor line is photographed to obtain an image of the baggage (hereinafter referred to as a baggage image), and the ID is read from the wireless tag attached to the baggage, and the baggage image and ID are associated.

When multiple pieces of baggage are moving close to each other on a conveyor line, it is possible that the IDs can be read from multiple wireless tags at the same time. In this case, the problem is how to determine which ID is stored in the wireless tag attached to which piece of baggage.

As disclosed in Patent Document 2, it is possible to determine the position of a wireless tag based on the magnitude of the RSSI. However, when using RSSI, the following problem occurs. That is, in an environment with a large amount of reflection from metal, etc., the reflected signal may be stronger than the direct signal. Therefore, the magnitude of the RSSI is not necessarily proportional to the distance from the tag reader to the wireless tag.

This disclosure was made based on these circumstances, and its purpose is to provide an item management system that can accurately identify the IDs of wireless tags attached to items moving on a conveyor line.

The above object is achieved by a combination of features as recited in the independent claims, and the subclaims define further advantageous specific examples. The reference characters in parentheses in the claims indicate a correspondence with the specific aspects described in the embodiments described below as one aspect, and do not limit the disclosed technical scope.

One disclosure for achieving the above object is:
a tag reader (40) that is installed at a position where a signal from the wireless tag can be received with the strongest intensity when an article (1) having a wireless tag (70) attached thereto is located at a reference position on a conveying line, and that continuously reads an ID from the wireless tag;
a position detection sensor (50) for detecting when an article moving on the conveyor line reaches a reference position;
a period determination unit (213) that determines an integrated period (Ti) that is determined based on the position detection sensor detecting that the article has reached a reference position, the integrated period including the time point at which the position detection sensor detects that the article has reached the reference position;
The item management system includes an ID identification unit (214) that determines the number of times an ID has been read by a tag reading device during an accumulation period for each ID, and determines the ID with the maximum number of reads to be the ID stored in a wireless tag attached to an item that has been detected by a position detection sensor to have reached a reference position.

In order to identify the ID stored in the wireless tag attached to the item that has reached the reference position, this item management system determines the number of reads read during an accumulation period for each ID. The accumulation period is determined based on the detection that the item has reached the reference position, and includes the time point at which it is detected that the item has reached the reference position. Because the accumulation period is such a period, the ID with the greatest number of reads read during the accumulation period is likely to be the ID stored in the wireless tag attached to the item that has been detected to have reached the reference position. Therefore, it is possible to accurately identify the ID stored in the wireless tag attached to the item moving on the conveyor line.

The article management system includes a camera (30) for photographing an article moving on a conveyor line;
a camera control unit (212) that causes a camera to capture an image of the article based on the position detection sensor detecting that the article has reached a reference position;
The system may further include a correlation unit (215) that correlates the image of the item captured by the camera with the ID identified by the ID identification unit.

In this way, it is possible to accurately match the image of an item that has been detected as having reached the reference position with the ID of the wireless tag attached to that item.

It is preferable that the length of the accumulation period is longer than the time when the number of reads per unit time is the maximum number, and is shorter than the time when the number of reads is greater than 0 and greater than the minimum number but less than the maximum number.

By setting the length of the accumulation period in this manner, even when multiple wireless tags are in close proximity, it is possible to prevent erroneous identification of the ID stored in the wireless tag attached to an item that has been detected as having reached the reference position.

In the above-mentioned article management system, the tag reading device is configured to determine a received signal strength of a signal received from the wireless tag,
The ID identifying unit may determine the number of times to read the signal, excluding received signals whose received signal strength is equal to or lower than a preset threshold value.

When the received signal strength is low, the wireless tag is likely to be located far from the reference position. In this way, the number of reads can be calculated excluding cases where the wireless tag is located far from the reference position. As a result, the IDs of the wireless tags attached to items moving on the conveyor line can be identified with greater accuracy.

In the above-mentioned article management system, the tag reading device is configured to determine a received signal strength of a signal received from the wireless tag,
The ID identifying unit may determine the number of reads by excluding received signals whose square of the received signal strength is equal to or smaller than a preset threshold value.

The squared value of the received signal strength also changes depending on the distance from the reference position. Therefore, even in this way, the number of reads can be calculated by excluding the read results when the item is far from the reference position, while retaining the read results when the item is close to the reference position. As a result, the accuracy of identifying the baggage number using the number of reads is further improved.

FIG. 1 shows the configuration of a baggage management system 100. FIG. 2 is a block diagram showing functions of a control unit 21. FIG. 4 is a diagram showing a process executed by a control unit 21. Two baggage tags 70a, 70b moving close to each other. 11 is a diagram showing the change over time of an integration period Ti and the number of reads N; 5 is a diagram showing a process executed by a control unit 21 in the first embodiment. Three baggage tags 70a, 70b, 70c moving close to each other. FIG. 8 is a graph showing the change over time in the number of times N that the baggage tag in FIG. 7 has been read; FIG. 11 is a diagram showing a process executed by a control unit 21 in the second embodiment. FIG. 13 is a diagram conceptually showing the relationship between the number of reads N, RSSI, and threshold TH1.

The following describes an embodiment with reference to the drawings. FIG. 1 is a diagram showing the configuration of a baggage management system 100. The baggage management system 100 is an example of an item management system, and manages baggage 1 of passengers boarding an airplane as an item.

The baggage management system 100 includes a check-in counter terminal 10, a management device 20, a camera 30, a tag reader 40, and a position detection sensor 50.

The check-in counter terminal 10 is installed at the check-in counter of the airport. There are multiple check-in counters, and a check-in counter terminal 10 is installed at each check-in counter. The check-in counter terminal 10 issues a baggage tag 70. The baggage tag 70 is a wireless tag, and the baggage number is stored electronically. The baggage tag 70 may be a passive tag or an active tag.

The baggage number corresponds to identification information, i.e., ID, that identifies baggage 1. The baggage number is sometimes called LPN (License Plate Number). Note that the ID of baggage 1 does not have to be a number as long as it can identify baggage 1.

The check-in counter terminal 10 is capable of sending and receiving signals to the management device 20 via wired or wireless communication. The check-in counter terminal 10 sends the names of passengers boarding the aircraft and their baggage numbers in association with each other to the management device 20. Baggage 1 to which a baggage tag 70 has been attached at the check-in counter is placed on the conveyor line 2 and conveyed. The conveyor line 2 conveys the baggage 1 to a specified destination at a constant speed.

The management device 20 includes a control unit 21, a storage unit 22, and a wireless communication unit 23. One example of the management device 20 is a passenger information management system (DCS: Departure Control System). The control unit 21 controls the storage unit 22 and the wireless communication unit 23. The control unit 21 stores in the storage unit 22 the passenger's name and baggage number provided by the check-in counter terminal 10 and an image of the baggage 1 taken by the camera 30 (hereinafter, the baggage image) as a set of baggage information. When it becomes necessary to search for the baggage 1, the baggage information is transmitted from the wireless communication unit 23 to a terminal held by a worker searching for the baggage 1, either directly or via another terminal.

The control unit 21 also controls the camera 30 and the tag reader 40. Note that the camera 30 and the tag reader 40 may be controlled by a device other than the management device 20.

The position detection sensor 50 detects when the baggage 1 moving on the conveyor line 2 reaches a reference position. The position detection sensor 50 may be, for example, a photoelectric sensor. The reference position is a position in the longitudinal direction of the conveyor line 2.

The camera 30 is installed in a position where it can photograph the baggage 1 moving on the conveyor line 2. More specifically, the camera 30 is installed in a position where it can photograph the baggage 1 located at the reference position. The camera 30 photographs the baggage 1 using a color image.

The tag reading device 40 is installed in a position where it can receive the strongest signal from the baggage tag 70 attached to the baggage 1 when the baggage 1 is located at the reference position. For example, when the conveying line 2 is straight, the tag reading device 40 is installed on a plane that includes the reference position and is perpendicular to the conveying line 2. As a more specific example, the tag reading device 40 is installed directly above the reference position. The camera 30 and the tag reading device 40 can also send and receive signals to and from the management device 20 via wired or wireless communication.

The tag reader 40 communicates with the baggage tag 70 and reads the baggage number stored in the baggage tag 70. Reading can be performed continuously. Continuous reading is referred to as continuous reading. Continuous means reading the baggage number multiple times from one or more baggage tags 70 within a short period of time, such as one second. If the received signal strength from the baggage tag 70 is sufficient, the tag reader 40 can read the baggage number more than 100 times per second.

Figure 2 shows the functions of the control unit 21 of the management device 20. The control unit 21 can be realized by a configuration including at least one processor. For example, the control unit 21 can be realized by a computer including a processor, non-volatile memory, RAM, I/O, and a bus line connecting these components. The non-volatile memory stores a program for operating a general-purpose computer as the control unit 21. The processor executes the program stored in the non-volatile memory while utilizing the temporary storage function of the RAM, so that the control unit 21 operates as a reading device control unit 211, a camera control unit 212, a period determination unit 213, an ID identification unit 214, and an association unit 215. The execution of these operations means that a method corresponding to the program is executed.

The reader control unit 211 controls the tag reader 40 to have the tag reader 40 continuously read the baggage numbers stored in the baggage tags 70. The camera control unit 212 issues a shooting instruction to the camera 30 to take an image.

The period determination unit 213 determines the accumulation period Ti. The accumulation period Ti is the period during which the number of reads N is accumulated. In this embodiment, the baggage number for which the number of reads N is the largest during the accumulation period Ti is determined to be the baggage tag 70 attached to the baggage 1 that the position detection sensor 50 detects has reached the reference position. The reason for using the number of reads N during the accumulation period Ti instead of the RSSI will be explained below.

Figure 3 shows one baggage tag 70 moving on the conveyor line 2. When the baggage tag 70 is in the position shown at time t1, the tag reading device 40 can read the baggage number stored in the baggage tag 70. After that, the number of reads N reaches a maximum at time t2. Note that the number of reads N means the number of reads per unit time. After time t3, the tag reading device 40 can no longer read the baggage number from the baggage tag 70.

The reason why the number of reads N changes over time in this way is that communication may fail if the received signal strength (hereinafter referred to as RSSI) is low. At times t1 and t3, the RSSI is at the lower limit level at which the tag reader 40 and baggage tag 70 can communicate. Therefore, the number of reads N is low. At time t2, the baggage tag 70 is located in the reference position. The number of reads N does not only reach a maximum at time t2. The number of reads N reaches a maximum for a certain period of time before and after time t2. This is because the read success rate is roughly the same as long as the RSSI is in a sufficiently high range.

In FIG. 3, there is only one baggage tag 70 within the communication range in which the tag reader 40 can communicate with the baggage tag 70. However, in reality, multiple baggage tags 70 may move close to each other on the conveyor line 2.

Figure 4 shows two baggage tags 70a, 70b moving close to each other on the conveyor line 2. In Figure 4, time t11 is the time when the baggage tag 70a is closest to the tag reader 40, i.e., the time when the RSSI from the baggage tag 70a is at its maximum. The solid line in the graph shown in Figure 4 represents the change over time in the number of times N the baggage number is read from the baggage tag 70a. The dashed line in the graph shown in Figure 4 represents the change over time in the number of times N the baggage number is read from the baggage tag 70b.

The high number of times N that the baggage tag 70b is read at time t11 indicates that the RSSI of the baggage tag 70b at time t11 is high. The RSSI varies depending on the radio wave environment. Therefore, at time t11, the RSSI of the baggage tag 70b may be higher than the RSSI of the baggage tag 70a. Therefore, in this embodiment, the number of times N that the baggage tag 70b is read during the accumulation period Ti is used instead of the RSSI.

Figure 5 shows the cumulative period Ti and the change over time in the number of reads N. The cumulative period Ti is a period that includes the point in time when the position detection sensor 50 detects that the baggage 1 has reached the reference position. In Figure 5, this point in time is time t21. The cumulative period Ti includes time t21 and the periods before and after it.

The length of the accumulation period Ti is determined in advance. The length of the accumulation period Ti is longer than the time T (Nmax) during which the number of reads N is the maximum number Nmax. The accumulation period Ti is also shorter than the time T (Nmin) during which the number of reads N is equal to or greater than the minimum number Nmin, which is greater than 0 and less than the maximum number Nmax. For example, the length of the accumulation period Ti can be the time T (Nmin).

In FIG. 5, the minimum number of times Nmin is set to 50% of the maximum number of times Nmax. However, the minimum number of times Nmin may be a number greater than 50% of the maximum number of times Nmax, such as 80% or 90% of the maximum number of times Nmax. Conversely, the minimum number of times Nmin may be a number less than 50% of the maximum number of times Nmax.

Times T(Nmax) and T(Nmin) are determined by measuring in advance. In order to measure times T(Nmax) and T(Nmin) with high accuracy, it is preferable to measure when there is only one baggage tag 70 within the communication range where the tag reading device 40 can communicate with the baggage tag 70.

Returning to FIG. 2 for explanation, the ID identification unit 214 determines the number of times N that the tag reading device 40 has read the baggage number during the accumulation period Ti for each baggage number. The baggage number with the maximum number of times N is then considered to be the baggage number stored in the baggage tag 70 attached to the baggage 1 that the position detection sensor 50 has detected as having reached the reference position.

The matching unit 215 matches the baggage number identified by the ID identification unit 214 with the image of the baggage 1 located at the reference position in the image captured by the camera 30, i.e., the baggage image.

Figure 6 shows a flow chart of the process executed by the control unit 21. In S1, the reader control unit 211 controls the tag reader 40 to cause the tag reader 40 to perform continuous reading.

In S2, the reading device control unit 211 acquires the reading results from the tag reading device 40. The reading results include the baggage number that was read and the number of times it was read. The reading device control unit 211 stores the acquired reading results in the memory unit 22 by time. The time may be the storage time or the reading result acquisition time. This is because there is almost no time difference between the storage time and the reading result acquisition time.

In S3, the camera control unit 212 determines whether or not a baggage detection signal has been acquired. The baggage detection signal is a signal that is output to the management device 20 when the position detection sensor 50 detects that the baggage 1 has reached a reference position. Note that S3 may also be executed by the reading device control unit 211.

If the determination result in S3 is NO, the process returns to S1. If the determination result in S3 is YES, the process proceeds to S4. In S4, the camera control unit 212 causes the camera 30 to capture an image. The camera 30 has a fixed imaging range so that it can capture an image of the baggage 1 located at the reference position. Therefore, in S4, the camera 30 captures an image of the baggage 1 located at the reference position. This results in an image of the baggage.

In S5, the period determination unit 213 determines the accumulation period Ti. In the example shown in FIG. 8, time t31 is the time when the baggage detection signal is acquired. The accumulation period Ti is from time t30 to time t32. Time t30 is earlier than time t31 by half the length of the accumulation period Ti, which is determined in advance. Time t32 is later than time t31 by half the length of the accumulation period Ti.

S6 is executed by the ID identification unit 214. In S6, the ID identification unit 214 obtains the baggage numbers read during the cumulative period Ti determined in S5 from the memory unit 22. Furthermore, the ID identification unit 214 calculates the number of reads N during the cumulative period Ti for each baggage number, and determines the baggage number with the maximum number of reads N.

S7 is executed by the association unit 215. In S7, the baggage number with the highest number of reads N determined in S6 is associated with the baggage image captured in S4 and stored in the memory unit 22.

The effect of this embodiment will be specifically explained using Figures 7 and 8. Figure 7 shows three baggage tags 70 moving close to each other on the conveyor line 2. In Figure 8, the solid line shows the change over time in the number of times N the baggage number is read from the baggage tag 70a attached to the baggage 1 that reached the reference position at time t31. The dashed line shows the change over time in the number of times N the baggage number is read from the baggage tag 70b. The dashed and dotted line shows the change over time in the number of times N the baggage number is read from the baggage tag 70c.

The number of reads N during the integration period Ti is the area of the part cut out by the integration period Ti in the solid line, dashed line, and dashed dotted line in Figure 8. This area is the largest for the solid line. Therefore, it is understood that the baggage number and the baggage image can be correctly associated with each other.
Summary of the First Embodiment
In order to identify the baggage number stored in the baggage tag 70 attached to the baggage 1 that has reached the reference position, the baggage management system 100 of this embodiment calculates the number of reads N read during an accumulation period Ti for each read number (S6). The accumulation period Ti is determined based on the detection that the baggage 1 has reached the reference position. The accumulation period Ti also includes the time point at which it is detected that the baggage 1 has reached the reference position (S5). Since the accumulation period Ti is such a period, the baggage number for which the number of reads N read during the accumulation period Ti is the largest is likely to be the baggage number stored in the baggage tag 70 attached to the baggage 1 that has been detected to have reached the reference position. In other words, according to this embodiment, the baggage number of the baggage tag 70 attached to the baggage 1 moving on the conveyor line 2 can be accurately identified.

In this embodiment, when a baggage detection signal is acquired, a baggage image is captured by the camera 30. This baggage image is then associated with the baggage number for which the number of reads N is the largest. This makes it possible to accurately associate the baggage image with the baggage number.

The length of the accumulation period Ti is longer than the time T (Nmax) when the number of reads N is the maximum number Nmax, and is shorter than the time T (Nmin) when the number of reads N is equal to or greater than the minimum number Nmin. Note that the minimum number Nmin is greater than 0 and less than the maximum number Nmax.

By setting the length of the accumulation period Ti in this manner, even when multiple baggage tags 70 are in close proximity, it is possible to prevent erroneous identification of the baggage number stored in the baggage tag 70 attached to the baggage 1 that has been detected as having reached the reference position.

Second Embodiment
Next, a second embodiment will be described. In the following description of the second embodiment, elements having the same reference numbers as those used up to that point are the same as those in the previous embodiment unless otherwise specified. Furthermore, when only a part of the configuration is described, the previously described embodiment can be applied to the other parts of the configuration.

In the second embodiment, the tag reader 40 determines the RSSI of the signal received from the baggage tag 70. Figure 9 shows the process executed by the control unit 21 in the second embodiment.

The process shown in FIG. 9 executes S2A instead of S2 in FIG. 6. Also, S5A is executed after S5. In S2A, the reader control unit 211 acquires the read results from the tag reader 40 and also acquires the RSSI of the received signal corresponding to each read result.

In S5A, the ID identification unit 214 excludes read results with an RSSI equal to or less than a threshold value TH1 from among the read results read during the accumulation period Ti. The threshold value TH1 is a value set in advance. The threshold value TH1 may be set to a value smaller than the RSSI at which the number of reads N becomes Nmax.

In the next step S6, the number of reads N is determined using the remaining read results that were not excluded in S5A among the read results read during the accumulation period Ti.

Figure 10 conceptually shows the relationship between the number of reads N, the RSSI, and the threshold TH1. In Figure 10, the threshold TH1 is lower than the RSSI at which the number of reads N is the maximum number Nmax, and is lower than the RSSI at which the number of reads N is the minimum number Nmin. Of course, the threshold TH1 is higher than the RSSI at which the number of reads N is 0.

When the RSSI is low, the number of reads N tends to be small. Therefore, in the second embodiment, the number of reads N is calculated by excluding the portion below the threshold TH1 shown in FIG. 10.

In this second embodiment, even if the baggage number can be read, signals with a low RSSI are excluded when calculating the number of reads N. When the RSSI signal is low, it is highly likely that the baggage tag 70 is located far from the reference position. Therefore, by following this second embodiment, it is possible to calculate the number of reads N while excluding cases in which the baggage tag 70 is located far from the reference position. As a result, it is possible to more accurately identify the baggage numbers of the baggage tags 70 attached to the baggage 1 moving on the conveyor line 2.

Although the embodiments have been described above, the disclosed technology is not limited to the above-mentioned embodiments, and the following modifications are also included within the scope of the disclosure. Furthermore, various modifications other than those described below can be made without departing from the spirit of the invention.

<Modification 1>
In the second embodiment, the ID identification unit 214 excludes read results in which the RSSI is equal to or less than the threshold TH1 to calculate the number of reads N. In contrast, in this modified example 1, the ID identification unit 214 excludes read results based on received signals in which the square of the RSSI is equal to or less than the threshold TH2 to calculate the number of reads N. The threshold TH2 is also a value that is set in advance.

The value obtained by squaring the RSSI varies more with distance from the reference position than the RSSI. Therefore, in this way, the number of reads N can be calculated by excluding read results when the baggage tag 70 is located farther from the reference position than in the second embodiment, while retaining read results when the baggage tag 70 is closer to the reference position. As a result, the accuracy of identifying the baggage number using the number of reads N is further improved.

<Modification 2>
In the second embodiment, in S5A, received signals with an RSSI equal to or lower than the threshold TH1 are excluded. However, in S2A, read results read from received signals with an RSSI equal to or lower than the threshold TH1 at the time of storage may be excluded.

1: Baggage (item) 2: Conveyor line 10: Check-in counter terminal 20: Management device 21: Control unit 22: Memory unit 23: Wireless communication unit 30: Camera 40: Tag reader 50: Position detection sensor 70: Baggage tag (wireless tag) 100: Baggage management system (item management system) 211: Reader control unit 212: Camera control unit 213: Period determination unit 214: ID identification unit 215: Correspondence unit N: Number of reads Nmax: Maximum number of reads Nmin: Minimum number of reads TH1: Threshold TH2: Threshold Ti: Accumulation period

Claims (6)

a tag reader (40) that is installed at a position where a signal from the wireless tag (70) can be received with the strongest intensity when an article (1) having a wireless tag (70) attached thereto is located at a reference position on a conveyor line, and that continuously reads an ID from the wireless tag;
a position detection sensor (50) that detects when the article moving on the conveyor line reaches the reference position;
a period determination unit (213) that determines an integrated period (Ti) that is determined based on the position detection sensor detecting that the article has reached the reference position, the integrated period including the time point at which the position detection sensor detects that the article has reached the reference position;
an ID specification unit (214) that determines the number of times that the tag reader has read an ID during the integration period for each ID, and determines the ID with the maximum number of times to be the ID stored in the wireless tag attached to the article that the position detection sensor has detected as having reached the reference position;
A camera (30) for photographing an article moving on the conveyor line;
a camera control unit (212) that causes the camera to capture an image of the article based on the position detection sensor detecting that the article has reached the reference position;
a matching unit (215) that matches the image of the item captured by the camera with the ID identified by the ID identifying unit;
An article management system comprising: The article management system according to claim 1 ,
An item management system, wherein the length of the accumulated period is longer than the time when the number of reads per unit time is the maximum number, and is shorter than the time when the number of reads is greater than 0 and greater than a minimum number but less than the maximum number. a tag reader (40) that is installed at a position where a signal from the wireless tag (70) can be received with the strongest intensity when an article (1) having a wireless tag (70) attached thereto is located at a reference position on a conveyor line, and that continuously reads an ID from the wireless tag;
a position detection sensor (50) that detects when the article moving on the conveyor line reaches the reference position;
a period determination unit (213) that determines an integrated period (Ti) that is determined based on the position detection sensor detecting that the article has reached the reference position, the integrated period including the time point at which the position detection sensor detects that the article has reached the reference position;
and an ID specification unit (214) that determines the number of times that the tag reader has read an ID during the integration period for each ID, and determines the ID with the maximum number of times that it has been read as the ID stored in the wireless tag attached to the article that the position detection sensor has detected as having reached the reference position ,
An item management system, wherein the length of the accumulated period is longer than the time when the number of reads per unit time is the maximum number, and is shorter than the time when the number of reads is greater than 0 and greater than a minimum number but less than the maximum number. The article management system according to any one of claims 1 to 3,
the tag reader is adapted to determine a received signal strength of a signal received from the wireless tag;
An item management system in which the ID identification unit determines the number of reads by excluding the received signal whose received signal strength is below a preset threshold. The article management system according to any one of claims 1 to 4 ,
the tag reader is adapted to determine a received signal strength of a signal received from the wireless tag;
An item management system in which the ID identification unit determines the number of reads by excluding the received signal whose square of the received signal strength is equal to or less than a preset threshold value. a tag reader (40) that is installed at a position where a signal from the wireless tag (70) can be received with the strongest intensity when an article (1) having a wireless tag (70) attached thereto is located at a reference position on a conveyor line, and that continuously reads an ID from the wireless tag;
a position detection sensor (50) that detects when the article moving on the conveyor line reaches the reference position;
a period determination unit (213) that determines an integrated period (Ti) that is determined based on the position detection sensor detecting that the article has reached the reference position, the integrated period including the time point at which the position detection sensor detects that the article has reached the reference position;
and an ID specification unit (214) that determines the number of times that the tag reader has read an ID during the integration period for each ID, and determines the ID with the maximum number of times to be the ID stored in the wireless tag attached to the article that the position detection sensor has detected as having reached the reference position ,
the tag reader is adapted to determine a received signal strength of a signal received from the wireless tag;
An item management system in which the ID identification unit determines the number of reads by excluding the received signal whose square of the received signal strength is equal to or less than a preset threshold value .

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