JP6279501B2 - Tag reader and tag reader control device - Google Patents

Description

  The present invention relates to a tag reader and a tag reader control device that perform wireless communication with a wireless tag.

  Conventionally, there is a tag reader that attaches a wireless tag such as an RFID (Radio Frequency Identification) tag to an article and monitors the removal of the article from a predetermined location and the placement of the article at a predetermined location through wireless communication with the wireless tag ( (See Patent Document 1). An example of a system configuration including such a tag reader is shown in FIGS. 9A and 9B. FIG. 9A shows a state (set state) in which the antenna 101 is connected to the tag reader 100 via the antenna cable 102 and the article 104 with the wireless tag 103 is placed on the antenna 101. On the other hand, FIG. 9B shows a state where the article 104 with the wireless tag 103 is taken out (lifted) above the antenna 101.

The tag reader detects, for example, a wireless tag attached to each article at regular time intervals using an anti-collision technology, so that each article is taken out from a predetermined location (for example, on or near the antenna), or It was judged whether it was put in place .
As another monitoring method, the tag reader measures, for example, the response signal strength of a wireless tag, that is, RSSI (Received Signal Strength Indicator), and the measured RSSI exceeds or falls below a predetermined threshold. In this case, it is determined whether the article has been placed in a predetermined place or taken out from the predetermined place.

JP 2005-173828 A

  However, in the case where it is determined whether the article is taken out from a predetermined place or placed in a predetermined place only by detecting whether or not the wireless tag attached to the article is detected, if the maximum communication distance of the wireless tag is long, the article In spite of having taken out, there was a problem that the presence of the article was erroneously determined due to the detection of the wireless tag. Even when the maximum communication distance of the wireless tag is not long, there is a problem that it is erroneously determined that there is an article due to reflection of radio waves, etc., even though the article is taken out.

  In addition, when judging the removal or placement of an article with the RSSI threshold, the RSSI may differ depending on the position where the article with the wireless tag is placed, and the removal or placement of the article is accurately judged only with the threshold. There was a problem that I could not. That is, as shown in FIG. 10A, even if the articles with the wireless tags placed at the placement positions A and B are the same at the placement position A and the placement position B of the article, FIG. 10B and FIG. As shown in FIG. 4, there is a case where the RSSI value received from the wireless tag 103 received by the tag reader 100 is different, and there is a problem that it is not possible to accurately determine whether the article is taken out or placed only by the threshold value. The reason why the RSSI value varies depending on the mounting position is considered to be due to the influence of an object (for example, metal) placed in the vicinity.

  In general, the RSSI increases as the wireless tag approaches the antenna, and decreases as it moves away. However, if there is a valley in the communication area between the wireless tag and the antenna, there is also a phenomenon that the RSSI decreases as the wireless tag approaches the antenna, and increases when the wireless tag moves away. There was a problem that it could not be judged accurately.

  In view of the above problems, the present invention can accurately detect placement of an article with a wireless tag on a predetermined place and removal from the predetermined place without being affected by the placement environment of the wireless tag. It is an object to provide a tag reader and a tag reader control device.

In order to achieve the above object, the tag reader control device of the present invention is connected to a tag reader that wirelessly communicates with a wireless tag, and whether the article with the wireless tag is placed at a predetermined place (placement at a predetermined place). ) Or a tag reader control device that detects whether it has been taken out from the predetermined place ( taken out from the predetermined place ) , and periodically acquires the ID assigned to the wireless tag and corresponds to the acquired ID A request for transmitting an ID detection command for acquiring the response signal strength of the wireless tag for each acquisition of the ID to the wireless tag via an antenna is transmitted to the tag reader; and The ID of the wireless tag transmitted from the wireless tag and the response signal strength of the wireless tag corresponding to the ID are transmitted via the antenna. Based on the transmission / reception unit received from the obtained tag reader, a storage unit that associates and stores the received ID of the wireless tag and the response signal strength, and the response signal strength stored in the storage unit, and a detection unit for detecting whether the article has been predetermined location preparative or the predetermined location or we are placed Ride, the detecting unit, for each ID of the wireless tag, stored in the storage unit Whether the first condition that the difference between the approximate value including the maximum value of the first response signal strength of the first number and the approximate value including the minimum value is smaller than the first threshold is satisfied. determines, when said first condition is determined to Ru Tei satisfied, wherein associated with the response signal strength based on the ID of the radio tag, the radio tag ID in the corresponding article is predetermined location that has been placed on the Detecting, when the first condition is determined not to be met, further said that the most recent first immediate response signal strength of the second number less than the number is not within the predetermined range second it is determined whether conditions are met, when said second condition is determined to Ru Tei satisfied, based on the ID of the radio tag associated with the response signal strength, ID of the wireless tag It is detected that the article corresponding to is taken out from the predetermined location. Here, the transmission / reception unit corresponds to a transmission / reception unit 20 described later, the storage unit corresponds to an RSSI storage unit B23 described later, and the detection unit corresponds to a control unit 21 described later.

Further, the tag reader control device of the present invention, the first condition is less than the minimum value and the difference between the first threshold value of the maximum value among the response signal strength of the most recent first number a condition that, the second condition, the front Symbol all response signal strength of the nearest second number, previously stored the most recent first number of response signal in the storage unit for storing the average value it is preferred from the average value of the intensity or below the value obtained by subtracting the second threshold value, or the a condition that exceeds the average value a third threshold value a value obtained by adding.

Further, the tag reader control device of the present invention, the detection unit may calculate the difference between the minimum and maximum values of the response signal strength of the most recent first number, the first condition is met If it is determined that the average value of the response signal strengths of the most recent first number is calculated, the average value is preferably stored in a storage unit that stores the average value.

  In the tag reader control device of the present invention, when the detection unit detects that an article corresponding to the ID of the wireless tag is placed at the predetermined location, or an article corresponding to the ID of the wireless tag is detected. When it is detected that the article has been taken out from the predetermined place, information indicating that the article has been placed at the predetermined place or has been taken out from the predetermined place may be displayed on a display unit that displays the information. preferable.

  In the tag reader control device of the present invention, when there are a plurality of the antennas, the plurality of antennas are switched by the tag reader in order to acquire the ID via the plurality of antennas, and the transmission / reception unit includes the antennas When a plurality of response signal strengths are received via different antennas for the same ID by switching, the maximum value of the received response signal strengths is the response signal of the wireless tag corresponding to the ID It is preferable to receive as intensity.

  In the tag reader control device of the present invention, when there are a plurality of the antennas, the plurality of antennas are switched by the tag reader in order to acquire the ID via the plurality of antennas, and the detection unit When the response signal strength of the wireless tag corresponding to the same ID is received via the plurality of antennas by switching, the article corresponding to the ID of the wireless tag has been placed at the predetermined location. Or detecting whether the antenna has been taken out from the predetermined location for each antenna, and in the detection by at least one or more antennas, the article of the wireless tag corresponding to the same ID is placed at the predetermined location. Or, if it is detected that it has been taken out from the predetermined location, in front of the wireless tag corresponding to the same ID The article is preferably determined that the state corresponding to the detection result.

  In the tag reader control device of the present invention, the detection unit may detect that the article has been placed at the predetermined location and detect that the article has been removed from the predetermined location for each of the plurality of antennas. It is preferable to detect that the article has been placed on or taken out of the predetermined location based on a preset setting.

  Moreover, in the tag reader control device of the present invention, the detection unit detects the number of detections that the article is placed at the predetermined location in the detection for each of the plurality of antennas, and the article is taken out from the predetermined location. It is preferable that the number of detections detected is counted, and it is detected that the article has been placed on or taken out of the predetermined location based on the greater number of detections.

  Further, in the tag reader control device of the present invention, the detection unit, when the number of detections assumed to be placed and the number of detections taken out are the same as a result of the counting, based on a preset setting, It is preferable to detect that the article has been placed on or taken out of the predetermined location.

  In the tag reader control device according to the present invention, the detection unit may detect that the article detected as being taken out from the predetermined place in the detection of the plurality of antennas is detected in the antenna other than the certain antenna. In the detection, when it is detected that the article is placed at the predetermined location, it is preferable that the state where the article is removed from the predetermined location is set as an undetermined state.

The tag reader of the present invention wirelessly communicates with a wireless tag, and whether the article with the wireless tag is placed at a predetermined place (placement at a predetermined place ) or removed from the predetermined place (the predetermined place ). A tag reader that detects the removal from a place ) , periodically acquiring an ID assigned to the wireless tag via an antenna, and determining a response signal intensity of the wireless tag corresponding to the acquired ID Based on the acquisition unit acquired for each acquisition of the ID, a storage unit that stores the acquired ID of the wireless tag and the response signal strength in association with each other, and the response signal strength stored in the storage unit, and a detection unit for detecting whether the article is said predetermined location preparative or the predetermined location or we are placed Ride, the detecting unit, for each ID of the wireless tag, the storage unit Ru the first condition is satisfied Tei that less than paid has been the most recent difference between the approximation thereof comprising an approximate value and the minimum value including the maximum value of the response signal strength of the first number first threshold value whether the determined, when said first condition is determined to Ru Tei satisfied, based on the ID of the radio tag associated with the response signal strength, the ID corresponding to the article of the wireless tag If it is detected that the device is placed at the predetermined location and it is determined that the first condition is not satisfied, the second response signal of the nearest second number smaller than the nearest first number is further obtained. intensity is determined whether or not satisfied the second condition that is not within a predetermined range, when it is determined that the second condition is Ru Tei satisfied, the radio associated with the response signal strength Corresponds to the ID of the wireless tag based on the tag ID Goods detects that retrieved from the predetermined location.

Also, the article state detection method of the tag reader control device of the present invention is connected to a tag reader that communicates wirelessly with a wireless tag, and whether the article with the wireless tag is placed at a predetermined place (placement at a predetermined place). ) Or an article state detection method of a tag reader control device for detecting whether the RFID tag is taken out from the predetermined place ( taken out from the predetermined place ) , and the ID assigned to the wireless tag is obtained and acquired periodically. A request for transmitting the ID detection command for acquiring the response signal strength of the wireless tag corresponding to the ID every time the ID is acquired to the wireless tag via the antenna is transmitted to the tag reader. Further, based on the request, an ID of the wireless tag transmitted from the wireless tag and a response signal strength of the wireless tag corresponding to the ID are calculated in advance. For each transmission / reception unit step received from the tag reader acquired via an antenna, a storage step for storing the received wireless tag ID and the response signal strength in association with each other in a storage unit, and for each wireless tag ID, A first condition is that a difference between the approximate value including the maximum value of the first first response signal intensity stored in the storage unit and the approximate value including the minimum value is smaller than a first threshold value. It determines whether or not met, if the first condition is determined to Ru Tei satisfied, based on the ID of the radio tag associated with the response signal strength, corresponding to the ID of the radio tag When it is detected that the article to be placed is placed at the predetermined location and it is determined that the first condition is not satisfied, a second second number that is smaller than the first first number is further included. Response signal strength of Determining whether a second condition that is not in the range of the constant is satisfied, if the second condition is determined to Ru Tei satisfied, the radio tag associated with the response signal strength And a detecting step of detecting that an article corresponding to the ID of the wireless tag is taken out from the predetermined location based on the ID.

Further, the article state detection method of the tag reader of the present invention wirelessly communicates with a wireless tag, and the article with the wireless tag is placed on a predetermined place (placed on a predetermined place ) or taken out from the predetermined place. A method of detecting an article state of a tag reader that detects whether it has been taken out ( taken out from the predetermined location ) , and periodically acquires an ID assigned to the wireless tag via an antenna, An acquisition step of acquiring the response signal strength of the corresponding wireless tag for each acquisition of the ID, a storage step of associating the acquired ID of the wireless tag and the response signal strength in a storage unit, and storing the wireless tag each ID tag, the difference between the approximation including the approximate value and the minimum value including the maximum value of the response signal strength of the most recent first number stored in the storage unit is a first threshold value The first condition is satisfied to determine Tei Luke not that also small, if the first condition is determined to Ru Tei satisfied, based on the ID of the radio tag associated with the response signal strength Te, the wireless article corresponding to the ID of the tag detects that it is placed in the predetermined location, if said first condition is determined not to be satisfied, and further, the most recent first number immediate response signal strength of the second number less than it is judged whether or not satisfied the second condition that is not within a predetermined range, the second condition is determined to Ru Tei met A detection step of detecting that an article corresponding to the ID of the wireless tag has been taken out from the predetermined location based on the ID of the wireless tag associated with the response signal strength.

  According to the present invention, it is possible to accurately detect the placement or removal of an article with a wireless tag from a predetermined location without being affected by the placement environment of the wireless tag.

It is a figure showing an example of composition of an article surveillance system in a 1st embodiment. It is a figure which shows an example of the functional block of the tag reader control apparatus 11 in 1st Embodiment. It is a figure which shows an example of the RSSI preservation | save part B which associates and preserve | saves radio tag ID and an RSSI value. It is a figure which shows an example of the hardware constitutions of a tag reader control apparatus and a tag reader. It is a flowchart for demonstrating an example of the detection process in the tag reader control apparatus of 1st Embodiment. It is a figure which shows an example of a structure of the article | item monitoring system in 2nd Embodiment. It is a figure which shows an example of a structure of the article | item monitoring system with which the one part of each electromagnetic wave output area of a some antenna overlaps. 10 is a table showing the state of each antenna when the wireless tag B is placed on the antenna 2; It is a table which shows the state for every antenna in the state where the radio | wireless tag B was extracted upwards from the antenna 2. FIG. 6 is a table showing the state of each antenna when the wireless tag B is placed immediately above the antenna 1. It is a figure which shows an example of the system configuration | structure containing the tag reader for demonstrating the prior art, Comprising: It is a figure which shows the state in which the articles | goods with a wireless tag were mounted on the antenna. It is a figure which shows an example of the system configuration | structure containing the tag reader for demonstrating the prior art, Comprising: It is a figure which shows the state by which the articles | goods with a wireless tag were taken out above the antenna. It is a figure which shows an example of the system configuration | structure containing the tag reader for demonstrating the prior art, Comprising: It is a figure for demonstrating that RSSI changes with places where the same article | item is mounted. It is a figure for demonstrating the prior art, Comprising: It is the figure which plotted the RSSI value in each mounting location. It is a figure for demonstrating the prior art, Comprising: It is the figure which made the RSSI value in each mounting location into a table | surface.

<First Embodiment>
Hereinafter, a first embodiment will be described with reference to the drawings. FIG. 1 shows a tag reader control device 11, a tag reader 12, antennas 13a to 13c, and wireless tags 14a-1 to 14a-3, 14b-1 to 14b-3, 14c-1 to 14c-3 attached to articles. It is a figure showing an example of composition of article surveillance system 10 provided with. The tag reader control device 11 is a PC (Personal Computer) or a server device, and is connected to the tag reader 12 via a network such as a LAN (Local Area Network) as shown in FIG. Here, only one tag reader 12 is connected to the tag reader control device 11, but a plurality of tag readers can be connected and the tag reader control device 11 can control a plurality of tag readers.

  The tag reader 12 is connected to the antennas 13a to 13c via the cables 26a to 26c. Although only three antennas are described here, the number is not limited to three, and the number of antennas to be connected can be determined within the range of the number connectable to the tag reader 12.

  Articles 15a-1 to 15a-3 with wireless tags 14a-1 to 14a-3 and articles 15b-1 to 15b with wireless tags 14b-1 to 14b-3, respectively, are mounted on the antennas 13a to 13c. 3 and articles 15c-1 to 15c-3 attached with wireless tags 14c-1 to 14c-3, respectively. Here, three articles are placed on the antennas 13a to 13c, respectively, but the number is not limited to three, and the positions of the placed articles are also on the antennas 13a to 13c. Well, the position is not limited to that shown in FIG. Further, here, the case where the article is placed on the antennas 13a to 13c is described, but the present invention is not limited to the case where the article is placed on the antennas 13a to 13c, and the article is located in the vicinity of the antennas 13a to 13c. The article may be placed at a position where the antenna can receive a response from each wireless tag.

  The wireless tags 14a-1 to 14a-3, 14b-1 to 14b-3, and 14c-1 to 14c-3 are articles 15a-1 to 15a-3, 15b-1 to 15b-3, and 15c-1 to 15c, respectively. Although it is attached to the side surface portion of -3, the attachment position is not limited to this, and it may be attached to the side facing the antenna (that is, in this case, the bottom surface of the article). Thereby, the person who picks up the article can easily pick up the article without feeling uncomfortable. In addition, the wireless tags 14a-1 to 14a-3, 14b-1 to 14b-3, and 14c-1 to 14c-3 here are assumed to be passive wireless tags that do not incorporate a battery. It is not limited to a wireless tag. The wireless tags 14a-1 to 14a-3, 14b-1 to 14b-3, and 14c-1 to 14c-3 here are general-purpose wireless tags that are generally used. Since a typical wireless tag has a configuration normally provided and is not a tag having a special configuration, detailed description thereof is omitted.

  The basic detection flow of the article monitoring system 10 is as follows. First, the tag reader control device 11 is uniquely assigned to the tag reader 12 from the wireless tags 14a-1 to 14a-3, 14b-1 to 14b-3, and 14c-1 to 14c-3. In order to acquire the ID, a request (request) is required to periodically transmit an ID detection command to the wireless tags 14a-1 to 14a-3, 14b-1 to 14b-3, and 14c-1 to 14c-3. To do. Upon receiving the request, the tag reader 12 periodically transmits an ID detection command to the wireless tags 14a-1 to 14a-3, 14b-1 to 14b-3, and 14c-1 to 14c-3. The wireless tag that has received the transmitted ID detection command transmits a response signal including an ID allocated to itself.

  The tag reader 12 receives the transmitted response signal and receives the RSSI of the wireless tag. The tag reader 12 transmits the received wireless tag ID and the corresponding RSSI value to the tag reader controller 11.

  The tag reader control device 11 that has received the ID of the wireless tag and the RSSI value includes the articles 15a-1 to 15a-3, 15b-1 to 15b-3, and 15c-1 to 15c-3 to which the wireless tag is attached. Whether the antennas 13a to 13c are taken out or placed is detected. A specific detection method will be described below.

  Here, an example of a functional block of the tag reader control device 11 will be described with reference to FIG. As shown in FIG. 2, the tag reader control device 11 includes a transmission / reception unit 20, a control unit 21, a display unit 22, an RSSI storage unit B23, a base RSSI storage unit D24, and a threshold storage unit 25. In order to acquire the ID of each wireless tag from the wireless tags 14a-1 to 14a-3, 14b-1 to 14b-3, and 14c-1 to 14c-3, the transmission / reception unit 20 uses the ID Requests for transmitting the detection commands to the wireless tags 14a-1 to 14a-3, 14b-1 to 14b-3, and 14c-1 to 14c-3 are transmitted to the tag reader 12. Further, the transmission / reception unit 20, based on the ID detection command transmitted from the tag reader 12, the wireless tag ID included in the response signal from the wireless tag received by the tag reader 12 and the wireless tag corresponding to the ID (ID) The RSSI value is received from the tag reader 12.

  The control unit 21 stores the received wireless tag ID and RSSI value in the RSSI storage unit B23. The RSSI storage unit B23 is provided with a storage area capable of storing at least a predetermined number A in order to store the received RSSI values. The numerical value of A here is, for example, a value such as 10, but is not limited to this value. Further, as shown in FIG. 3, the RSSI storage unit B23 stores the received wireless tag ID and the RSSI value in association with each other, and stores a maximum of 10 RSSI values for each wireless tag ID. For example, when a new RSSI value is received after 10 RSSI values are stored, the new RSSI value is the oldest value among the 10 currently stored RSSI values. Is overwritten and saved. In addition, when the control unit 21 transmits the ID detection command but the ID of the wireless tag cannot be detected, the control unit 21 stores a special value indicating that the ID has not been detected in the RSSI storage unit B23.

  When the control unit 21 stores the received ID and RSSI value of the wireless tag in the RSSI storage unit B23, whether or not the number of RSSI values in the RSSI storage unit B23 is less than a predetermined number A is determined for each wireless tag ID. If it is determined that the number is A or more (here, A is the area for storing RSSI values because only 10 RSSI values are prepared), the latest ASI of the RSSI values stored in the RSSI storage unit B23. It is determined whether or not the wireless tag is not detected. When there is no undetected one, the control unit 21 takes the difference between the minimum value and the maximum value among the latest A RSSI values of the RSSI storage unit B23, and the difference is a predetermined threshold (mounting blur). It is determined whether or not the width C value is smaller. Note that a condition that the difference is smaller than a predetermined threshold is defined as a first predetermined condition. The difference is the difference between the minimum value and the maximum value of the latest A RSSI values, but may be the difference between the approximate value of the minimum value and the approximate value of the maximum value. The placement blur width C value is used to determine whether or not the wireless tag-attached article is placed on the antenna, and is a first predetermined threshold value. , For example, 2 dBm, and stored in the threshold storage unit 25. Further, the number of sampling detections E, F value for subtraction detection determination value subtraction (to be referred to as a second predetermined threshold), and G value for sampling detection determination addition (to be referred to as a third predetermined threshold), which will be described later, are also stored in a threshold storage unit. 25.

  When the difference is smaller than the mounting blur width C value, the control unit 21 calculates an average value of the latest A RSSI values of the RSSI storage unit B23 and sends the calculated average value to the base RSSI storage unit D24. save. When the RSSI value is newly received after storage, and the difference between the minimum value and the maximum value among the latest A RSSI values including the received new RSSI value is smaller than the mounting blur width C value. Then, the average value of the last A pieces added with the new received RSSI value is calculated, and if the average value has already been stored in the base RSSI storage unit D24, it is updated (overwritten) and stored.

  When the average value is stored, the control unit 21 determines that an article with a wireless tag corresponding to the wireless tag ID currently being detected has been placed on the antenna. Judgment here uses the fact that when an article with a wireless tag is placed on the antenna, the RSSI value is less changed than when it is held by hand, and becomes stable. Yes, since the latest A RSSI values are almost constant and there is no blur, it is determined that the article is placed on the antenna. When the control unit 21 determines that the article is placed on the antenna, the control unit 21 displays on the display unit 22 such as a display that the article is placed on the antenna.

  On the other hand, if there is an RFID tag that has not been detected, the control unit 21 does not determine whether the difference is smaller than the placement blur width C value or not, and the base RSSI storage unit D24 receives the latest A RSSIs. It is determined whether or not the average value is stored. The control unit 21 also determines whether or not the average value of the latest A RSSI values is stored in the base RSSI storage unit D24 even when the difference is equal to or greater than the mounting blur width C value. When stored, the control unit 21 determines that all of the most recent predetermined number E of RSSI values stored in the RSSI storage unit B23 are less than the value obtained by subtracting the sampling detection determination value subtraction F value from the average value. Or the value obtained by adding the G value for sampling detection determination addition to the average value is determined. If there is an undetected wireless tag, it is determined that it is below. The value E is smaller than the value A.

  Note that the difference between the minimum value and the maximum value of the latest A RSSI values in the RSSI storage unit B23 is equal to or greater than a predetermined threshold (mounting blur width C value), and the latest stored in the RSSI storage unit B23. All of the predetermined number E of RSSI values are less than the value obtained by subtracting the F value for subtraction detection determination value subtraction from the above average value, or exceed the value obtained by adding the G value for sampling detection determination addition to the above average value. This condition is set as a second predetermined condition. In the above, the second predetermined condition is based on the average value, but is not limited to this, and may be based on the distribution tendency of the latest A RSSI values. Of these, a value having the highest appearance frequency may be used instead of the average value, and a deviation of A values may be used instead of the average value.

  All of the most recent predetermined number E of RSSI values are less than the value obtained by subtracting the F value for subtraction detection determination value subtraction from the average value, or the value obtained by adding the G value for sampling detection determination addition to the average value If it is determined that the number exceeds that, the control unit 21 determines that the article with the wireless tag corresponding to the wireless tag ID currently being detected has been taken out from the antenna. Based on the determination, the control unit 21 displays on the display unit 22 such as a display that the article has been removed from the antenna.

  Note that if the average value is below the value obtained by subtracting the F value for subtraction detection determination value subtraction, it is determined that the article has been taken out when the article with the wireless tag is taken out from the antenna. Since the value is smaller, this phenomenon is reflected. Further, when the value obtained by adding the G value for sampling detection determination addition to the average value is higher, it is determined that the article with the wireless tag is originally taken out from the antenna. Although the RSSI value is small, the reverse phenomenon may occur depending on the reflection and distortion of the radio wave, and this phenomenon is reflected.

  The sampling detection determination value subtraction F value is, for example, 5 dBm, and the sampling detection determination addition G value is, for example, 3 dBm, but is not limited to these values, and the sampling detection determination value subtraction F value is And the G value for sampling detection determination addition may be the same value, and can be changed to an optimum value according to the environment in which the placement or removal of the article is detected.

  Next, an example of a hardware configuration for realizing the tag reader control device 11 will be described with reference to FIG. As shown in FIG. 4, the hardware configuration includes, for example, a CPU (Central Processing Unit) 41, a RAM (Random Access Memory) 42, an HDD (Hard Disk Drive) 43, a communication interface 44, an input / output unit 45, and a bus 46. I have. The CPU 41, RAM 42, HDD 43, communication interface 44, and input / output unit 45 are connected to each other via a bus 46.

  The CPU 41 reads a program for performing the above-described processing of the tag reader control device 11 stored in the HDD 43 or the like via the bus 46, temporarily stores the read program in the RAM 42, and performs various processes according to the program. This is performed and functions mainly as the control unit 21 described above.

  The RAM 42 temporarily stores a part of an OS (Operating System) program and application programs to be executed by the CPU 41. The RAM 42 stores various data necessary for processing by the CPU 41. The HDD 43 stores application programs for performing various processes of the tag reader control device 11, data necessary for the processing of the tag reader control device 11, and the like, and mainly the above-described RSSI storage unit B23, base RSSI storage unit D24, threshold storage. The unit 25 functions.

  The communication interface 44 transmits / receives data to / from the outside (here, the tag reader 12 and the like), and performs data transmission / reception to / from the tag reader 12 via a network such as a LAN in accordance with an instruction from the CPU 41. Functions as the transmission / reception unit 20. The input / output unit 45 includes an input device such as a touch panel for inputting data and an output device such as a display for displaying information, and mainly functions as the display unit 22 described above.

The bus 46 is a path that mediates transmission / reception of control signals, data signals, and the like between the devices.
Next, an example of functional blocks of the tag reader 12 will be described with reference to FIG. As shown in FIG. 1, the tag reader 12 includes a transmission / reception processing unit 16, a reader control unit 17, an antenna changeover switch 18, and an upper communication processing unit 19. The transmission / reception processing unit 16 performs general processing (signal modulation, amplification, demodulation, etc.) performed by a normal tag reader. In addition to the above, here, the tag reader control is performed via the host communication processing unit 19. An ID detection command transmission request is received from the device 11, and an ID detection command is transmitted based on the transmission request. That is, the transmission / reception processing unit 16 sends an ID detection command to obtain the ID of each wireless tag from the wireless tags 14a-1 to 14a-3, 14b-1 to 14b-3, and 14c-1 to 14c-3. The wireless tags 14a-1 to 14a-3, 14b-1 to 14b-3, and 14c-1 to 14c-3 are transmitted. The transmission / reception processing unit 16 also transmits the ID detection command from the wireless tags 14a-1 to 14a-3, 14b-1 to 14b-3, and 14c-1 to 14c-3 via the antennas 13a to 13c. The ID of each wireless tag is acquired and the corresponding RSSI value is received.

  The reader control unit 17 controls the overall processing of the tag reader 12, and can also control antenna switching of an antenna switch 18 described later.

  The antenna changeover switch 18 is for sequentially switching the antennas 13a to 13c connected to the tag reader 12. For example, the antenna 13a is first connected to the tag reader 12 to acquire the ID and RSSI value of the wireless tag of the article on the antenna 13a. Then, the connection of the antenna is sequentially switched by switching the connection from the antenna 13a to the antenna 13b and acquiring the ID and RSSI value of the wireless tag of the article on the antenna 13b.

  As described above, a plurality of antennas are used because an area where an article for detecting movement (removal) is placed cannot be covered by only one antenna. A detection area is detected by detecting a wireless tag with a plurality of antennas. This is because there is a case of securing. In that case, in order to reduce the cost, as described above, an antenna changeover switch 18 is provided in the tag reader 12 or outside the tag reader 12, and a plurality of antennas are connected to the tag reader 12 main body. When the acquisition of the wireless tag ID and RSSI is completed with one antenna, the antenna switch 18 is controlled to switch to the next antenna, the wireless tag ID and RSSI are acquired again, and this is performed for all antennas. It is common to do this.

The upper communication processing unit 19 mainly transmits / receives information to / from the tag reader control device 11.
Next, an example of a detection processing flow for placing or taking out articles by the tag reader control device 11 will be described with reference to FIG. In addition, although the detection process of mounting or taking out of one item with a certain wireless tag is described here, the following detection processing is performed not only for one item but also for each wireless tag. The same applies to each article. In addition, here, processing when one antenna is connected to the tag reader 12 is described, and switching of the antenna is not described. However, an ID from an RFID tag of an article on the antenna is obtained by one antenna. If the RSSI value can be acquired, the antenna changeover switch 18 switches the connection to another antenna, and the same processing is performed.

  As shown in FIG. 5, the control unit 21 first clears (deletes) the information stored in the RSSI storage unit B23 and the information stored in the base RSSI storage unit D24 (step S501). The control unit 21 determines whether or not the detection processing for placing or taking out the article has been completed according to the intention of the operator of the tag reader control device 11 (step S502).

  When it is determined that the detection process has been completed (YES), the detection process is terminated, but when it is determined that the detection process has not been completed (NO), the control unit 21 performs the wireless tag detection process. Implement (step S503). Specifically, the control unit 21 transmits the ID of each wireless tag from the wireless tags 14a-1 to 14a-3, 14b-1 to 14b-3, and 14c-1 to 14c-3 via the transmission / reception unit 20. In order to acquire it, the request | requirement which transmits ID detection command with respect to wireless tag 14a-1 to 14a-3, 14b-1 to 14b-3, 14c-1 to 14c-3 is transmitted to the tag reader 12. Based on the ID detection command transmitted from the tag reader 12, the ID of the wireless tag included in the response signal from the wireless tag received by the tag reader 12, and the RSSI value of the wireless tag corresponding to the ID (ID), The control unit 21 receives from the tag reader 12 via the transmission / reception unit 20.

  The control unit 21 stores the received (acquired) ID of the wireless tag and the RSSI value in the RSSI storage unit B23 (step S504). Here, when the wireless tag cannot be detected, the control unit 21 stores a special value in the RSSI storage unit B23 so that it can be understood that the wireless tag has not been detected (not detected).

  The control unit 21 determines whether or not the number of RSSIs stored in the RSSI storage unit B23 is less than A (step S505). If it is determined that the number of RSSIs is less than A (YES), the process returns to step S502, and the processes of steps S502 to S505 are repeated until the number of RSSIs becomes A. If it is determined that the number of RSSIs is A or more (A when there are only 10 RSSI values for the area for storing RSSI values) (NO), the RSSI is stored in the RSSI storage unit B23. It is determined whether or not the latest ASI of the RSSI values include those for which no wireless tag has been detected (step S506).

  If there is an undetected wireless tag (YES), the process of step S510 described later is performed. When there is no undetected wireless tag (NO), the control unit 21 takes the difference between the minimum value and the maximum value among the latest A RSSI values of the RSSI storage unit B23, and the difference is a predetermined threshold value. It is determined whether or not it is smaller than (mounting blur width C value) (step S507). The placement blur width C value is used to determine whether or not the wireless tag-attached article is placed on the antenna, and is a first predetermined threshold value. For example, 2 dBm and stored in the threshold storage unit 25.

  When the difference is smaller than the mounting blur width C value (YES), the control unit 21 calculates an average value of the latest A RSSI values of the RSSI storage unit B23, and uses the calculated average value as a base RSSI storage unit D24. (Step S508). When the RSSI value is newly received after storage, and the difference between the minimum value and the maximum value among the latest A RSSI values including the received new RSSI value is smaller than the mounting blur width C value. Then, the average value of the last A pieces added with the new received RSSI value is calculated, and if the average value has already been stored in the base RSSI storage unit D24, it is updated (overwritten) and stored.

  The control unit 21 stores the average value, determines that an article with a wireless tag corresponding to the wireless tag ID currently being detected is placed on the antenna, and places the article on the antenna. The display unit 22 displays the information indicating that it has been placed (step S509).

  On the other hand, if it is determined in step S506 that there is an undetected wireless tag (YES), or if it is determined in step S507 that the difference is equal to or greater than the mounting blur width C value (NO), the control unit 21 determines whether the average value of the last A RSSI values is not stored in the base RSSI storage unit D24, that is, whether the average value is in the clear state (step S510). If the average value is not stored (is in a clear state) (YES), the average value of the RSSI A values does not exist, so the process returns to step S502 and the process is performed until the average value is stored. Is repeated.

  When the average value is stored (not in the clear state) (NO), the control unit 21 subtracts the sampling detection determination value from the average value for all the latest E RSSI values stored in the RSSI storage unit B23. It is determined whether it is below the value obtained by subtracting the F value for use, or above the value obtained by adding the G value for sampling detection determination addition to the average value (step S511). If there is an undetected wireless tag, it is determined that it is below.

  All of the latest E RSSI values are below the average value minus the F value for subtraction detection judgment value subtraction, or above the average value plus the G value for sampling detection judgment addition. (YES), the control unit 21 determines that the article with the wireless tag corresponding to the wireless tag ID currently being detected has been removed from the antenna, and has been removed. A message to that effect is displayed on the display unit 22 (step S512).

On the other hand, in step S511, all of the latest E RSSI values stored in the RSSI storage unit B23 are not less than the value obtained by subtracting the sampling detection determination value subtraction F value from the average value, and the average When it is determined that the value obtained by adding the G value for sampling detection determination addition to the value is not exceeded (NO), it is not in a state where it can be determined that the article has been removed, so the process returns to step S502 and the process is repeated.

  Since the determination is made based on the difference from the average value of the most recent RSSI values, the above processing flow is affected by the wireless tag placement environment (the place where the wireless tag is placed and the number of other wireless tags present in the vicinity). It is possible to accurately detect the placement and removal of the article with the wireless tag. It goes without saying that the same effect can be obtained not only when the antenna is positioned under the article, but also when the antenna is positioned laterally or upward of the article.

  Here, the case where it is determined that the article has been placed or taken out will be specifically described with reference to FIG. In FIG. 3, RSSI values corresponding to the wireless tag IDs 1 to 3 are respectively described. In the wireless tag ID1, the average RSSI value of the wireless tag ID1 is −34.5 dBm, and the difference between the maximum RSSI value of −34 dBm and the minimum value of −35 dBm is 1 dBm. When the placement blur width C value is 2 dBm, since the difference is smaller than the placement blur width C value 2 dBm, it is determined that the article with the wireless tag ID 1 is placed. In the wireless tag ID2, the average RSSI value of the wireless tag ID2 is −40.6 dBm, and the difference between the maximum RSSI value of −40 dBm and the minimum value of −41 dBm is 1 dBm. When the placement blur width C value is 2 dBm, the difference is smaller than the placement blur width C value 2 dBm, so it is determined that the article with the wireless tag ID 2 is placed.

  On the other hand, in the wireless tag ID3, the average RSSI value of the wireless tag ID3 is −42.8 dBm, and the difference between the maximum RSSI value of −36 dBm and the minimum value of −60 dBm is 24 dBm. When the mounting blur width C value is 2 dBm, the difference is equal to or more than the mounting blur width C value of 2 dBm, and thus the determination in step S511 described above is performed. In step S511, all the RSSI values of the latest E (for example, 3), that is, the 8th to 10th RSSI values are average values of the RSSI values stored in the base RSSI storage unit D24− It is determined whether it is below the F value (5 dBm) or above the average RSSI value + G value (3 dBm).

  For example, when the average value stored in the base RSSI storage unit D24 is −36.5 dBm, the average value of the RSSI value−F value (5 dBm) = − 41.5 dBm, and the average value of the RSSI value + G value (3 dBm) ) = − 33.5 dBm. The latest three RSSI values are -55 dBm, -60 dBm, and -57 dBm, respectively. From this, it is determined that all the latest three RSSI values are below the average RSSI value−F value (5 dBm) = − 41.5 dBm. Accordingly, it is determined that the article with the wireless tag ID 3 has been taken out, and a display to the effect that the article with the wireless tag ID 3 has been taken out is displayed on the display unit 22.

<Second Embodiment>
In the first embodiment, the tag reader control device 11 performs a detection process for placing or taking out an article. In the second embodiment, the tag reader control device 11 has a detection processing function (for example, a control unit). 21, the RSSI storage unit B23, the base RSSI storage unit D24, and the threshold storage unit 25) are moved into the tag reader, the tag reader detects the placement or removal of the article, and the detection result is displayed on the display unit of the tag reader controller 11. 22 and so on.

  FIG. 6 is a diagram illustrating an example of a configuration of an article monitoring system 60 including a tag reader 62 having a detection processing function. The difference between the article monitoring system 60 shown in FIG. 6 and the article monitoring system 10 shown in FIG. 1 is only a difference in whether the tag reader has a detection processing function or the tag reader controller. The antenna system connected to the tag reader, the cable connecting the antenna and the tag reader, the article on the antenna, and the wireless tag attached to the article are the same in both systems. For this reason, in the configuration of the article monitoring system 60 shown in FIG. 6, the same reference numerals as those in FIG.

  As shown in FIG. 6, the tag reader 62 includes a transmission / reception processing unit 63, a control unit 64, an RSSI storage unit B 65, a base RSSI storage unit D 66, a threshold storage unit 67, and the antenna changeover switch 18. The control unit 64, the RSSI storage unit B65, the base RSSI storage unit D66, and the threshold storage unit 67 are the same as the control unit 21, the RSSI storage unit B23, the base RSSI storage unit D24, and the threshold storage unit 25 of the tag reader controller 11 described above. Since it has the same function, description is abbreviate | omitted here.

  The transmission / reception processing unit 63 performs general processing (signal modulation, amplification, demodulation, etc.) performed by a normal tag reader. In addition to these, here, the wireless tags 14a-1 to 14a-3, 14b are used. In order to obtain the ID of each wireless tag from -1 to 14b-3 and 14c-1 to 14c-3, ID detection commands are sent to the wireless tags 14a-1 to 14a-3, 14b-1 to 14b-3, 14c. Transmission is performed via antennas 13a to 13c to -1 to 14c-3. Further, the transmission / reception processing unit 63 obtains the ID of the wireless tag included in the response signal from the wireless tag transmitted based on the transmitted ID detection command, and the RSSI value of the wireless tag corresponding to the ID (ID). And received via the antennas 13a to 13c.

  The hardware configuration for realizing the tag reader 62 is basically the same as the hardware configuration shown in FIG.

  Further, the detection processing flow for taking out or placing the article in the tag reader 62 is basically the same as the detection processing flow shown in FIG. However, since the tag reader 62 notifies the tag reader control device 61 that the article has been placed on the antenna in the process of step S509, this point is different. At this time, the tag reader control device 61 displays on the display section that the article has been placed on the antenna based on this notification.

  By the way, the content described above is to switch the connection of a plurality of antennas and acquire the RSSI value of the wireless tag via each antenna, and the RSSI value of a certain wireless tag is obtained via only one antenna. It is about the case where it is acquired. That is, the case where the RSSI value of the same wireless tag is acquired via a plurality of antennas is not described.

  Hereinafter, for example, a process when a part of the radio wave output areas of a plurality of antennas overlap and the RSSI values of the wireless tags having the same ID are acquired by different antennas will be described.

The article monitoring system shown in FIG. 7 corresponds to the article monitoring system shown in FIG. 1, and in the article monitoring system shown in FIG. 7, the article is placed on the host device 11a (corresponding to the tag reader control device 11). Alternatively, there is a detection function for taking out, but the above-mentioned detection function may be provided on the tag reader 12 side. As shown in FIG. 7, the four antennas 1 to 4 are connected to the tag reader 12 by switching the antenna changeover switch 18. Each configuration shown in FIG. 7 are the same as configuration already described, here omitted for each component.

  As shown in FIG. 7, each of the antennas 1 to 4 has a unique radio wave output area, and some radio wave output areas overlap. Specifically, a part of the radio wave output area of the antenna 1 overlaps with the radio wave output areas of the antenna 2 and the antenna 3. A part of the radio wave output area of the antenna 2 overlaps the radio wave output areas of the antenna 1 and the antenna 4. A part of the radio wave output area of the antenna 3 overlaps the radio wave output areas of the antenna 1 and the antenna 4. A part of the radio wave output area of the antenna 4 overlaps the radio wave output areas of the antenna 2 and the antenna 3.

  In such an arrangement of the antennas 1 to 4, the wireless tag A is in a state of being extracted (extracted) above the antenna 1, and the wireless tag B is in a state of being set (set) on the antenna 2. is there.

  In such a situation, the antenna connection is switched by the antenna changeover switch 18, and processing is performed as if the plurality of antennas connected to one tag reader 12 are one antenna, so that the same wireless tag is connected. On the other hand, when different RSSI values are obtained with different antennas, the largest RSSI value (maximum value) among the obtained RSSI values is regarded as the RSSI value of the wireless tag so as to perform detection processing. It may be.

  Specifically, the RSSI value acquired by any one of the antennas 1 to 4 is regarded as being acquired by one antenna, and the placement state (set state) of the wireless tag-attached article / the wireless tag-attached article A detection process of the removal state (sampling state) is performed. In the case of FIG. 7, different RSSI values may be acquired for a plurality of antennas for the wireless tag B (for example, different RSSI values are acquired for both the antenna 2 and the antenna 4 for the wireless tag B). ). In this case, it is assumed that the largest RSSI value among a plurality of RSSIs acquired for one wireless tag is acquired by any of the antennas 1 to 4. This makes it possible to easily increase the detection area of the wireless tag without changing the processing contents of RSSI.

  In addition, when the RSSI value is independently managed for each of the plurality of antennas connected to one tag reader 12, and at least one or more of the plurality of antennas is determined to be in the set state or the sampling state, the wireless You may make it determine a tagged article as a set state or a extraction state. That is, the RSSI value is managed independently for each of the plurality of antennas connected to one tag reader 12, and the detection of at least one of the plurality of antennas is performed for the wireless tag corresponding to the same ID. When it is detected that the article is placed on or taken out of the antenna, it is determined that the article of the wireless tag corresponding to the same ID is placed on or taken out of the antenna. You may do it.

  Specifically, in FIG. 7, the RSSI value of the wireless tag B is acquired via the antenna 2, and the RSSI value of the wireless tag B is also acquired via the antenna 4. At this time, the RSSI values acquired via the antenna 2 and the antenna 4 are managed independently. The tag reader 12 detects whether the article with the wireless tag B is placed on the antenna 2 or taken out from the antenna 2 using the RSSI value acquired via the antenna 2. Similarly, the tag reader 12 uses the RSSI value acquired through the antenna 4 to detect whether the article with the wireless tag B is placed on the antenna 4 or taken out from the antenna 4. . At this time, for example, in the detection by the antenna 4, it is not possible to detect whether the article with the wireless tag B is placed on the antenna 4 or taken out from the antenna 4 (for example, when the determination in step S511 in FIG. 5 is NO) ) If the detection with the antenna 2 detects that the article with the wireless tag B is placed on the antenna 2, the article with the wireless tag B may be placed on the antenna 2. Good.

  Further, the RSSI value is managed independently for each of the plurality of antennas connected to one tag reader 12, and the detection of at least two or more antennas of the plurality of antennas is performed for the wireless tags corresponding to the same ID. When it is detected that the article is placed on or taken out of the antenna, it is determined that the article of the wireless tag corresponding to the same ID is placed on or taken out of the antenna. At this time, when the set state and the sampling state occur at the same time, the setting state or the sampling state may be determined based on a preset setting. That is, when the detection that the article with the wireless tag is placed on the antenna and the detection that the article with the wireless tag is taken out from the antenna occur simultaneously in the detection for each of the plurality of antennas, for example, It may be detected that the article is placed on the antenna based on a pre-set setting such as preferentially adopting detection that the article with the wireless tag is placed on the antenna. This is based on the assumption that, when the RFID tag at the end of the antenna is moved slightly, it will remain in the set state with one antenna, but it has moved out of the reading range with another antenna. Even in such a case, the placement or removal of the article can be detected.

  Further, the RSSI value is managed independently for each of the plurality of antennas connected to one tag reader 12, and the detection of at least two or more antennas of the plurality of antennas is performed for the wireless tags corresponding to the same ID. When it is detected that the article is placed on or taken out of the antenna, it is determined that the article of the wireless tag corresponding to the same ID is placed on or taken out of the antenna. At this time, the number of set states and sampling states may be counted, and the state with the largest number may be determined as the state of the article with the wireless tag. That is, in the detection for each of the plurality of antennas, the number of detections that the article is placed on the antenna and the number of detections that the article is taken out from the antenna are counted, respectively, and based on the larger number of detections, It may be detected that the article is placed on the antenna or removed from the antenna. When the number of set states is the same as the number of sampling states, the set state or the sampling state may be determined based on a preset setting. That is, when the number of detections that are placed and the number of detections that are taken out are the same, it may be detected that the article has been placed on or taken out of the antenna based on a preset setting. Good.

  In addition, the RSSI value is managed independently for each of the plurality of antennas connected to one tag reader 12, and a wireless tag that is in a sampling state in one antenna is newly set in any other antenna. If it becomes, the sampled state may be returned to the undecided state which is neither the set state nor the extracted state. Thereby, it can be reflected in the state that the wireless tag has moved to another antenna area. Specifically, a case where the wireless tag B is moved from directly above the antenna 2 to just above the antenna 1 will be described with reference to FIGS. 7 and 8A to 8C.

  The wireless tag B is in a state of being placed on the antenna 2, and the initial state is the state shown in FIG. 8A. That is, the antenna 1 is in an undetermined state because it is outside the radio wave output area of the antenna 1. The antenna 2 is set on the antenna 2 and is in a set state. Since the antenna 3 is outside the radio wave output area of the antenna 3 as in the antenna 1, the antenna 3 is in an undetermined state. The antenna 4 is set on the antenna 2 and is in a set state.

  When the wireless tag B is extracted upward from the above state, the state at that time becomes the state shown in FIG. 8B. That is, the antenna 1 is in an undetermined state because it is outside the radio wave output area of the antenna 1. Since the antenna 2 is extracted above the antenna 2, the antenna 2 is in an extracted state. Since the antenna 3 is outside the radio wave output area of the antenna 3, the antenna 3 is in an undetermined state. The antenna 4 is extracted above the antenna 2 and is out of the radio wave output area, and is in an extracted state.

  When the wireless tag B is set immediately above the antenna 1 from the above state, the wireless tag B that is in the extracted state in the antenna 2 and the antenna 4 is newly set in the other antenna (antenna 3). As shown in FIG. 8, the antenna 2 and the antenna 4 that have been in a sampling state (FIG. 8B) are set to an undetermined state. Thereby, it can be reflected in the state that the wireless tag B has moved to the area of another antenna (in this case, the antenna 1).

  As described above, according to the present invention, it is possible to accurately detect the placement or removal of an article with a wireless tag from a predetermined place without being affected by the placement environment of the wireless tag. .

  In general, the output of an inquiry for detecting a wireless tag by a tag reader needs to have a certain size so that all wireless tags can be detected even if there is an influence such as reflection. However, if the output is large, the wireless tag taken out to a long distance (1 meter or more) is detected, and it is determined that it has not been taken out (mounted). For this reason, it has not been possible to meet the need for detection at a short distance (for example, about 30 centimeters). To meet this need, the output must be reduced. However, if the output is reduced, the wireless tag may not be detected. In this case, since the wireless tag is not detected even though it has not been extracted, it is determined that the wireless tag has been extracted. Therefore, according to the tag reader control device 11 or the tag reader 62 described above, it is necessary for a visitor to take a close look at an item in a store or the like, for example, a need for detection of a short distance while maintaining the magnitude of the output. It is possible to respond to the need to detect what has been taken.

  In the above description, the placement or removal of an article is detected based on A (10) RSSI values. For example, the placement of an article is performed based on the number of RSSI values received within a predetermined time. Alternatively, the removal may be detected. For example, it is possible to set the RSSI value to be acquired every second for a predetermined time of 10 seconds, which is the same as acquiring the 10 RSSI values described above.

  In the above description, one wireless tag is attached to one article and the detection process is performed. However, a plurality of wireless tags can be attached to one article and the detection process can be performed. By using RSSI values from a plurality of wireless tags attached to one article, it is possible to detect the removal of the article more accurately.

  In the above-described embodiment, the main processing of the tag reader control device and the tag reader is described as being executed by software processing by the CPU. However, all or part of this processing may be realized by hardware. .

  Further, the above-described embodiment is not limited to the above-described embodiment, and various changes can be made without departing from the gist of the embodiment.

10, 60 Article monitoring system 11, 11a, 61 Tag reader control device 12, 62, 100 Tag reader 1, 2, 3, 4, 13a, 13b, 13c, 101 Antenna 14a-1, 14a-2, 14a-3, 14b- 1, 14b-2, 14b-3, 14c-1, 14c-2, 14c-3, 103 Wireless tags 15a-1, 15a-2, 15a-3, 15b-1, 15b-2, 15b-3, 15c -1, 15c-2, 15c-3, 104 Article 16, 63 Transmission / reception processing unit 17 Reader control unit 18 Antenna switch 19 Upper communication processing unit 20 Transmission / reception unit 21, 64 Control unit 22 Display unit 23, 65 RSSI storage unit B
24, 66 Base RSSI storage D
25, 67 Threshold storage unit 26a, 26b, 26c Cable 41 CPU
42 RAM
43 HDD
44 Communication Interface 45 Input / Output Unit 46 Bus 102 Antenna Cable

Claims (13)

Connected to the radio tag and the radio communication to tag reader, the article with a radio tag is a tag reader controller that detects whether the Ride preparative or the predetermined location or we are placed at a predetermined location,
An ID detection command for periodically acquiring the ID assigned to the wireless tag and acquiring the response signal strength of the wireless tag corresponding to the acquired ID for each acquisition of the ID via the antenna The wireless tag transmits a request for transmission to the tag reader, and further, based on the request, an ID of the wireless tag transmitted from the wireless tag and a response of the wireless tag corresponding to the ID A transmission / reception unit that receives the signal strength from the tag reader acquired via the antenna;
A storage unit that stores the ID of the received wireless tag and the response signal strength in association with each other;
Based on the response signal intensities stored in the storage unit, and a detection unit for detecting whether the article is said predetermined location preparative or the predetermined location or we are placed Ride,
The detection unit, for each ID of the wireless tag,
A first condition is that a difference between the approximate value including the maximum value of the first first response signal intensity stored in the storage unit and the approximate value including the minimum value is smaller than a first threshold value. Determine if it ’s met,
If the first condition is determined to Ru Tei satisfied, based on the ID of the radio tag associated with the response signal strength, the the article corresponding to the ID of the radio tag is placed in the predetermined location it detects the are,
If it is determined that the first condition is not satisfied, a second condition that the response signal strength of the second closest number less than the first first number is not within a predetermined range is further provided. Determine if it ’s met,
If the second condition is determined to Ru Tei satisfied, on the basis of the ID of the radio tag associated with the response signal strength, said an article corresponding to the ID of the radio tag has been removed from the predetermined location detecting the tag reader controller, characterized in that. The first condition is the minimum value, the condition that the difference between the maximum value is smaller than the first threshold value among the response signal strength of the most recent first number,
The second condition is pre SL all response signal strength of the nearest second number, the average value of the previously stored the most recent response signal strength of the first number in the storage unit for storing the average value or is below the value obtained by subtracting the second threshold value, or the average value to a third reader control device according to claim 1, characterized in that a condition that exceeds the value obtained by adding the threshold value . Wherein the detection unit, when the calculating the difference between the most recent minimum value and maximum value of the response signal strength of the first number, it is determined that the first condition is satisfied, the most recent The tag reader control device according to claim 2, wherein an average value of the first number of response signal intensities is calculated and stored in a storage unit that stores the average value. Said detection unit, an article corresponding to the ID of the radio tag when it is detected that is placed in the predetermined location, or the the article corresponding to the ID of the radio tag has been removed from the predetermined location when detecting, information indicating that the article is removed from it or the predetermined location is placed in the predetermined location, from claim 1, characterized in that on the display unit for displaying information 3 The tag reader control device according to any one of the above. When there are a plurality of the antennas, the plurality of antennas are switched by the tag reader to obtain the ID via the plurality of antennas,
When the transmission / reception unit receives a plurality of response signal strengths via different antennas for the same ID by switching the antenna, a maximum value of the received response signal strengths corresponds to the ID. The tag reader control device according to claim 1, wherein the tag reader control device receives the response signal strength of the wireless tag. When there are a plurality of the antennas, the plurality of antennas are switched by the tag reader to obtain the ID via the plurality of antennas,
When the detection unit receives response signal strengths of the wireless tags corresponding to the same ID through the plurality of antennas by switching the antennas, the article corresponding to the ID of the wireless tag is or is placed in a predetermined location, or the or retrieved from the predetermined location is detected for each of the antenna, the detection of at least one or more antennas, the article of the wireless tag corresponding to the same ID is , determines that the predetermined location when it is detected to have been removed from or the predetermined location is placed, the article of the wireless tag corresponding to the same ID is the state corresponding to the detection result The tag reader control device according to any one of claims 1 to 4, wherein Wherein the detection unit, when the article is the detection that is placed at a predetermined location, and a detector that the article is removed from the predetermined location, occur simultaneously in the detection of each of the plurality of antennas, previously based on the configuration, tag reader control apparatus according to claim 6, wherein the article is characterized by detecting and taken from or the predetermined location is placed in the predetermined location. Wherein the detection unit, in the detection of each of the plurality of antennas, and detects the number of the said article is placed in the predetermined location, and a detection number and the article is removed from the predetermined location and counting each , on the basis of the detected number of one large, reader control apparatus according to claim 6, wherein the article and detecting the retrieved from or the predetermined location is placed in the predetermined location. Wherein the detection unit, the counted result, if the number of detection of a tie to the retrieved said a detection number and are the placement, based on previously set, placing the article in the predetermined location The tag reader control device according to claim 8, wherein the tag reader control device detects that the tag reader has been taken out or removed from the predetermined location. Wherein the detection unit, in the detection of each of the plurality of antennas, the article that has been detected to have been removed from the predetermined location in the detection of some antennas, the article in the detection of the antenna other than the certain antenna mounting to said predetermined location The tag reader control device according to claim 6, wherein when it is detected that the device is placed, the state of being taken out from the predetermined place is set as an undetermined state. Wireless tag by radio communication, said article with a radio tag is a tag reader for detecting whether a Ride preparative or the predetermined location or we are placed at a predetermined location,
An acquisition unit that periodically acquires an ID assigned to the wireless tag via an antenna and acquires a response signal strength of the wireless tag corresponding to the acquired ID for each acquisition of the ID;
A storage unit that stores the acquired ID of the wireless tag and the response signal intensity in association with each other;
Based on the response signal intensities stored in the storage unit, and a detection unit for detecting whether the article is said predetermined location preparative or the predetermined location or we are placed Ride,
The detection unit, for each ID of the wireless tag,
A first condition is that a difference between the approximate value including the maximum value of the first first response signal intensity stored in the storage unit and the approximate value including the minimum value is smaller than a first threshold value. filled to determine Tei Luke not,
If the first condition is determined to Ru Tei satisfied, based on the ID of the radio tag associated with the response signal strength, the the article corresponding to the ID of the radio tag is placed in the predetermined location it detects the are,
If it is determined that the first condition is not satisfied, a second condition that the response signal strength of the second closest number less than the first first number is not within a predetermined range is further provided. Determine if it ’s met,
If the second condition is determined to Ru Tei satisfied, based on the ID of the radio tag associated with the response signal strength, the the article corresponding to the ID of the radio tag has been removed from the predetermined location tag reader, wherein the detection is, that the. Connect to the tag reader to the RFID wireless communication, the article status detection method of articles with a wireless tag reader controller that detects whether the Ride preparative or the predetermined location or we are placed at a predetermined location Because
An ID detection command for periodically acquiring the ID assigned to the wireless tag and acquiring the response signal strength of the wireless tag corresponding to the acquired ID for each acquisition of the ID via the antenna The wireless tag transmits a request for transmission to the tag reader, and further, based on the request, an ID of the wireless tag transmitted from the wireless tag and a response of the wireless tag corresponding to the ID A transmitter / receiver step for receiving signal strength from the tag reader acquired via the antenna; and
A storage step of associating the received ID of the wireless tag with the response signal strength and storing it in a storage unit;
For each ID of the wireless tag,
A first condition is that a difference between the approximate value including the maximum value of the first first response signal intensity stored in the storage unit and the approximate value including the minimum value is smaller than a first threshold value. Determine if it ’s met,
If the first condition is determined to Ru Tei satisfied, based on the ID of the radio tag associated with the response signal strength, the the article corresponding to the ID of the radio tag is placed in the predetermined location it detects the are,
If it is determined that the first condition is not satisfied, a second condition that the response signal strength of the second closest number less than the first first number is not within a predetermined range is further provided. Determine if it ’s met,
If the second condition is determined to Ru Tei satisfied, based on the ID of the radio tag associated with the response signal strength, the the article corresponding to the ID of the radio tag has been removed from the predetermined location A detecting step for detecting
An article state detection method for a tag reader control device, comprising: Wireless tag by radio communication, said article with a radio tag is an article method for detecting the state of the tag reader for detecting whether a Ride preparative or the predetermined location or we are placed at a predetermined location,
An acquisition step of periodically acquiring an ID assigned to the wireless tag via an antenna and acquiring a response signal strength of the wireless tag corresponding to the acquired ID for each acquisition of the ID;
A storage step of associating the acquired ID of the wireless tag and the response signal strength in association with each other and storing it in a storage unit;
For each ID of the wireless tag,
A first condition is that a difference between the approximate value including the maximum value of the first first response signal intensity stored in the storage unit and the approximate value including the minimum value is smaller than a first threshold value. filled to determine Tei Luke not,
If the first condition is determined to Ru Tei satisfied, based on the ID of the radio tag associated with the response signal strength, the the article corresponding to the ID of the radio tag is placed in the predetermined location it detects the are,
If it is determined that the first condition is not satisfied, a second condition that the response signal strength of the second closest number less than the first first number is not within a predetermined range is further provided. Determine if it ’s met,
If the second condition is determined to Ru Tei satisfied, based on the ID of the radio tag associated with the response signal strength, the the article corresponding to the ID of the radio tag has been removed from the predetermined location A detecting step for detecting
A method of detecting an article state of a tag reader, comprising:

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