JP2010165237A - Wireless tag communications system, remaining battery level estimation method for wireless tag and monitoring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless tag communications system capable of detecting a remaining battery level of the wireless tag exactly at a center device side without adding a new component to a wireless tag. <P>SOLUTION: By arranging a tag position calculation part 123 for calculating a distance between a wireless tag 110 and a tag reader 120, a receiving level detecting part 122 for detecting a receiving level of a signal from the wireless tag 110, and a remaining battery level determination part 131 for determining the remaining battery level of the above wireless tag based on the above distance and the above receiving quality, the need for adding the new component to the wireless tag 110 is eliminated and a wireless tag communications system 100, capable of detecting the remaining battery level of the wireless tag 110 exactly at the center device (the tag reader 120 and a controlling device 130) side, can be realized. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wireless tag communication system, a wireless tag battery remaining amount estimation method, and a monitoring device.

  In recent years, communication systems using wireless tags have been widely used. As an example of a communication system using a wireless tag, there is a security system using a wireless sensor (corresponding to a wireless tag) that detects radio waves and transmits radio waves (for example, see Patent Document 1). In addition, there is a system for tracking and managing a product using a wireless tag attached to the product (see, for example, Patent Document 2). In addition to these examples, communication systems using wireless tags are widely used in, for example, electronic shelf label systems and person authentication systems.

  By the way, grasping the battery remaining amount of the wireless tag is very important in terms of security and management. For example, in a security system realized by a person attaching a wireless tag, (i) when the door unlocking of the room is linked to the ID of the wireless tag, the wireless tag is carried and the door unlocked to the room. When a person who has entered a room runs out of the battery of the wireless tag of the person before leaving the room, the person is locked without being unlocked. (Ii) Security combined with person detection by a sensor (such as a camera) other than the wireless tag In the case of the system, since the person authorized to enter the specified area should be detected by both the wireless tag and other sensors, if the battery of the wireless tag-attached person runs out halfway after entering, the sensor other than the wireless tag detects However, it is not detected by the wireless tag, and there is a problem that it is erroneously detected as a suspicious person who does not have the wireless tag attached.

  When the wireless tag runs out of battery or the remaining battery level is detected on the wireless tag side, (i) a new function for each wireless tag (such as a battery remaining amount detection circuit or a function for notifying the center device side of the detected remaining amount) ) Is necessary and the cost is high, (ii) even if the detection result is displayed on the wireless tag, if the person attached to the wireless tag does not notice that the battery level is low, the battery runs out, etc. Problem arises. In particular, in communication systems using wireless tags, an enormous number of wireless tags are often provided. Further, wireless tags are not necessarily used with a person attached. It is desirable to centrally manage on the center device side.

  For example, Patent Literature 3 and Patent Literature 4 disclose a technique for detecting the battery dead or the remaining battery level of the wireless tag on the center device side.

  In Patent Document 3, communication is performed between the wireless tag for security and the receiver (corresponding to the center device) when the door is opened and closed. If the receiver cannot receive the signal when the door is opened and closed, the security wireless tag is dead. Alternatively, a technique for determining a failure is disclosed.

Patent Document 4 discloses a technique in which a receiver detects a reception level of a radio wave transmitted from a transmitter and calculates a remaining battery level of the transmitter based on the reception level.
JP 2000-90381 A JP 2002-169879 A JP 2004-252790 A JP 2006-50398 A

  By the way, according to the technique disclosed in Patent Document 3, it can be detected on the center device side that the battery has run out, but it cannot be detected that the remaining battery level is low, which is insufficient.

  According to the technique disclosed in Patent Document 4, the battery level of the transmitter can be detected on the receiver side based on the reception level of the transmitter, but (i) the reception level is low because the battery level is low. This is insufficient because the user with the transmitter has to determine whether it is weak or (ii) the reception level is weak because the distance between the transmitter and the receiver is long.

  The present invention has been made in view of such points, and a wireless tag communication system and a wireless tag that can accurately detect the remaining battery level of the wireless tag on the center device side without adding a new configuration to the wireless tag. A battery remaining amount estimating method and a monitoring device are provided.

  One aspect of the wireless tag communication system of the present invention includes distance calculation means for calculating a distance between a wireless tag and a tag reader, and reception quality detection means for detecting reception quality of a signal from the wireless tag in the tag reader. And determining means for determining the remaining battery level of the wireless tag based on the distance and the reception quality.

  One aspect of the method of estimating the remaining battery level of a wireless tag according to the present invention is a distance calculating step for calculating a distance between the wireless tag and the tag reader, and detecting reception quality of a signal from the wireless tag in the tag reader. A reception quality detection step, and a determination step of determining a remaining battery level of the wireless tag based on the distance and the reception quality.

  According to the present invention, the battery level of the wireless tag can be accurately detected on the center device side without adding a new configuration to the wireless tag.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
[1] Overall Configuration FIG. 1 shows a configuration of a wireless tag communication system according to Embodiment 1 of the present invention. Although FIG. 1 shows only the main part for realizing the battery remaining amount estimation method of the present embodiment, the RFID tag communication system 100 actually has various configurations in addition to the configuration of FIG. It has a configuration for realizing the application.

  The wireless tag communication system 100 includes a wireless tag 110, a tag reader 120, and a monitoring device 130.

  In the case of the present embodiment, the wireless tag 110 is attached to a person. However, the method of using the wireless tag 110 is not limited to this. For example, the wireless tag 110 may be attached to an object such as a car, a cargo, a fixture, or an article. The tag reader 120 and the monitoring device 130 constitute a center device. In practice, the wireless tag communication system 100 is provided with a plurality of wireless tags 110. Further, the number of tag readers 120 is not limited to one, and a plurality of tag readers 120 may be provided.

  The wireless tag 110 includes a transmission / reception unit 111, a memory 112, and a battery 113. For example, an ID (identification information) assigned to each wireless tag 110 is stored in the memory 112. The battery 113 supplies power to each circuit in the wireless tag 110.

  The tag reader 120 includes a transmission / reception unit 121, a reception level detection unit 122, and a tag position calculation unit 123. The transmission / reception unit 121 transmits radio waves to the transmission / reception unit 111 of the wireless tag 110 and receives radio waves from the transmission / reception unit 111 of the wireless tag 110.

  The reception level detection unit 122 detects the reception level of the radio wave received by the transmission / reception unit 121. In addition, in the case of the present embodiment, reception level detection section 122 has a reception rank determination table, ranks the detected reception levels using this reception rank determination table, and outputs reception rank information S1. The rank classification of reception levels will be described in detail later.

  The tag position calculation unit 123 calculates the position of the wireless tag 110 based on the radio wave received by the transmission / reception unit 121. In practice, the tag position calculation unit 123 calculates the distance between the tag reader 120 and the wireless tag 110 based on the radio wave received by the transmission / reception unit 121, and determines the position of the wireless tag 110 from the calculated distance and the radio wave reception direction. calculate. The tag position calculation unit 123 outputs the calculated position information S2 of the wireless tag 110.

  In addition, since the battery remaining amount estimation method of the present invention essentially performs the remaining amount estimation using the distance between the tag reader 120 and the wireless tag 110, the distance between the tag reader 120 and the wireless tag 110 is used as the position information S2. It may be output. However, since the distance between the tag reader 120 and the wireless tag 110 is uniquely determined from the position of the wireless tag 110 because the position of the tag reader 120 is fixed, in the example of this embodiment, the distance from the tag position calculation unit 123 is determined. A description will be given assuming that the position information of the wireless tag 110 is output. Therefore, “position” in the following description may be read as “distance”.

  The monitoring device 130 includes a remaining battery level determination unit 131, a standard reception rank determination table 132, and a remaining battery level display unit 133.

  The remaining battery level determination unit 131 receives the reception rank information S1 from the reception level detection unit 122 and the position information S2 from the tag position calculation unit 123. The battery remaining capacity determination unit 131 reads standard reception rank information S3 corresponding to the input position information S2 from the standard reception rank determination table 132. Then, the remaining battery level determination unit 131 determines the remaining battery level of the battery 113 by comparing the reception rank information S1 and the standard reception rank information S3. The determination result S4 obtained by the remaining battery level determination unit 131 is sent to the remaining battery level display unit 133, and the remaining battery level of the battery 113 is displayed on the remaining battery level display unit 133. The user can recognize the remaining battery level of the wireless tag 110 based on the remaining battery level displayed on the remaining battery level display unit 133.

  In the present embodiment, the case where the reception level detection unit 122 and the tag position calculation unit 123 are provided in the tag reader 120 has been described, but the reception level detection unit 122 and the tag position calculation unit 123 may be provided in the monitoring device 130. Good. Moreover, although the case where the remaining battery level determination unit 131 and the standard reception rank determination table 132 are provided in the monitoring device has been described, the remaining battery level determination unit 131 and the standard reception rank determination table 132 may be provided in the tag reader 120.

  The present embodiment can also be applied to a case where the transmission / reception unit 111 of the wireless tag 110 spontaneously transmits radio waves and the transmission / reception unit 121 of the tag reader 120 has a function of only receiving radio waves of the wireless tag 110. That is, the wireless tag 110 may be either a semi-passive tag type or an active tag type.

[2] Operation and Detailed Configuration [2-1] Overall Operation First, an overview of the overall operation of the wireless tag communication system 100 will be described with reference to FIG.

  When the wireless tag communication system 100 starts the battery remaining amount estimation process in step ST10, the wireless tag communication system 100 transmits radio waves from the transmission / reception unit 121 of the tag reader 120 to the wireless tag 110 in step ST11. Next, in step ST12, the transmission / reception unit 121 of the tag reader 120 receives a response radio wave from the wireless tag 110. Next, in step ST13, the tag position calculation unit 123 calculates the position of the wireless tag 110 from the relationship between the transmission radio wave and the response radio wave. Next, in step ST14, the reception level detection unit 122 calculates the reception rank of the response radio wave. Of course, the processing of step ST13 and step ST14 may be performed in parallel or in the reverse order. Next, in step ST15, the remaining battery level calculation unit 131 calculates the remaining battery level from the standard reception rank of the tag position and the reception rank of the response radio wave. Next, in step ST16, the remaining battery level display unit 133 displays the calculated remaining battery level. Next, the wireless tag communication system 100 ends the battery remaining amount estimation process in step ST17.

  2 shows a case where the wireless tag 110 is a semi-passive tag (transmits radio waves in response to radio waves from the tag reader 120). However, when the wireless tag 110 is an active tag, the tag reader 120 Step ST11 for transmitting radio waves from the transmission / reception unit 121 to the wireless tag 110 becomes unnecessary, and in step ST12, the transmission / reception unit 121 of the tag reader 120 receives the radio waves spontaneously transmitted from the wireless tag 110. In step ST13, the tag position calculation unit 123 calculates the tag position based on the radio wave (for example, radio wave intensity) received from the wireless tag 110. The above processing in the case where an active tag is used as the wireless tag 110 can be similarly implemented in the following embodiments and other embodiments, but is omitted in the following description.

[2-2] Processing of Tag Position Calculation Unit 123 FIG. 3 shows a processing flow of the tag position calculation unit 123. When the tag position calculation process starts in step ST20, the tag position calculation unit 123 acquires the transmission radio wave transmission time, the response radio wave reception time, and the response radio wave reception direction from the transmission / reception unit 121 in step ST21. For example, when the transmission / reception unit 121 has a plurality of antennas, the reception direction can be obtained based on a reception time difference between the plurality of antennas. Next, in step ST22, a time difference between the transmission radio wave transmission time and the response radio wave reception time is calculated. Next, in step ST23, the distance between the wireless tag 110 and the tag reader 120 is calculated from the time difference. Next, in step ST24, the position of the wireless tag 110 is calculated from the reception direction and distance. Next, the tag position calculation unit 123 ends the tag position calculation process in step ST25.

[2-3] Processing of Reception Level Detection Unit 122 FIG. 4 shows a processing flow of the reception level detection unit 122. The reception level detection part 122 will acquire a received radio wave from the transmission / reception part 121 by step ST31, if a reception level detection process is started by step ST30. Next, at step ST32, the reception level of the received radio wave is detected. In the present embodiment, RSSI (Received Signal Strength Indicator) is acquired as the reception level. Next, in step ST33, the reception rank is determined from the reception level and the reception rank determination table. Next, the reception level detection part 122 complete | finishes a reception level calculation process by step ST34.

  FIG. 5 shows an example of a reception rank determination table provided in the reception level detection unit 122. When the reception rank determination table of FIG. 5 is used, a reception rank having a larger value is output as the detected RSSI value is larger.

[2-4] Processing of Battery Remaining Determination Unit 131 FIG. When the battery remaining capacity determining unit 131 starts the battery remaining capacity determining process in step ST40, the battery remaining capacity determining unit 131 acquires the position of the wireless tag 110 from the tag position calculating unit 123 in step ST41. Next, in step ST42, using the standard reception rank determination table 132, the standard reception rank corresponding to the position of the wireless tag 110 is acquired.

  FIG. 7 shows an example of the standard reception rank determination table 132. The standard reception rank determination table 132 stores standard reception ranks according to the distance between the wireless tag 110 and the tag reader 120 (which may be referred to as the position of the wireless tag 110 as described above). The standard reception rank determination table 132 outputs a standard reception rank having a larger value as the calculated distance is smaller. The standard reception rank indicates a standard size of the reception level (reception quality) corresponding to the distance when the remaining battery level is sufficient. In other words, the standard reception rank indicates a standard reception rank that takes into account the distance.

  In step ST43, the remaining battery level determination unit 131 acquires the reception rank of the received radio wave from the reception level detection unit 122. Next, in step ST44, the reception rank is compared with the standard reception rank. In the case of the present embodiment, it is determined in step ST44 whether or not the reception rank is “standard reception rank / 2” or less. When the reception rank is “standard reception rank / 2” or less (step ST44; Yes), the process proceeds to step ST45, where it is determined that the remaining battery level is low. On the other hand, if the reception rank is greater than “standard reception rank / 2” (step ST44; No), the process proceeds to step ST46 and it is determined that the remaining battery level is high. The battery remaining capacity determining unit 131 ends the battery remaining capacity determining process in step ST47.

  In the present embodiment, it is determined whether or not the reception rank is “standard reception rank / 2” or less. However, the present invention is not limited to this. For example, it is determined whether the battery level is low or high by determining whether the reception rank is “standard reception rank / 3” or less, or whether it is “standard reception rank-1” or less. May be. In short, it is only necessary to determine the remaining battery level using the reception rank and the standard reception rank, but to adjust the sensitivity related to the determination / notification of the remaining battery level by making this determination criterion changeable as a set value. Is also possible. For example, by changing the standard of “standard reception rank / 2” to the standard of “standard reception rank / 3”, it is possible to set to notify the remaining battery level when the remaining battery level is lower. If the standard set as the initial value is too strict (in the case where the remaining battery level is actually sufficient but it is determined that the remaining battery level is low), this standard may be changed later. The same applies to other embodiments described later.

[2-5] Display on Battery Level Display Unit 133 FIGS. 8 and 9 show examples of battery level display in the battery level display unit 133. FIG. The display by the battery remaining amount display unit 133 may be performed using a display such as a personal computer used as the monitoring device 130, but it is also possible to use a dedicated display (this is another embodiment described later). The same applies to the above).

  As shown in FIG. 8, if the tag ID, the tag holder name, and the detected detection time when the remaining battery level is low are displayed, the administrator can replace the battery quickly and accurately. . That is, the administrator can specify the wireless tag whose battery should be replaced based on the displayed tag ID and tag holder name, and can notify the tag holder that the battery should be replaced. Further, since it can be predicted that the remaining battery level is lower as the detection time is in the past, it is possible to determine the wireless tag whose battery should be replaced with priority from the detection time.

  In addition, when a user holding a wireless tag is designated, a point indicating a tag reader is displayed at the center of a concentric circle as shown in FIG. 9, and when the remaining amount of battery of the wireless tag held by the designated user is large According to the remaining amount, a color is provided up to a circle away from the center (FIG. 9A), and when the remaining battery level is low, only a circle close to the center is colored according to the color (FIG. 9B). It is possible to determine at a glance how far the tag can be transmitted and received from the tag reader.

  Also, as shown in FIG. 9C, the user holding the wireless tag is displayed on the plane map, and a point indicating the position of the user is displayed. Color up to a circle away from the center, and if the battery level is low, only the circle near the center is colored according to the battery level, so where is the user holding the tag with the low battery level? You can judge at a glance.

[2-6] Effects According to the present embodiment, the tag position calculation unit 123 that calculates the distance between the wireless tag 110 and the tag reader 120 and the reception level detection unit 122 that detects the reception level of the signal from the wireless tag 110. And a remaining battery level determination unit 131 that determines the remaining battery level of the wireless tag based on the distance and the reception level, without adding a new configuration to the wireless tag 110. The wireless tag communication system 100 that can accurately detect the remaining battery level of the wireless tag 110 on the device (tag reader 120 and management device 130) side can be realized.

  In addition, a preset standard reception level corresponding to the distance from the tag reader 120 to the wireless tag 110 is stored, and the standard reception level taking this distance into account and the reception level detection unit 122 detect it. By comparing the remaining battery level with the actual reception level, it is possible to accurately detect the remaining battery level regardless of the distance from the tag reader 120 to the wireless tag 110 by determining the remaining battery level.

  In the present embodiment, the reception level detection unit 122 is provided and the reception level such as the RSSI value is used as an indicator of the remaining battery level. However, the present invention is not limited to this, and the reception level is an indicator of the remaining battery level. Can be widely used. For example, instead of the reception level detection unit 122, reception for detecting reception quality indicators such as RSSI, WEI (Word Error Indicator), BEI (Bit Error Indicator), BER (Bit Error Rate), or SNR (Signal to Noise Ratio). Quality detection means may be provided. The reception quality detecting means may determine the reception quality comprehensively based on a plurality of reception quality indexes. The same applies to other embodiments described later.

  In the present embodiment, the reception level and the standard reception level are ranked by the reception level detection unit 122 and the standard reception rank determination table 132, and the reception level and the standard reception level ranked by the battery remaining amount determination unit 131 are compared. However, the remaining battery level may be determined using the actual value without ranking. However, when ranking is performed as in the present embodiment, the determination becomes easier, and if the ranking result is displayed, the administrator has a relationship between the reception level and the standard reception level than when displaying the actual value. Can be easily grasped. For example, even if the determination by the remaining battery level determination unit 131 is not performed, the administrator can estimate the remaining battery level to some extent from only the ranking result of the reception level and the standard reception level.

(Embodiment 2)
FIG. 10 in which the same reference numerals are assigned to the parts corresponding to those in FIG. 1 shows the configuration of the wireless tag communication system of the present embodiment. The wireless tag communication system 200 has the same configuration as the wireless tag communication system 100 in FIG. 1 except that the wireless tag communication system 200 includes a camera 210 and the monitoring device 130 includes a position detection unit 134.

  The camera 210 shoots a person who is attached to the wireless tag 110 by the shooting unit 211, and sends an image obtained thereby to the person position calculation unit 212. The person position calculation unit 212 calculates the position of the person attached to the wireless tag 110 from the input video. Here, the person position calculation unit 212 may calculate the position after specifying the person corresponding to the ID of the wireless tag 110 using a method such as face recognition, for example. Similarly, when the wireless tag is attached to an object such as a car, cargo, furniture, or article, similarly, the ID of the wireless tag 110 can be obtained by recognizing and identifying the feature information of the object and the character information written on the surface. The corresponding object may be specified. The person position calculation unit 212 calculates the position of the person detected by image recognition without performing the person identification, the person position calculated by the person position calculation unit 212, and the wireless position calculated by the tag position detection unit 123. Based on the mutual relationship with the position of the tag 110 (distance and time at which the position is detected), the wireless tag 110 and the person may be associated with each other by the position detection unit 134 described later. The same association may be performed when the wireless tag is attached to the object.

  The monitoring device 130 includes, in the position detection unit 134, position information S2 of the wireless tag 110 obtained by the tag position calculation unit 123, and position information S5 of a person attached to the wireless tag 110 obtained by the person position calculation unit 212. Enter. The position detection unit 134 obtains position information S6 obtained by integrating the position information S2 and the position information S5, and sends the position information S6 to the battery remaining amount determination unit 131. The position detection unit 134 obtains the integrated position information S6 by, for example, averaging the position information S2 and the position information S5.

  FIG. 11 shows an outline of the overall operation of the wireless tag communication system 200. In FIG. 11, processes corresponding to those in FIG. 2 are denoted by the same reference numerals, and description of the processes denoted by the same reference numerals is omitted. When the wireless tag communication system 200 starts the battery remaining amount estimation process in step ST50, the process proceeds to step ST51 after the processes of steps ST11 to ST14 described above. In step ST51, the person position calculation unit 212 calculates the position of the person photographed by the photographing unit 211. Next, in step ST52, the position detection unit 134 integrates the position of the person and the position of the wireless tag 110. Next, in step ST53, the remaining battery level is calculated by the remaining battery level determination unit 131 from the standard reception rank of the integrated position and the reception rank of the response radio wave. Next, in step ST54, the remaining battery level display unit 133 displays the calculated remaining battery level. Next, the wireless tag communication system 200 ends the battery remaining amount estimation process in step ST55.

  FIG. 12 shows a processing flow of the person position calculation unit 212. When the person position calculation unit 212 starts the person position calculation process in step ST60, the person position calculation unit 212 acquires the video imaged from the imaging unit 211 in step ST61. Next, in step ST62, it is determined whether or not the target person (person with the wireless tag 110) appears in the acquired video. If it is determined that the person has moved (step ST62; Yes), Moving to step ST63, the position of the person is calculated from the position of the detected person on the video. The person position calculation unit 212 moves to step ST64 after the process of step ST63 or when it is determined in step ST62 that no person is shown (step ST62; No), and ends the person position calculation process.

  FIG. 13 shows a processing flow of the position detection unit 134. When the position detection process starts in step ST70, the position detection unit 134 acquires the position of the wireless tag 110 from the tag position calculation unit 123 in step ST71. In step ST72, the position detection unit 134 acquires the wireless tag 110 from the person position calculation unit 212. Get the position of an accompanying person. Next, in step ST73, the average value of the position of the wireless tag 110 and the position of the person is calculated as an integrated position, and the position detection process is ended in step ST74.

  FIG. 14 shows a processing flow of the remaining battery level determination unit 131 of the present embodiment. When the battery remaining capacity determining unit 131 starts the battery remaining capacity determining process in step ST80, the battery remaining capacity determining unit 131 acquires the integrated position from the position detecting unit 134 in step ST81. Next, in step ST82, the standard reception rank corresponding to the integrated position is acquired using the standard reception rank determination table 132. Next, in step ST83, the reception rank of the received radio wave is acquired from the reception level detection unit 122. Next, in step ST84, the reception rank is compared with the standard reception rank. In the case of the present embodiment, it is determined in step ST84 whether or not the reception rank is “standard reception rank / 2” or less. If the reception rank is “standard reception rank / 2” or less (step ST84; Yes), the process proceeds to step ST85, where it is determined that the remaining battery level is low. On the other hand, when the reception rank is greater than “standard reception rank / 2” (step ST84; No), the process proceeds to step ST86, where it is determined that the remaining battery level is high. In step ST87, the remaining battery level determination unit 131 ends the remaining battery level determination process.

  According to the present embodiment, the position information S2 of the wireless tag 110 acquired by the tag position calculation unit 123 and the position information S5 of the person attached with the wireless tag 110 acquired by the person position calculation unit 212 are integrated. By determining the remaining battery level using S6, the battery remaining level is more reliable than when determining the remaining battery level using only the position information S2 of the wireless tag 110 acquired by the tag position calculation unit 123. Since the remaining battery level can be determined using the position information S5, the detection accuracy of the remaining battery level can be improved. In addition, when the remaining battery level of the wireless tag 110 rapidly decreases and radio wave transmission / reception becomes impossible, the position information S2 cannot be obtained by the tag position calculation unit 123, but the position information S5 by the person position calculation unit 212 can be obtained. It is possible to acquire the position of a person using only this, and detect that the battery of the wireless tag 110 associated with the person is depleted.

  In the present embodiment, an image including the person with the wireless tag 110 obtained by the photographing unit 211 is sent to the battery remaining amount display unit 133. Then, the battery remaining amount display unit 133 uses the determination result S4 by the battery remaining amount determination unit 131 and the video including the person, for example, as shown in FIG. An image surrounded by a frame and a name corresponding to the wireless tag are displayed. In this way, the administrator can easily recognize a person attached with a wireless tag with a low battery level from the display image of the battery level display unit 133 and where the person is. Can be easily recognized from surrounding images.

(Embodiment 3)
FIG. 16, in which parts corresponding to those in FIG. 10 are assigned the same reference numerals, shows the configuration of the wireless tag communication system of this embodiment. In the wireless tag communication system 300, the camera 210 is provided with a surrounding state detection unit 213. The monitoring device 130 is provided with a non-detection area information storage unit 135.

  The surrounding state detection unit 213 receives the image from the photographing unit 211 and the position from the person position calculation unit 212, and detects the surrounding state of the person attached with the wireless tag 110. Specifically, the surrounding state detection unit 213 detects radio wave reflectors and radio wave shields present around the wireless tag 110 by image recognition processing from video, and uses this as surrounding state information S10 to determine the remaining battery level. To the unit 131.

  A radio tag (not shown) is attached to a radio wave reflector or radio wave shield, and the radio wave of the radio wave reflector / shield is calculated by the tag position calculation unit 123 of the tag reader 120 based on radio waves received from these radio tags. It is also possible to configure the surrounding state detection unit 213 to detect a radio wave reflector and a radio wave shield present around the wireless tag 110 attached to a person from the tag position.

  In the non-detection area information storage unit 135, information on the position of the wireless tag 110 that is not capable of wireless communication between the wireless tag 110 and the tag reader 120 is stored as non-detection area information S11. Based on the position information S6 and the non-detection area information S11 input from the position detection unit 134, the remaining battery level determination unit 131 determines whether or not the detected position is a non-detection area. And when it is judged that it is a non-detection area, a battery remaining charge determination process is stopped. Thereby, the remaining battery level determination unit 131 can avoid erroneously determining that the remaining battery level is low although the remaining battery level is high. That is, when the wireless tag 110 is located in the non-detection area, even if the remaining battery level is large, the reception level detection unit 122 outputs a reception rank with a small value. There is a risk of erroneously determining that the remaining battery level is low. In the configuration of the present embodiment, such erroneous determination can be effectively avoided.

  FIG. 17 shows a processing flow of the surrounding situation detection unit 213. When the peripheral state detection unit 213 starts the peripheral state detection process in step ST90, the peripheral state detection unit 213 acquires the image captured by the photographing unit 211 in step ST91, and the person position calculated by the person position calculation unit 212 in step ST92. To get. Next, in step ST93, it is determined whether there is a radio wave reflector around the person. If it is determined that there is a radio wave reflector around the person (step ST93; Yes), the process moves to step ST94-1, adds the reflector information to the surrounding situation information S10, and then proceeds to step ST95. On the other hand, when it is determined that there is no radio wave reflector around the person (step ST93; No), the process proceeds to step ST94-2, and “no reflector” is added to the surrounding situation information S10, and then the process goes to step ST95. move on. In step ST95, it is determined whether or not there is an obstacle between the person and the tag reader 120. If it is determined that there is an obstacle between the person and the tag reader 120 (step ST95; Yes), the process proceeds to step ST96-1 to add the obstacle information to the surrounding situation information S10. On the other hand, when it is determined that there is no shielding object (step ST95; No), the process proceeds to step ST96-2 and “no shielding” is added to the surrounding situation information S10. The peripheral condition detection unit 213 detects the incidental position of the wireless tag 110 in step ST97 after the process of step ST96-1 or step ST96-2, and if it can detect the situation (the incidental position is the chest, the incidental position is Is overhead) or the like is added to the surrounding situation information S10. The surrounding state detection unit 213 moves to step ST98 after the process of step ST97, and ends the surrounding state detection process.

  FIG. 18 shows an example of the surrounding situation information S10. As shown in the figure, the surrounding situation information S10 may be configured by information such as the presence / absence of a reflecting object and a shielding object, the type and size, and the incidental situation of the tag.

  FIG. 19 shows a processing flow of the remaining battery level determination unit 131 of the present embodiment. When the remaining battery level determination unit 131 starts the remaining battery level determination process in step ST100, the battery remaining level determination unit 131 acquires the integrated position from the position detection unit 134 in step ST101. Next, in step ST102, based on the acquired position and the non-detection area information, it is determined whether or not the acquired position (corresponding position) corresponds to a non-detection area. If it is determined in step ST102 that the corresponding position is a non-detection area (step ST102; Yes), the battery remaining amount determination process is terminated without moving to step ST110 without determining the remaining battery amount.

  FIG. 20 shows an example of the non-detection area information S11. In the example in the figure, the non-detection area is indicated by rectangular coordinates with the tag reader 120 as the origin. The method of setting the non-detection area is not limited to the coordinate setting as shown in FIG. 20, for example, using the GUI (Graphical User Interface), for example, the entire area monitored by the camera 210 or the tag reader 120 on the screen of the monitoring device 130. May be displayed and the area of the non-detection area may be designated with a mouse or the like.

  On the other hand, if it is determined in step ST102 that the corresponding position is not a non-detection area (step ST102; No), the process proceeds to step ST103. In step ST103, using the standard reception rank determination table 132, the standard reception rank corresponding to the integrated position is acquired. Next, in step ST104, the reception rank of the received radio wave is acquired from the reception level detection unit 122. Next, in step ST105, the surrounding state information S10 is acquired from the surrounding state detection unit 213. Next, in step ST106, a weighting factor corresponding to the surrounding situation is acquired using the surrounding situation information S10 and the reception rank weighting table, and the receiving rank information S1 is weighted using this weighting coefficient.

  FIG. 21 shows an example of a reception rank weighting table provided in the battery remaining amount determination unit 131. As can be seen from the figure, a larger weighting factor is set in the reception rank weighting table as an object existing around the wireless tag 110 has a higher degree of hindering communication between the wireless tag 110 and the tag reader 120. ing. Thus, by multiplying the reception rank by the weighting coefficient of FIG. 21, it is possible to obtain a reception rank (weighted reception rank) obtained by correcting the fluctuation of the reception level (reception quality) that has fluctuated on the propagation path.

  When a plurality of situations are detected, a weighting factor corresponding to each situation is multiplied. For example, when three situations of “reflecting object (other)”, “shielding object (middle)”, and “tag position (head)” are detected, the weighting coefficient corresponding to each situation is multiplied. 1.1 × 1.2 × 0.9, and the reception rank is multiplied by 1.188.

  Next, in step ST107, the weighted reception rank is compared with the standard reception rank. In the case of the present embodiment, it is determined in step ST107 whether or not the weighted reception rank is “standard reception rank / 2” or less. When the weighted reception rank is “standard reception rank / 2” or less (step ST107; Yes), the process proceeds to step ST108, where it is determined that the remaining battery level is low. On the other hand, when the weighted reception rank is larger than “standard reception rank / 2” (step ST107; No), the process proceeds to step ST109, where it is determined that the remaining battery level is high. In step ST110, the remaining battery level determination unit 131 ends the remaining battery level determination process.

  As described above, according to the present embodiment, the camera 210 detects the surrounding situation of the wireless tag 110, and compares the reception rank weighted according to the surrounding situation with the standard reception rank, so By calculating the amount, the remaining battery level can be calculated based on the reception rank (weighted reception rank) obtained by correcting the variation of the reception level (reception quality) that varies depending on the surrounding situation. The remaining battery level can be detected without being affected by the surrounding conditions.

  Further, since the non-detection area information storage unit 135 is provided and the wireless tag 110 is located in a non-detection area where communication with the tag reader 120 cannot be performed, the battery remaining amount determination is not performed. Although the amount is large, it is possible to avoid erroneously determining that the remaining battery level is low.

  Note that the non-detection area stored in the non-detection area information storage unit 135 is not necessarily an area where communication between the wireless tag 110 and the tag reader 120 is impossible, and communication between the wireless tag 110 and the tag reader 120 is based on a predetermined threshold. If it is a bad area.

(Embodiment 4)
FIG. 22, in which the same reference numerals are assigned to the parts corresponding to those in FIG. 1, shows the configuration of the wireless tag communication system of the present embodiment. The wireless tag communication system 400 is provided with a history information storage unit 136 instead of the standard reception rank determination table 132 as compared with the wireless tag communication system 100 of FIG.

  In the history information storage unit 136, the position information S2 and the reception rank information S1 are written as history information via the battery remaining amount determination unit 131.

  FIG. 25 shows an example of history information written in the history information storage unit 136. As can be seen from FIG. 25, the position information S2 and the reception rank information S1 are written in association with the ID of the wireless tag 110. The remaining battery level determination unit 131 reads the history of the reception rank information S1 written in the history information storage unit 136 as necessary, and uses it for determining the remaining battery level.

  FIG. 23 shows a processing flow of the remaining battery level determination unit 131 of the present embodiment. When the remaining battery charge determination unit 131 starts the remaining battery charge determination process in step ST120, the remaining battery charge determination unit 131 acquires the position of the wireless tag 110 from the tag position calculation unit 123 in step ST121. Next, in step ST122, the reception rank of the received radio wave is acquired from the reception level detection unit 122.

  Next, in step ST123, it is determined whether or not there is a history of the same area in the information stored in the history information storage unit 136. For example, a case where an area (distance range) with a distance of 2 [m] from the tag reader 120 is set will be described. In the example of FIG. 25, an area having a “position” of 4.0 [m] to 6.0 [m] and an area of 6.0 [m] to 8.0 [m] are divided. If the ID of the wireless tag detected this time is “001” and the distance (position) is 5.2 [m], from FIG. It can be seen that there are three histories: a history of reception rank 4, a history of reception rank 5 at position 5.5 [m], and a history of reception rank 4 at position 5.9 [m]. In such a case, an affirmative result is obtained in step ST123, the process proceeds to step ST126, and the largest reception rank in the history is selected and set as the history reception rank. In the above-described example, the highest reception rank in the own history of the same area is the reception rank 5, so this is set as the history reception rank.

  Next, in step ST127, the current (current) reception rank is compared with the history reception rank. In the case of the present embodiment, in step ST127, it is determined whether or not the current reception rank is “history reception rank / 2” or less. If the current reception rank is “history reception rank / 2” or less (step ST127; Yes), the process proceeds to step ST128, where it is determined that the remaining battery level is low. On the other hand, if the current reception rank is greater than “history reception rank / 2” (step ST127; No), the process proceeds to step ST129, and the history information storage unit 136 stores the own ID, distance (position), and current reception. The rank is stored, and it is determined in the subsequent step ST130 that the remaining battery level is high. In step ST131, the remaining battery level determining unit 131 ends the remaining battery level determining process.

  If it is determined in step ST123 that the information stored in the history information storage unit 136 does not have its own history in the same area (step ST123; No), the process proceeds to step ST124 to store history information. The own ID, distance (position), and current reception rank are stored in the unit 136, and it is determined in step ST125 that the remaining battery level is high.

  As described above, according to the present embodiment, the history information storage unit 136 that stores the history of the distance between the wireless tag 110 and the tag reader 120 and the reception level is provided. By determining the remaining battery level by comparing the level and the reception level in the same area (distance range) as the currently calculated distance among the reception levels stored in the history information storage unit 136, The same effect as in the first embodiment can be obtained.

  In addition, the reception level stored in the history information storage unit 136 includes the peripheral conditions and communication characteristics of the wireless tag 110 and the tag reader 120. In this embodiment, the battery level is based on this reception level. Since the remaining amount is determined, the remaining battery level is compared with the case where the remaining battery level is determined based on the specified value output from the standard reception rank determination table 132 (FIG. 1) as in the first embodiment. It is expected that the remaining battery level can be determined with higher accuracy in consideration of the characteristics of the wireless tag held by the amount determination target and the characteristics of the position.

  In the processing example of FIG. 23, when the own history of the same area is used as a reference for determining the remaining battery level, that is, the history information of the wireless tag other than the own ID is not used as the reference for determining the remaining battery level. As described above, history information of a wireless tag other than its own ID may also be used as a reference for determining the remaining battery level.

  FIG. 24, in which parts corresponding to those in FIG. 23 are assigned the same reference numerals, shows a processing flow of the battery remaining capacity determination unit 131 when history information of wireless tags other than the self ID is also used as a reference for battery remaining capacity determination. . The processing flow in FIG. 24 differs from the processing flow in FIG. 23 only in the processing in step ST141. In step ST <b> 141, the remaining battery level determination unit 131 determines whether there is a history of the same area in the information stored in the history information storage unit 136. If there is a history of the same area, even if the history is a history of a wireless tag other than the own wireless tag, an affirmative result is obtained in step ST141, and the process proceeds to step ST126.

  As a result, data other than the self-radio tag is also used, so that it is possible to expect the battery remaining amount determination with high accuracy in consideration of the position characteristics obtained based on a large number of data.

(Embodiment 5)
FIG. 26, in which parts corresponding to those in FIGS. 1 and 22 are assigned the same reference numerals, shows the configuration of the wireless tag communication system of this embodiment. The wireless tag communication system 500 includes a standard reception rank determination table 132 and a history information storage unit 136.

  The outline of the processing according to the present embodiment will be described with reference to FIG. In the present embodiment, as shown by the dotted lines in FIG. 27A, a plurality of areas (distance ranges) are set by dividing the distance from the tag reader 120 at predetermined intervals. For example, an area having an interval of 2 [m] is set. In the example of FIG. 27A, when the wireless tag 110 is located at the positioning points 1, 2, and 3, it can be said that the wireless tag 110 is located in the same area. And in this Embodiment, as shown to FIG. 27B, when the wireless tag 110 moves to the positioning points 1-4 sequentially, when it is located in the same area continuously, a receiving rank is averaged. . In the example of FIG. 27B, when the wireless tag 110 is located at the positioning points 1, 2, 3, it can be said that the wireless tag 110 is continuously located in the same area. , 3 are sequentially averaged for the reception ranks 4, 5, and 4 obtained. On the other hand, when the wireless tag 110 moves to a different area such as the positioning point 4, the average reception rank is reset.

  FIG. 28 shows a processing flow when the remaining battery level determination unit 131 determines the remaining battery level using such an average reception rank. When the remaining battery level determination unit 131 starts the remaining battery level determination process in step ST150, the remaining battery level determination unit 131 acquires the position of the wireless tag 110 from the tag position calculation unit 123 in step ST151. Next, in step ST152, using the standard reception rank determination table 132, a standard reception rank corresponding to the position of the wireless tag 110 is acquired. Next, in step ST153, the reception rank of the received radio wave is acquired from the reception level detection unit 122.

  Next, in step ST154, with reference to the history information storage unit 136, it is determined whether there is a positioning point history of the same area with continuous time in relation to the current detection result. If an affirmative result is obtained in step ST154, the process proceeds to step ST155, and the current reception rank is added to the overall reception rank (the addition of the reception rank in the positioning point history of the same area where time has continued), and then step ST156. Proceed to On the other hand, if a negative result is obtained in step ST154, since the total reception rank is only the current reception rank, the process proceeds to step ST156. In step ST156, an average reception rank is calculated from the total reception rank.

  Next, in step ST157, the average reception rank is compared with the standard reception rank. In the case of the present embodiment, it is determined in step ST157 whether or not the average reception rank is “standard reception rank / 2” or less. If the average reception rank is “standard reception rank / 2” or less (step ST157; Yes), the process proceeds to step ST158, where it is determined that the remaining battery level is low. On the other hand, when the average reception rank is larger than “standard reception rank / 2” (step ST157; No), the process proceeds to step ST159 and it is determined that the remaining battery level is high. In step ST160, the remaining battery level determining unit 131 ends the remaining battery level determining process.

  As described above, according to the present embodiment, the history information storage unit 136 that stores the history of the distance between the wireless tag 110 and the tag reader 120 and the reception level is provided, and the standard reception rank is determined by the remaining battery level determination unit 131. In addition to the effect of the first embodiment, the reception level detection unit 122 detects a low reception rank by chance by comparing the average reception rank in the same area with the average reception rank. Can be avoided. That is, even if the remaining battery level is sufficient, even if a low reception rank is detected by the reception level detection unit 122 for some reason, the remaining battery level determination unit 131 determines the average reception rank within the same area. Since the remaining battery level is determined using, it is not necessary to erroneously determine that the remaining battery level is low.

  In FIGS. 27 and 28, the case where the remaining battery level is determined using the average reception rank in the same area has been described. However, even if the remaining battery level is determined using the average reception rank within a certain period, the same applies. The effect of can be obtained.

  A process for determining the remaining battery level using the average reception rank within a certain period will be described with reference to FIGS. 29 and 30.

  FIG. 29 shows an average reception rank obtained by averaging reception ranks for 5 seconds as an example.

  FIG. 30 shows a processing flow when the remaining battery level determination unit 131 determines the remaining battery level using such an average reception rank. In FIG. 30, processes corresponding to those in FIG. 28 are denoted by the same reference numerals, and description of the processes denoted by the same reference numerals is omitted. In step ST171, the remaining battery level determination unit 131 refers to the history information storage unit 136 and determines whether there is a measurement point history within a certain period in relation to the current detection result. If an affirmative result is obtained in step ST171, the process proceeds to step ST172 to calculate the total reception rank by adding all the reception ranks of the history within a certain period, and then proceeds to step ST173. On the other hand, if a negative result is obtained in step ST171, only the current reception rank is set as the overall reception rank, and the process proceeds to step ST173. In step ST173, an average reception rank is calculated from the total reception rank.

  In each of the processing units other than the transmission / reception unit 121 in the tag reader 120 and the processing units other than the imaging unit 211 in the camera 210 in the first to fifth embodiments described above, the CPU reads out the computer program stored in the memory. This can be realized by executing processing. Alternatively, it may be realized by operating / processing an IC chip / LSI chip. The transmission / reception unit 121 of the tag reader 120 includes an LSI that performs communication control with a transmission / reception antenna, the imaging unit 211 of the camera 210 includes a lens and an image sensor (CCD, CMOS, etc.), and the person position calculation unit 212 performs stereo positioning. When performing the above, a configuration capable of stereo shooting (one image sensor for a plurality of lenses, a plurality of lens / image sensor pairs, etc.) is provided. Also, use a compound eye convex mirror as shown in “Kojima et al.“ Distance Measurement Using Hierarchical Compound Eye Omnidirectional Image for Approaching Object Detection ”, Image Recognition and Understanding Symposium (MIRU 2006), July 2006”. It may be realized by an omnidirectional stereo camera or the like.

  The monitoring device 130 includes a computer main body such as a personal computer including a memory / CPU and an input / output device (mouse, keyboard, display, etc.). The functions of the remaining battery level determination unit 131 and the position detection unit 134 can be realized by the CPU reading and executing the computer program stored in the memory. The standard reception rank determination table 132 is realized by a file or database stored in a memory or HDD. The non-detection area information storage unit 135 and the history information storage unit 136 are realized by a storage medium such as a memory / HDD. The battery remaining amount display unit 133 is realized by a display that displays display data. Needless to say, the monitoring device 130 can also be realized by a dedicated device other than a general-purpose computer such as a personal computer.

  In the first to fifth embodiments described above, the monitoring system has been described as an example. However, the present invention is an application that detects the position of a person or the like using a wireless tag, for example, a work analysis of a factory worker It is apparent that the present invention can be applied to a system, an article management system in physical distribution, and the like to detect the battery remaining amount of the wireless tag.

  INDUSTRIAL APPLICABILITY The present invention has an effect of accurately detecting the remaining battery level of a wireless tag on the center device side without adding a new configuration to the wireless tag, and is widely effective for a wireless tag communication system using a wireless tag. .

The block diagram which shows the structure of the radio | wireless tag communication system which concerns on Embodiment 1 of this invention. Flowchart showing an outline of the overall operation of the wireless tag communication system according to the first embodiment. The flowchart which shows the process in a tag position calculation part Flow chart showing processing in reception level detection unit The figure which shows the example of a reception rank judgment table The flowchart which shows the process in a battery remaining charge determination part The figure which shows the example of a standard reception rank judgment table Figure showing a display example of the remaining battery level Figure showing a display example of the remaining battery level FIG. 3 is a block diagram illustrating a configuration of a wireless tag communication system according to a second embodiment. The flowchart which shows the outline | summary of the whole operation | movement of the radio | wireless tag communication system of Embodiment 2. FIG. The flowchart which shows the process in a person position calculation part Flow chart showing processing in the position detection unit The flowchart which shows the process in a battery remaining charge determination part The figure which shows the example of a display in a battery remaining charge display part FIG. 9 is a block diagram illustrating a configuration of a wireless tag communication system according to a third embodiment. The flowchart which shows the process in a periphery condition detection part The figure which shows the example of surrounding situation information The flowchart which shows the process in a battery remaining charge determination part The figure which shows the example of non-detection area information The figure which shows the example of a receiving rank weighting table FIG. 9 is a block diagram illustrating a configuration of a wireless tag communication system according to a fourth embodiment. The flowchart which shows the process in a battery remaining charge determination part The flowchart which shows the process in a battery remaining charge determination part Figure showing an example of history information FIG. 9 is a block diagram illustrating a configuration of a wireless tag communication system according to a fifth embodiment. FIG. 27A is a diagram for explaining the area average, FIG. 27A is a diagram showing the position (positioning point) of the wireless tag, and FIG. 27B is a diagram showing an example of the area average. The flowchart which shows the process in a battery remaining charge determination part Diagram showing an example of area averaging The flowchart which shows the process in a battery remaining charge determination part

100, 200, 300, 400, 500 RFID tag communication system 110 RFID tag 113 battery 120 tag reader 122 reception level detection unit 123 tag position calculation unit 130 monitoring device 131 remaining battery level determination unit 132 standard reception rank determination table 133 remaining battery level display Unit 134 position detection unit 135 non-detection area information storage unit 136 history information storage unit 210 camera 211 photographing unit 212 person position calculation unit 213 peripheral condition detection unit S1 reception rank information S2, S5, S6 position information S3 standard reception rank information S4 determination Result S10 Surrounding situation information S11 Non-detection area information

Claims (13)

Distance calculating means for calculating the distance between the wireless tag and the tag reader;
Reception quality detection means for detecting the reception quality of the signal from the wireless tag in the tag reader;
Determination means for determining a battery remaining amount of the wireless tag based on the distance and the reception quality;
A wireless tag communication system comprising: The determination means includes
The remaining battery level is determined by comparing a preset standard reception quality corresponding to the distance between the tag reader and the wireless tag with an actual reception quality detected by the reception quality detection means. ,
The wireless tag communication system according to claim 1. The distance calculating means calculates the distance using a response time of the wireless tag.
The wireless tag communication system according to claim 1. The distance calculation means calculates the distance using an image captured by a camera.
The wireless tag communication system according to claim 1. The camera further comprises a camera for detecting a surrounding situation of the wireless tag,
The determination unit determines a remaining battery level of the wireless tag based on the reception quality weighted according to the surrounding situation and the distance.
The wireless tag communication system according to claim 1. Non-detection area information storage means for storing information on a non-detection area that is an area where the communication quality between the wireless tag and the tag reader is worse than a predetermined threshold,
The determination means does not determine the remaining battery level when the wireless tag is located in the non-detection area.
The wireless tag communication system according to claim 1. Further comprising history information storage means for storing the history of the distance and the reception quality,
The determination unit compares the current reception quality with the reception quality in the same distance range as the currently calculated distance among the reception qualities stored in the history information storage unit. Determine
The wireless tag communication system according to claim 1. The history information storage means stores the distance and the history of the reception quality in association with the ID of each wireless tag,
The determination unit compares the reception quality at the current time with the reception quality of the same ID in the same distance range as the currently calculated distance among the reception qualities stored in the history information storage unit. Determine battery level,
The wireless tag communication system according to claim 7. Further comprising history information storage means for storing the history of the distance and the reception quality,
The determination unit compares a standard reception quality set in advance corresponding to the distance between the tag reader and the wireless tag with an average value of the reception quality within the same distance range stored in the history information storage unit. To determine the remaining battery level,
The wireless tag communication system according to claim 1. Further comprising history information storage means for storing the history of the distance and the reception quality,
The determination unit compares a standard reception quality set in advance corresponding to the distance between the tag reader and the wireless tag with an average value of the reception quality stored in the history information storage unit within a predetermined period. The battery remaining amount is determined by
The wireless tag communication system according to claim 1. A distance calculating step for calculating a distance between the wireless tag and the tag reader;
A reception quality detection step of detecting a reception quality of a signal from the wireless tag in the tag reader;
A determination step of determining a remaining battery level of the wireless tag based on the distance and the reception quality;
A method for estimating the remaining battery level of a wireless tag including: Based on the information on the distance between the wireless tag and the tag reader and the information on the reception quality of the signal from the wireless tag in the tag reader, the wireless communication is based on the information on the distance and the information on the reception quality. Determining means for determining the remaining battery level of the tag,
Monitoring device. On the computer,
Calculating or inputting information on the distance between the wireless tag and the tag reader;
Detecting or inputting information relating to reception quality of a signal from the wireless tag in the tag reader;
Based on the information on the distance and the information on the reception quality, determining a battery remaining amount of the wireless tag;
A program that executes

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