JP2008017947A - Sleeping posture monitoring system and spacial position measuring system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that an actigraph cannot detect posture of a sleeping subject. <P>SOLUTION: A sleeping posture monitoring system for monitoring posture of a sleeping subject is provided. The sleeping posture monitoring system comprises RFID tags 102 which are arranged at joint positions of the subjects and send identification IDs when power is supplied, a plurality of antenna sections 101 which supply power to the RFID tags 102 at a predetermined measuring time and receive the identification IDs from the RFID tags 102, an electromagnetic field intensity measuring part 103 which measures a received electromagnetic intensity in the antenna sections 101 that has received the identification IDs, and a joint position calculating section 109 which calculates the spacial positions of the joints using the received identification IDs, positions of the antenna section 101 that has received the identification IDs and strength of electromagnetic fields measured by the antenna and detects the sleeping posture or changes in postures of the subject on the basis of the calculated spacial positions of the joints. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sleep posture monitoring system that monitors a posture of a subject during sleep and changes thereof by measuring a spatial position of the joint of the subject. The spatial position measurement method in the sleep posture monitoring system of the present invention can be applied to a general spatial position measurement system.

  Due to changes in lifestyle and increased stress, sleep disorders are rapidly increasing regardless of gender. Poor sleep and sleep disorders are known to cause mood and mood when waking up, and to reduce motivation and depression in the elderly, and to reduce social activities. In the youth of the development period, it is one of the social problems that causes a decline in learning function due to memory and concentration problems, a decline in emotional control function, a decline in exercise ability, and irregular lifestyle habits.

  In order to evaluate sleep disorder improvement measures and treatment methods, examination methods that qualitatively and quantitatively capture sleep are essential, and physiological indices such as heart rate variability, brain waves, and body temperature have been used in the past. All-night sleep polygraph examination evaluates biological phenomena using a combination of electroencephalogram, eye movement, gluteus electromyogram, respiratory movement, electrocardiogram, anterior tibial electromyogram, pulse wave, blood oxygen saturation, video monitoring, etc. However, because the quality of sleep is greatly influenced by the environment, it may not be possible to grasp a disease image by a single day test, and a test over several days may be required. Moreover, in the present situation that 20% to 30% of the population is experiencing sleep disorders, there is a limit to deal with limited medical resources. Therefore, an inspection method that can be easily performed at home is desired.

On the other hand, a measuring instrument called actigraph has been devised. An actigraph is a device that detects three-dimensional acceleration, and can be attached to a wrist or the like like a wristwatch, and can detect the activity state of a subject from the acceleration generated on the wrist due to the movement of the hand or the movement of the entire body. (See Patent Document 1). The acceleration is automatically measured, for example, every 3 minutes. FIG. 10 is a graph showing an example of a subject's movement during sleep and awakening measured using an actigraph. In the figure, the horizontal axis represents time, and the vertical axis represents the magnitude of the measured three-dimensional acceleration. As shown in the graph, no significant movement is observed during sleep, and frequent large movement is observed during arousal. In the figure, it can be seen that, for example, the subject sleeps from about 22:00 to about 6:30 and is awake after 6:30. Thus, according to the actigraph, the sleep / wake state of the subject can be measured relatively easily. Also, according to Actigraph, depending on whether the subject's body is moving or not moving, the sleep latency (time from lying down to sleep), the sleep efficiency of the subject (lie down) The ratio of sleep time to time) and awakening episodes (number of awakenings during sleep) can be examined. Furthermore, in this case, it is detected that the subject moves slightly at regular time intervals during sleep. In addition to the actigraph, there is a position sensor, and by wrapping it around the trunk, it can be determined whether the position is the supine position, the lateral position or the prone position.
International Publication No. 00/26841 Pamphlet

  However, recently, the posture of sleep has been cited as one of the causes of sleep disorders. If the posture of sleep can be easily evaluated, it may be possible to develop a new sleep therapy. In this regard, since the actigraph is expensive, it is usually used with only one wound around one arm. For this reason, even if the presence or absence of the subject's movement can be detected, the posture of the subject during sleep cannot be detected. Further, since the position sensor is used by being wound around the trunk, there is a problem that it is impossible to detect movements of limbs and complicated postures.

  The objective of this invention is providing the sleep posture monitoring system which can detect the change of the attitude | position of a test subject and a posture during sleep, and solves the said subject easily. The second object of the present invention is to provide a spatial position measurement system to which the spatial position measurement method in the sleep posture monitor system is applied.

  In order to solve the above problems, the sleep posture monitor system of the present invention is a sleep posture monitor system that monitors the posture of the subject during sleep, and is identified by being placed at the joint position of the subject and being supplied with power. An RFID tag that transmits an ID, a plurality of antennas that are arranged at a plurality of predetermined positions, supply power to the RFID tag, receive an identification ID from the RFID tag, and an antenna that receives the identification ID Distance measuring means for measuring the distance from the RFID tag that transmitted the identification ID to the RFID tag, the received identification ID, the position of the antenna that received the identification ID, and the distance between the antenna and the RFID tag , The joint position calculating means for calculating the spatial position of the joint, and the subject based on the calculated spatial position of the joint Characterized in that it comprises a position detection means for detecting a change in the attitude or posture during sleep.

  The distance measuring unit includes an electromagnetic field strength measuring unit that measures an electromagnetic field strength at the antenna that has received the identification ID, and the distance measuring unit converts the measured electromagnetic field strength into a distance, and The position calculation means may calculate, as the joint spatial position, a spatial position where the condition that the RFID tag exists at a position away from the antenna position by the converted distance is satisfied for each antenna.

  Further, the electromagnetic field strength measurement unit may measure the electromagnetic field strength of the identification ID from the RFID tag received by the antenna.

  The antenna generates an electromagnetic wave by gradually changing the intensity of the generated electromagnetic wave from a strong side to a weak side or from a weak side to a strong side, and the electromagnetic field strength measurement unit is configured to identify the RFID tag from the RFID tag. The strength of the electromagnetic wave in the antenna when the ID becomes unreceivable or receivable is measured as the electromagnetic field strength, and the joint position calculation means is based on the electromagnetic field strength measured by at least three antennas for one RFID tag. The spatial position of the joint corresponding to the identification ID may be calculated.

  Furthermore, the plurality of antennas are arranged in a matrix on the floor on which the subject lies, and the sleep posture monitoring system further repeats the plurality of antennas in a row direction and a column at predetermined measurement times. An antenna switching means for sequentially switching and driving in the directions may be provided.

  Further, the antenna switching means sequentially drives in the row direction and the column direction in units of an antenna group composed of a plurality of antennas, and if there is an antenna group that has received the identification ID among the driven antenna groups, A group of a smaller number of antennas included in the antenna group may be driven by sequentially switching in the row direction and the column direction.

  Further, the antenna switching means sequentially drives the antenna for each predetermined number of rows and columns, and if there is an antenna that has received the identification ID among the driven antennas, the antenna switching means The antennas positioned at may be switched and driven in a predetermined order.

  Furthermore, the sleep posture monitoring system further includes storage means for storing in advance a distance from a predetermined joint of each subject to the joint, and the joint position calculating means is configured to store the joint position from the joint stored in advance. The spatial position of each joint may be corrected using the distance to the joint.

  The present invention can be realized not only as a sleep posture monitor system and a sleep posture monitor device, but also as a method that uses processing means constituting the system and device as steps, or as a program that causes a computer to execute these steps. Or a recording medium such as a computer-readable CD-ROM in which the program is recorded, or information, data, or a signal indicating the program. These programs, information, data, and signals may be distributed via a communication network such as the Internet.

  According to the present invention, in the sleep posture monitoring system, the RFID tag is arranged from the identification ID transmitted from the RFID tag, the position of the antenna that received the identification ID, and the distance between the antenna and the RFID tag. The spatial position of the joint can be calculated, and based on the calculated spatial position of the joint, the posture of the subject during sleep or a change in the posture can be detected. Thereby, the sleep posture monitoring system can reduce the burden on both the subject and the doctor for measuring the posture of the subject during sleep and the change in posture. In addition, doctors and other people involved in the treatment and research of sleep disorders use the measurement results of the sleep posture monitoring system to analyze the posture and changes in posture of the subject during sleep, There is an effect that the influence on the sleep by the environment can be easily evaluated.

  In addition, since the antennas are arranged in a matrix, the joint position calculation unit can easily calculate the coordinates of each antenna, so that the processing load on the joint position calculation unit can be reduced. In addition, the antenna switching means repeats every predetermined measurement time, and sequentially drives the plurality of antennas in the row direction and the column direction so that the posture during sleep can be detected at each measurement time. By comparing postures during sleep at successive measurement times, a change in posture of the subject during sleep can be detected.

  Further, the antenna switching means sequentially drives in the row direction and the column direction in units of an antenna group composed of a plurality of antennas, and if there is an antenna group that has received the identification ID, a smaller number of antennas included in the antenna group These groups are sequentially switched in the row direction and the column direction for driving. Accordingly, the identification ID reception range can be roughly specified in a large unit called the antenna group, and the identification ID reception range can be narrowed down to a smaller range within the antenna group from which the identification ID is received. There is an effect that the antenna can be driven more efficiently.

  Further, the antenna switching means sequentially drives the antennas for every predetermined number, and if there is an antenna that has received the identification ID, drives the antenna located in the vicinity thereof. Thus, there is an effect that the antenna can be driven more efficiently.

  Further, according to the sleep posture monitoring system of the present invention, the distance from the joint of the subject to the joint is stored in advance, and the spatial position of each joint is corrected using the distance stored in advance. There is an effect that a more accurate sleep posture can be monitored by absorbing individual differences in body type.

  Hereinafter, a sleep posture monitoring system 100 according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a sleep posture monitoring system 100 according to an embodiment of the present invention.

  The sleep posture monitoring system 100 is a system that monitors the posture of a subject during sleep by specifying the spatial position of an RFID tag arranged at each joint position of the subject, and includes an antenna unit 101, an RFID tag 102, and a printer 112. The monitor 113 and the sleep posture monitor device 120 are provided. The sleep posture monitoring device 120 is a device that monitors a posture of a subject during sleep by driving a measurement unit including an antenna unit 101 and an RFID tag 102 and processing a measurement result obtained from the measurement unit. An intensity measuring unit 103, an antenna switching unit 104, a control unit 105, a time measuring unit 106, a received data writing unit 107, a joint position accumulating unit 108, a joint position calculating unit 109, a graph creating unit 110, and an image generating unit 111 are provided.

  The antenna unit 101 corresponds to “a plurality of antennas which are arranged at a plurality of predetermined positions and supply power to the RFID tag and receive an identification ID from the RFID tag” in the claims. The antenna unit 101 supplies power to the RFID tag 102 wirelessly and receives an identification ID from the RFID tag 102. The RFID tag 102 refers to the “RFID tag that is placed at the joint position of the subject and transmits an identification ID when power is supplied” and “the RFID tag 102 is placed on the target object and supplied with power” This corresponds to an “RFID tag that transmits an identification ID”. When power is supplied from the antenna unit 101, the RFID tag 102 transmits an identification ID stored therein in advance. The electromagnetic field intensity measuring unit 103 is the “distance measuring means for measuring the distance from the antenna that has received the identification ID to the RFID tag that has transmitted the identification ID” in the claims, and “at the antenna that has received the identification ID” This corresponds to an “electromagnetic field strength measuring unit that measures the electromagnetic field strength” and “the electromagnetic field strength measuring unit that measures the electromagnetic field strength of the identification ID from the RFID tag received by the antenna”. The electromagnetic field strength measuring unit 103 measures the received electromagnetic field strength for each identification ID received by the antenna unit 101 under the control of the control unit 105. Further, the electromagnetic field strength measuring unit 103 outputs the electromagnetic field strength measured for each identification ID and the coordinates of the antenna unit 101 to the reception data writing unit 107 together with the current time acquired via the control unit 105. The antenna switching unit 104 switches and drives the antenna units 101 arranged in a matrix in order in a row direction and a column direction at regular time intervals. The control unit 105 stores the measurement time at which the joint position should be measured in advance in a table or the like. The control unit 105 refers to the time measuring unit 106 and drives the electromagnetic field intensity measuring unit 103 and the antenna switching unit 104 when the current time is a measurement time for measuring the joint position. The timer 106 measures the current time. The antenna switching unit 104, the control unit 105, and the time measuring unit 106 are referred to in the claims as "an antenna switching unit that repeatedly drives each of the plurality of antennas in the row direction and the column direction and drives them at predetermined measurement times" It corresponds to. When the current time, the electromagnetic field strength, and the coordinates of the antenna unit 101 are input by the electromagnetic field strength measuring unit 103, the reception data writing unit 107 receives the identification ID received by the antenna unit 101 and data such as the current time and the electromagnetic field strength. The information is stored in the joint position storage unit 108 in association with each other.

  The joint position calculation unit 109 calculates the spatial position of the joint from the received identification ID, the position of the antenna that has received the identification ID, and the distance between the antenna and the RFID tag. "Joint position calculating means", "posture detecting means for detecting the posture of the subject during sleep or a change in posture based on the calculated spatial position of the joint", and "converting the measured electromagnetic field strength into distance" The joint position calculating means for calculating, as the joint spatial position, the spatial position where the condition that the RFID tag exists at a position away from the antenna position by the converted distance is satisfied for each antenna. ”,“ The condition that the RFID tag is present at a position away from the antenna position by the converted distance is about each antenna. The spatial position measuring means for calculating the spatial position to be calculated as the spatial position of the object ”and“ the received identification ID, the position of the antenna that has received the identification ID, and between the antenna and the RFID tag ” It corresponds to “spatial position measuring means for measuring the spatial position of the object from the distance”. The joint position calculation unit 109 scans the antenna unit 101 for each measurement time from the measurement time for each identification ID accumulated in the joint position accumulation unit 108, the coordinates of the antenna unit 101, and the electromagnetic field strength. Calculate the spatial position of each joint in minutes. Specifically, the joint position calculation unit 109 stores in advance the relationship between the received electromagnetic field strength of the identification ID and the distance between the antenna and the RFID tag, and receives the identification ID received by the antenna unit 101. From the electromagnetic field strength and the coordinates of the antenna unit 101, three-dimensional position coordinates representing the spatial position of the joint specified by the received identification ID are calculated by triangulation or the like. By performing this calculation for all identification IDs, the spatial position of each joint is calculated. Based on the calculation result by the joint position calculation unit 109, the graph creation unit 110 generates, for example, a graph showing a temporal change in the joint spatial position for each joint. Based on the calculation result by the joint position calculation unit 109, the image generation unit 111 generates, for example, an image of a sleeping figure for each measurement time of the subject generated by computer graphics. The printer 112 prints the graph generated by the graph creation unit 110 and the image generated by the image generation unit 111. The monitor 113 displays the graph generated by the graph creation unit 110 and the image generated by the image generation unit 111. Here, it has been described that the printer 112 prints the graph created by the graph creation unit 110 and the monitor 113 displays the image created by the image generation unit 111, but the present invention is not limited to this. Since both the printer 112 and the monitor 113 are external devices of the sleep posture monitoring device 120, one or both of the graph generated by the graph generating unit 110 and the image generated by the image generating unit 111 are printed and displayed. It is also good.

  In FIG. 1, the electromagnetic field strength measuring unit 103, the antenna switching unit 104, the control unit 105, the time measuring unit 106, the received data writing unit 107, the joint position accumulating unit 108, the joint position calculating unit 109, the graph creating unit 110, and the image generation Although the unit 111 is the sleep posture monitoring device 120, the present invention is not limited to this. For example, the sleep posture monitoring device 120 with the electromagnetic field intensity measuring unit 103, the antenna switching unit 104, the control unit 105, the time measuring unit 106, the reception data writing unit 107, and the joint position accumulation unit 108 as a controller connected to the antenna unit 101 The sleep posture monitor device 120 may be provided with a joint position calculation unit 109, a graph creation unit 110, an image generation unit 111, and the like. In this case, the joint position accumulating unit 108 is a recording medium such as a memory card or an IC memory, the received data writing unit 107 is a writing drive for the recording medium, and the recording / reading drive for the recording medium is also added to the sleep posture monitoring device 120. It is preferable to provide. By doing so, the subject can take the RFID tag 102, the antenna unit 101, the controller, and the recording medium home and measure the joint position during sleep at home. Therefore, the joint position during sleep can be measured without being constrained by a facility such as a hospital for many days at night. Then, by storing the measured joint positions in a recording medium and bringing the recording medium to a facility equipped with a sleep posture monitoring device 120 such as a hospital, appropriate advice and treatment can be obtained from a doctor or the like. There is an effect.

  FIG. 2 is an external view showing an example of a usage pattern of the sleep posture monitor system 100. Here, the RFID tag 102 is attached to the pajamas, for example, by being sewed on the subject's pajamas or bonded with Velcro or a double-sided adhesive tape. The RFID tag 102 is attached to the front and back surfaces of each joint such as a subject's shoulder, elbow, wrist, hip joint, knee, and ankle. In addition, here, the RFID tag 102 is installed not only on the joint parts as described above but also on trunks such as the front and back of the left and right chests, sides, and flank. Furthermore, as shown in the figure, by placing the RFID tag 102 on the head using a belt or the like, the posture of the subject can be specified more accurately. Each antenna unit 101 has a size of about 5 cm square, for example, and is arranged in a matrix on the back surface of the sheet 201 on which the subject is lying. A signal line connecting the antenna unit 101 and the sleep posture monitoring device 120 is collected at one end of the sheet 201, for example.

  FIG. 3 is a diagram illustrating an example of the arrangement of the antenna unit 101 provided in the sheet 201. As shown in the figure, the antenna units 101 are arranged in a matrix. The antenna unit 101 arranged in this manner is switched in the order of (1, 1), (1, 2), (1, 3), (1, 4),. Driven. In this way, when all the antenna units 101 in the first row are driven, the antenna units 101 in the second row are (2, 1), (2, 2), (2, 3), (2, 4). ,... Similarly, the third row, the fourth row, and so on are sequentially switched to the last row, and all the antenna units 101 are switched and driven.

  Note that, here, each antenna unit 101 is described as being installed in a tile shape without a gap, but the present invention is not limited to this, and the antenna units 101 may be installed at regular intervals in the row direction and the column direction. Although an example in which the antenna units 101 are sequentially switched and driven one by one is shown here, the present invention is not limited to this method. Another example of the method for driving the antenna unit 101 will be described below.

  FIG. 4 is a diagram illustrating an example of a method for driving the antenna unit 101 for efficiently receiving the identification ID from the RFID tag 102. FIG. 4A illustrates an example in which the antenna group 401 including 3 × 3 antenna units 101 is sequentially switched and driven, and the identification ID from the RFID tag 102 is received by the entire driven antenna group 401. FIG. In the figure, the hatched portion indicates the antenna group 401 that has received the identification ID. In this case, the antenna switching unit 104 sequentially drives in the row direction and the column direction in units of an antenna group including a plurality of antennas, and among the driven antenna groups, the antenna belonging to the antenna group If one of the antennas receives the identification ID, it corresponds to “antenna switching means for sequentially switching and driving a group of a smaller number of antennas included in the antenna group in the row direction and the column direction”. The arrows in the figure indicate the direction in which the antenna group 401 is scanned, and indicate that the antenna group 401 is sequentially switched and driven in the row direction. Specifically, the antenna group 401 includes an antenna group 401 in which the (1, 1) antenna unit 101 is located in the upper left, and an antenna group 401 in which the (1, 4) antenna unit 101 is located in the upper left. The antenna unit 101 of 7) is switched and driven in the order of the antenna group 401 located at the upper left. When all the antenna groups 401 are driven in the row direction in this way, the antenna unit 101 of (4, 1) is located at the upper left, and the antenna unit 101 of (4, 4) is located at the upper left. The antenna group 401 in the next row is sequentially driven like the antenna group 401 in which the antenna unit 101 of the antenna group 401 and (4, 7) is located in the upper left. At this time, when any identification ID is received by the driven antenna group 401, the antenna switching unit 104 identifies and stores the antenna group 401. After all the antenna groups 401 are driven, the stored antenna group 401 is scanned with a smaller number of antenna units 101 as a unit.

  FIG. 4B shows the antenna group 401 having received the identification ID among the antenna groups 401 shown in FIG. 4A, and drives the inside by switching one antenna unit 101 as a unit. It is a figure which shows an example which receives ID. The arrow in the figure indicates the direction in which the antenna unit 101 is scanned. Here, the antenna unit 101 is driven by sequentially switching the inside of the antenna group 401 that has received the identification ID in the row direction. When the driven antenna unit 101 receives the identification ID, the antenna unit 101 outputs the received identification ID to the reception data writing unit 107. At this time, the received electromagnetic field strength in the antenna unit 101 is measured by the electromagnetic field strength measuring unit 103 for each received identification ID. In this manner, when the three antenna units 101 in the row are driven, three in the next row are sequentially driven. When all of the antenna units 101 arranged in 3 rows and 3 columns in the antenna group 401 are driven, the antenna unit 101 in the next antenna group 401 stored in the antenna switching unit 104 is driven in the same manner. Is done. In this way, the entire antenna unit 101 is scanned in units of the antenna group 401, and then the identification group is received more efficiently by scanning in detail only for the antenna group 401 that has received the identification ID. There is an effect that can be done.

  FIG. 5 is a diagram illustrating another example of the driving method of the antenna unit 101 for efficiently receiving the identification ID from the RFID tag 102. FIG. 4 shows an example in which the antenna group 401 including the plurality of antenna units 101 is set as one unit, and the antenna group 401 is sequentially switched and driven in the row direction to receive the identification ID. However, the present invention is not limited to this, and as shown in FIG. 5, the individual antenna units 101 may be driven while being switched. The antenna switching unit 104 drives the antenna sequentially for each predetermined number in the row direction and the column direction in the claim, and if there is an antenna that has received the identification ID among the driven antennas, This corresponds to the “antenna switching means for switching and driving the antennas located around the antenna in a predetermined order”. Here, the driving antenna unit 501 that is the driven antenna unit 101 is switched every other antenna unit 101 in the row direction, for example, (1, 1), (1, 3),. Driven. At this time, when an identification ID is received by a certain drive antenna unit 501, the antenna switching unit 104 specifies and stores the antenna unit 101 that is the current drive antenna unit 501 that has received the identification ID, and stores the drive antenna. The unit 501 is switched to the next antenna unit 101. When all the antenna units 101 in the first row have been driven, the antenna switching unit 104 divides one row as shown in (3, 1), (3, 3),. Scan by 101 is performed. When all the antenna units 101 have been driven in this way, the antenna switching unit 104 switches between the antenna unit 101 stored at the time of the previous scan and the antenna unit 101 adjacent to the antenna unit 101. Switch and drive sequentially. For example, when the identification ID is received by the antenna unit 101 of (3, 3), the antenna switching unit 104 first drives the antenna unit 101 of (3, 3) to receive the identification ID, and the identification ID Is stored in the joint position storage unit 108, the received identification ID, the coordinates of the antenna unit 101 that is the drive antenna unit 501, and the electromagnetic field strength. Next, the antenna switching unit 104 moves the antenna unit 101 adjacent to the (3, 3) antenna unit 101 to (2, 2), (2, 3), (2, 4), (3, 4), (4 4), (4, 3), (4, 2), (3, 2) are switched and driven in this order, and if there is an antenna unit 101 that has received the identification ID, the current time at which the identification ID is received is received. The identification ID, the coordinates of the antenna unit 101 that is the drive antenna unit 501, and the electromagnetic field strength are stored in the joint position storage unit 108. Thus, there is an effect that when there is an antenna that has received the identification ID by scanning the antenna unit 101, the identification ID can be efficiently received by examining the peripheral portion in detail.

  In FIG. 5, it is described that the antenna units 101 are switched and driven one by one. However, even when the antenna units 101 are driven in a jumping manner, it is not necessary to drive one by one. As described with reference to FIG. Alternatively, the antenna group 401 including the antenna units 101 may be switched so as to be driven in units. In FIG. 5, every other antenna unit 101 is driven, but the present invention is not limited to this. For example, the center portion of the sheet 201 is scanned densely, It may be determined to drive at different intervals and densities depending on the location, such as driving only about three places of the part. Further, in general, based on an average joint position such as sex, age, etc., the driving antenna unit 501 is configured so that a highly-established region where the joint position of the subject exists is scanned intensively and with high density. Patterns such as arrangement and switching order may be determined in advance.

  FIG. 6 is a flowchart showing an operation at the time of joint position measurement of the sleep posture monitoring system 100 of the present embodiment. When the sleep posture monitoring system 100 is turned on, the control unit 105 first refers to the time measuring unit 106 to determine whether or not the current time is a measurement time at which the joint position should be measured (S601). If the current time is not the measurement time at which the joint position is to be measured, the control unit 105 waits until the measurement time is reached. The control unit 105 drives the electromagnetic field strength measurement unit 103 and the antenna switching unit 104 if the current time is a measurement time at which the joint position should be measured. The antenna switching unit 104 switches and drives the antenna unit 101 (S602), and the driven antenna unit 101 supplies power to the RFID tag 102 (S603). The electromagnetic field strength measurement unit 103 measures the electromagnetic field strength at the driven antenna unit 101. At this time, when the electromagnetic field strength of a certain level or more is measured, the electromagnetic field strength measuring unit 103 determines that the identification ID has been received. When the identification ID is received by the driven antenna unit 101 (S604), the electromagnetic field strength measurement unit 103 measures the electromagnetic field strength for each identification ID. The electromagnetic field strength measuring unit 103 outputs the measured electromagnetic field strength, the current time acquired via the control unit 105 and the coordinates of the driven antenna unit 101 to the reception data writing unit 107. For each identification ID received by the antenna unit 101, the reception data writing unit 107 stores the electromagnetic field strength input from the electromagnetic field strength measurement unit 103, the current time, and the coordinates of the antenna unit 101 in association with each other in the joint position storage unit 108. (S605). The antenna switching unit 104 determines whether all the antenna units 101 have been driven (S606). If all the antenna units 101 have not been driven yet, the antenna switching unit 104 switches to the next antenna unit 101 to drive (S602). If all the antenna units 101 have been driven, the process waits until the next measurement time (step S601). As described above, the joint position of the subject who is sleeping can be measured at each predetermined measurement time.

  FIG. 7 shows the operation of the sleep posture monitor system 100 when displaying an image showing the sleep posture at each measurement time of the subject on the monitor 113 based on the data regarding each joint position accumulated in the joint position accumulation unit 108. It is a flowchart. The joint position calculation unit 109 reads from the joint position storage unit 108 a data set including an identification ID, an electromagnetic field strength, and coordinates of the antenna unit 101 corresponding to a time within a certain range from a predetermined measurement time (S701). . The joint position calculation unit 109 sorts the read data sets by the identification ID, and further receives one or more antenna units that received the identification ID based on the electromagnetic field strength measured for the same identification ID in the same time zone and the electromagnetic field strength. From the coordinates of 101, the spatial position of the joint specified by the identification ID is calculated. Specifically, the calculation of the spatial position of the joint refers to the relationship between the electromagnetic field strength stored in advance and the distance between the tag and the antenna. By performing this process for all identification IDs, the joint position calculation unit 109 calculates the spatial positions represented by the three-dimensional coordinates of all the joints of the subject in the same time zone with a certain measurement time as a reference (S702). ). Based on the three-dimensional coordinates of each joint calculated by the joint position calculation unit 109, the image generation unit 111 generates image data indicating the sleep posture of the subject at a certain measurement time by computer graphics or the like (S703). The monitor 113 displays an image represented by the generated image data (S704). The sleep posture monitoring system 100 can sequentially display the CG images of the subject's sleep posture at each measurement time by repeating the processing from step S701 to step S704.

  FIG. 8 is a flowchart showing the procedure of the method of driving the antenna unit 101 for efficiently receiving the identification ID shown in FIGS. 4 (a) and 4 (b). The antenna switching unit 104 switches and drives the antenna group 401 in units of the antenna group 401 including the 3 × 3 antenna units 101, and receives the identification ID from the RFID tag 102 throughout the driven antenna group 401. (S801). When any identification ID is received by the driven antenna group 401 (S802), the antenna switching unit 104 identifies and stores the antenna group 401 (S803). Then, it is determined whether or not all the antenna groups 401 have been driven (S804). If all the antenna groups 401 have not been driven yet, the antenna group 401 is switched to the next antenna group 401 and driven. The entire antenna group 401 receives the identification ID (S801).

  If all the antenna groups 401 have been driven (S804), the antenna switching unit 104 moves the inside of the stored antenna groups 401 one by one as shown in FIG. The antenna unit 101 is switched and driven as a unit, and the identification unit ID is received by the driven antenna unit 101 (S805). In this case, the switching order of the antenna unit 101 is, for example, switched by driving the antenna unit 101 in the row direction one by one inside the one antenna group 401 stored in the antenna switching unit 104. When all the antenna units 101 in the middle are driven, the antenna units 101 in the next row are sequentially switched and driven in the row direction. When all the antenna units 101 in one antenna group 401 are driven, the antenna switching unit 104 performs the antenna units 101 one by one in the same manner in the stored next antenna group 401. Switch to the direction and drive.

  When the antenna unit 101 switched and driven in this order receives the identification ID (S806), the antenna unit 101 outputs the received identification ID to the reception data writing unit 107. At this time, the received electromagnetic field strength in the antenna unit 101 is measured by the electromagnetic field strength measuring unit 103 for each received identification ID. From the electromagnetic field strength measuring unit 103, the current time and the coordinates of the antenna unit 101 are input to the received data writing unit 107 in addition to the measured electromagnetic field strength. The reception data writing unit 107 stores the input current time, identification ID, electromagnetic field strength, and coordinates of the antenna unit 101 in association with each other in the joint position storage unit 108 (S807). When the driven antenna unit 101 has not received the identification ID (S806), the antenna switching unit 104 switches the driving antenna unit 501 to the next antenna unit 101 (S805). The driven antenna unit 101 receives the identification ID.

  The antenna switching unit 104 determines whether or not all the antenna units 101 in all the stored antenna groups 401 have been driven (S808). If all the antenna units 101 have been driven, the process is terminated. To do. If all the antenna units 101 are not yet driven, the antenna switching unit 104 switches the drive antenna unit 501 to the next antenna unit 101 to drive, and receives the identification ID (S805).

  FIG. 9 is a diagram illustrating an example of a CG image representing the sleep posture of the subject displayed based on the spatial position of each joint calculated by the joint position calculation unit 109. This figure shows, for example, a list of subjects' sleep postures displayed as thumbnails on the monitor 113. Each image displayed as a thumbnail is, for example, an image created from the joint position of the subject measured every 30 minutes. Here, the joint position calculation unit 109 says in the claims “the posture detection means for detecting the time from when the identification IDs of all RFID tags are received until all the joints come to rest as sleep latencies” It corresponds to. In the figure, the 22:00 image shows the subject sleeping sideways with the right side down. Next, the image at 22:30 shows the subject turning over and turning up. In the 23:00 image, the test subject is sleeping right up and continues the same posture until 00:30. On the other hand, the joint position calculation unit 109 starts the measurement at 22:00 and receives the identification IDs of all RFID tags, that is, starts the measurement and measures the positions of all joints. The time from when the change is made until the change in all joint positions becomes small enough to be regarded as still is calculated as the sleep onset latency. However, it is a condition that, after resting, for example, a resting state of at least 3 minutes continues. Accordingly, the subject is determined to have fallen asleep at 23:00. Therefore, if the subject starts measuring on the floor at 22:00, the sleep latency is calculated as 1 hour. Further, the joint position calculating unit 109 refers to the subject based on “the joint position calculating means for calculating the spatial position of the shoulders at each measurement time and the change in the spatial position of both feet at each measurement time” Corresponds to the above-mentioned posture detecting means for detecting the movement of the foot. At 01:00, the subject is moving the position of the right foot compared to the image at 00:30, and sleep can be seen shallowly and the feet are being stripped. In this case, based on the identification IDs of the RFID tags 102 arranged at the joints of both feet, the joint position calculation unit 109 has each of the foot joints from the coordinate position at 00:30 to the coordinate position at 01:00. The movement distance is calculated, and if the calculated movement distance is, for example, 3 cm or more, it is determined that there is a movement of the foot. In this case, the joint position calculation unit 109 may cause the image generation unit 111 to display, for example, “There is a foot movement” on the image indicating the 01:00 posture. Thereafter, the subject continues the same posture from 00:30 to 02:30, and is determined to be asleep. Furthermore, at 03:00, it is shown that the subject is placing his right hand on the waist, and the possibility of itching on the waist is estimated. Also, after that, the images at 03:30 and 04:00 show the subject lying down and sleeping sideways with the left body side down, from 04:30 to 05. ： The figure of sleeping up to 30 is shown.

  Thus, by analyzing the change in the joint position (sleep posture) of the subject at each measurement time, the sleep posture monitor system 100 simply displays the posture during sleep or displays a graph indicating the position change of each joint. In addition, the joint position calculation unit 109 can measure the number of times of turning over, the number of toilets, the movement of limbs, the sleep latency, the awakening episode (number of times awakened), the sleep efficiency, and the like. In this case, the joint position calculation unit 109 is based on “the joint position calculation means for calculating the spatial position of the shoulders at each measurement time and the change in the spatial position of the shoulders at each measurement time”. Corresponds to “the posture detecting means for detecting the number of times of turning during sleep”. The joint position calculation unit 109 checks the change in the spatial position of both shoulders at each measurement time, and counts as one turn when the line connecting both shoulders rotates, for example, 90 ° or more. In this case, the number of times the subject turns over is two. Further, the joint position calculation unit 109 states that the subject wakes up when detecting that the spatial position of any joint has changed after a predetermined time has elapsed since all the joints are stationary. It is determined that the subject has fallen asleep when all joints are stationary again, and corresponds to the posture detecting means for detecting the number of times the subject has awakened. There are two awakening episodes: 01:00 and 03:00. Further, the joint position calculation unit 109 refers to the claim that “the time when all the joints are stationary is set as the sleep time of the subject, and the time when the identification IDs of all the RFID tags are received is laid down by the subject. It corresponds to “the posture detection means for detecting the sleep efficiency of the subject” from Equation 1. The sleep efficiency of this test subject is 68.75% from the following formula because the total sleeping time is 5 hours 30 minutes and the total lying time (referred to as “bedtime”) is 8 hours. Is calculated.

(Sleep efficiency) = ((total sleep time) / (total bedtime)) × 100
= 5.5 ÷ 8 × 100
= 68.75

  The joint position calculation unit 109 determines that the subject has reached the toilet when the identification ID is not received by any antenna, and then the subject returns from the toilet when the identification ID is received by any antenna. The number of times the subject has gone to the toilet after going to bed is detected by counting the number of times the subject has returned from the toilet. Also in this case, the image generation unit 111 may synthesize the 5:30 image and display “the number of toilets: ○” or the like. Here, it is determined that the subject has gone to the toilet when the identification ID is no longer received by any antenna, but even if the subject stands on the floor, the subject does not necessarily go to the toilet. It is also possible to determine that Then, after that, when the identification ID is received by any one of the antennas, it may be determined that the subject has “goed to bed” and the number of times of getting out of bed is detected by counting the number of times of getting up.

  As described above, according to the sleep posture monitoring system of the present invention, the subject wears the pajamas with the RFID tag 102 attached thereto, and lies on the bed sheet 201 and sleeps. Since the joint position data is automatically acquired, data representing the posture during sleep can be acquired very easily. In addition, since the subject can easily acquire data at home, there is an effect that data regarding the sleeping posture can be acquired continuously for many days. In addition, the sleep posture monitor system of the present invention does not perform image analysis or visual sleep posture monitoring, and detects joint positions by non-contact, so it is said that there is no problem even if a blanket is hung on the subject. There are also benefits.

  Furthermore, the sleep posture monitoring system of the present invention may have a function of linking with an external measurement device by communication or the like in addition to measuring the joint position of the subject during sleep. This external device is a device that performs measurements in parallel to examine the sleep state of the subject. For example, it measures PSG data (sleep stage, heart rate variability, external environment (illuminance of illumination, temperature, humidity, etc.)). It is a device to do. In this case, the sleep posture monitoring system exchanges data with such an external measurement device, and stores the data acquired from the external measurement device in association with the data indicating the joint position of the subject. As described above, the sleep posture monitoring system of the present invention can associate the data obtained from the outside with the posture during sleep of the subject by linking with the external measurement device. There is an effect that more accurate evaluation can be performed. Further, according to the sleep posture monitoring system of the present invention, there is an effect that an appropriate sleep environment (temperature, humidity, noise, light, allergy, bed, pillow, etc.) can be evaluated. Moreover, the sleep posture monitoring system of the present invention can also be used to determine the effect of sleep disorder treatment.

  Moreover, in the said embodiment, although electromagnetic waves were transmitted from the antenna part 101 and the weak electromagnetic wave used as the response from the RFID tag 102 by that was measured, the electromagnetic field intensity | strength measurement part 103 measured, However, This invention is not limited to this. For example, the electromagnetic wave generated when the intensity of the electromagnetic wave generated from the antenna unit 101 is changed stepwise from strong to weak, or from weak to strong, and the identification ID from the RFID tag 102 becomes detectable or undetectable. May be measured as the electromagnetic field strength. Here, the antenna unit 101 corresponds to “the antenna that generates an electromagnetic wave by changing the intensity of the generated electromagnetic wave stepwise from strong to weak or from weak to strong” in the claims. The intensity measuring unit 103 corresponds to “the electromagnetic field intensity measuring unit that measures the intensity of the electromagnetic wave in the antenna when the identification ID from the RFID tag is unreceivable or receivable as the electromagnetic field intensity”, and the joint position The calculation unit 109 is “the joint position calculation means for calculating the spatial position of the joint corresponding to the identification ID from the electromagnetic field strength measured by at least three antennas for one RFID tag” and “at least one RFID tag. Corresponding to the “spatial position measuring means for calculating the spatial position of the object from the electromagnetic field strengths measured by three antennas”. . According to the measurement method as in the above embodiment, the measurement of the electromagnetic field strength does not take time, and the real-time property is excellent. However, since the measurement target is a weak electromagnetic field, a high measurement accuracy is required. There is. On the other hand, in this example, since the intensity of the electromagnetic wave is measured on the side where the electromagnetic wave is generated, there is an advantage that the electromagnetic field intensity can be accurately measured with a simple configuration. However, in this example, the antenna unit 101 generates an electromagnetic wave by gradually changing the strength of the electromagnetic wave from strong to weak, or from weak to strong, so that the circuit configuration of the antenna unit 101 is complicated. There is a disadvantage that real-time performance is sacrificed. Furthermore, as another example, an electromagnetic field strength measuring unit 103 is provided on the RFID tag 102 side, and a weak electromagnetic wave for transmitting an identification ID as a response from the RFID tag 102 is transmitted to the electromagnetic field strength measuring unit inside the RFID tag 102. 103 may be measured. In this case, the electromagnetic field strength of the weak electromagnetic wave can be measured with higher accuracy and excellent in real time as compared with the case of measuring on the antenna unit 101 side that receives the identification ID from the RFID tag 102. There is. However, there is a disadvantage that the circuit configuration of the RFID tag 102 becomes complicated for electromagnetic field strength measurement and measurement value transmission, and a battery or the like is required to secure power for the processing.

  Here, the case where the joint position of the subject is measured every 30 minutes has been described, but the present invention is not limited to this, and the joint position may be measured at shorter time intervals. For example, since the posture during sleep does not change as frequently as when awake, this is preferably 1-10 minutes, but may be measured every 3 minutes, every 30 seconds, every 10 seconds, or the like. By measuring the joint position at such a short time interval, it is possible to observe a smoother movement of the subject during sleep and to determine a more accurate movement. In addition, it is not necessary to measure joint positions at regular time intervals. In general, joint positions should be measured at short time intervals when sleep is shallow and at long time intervals when sleep is deep. The measurement time may be set. In addition, obtain information such as the time zone when you wake up well by interviewing the subject in advance, and measure the joint position at short time intervals in that time zone and at long time intervals in other time zones. Measurement time may be set.

  In addition, the measurement time for measuring the joint position is set at a short time interval, for example, at an interval of 10 seconds, and each time the measurement is performed, the position of each joint accumulated last time and the corresponding joint measured this time are set. The deviation from the position is calculated. Then, when the magnitude of movement of each joint represented by the deviation does not reach a predetermined threshold value, it is possible to erase the joint position data measured this time as no movement. . As a result, the joint position accumulating unit 108 holds the data of the joint position when the subject is asleep, only for one measurement. As a result, there is an effect that more joint position data can be accumulated when the storage area of the joint position accumulation unit 108 is effectively used and the subject's sleep posture moves. When there is a movement in the sleep posture of the subject, a more accurate movement can be analyzed based on more accumulated joint position data.

  The sleep posture monitor device 120 may be provided with an input unit such as a mouse and a keyboard and a storage unit, and the operator may input the body data of the subject measured in advance for correction. The inputted body data of the subject is stored in the joint position calculation unit 109, for example. Specifically, the body data of the subject is a distance between a specific joint and a joint, such as a distance from the wrist to the elbow joint, a distance from the ankle to the knee, and the like. Here, the joint position calculation unit 109 corresponds to “storage means for storing in advance the distance from a predetermined joint of each subject to the joint” in the claims. The body data for correction may be measured for both arms and both feet, may be measured for all joints where RFID tags are placed, or is measured only at one predetermined location. You may keep it. The joint position calculation unit 109 corresponds to “the joint position calculation unit that corrects the spatial position of each joint using the distance from the joint stored in advance to the joint” in the claims. The joint position calculation unit 109 compares the stored body data obtained by actual measurement of the subject and the distance between the joints calculated based on the electromagnetic field strength for the same part, and based on the comparison result, By correcting the distance, a more accurate spatial position of each joint can be calculated. For example, the operator of the sleep posture monitoring device 120 measures the distance from the subject's knee joint to the ankle joint in advance, inputs the measurement value from the input unit, and calculates the distance between the knee and the ankle to the joint position calculation unit 109. Store it in. The joint position calculation unit 109, when the first measurement is performed on the same subject, the spatial position of the RFID tag 102 arranged at the joint of the knee and the spatial position of the RFID tag 102 arranged at the joint of the ankle From the above, the distance between the knee and the ankle is calculated. The joint position calculation unit 109 compares the actually measured value stored in advance with the distance between the knee and the ankle calculated from the spatial position of each joint, and determines the relationship between the electromagnetic field strength and the distance according to the comparison result. to correct.

  Furthermore, the distance between adjacent joints is measured for all the joints where the tags are arranged, and the spatial positions of the corresponding joints calculated by the joint position calculation unit 109 based on the electromagnetic field strength are corrected. Thus, it is possible to correctly reflect the distance between the joints for each joint, which varies depending on the individual, in the sleeping posture. Thereby, there is an effect that it is possible to absorb individual differences in body shape and monitor a more accurate sleep posture.

  Furthermore, a set of the distance from the specific antenna unit 101 to the specific joint and the received electromagnetic field strength of the identification ID corresponding to the joint received by the antenna unit 101 is measured in advance, and the joint position calculation unit 109 It may be stored. The joint position calculation unit 109 obtains, for example, a ratio between the actually measured antenna-joint distance and the antenna-joint distance calculated from the electromagnetic field strength, and the received electromagnetic field strength stored in advance by the obtained ratio. And the distance between the antenna and the tag are corrected. There may be only one set of the distance between the antenna-joint measured in advance and the electromagnetic field strength of the received identification ID, or a plurality of sets. When a plurality of sets of distances and electromagnetic field strengths are measured, for example, an average value of each may be obtained, and a ratio may be obtained from the average value to correct the whole.

  In the above embodiment, the RFID tag 102 is attached to the joint and trunk of the subject covered with the pajamas. However, the present invention is not limited to this, and for example, it is not judged to be very important for specifying the posture. The attachment may be omitted for locations such as the trunk. Further, instead of omitting the attachment of the RFID tag 102, data relating to unnecessary joint positions may be specified by the identification ID, and the accumulation and calculation of the joint positions may be omitted. Further, by specifying an unnecessary joint position by an input operation from the operator and omitting data processing related to the specified joint position, for example, the RFID tag 102 that performs data processing is switched according to circumstances. Also good. As a result, it is possible to reduce the processing load of the electromagnetic field strength measurement unit 103, the reception data writing unit 107, the joint position calculation unit 109, and the like, and it is possible to save the storage area of the joint position storage unit 108. . Conversely, when it is determined that it is necessary to measure a more detailed posture and body movement, the RFID tag 102 may be attached to a joint of a finger or toe. In this case, the RFID tag 102 may be attached to, for example, a joint of a limb or finger with an adhesive tape or the like, or a glove or a sock attached with the RFID tag 102 may be put on the subject. Good.

  Each functional block in the block diagram (such as FIG. 1) is typically realized as an LSI which is an integrated circuit. These may be individually made into one chip, or may be made into one chip so as to include a part or all of them. For example, the part including the electromagnetic field strength measuring unit 103, the antenna switching unit 104, the control unit 105, the time measuring unit 106, and the reception data writing unit 107 in FIG. A portion including the calculation unit 109, the graph creation unit 110, the image generation unit 111, and the like may be integrated into one chip.

  Further, for example, functional blocks other than the memory (joint position accumulation unit 108) of the sleep posture monitoring device 120 may be integrated into one chip.

  The name used here is LSI, but it may also be called IC, system LSI, super LSI, or ultra LSI depending on the degree of integration.

  Further, the method of circuit integration is not limited to LSI, and implementation with a dedicated circuit or a general-purpose processor is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

  Further, if integrated circuit technology comes out to replace LSI's as a result of the advancement of semiconductor technology or a derivative other technology, it is naturally also possible to carry out function block integration using this technology. Biotechnology can be applied.

  INDUSTRIAL APPLICABILITY The present invention can be applied to a sleep posture monitor system that monitors the posture of a subject during sleep and changes in posture, and the joint spatial position measurement method in the sleep posture monitor system is a space that measures the spatial position of any article. It can be applied to a position measurement system.

It is a block diagram which shows the structure of the sleep posture monitoring system of embodiment of this invention. It is an external view which shows an example of the usage pattern of a sleep posture monitor system. It is a figure which shows an example of arrangement | positioning of the antenna part provided in the sheet. FIG. 4 is a diagram illustrating an example of a driving method of the antenna unit for efficiently receiving the identification ID from the RFID tag. (A) is a figure which shows the example which receives and receives identification ID from a RFID tag in the whole antenna group which is driven by switching sequentially by making the antenna group which consists of a 3x3 antenna part into a unit. FIG. 4B shows an example of receiving the identification ID by switching the antenna group in which the identification ID is received among the antenna groups shown in FIG. FIG. It is a figure which shows the other example of the drive method of the antenna part for receiving identification ID from a RFID tag efficiently. It is a flowchart which shows the operation | movement at the time of the joint position measurement of the sleep posture monitoring system of this Embodiment. It is a flowchart which shows operation | movement of the sleep posture monitoring system in the case of displaying on the monitor the image which shows the sleep posture for every measurement time based on the data regarding each joint position accumulate | stored in the joint position storage part. It is a flowchart which shows the procedure of the drive method of the antenna part for receiving identification ID efficiently shown to Fig.4 (a) and (b). It is a figure which shows an example of the CG image showing the test subject's sleep posture displayed based on the spatial position of each joint calculated by the joint position calculation part. It is a graph which shows a test subject's movement at the time of sleep and awakening measured using the actigraph.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Sleep posture monitoring system 101 Antenna part 102 RFID tag 103 Electromagnetic field strength measurement part 104 Antenna switching part 105 Control part 106 Timekeeping part 107 Reception data writing part 108 Joint position storage part 109 Joint position calculation part 110 Graph creation part 111 Image generation part 112 Printer 113 Monitor 120 Sleep posture monitor device 201 Sheet 401 Antenna group 501 Drive antenna section

Claims (19)

A sleep posture monitor system for monitoring a posture of a subject during sleep,
An RFID tag that is placed at the joint position of the subject and that transmits an identification ID when supplied with power,
A plurality of antennas arranged at a plurality of predetermined positions, supplying power to the RFID tag and receiving an identification ID from the RFID tag;
Distance measuring means for measuring a distance from an antenna that has received the identification ID to an RFID tag that has transmitted the identification ID;
Joint position calculating means for calculating the spatial position of the joint from the received identification ID, the position of the antenna that has received the identification ID, and the distance between the antenna and the RFID tag;
A sleep posture monitoring system comprising: a posture of the subject during sleep or posture detection means for detecting a change in posture based on the calculated joint spatial position. The distance measuring means includes
An electromagnetic field strength measuring unit that measures the electromagnetic field strength at the antenna that has received the identification ID;
The distance measuring means converts the measured electromagnetic field strength into a distance,
The joint position calculating means calculates, as a joint spatial position, a spatial position where the condition that the RFID tag exists at a position away from the antenna position by the converted distance is satisfied for each antenna. The sleep posture monitoring system according to claim 1. The sleep posture monitoring system according to claim 2, wherein the electromagnetic field strength measurement unit measures the electromagnetic field strength of the identification ID from the RFID tag received by the antenna. The antenna generates electromagnetic waves by gradually changing the intensity of generated electromagnetic waves from strong to weak or weak to strong,
The electromagnetic field strength measurement unit measures the electromagnetic field strength at the antenna when the identification ID from the RFID tag is unreceivable or receivable as the electromagnetic field strength,
The sleep posture monitor according to claim 2, wherein the joint position calculation means calculates a spatial position of the joint corresponding to the identification ID from the electromagnetic field strength measured by at least three antennas for one RFID tag. system. The plurality of antennas are arranged in a matrix on the floor on which the subject lies,
The sleep posture monitoring system further includes:
The sleep posture monitoring system according to claim 1, further comprising an antenna switching unit that repeatedly drives the plurality of antennas in a row direction and a column direction repeatedly at every predetermined measurement time. The antenna switching means sequentially drives in a row direction and a column direction with an antenna group including a plurality of antennas as a unit, and among the driven antenna groups, even one of the antennas belonging to the antenna group has the identification ID. The sleep posture monitoring system according to claim 5, wherein if there is a received antenna, a group of a smaller number of antennas included in the antenna group is sequentially switched and driven in a row direction and a column direction. The antenna switching means sequentially drives the antenna for each predetermined number in the row direction and the column direction, and if there is an antenna that has received the identification ID among the driven antennas, the antenna switching means is positioned around the antenna. The sleep posture monitor system according to claim 5, wherein the antenna to be driven is switched and driven in a predetermined order. The sleep posture monitoring system further includes:
Comprising storage means for preliminarily storing the distance from a predetermined joint of each subject to the joint;
The sleep posture monitoring system according to claim 5, wherein the joint position calculation unit corrects the spatial position of each joint using a distance from the joint stored in advance. The RFID tag is disposed at a joint position including both shoulders of the subject,
The joint position calculation means calculates the spatial position of the shoulders for each measurement time,
The sleep posture monitoring system according to claim 5, wherein the posture detection means detects the number of times of turning over during sleep based on a change in the spatial position of the shoulders at each measurement time. The posture detection means determines that the subject has left when the identification ID is not received by any antenna, and then determines that the subject has gone to bed when the identification ID is received by any antenna, The sleep posture monitoring system according to claim 5, wherein the number of times the subject leaves bed after going to bed is detected. The RFID tag is disposed at a joint position including the joints of both arms or both feet of the subject and the trunk,
The joint position calculating means calculates the spatial positions of the arms, both legs and the trunk at each measurement time,
6. The posture detecting means detects movements of both arms, both legs and a trunk of a subject based on a change in a spatial position of both arms, both legs and a trunk of each measurement time. The sleep posture monitoring system described. The posture detection means is a time from when the identification IDs of all RFID tags are received until the position change of all joints is less than or equal to a range where it can be regarded as stationary, and the stationary state is longer than a predetermined time. The sleep posture monitoring system according to claim 5, wherein a persistent case is detected as a sleep onset latency. The posture detection means determines that the subject has awakened when detecting that the spatial position of any joint has changed after a predetermined time has elapsed since all the joints are stationary. The sleep posture monitoring system according to claim 5, wherein the sleep posture is determined by determining that the subject has fallen asleep when the subject is stationary and the number of times the subject has awakened. The posture detection means is the time when all the joints are stationary as the sleep time of the subject, the time when the identification IDs of all the RFID tags are received as the time when the subject is lying, The sleep efficiency of the subject is detected (sleep efficiency) = ((total sleep time) / (total bedtime)) × 100 (Equation 1)
The sleep posture monitoring system according to claim 5. A sleep posture monitoring method for monitoring a posture of a subject during sleep,
An RFID tag that is arranged at the joint position of the subject and transmits an identification ID when supplied with power, and is arranged at a plurality of predetermined positions to supply power to the RFID tag and identify from the RFID tag A plurality of antennas for receiving the ID,
Measure the distance from the antenna that received the identification ID to the RFID tag that transmitted the identification ID,
From the received identification ID, the position of the antenna that received the identification ID, and the distance between the antenna and the RFID tag, the spatial position of the joint is calculated,
A sleep posture monitoring method characterized by detecting a posture or a change in posture of the subject during sleep based on the calculated spatial position of the joint. A spatial position measurement system for measuring a spatial position of an object,
An RFID tag that is placed on a target object and that transmits an identification ID when supplied with power;
A plurality of antennas arranged at a plurality of predetermined positions, supplying power to the RFID tag and receiving an identification ID from the RFID tag;
Distance measuring means for measuring a distance from an antenna that has received the identification ID to an RFID tag that has transmitted the identification ID;
Spatial position measuring means for measuring the spatial position of the object from the received identification ID, the position of the antenna that has received the identification ID, and the distance between the antenna and the RFID tag. Spatial position measurement system. The distance measuring means includes
An electromagnetic field strength measuring unit that measures the electromagnetic field strength at the antenna that has received the identification ID;
The distance measuring means converts the measured electromagnetic field strength into a distance,
The spatial position measuring means calculates, as the spatial position of the object, a spatial position where the condition that the RFID tag exists at a position away from the antenna position by the converted distance is satisfied for each antenna. The spatial position measurement system according to claim 16. The antenna generates electromagnetic waves by gradually changing the intensity of generated electromagnetic waves from strong to weak or weak to strong,
The electromagnetic field strength measurement unit measures the electromagnetic field strength at the antenna when the identification ID from the RFID tag is unreceivable or receivable as the electromagnetic field strength,
The spatial position measurement unit according to claim 17, wherein the spatial position measurement unit calculates a spatial position of an object corresponding to the identification ID from an electromagnetic field intensity measured by at least three antennas for one RFID tag. system. A spatial position measuring method for measuring a spatial position of an object,
An RFID tag that is arranged on a target object and transmits an identification ID when supplied with power, and a plurality of antennas that supply power to the RFID tag and receive the identification ID from the RFID tag,
Measure the distance from the antenna that received the identification ID to the RFID tag that transmitted the identification ID,
A spatial position measurement method, comprising: measuring the spatial position of the object from the received identification ID, the position of the antenna that has received the identification ID, and the distance between the antenna and the RFID tag.

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