JP2008307363A - Prediction system and method for getting out of bed - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To early and securely predict the starting of rising motion of a patient's body on a bed. <P>SOLUTION: The prediction system 1 includes a transmitter 2 for continuously transmitting ultrasonic signals to a management area including a bed in a condition attached to the ceiling, a receiver 3 for receiving ultrasonic signals reflected within the management area in a condition attached to the ceiling, a position calculation means 4 for calculating a three-dimensional position of the head of a patient on a bed from moment to moment from the reflected ultrasonic data acquired by the receiver 3 at every predetermined time corresponding to the ultrasonic signals transmitted from the transmitter 2, a determination means 5 for sensing temporal variation from a lying position in the three-dimensional position of the patient from a calculation result by the position calculation means 4 and determining whether the patient on the bed started rising motion or not based on the sensing result, and a notice means 6 for transmitting notice signals when the starting of rising motion of the patient is sensed by the discrimination means 5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a bed leaving prediction apparatus and method for determining whether or not a person on a bed has started a bed leaving operation.

Conventionally, mainly hospitals are equipped with a bed detection device that automatically detects a patient's bed leaving the bed in order to reduce the labor of patrol monitoring. A bed detection device includes a pressure sensor installed on the floor around the bed and detects the patient's bed removal by the pressure change that occurs when the patient lowers the foot on the sensor. There is a sensor that attaches a load sensor to the sensor and detects the presence or absence of the patient's bed by changing the output of the sensor. Moreover, as a technique similar to bed detection, a roll-over management system that detects a change in the posture of a patient has been proposed (see Patent Document 1). In this system, measurement sensors are attached to a shoulder and a waist of a patient, and radio waves and ultrasonic waves transmitted from the measurement sensor are received by a receiving antenna and an ultrasonic microphone installed on a bed, respectively. A change in the posture of the patient is detected based on the time difference that occurs during the reception. Furthermore, this system limits the radio wave communication range between the measurement sensor and the receiving antenna to the space above the bed, and determines that the patient has left the floor when the radio wave communication is interrupted. Like that.
JP 2006-325683 A

  In the above-described bed detection device using a pressure sensor or a load sensor, the patient's bed is detected only when the patient steps down from the bed. Therefore, when the nurse arrives, the patient has already left the bed. Time has passed since then. Therefore, there is a problem in terms of early detection of the patient's bed and ensuring sufficient patient safety.

  In the system disclosed in Patent Literature 1, the patient's bed is detected for the first time in a state where the patient no longer exists in the space above the bed. For this reason, a patient's bed cannot be discovered at an early stage like the above-mentioned pressure-sensitive sensor.

  In addition, when the measurement sensor attached to the patient's shoulder and waist is hidden in the futon, the ultrasonic wave does not reach the ultrasonic microphone, and therefore the patient's posture change or bed movement cannot be detected.

  In addition, the above problems may occur not only in hospitals but also in various facilities such as nursing homes provided with a bed-separating device and general homes.

  In view of the above circumstances, it is an object of the present invention to detect early and accurately the start of a human bed leaving operation on a bed.

  An apparatus according to the present invention, which was created to solve the above-described problems, is a transmitter that continuously transmits an ultrasonic signal to a management area including a bed while being attached to a stationary system, and is attached to the stationary system. A receiver that receives the ultrasonic signal reflected in the management area, and is acquired at a predetermined time by the receiver corresponding to the ultrasonic signal transmitted from the transmitter. Position calculation means for calculating momentarily the head three-dimensional position of the human body on the bed from the reflected wave data, and the temporal change from the lying position of the human head three-dimensional position from the calculation result of the position calculation means And determining means for determining whether or not the human body on the bed has started leaving the bed based on the detection result, and issuing a notification signal when the start of the bed leaving action of the human body is detected by the determining means Provide notification means And features.

  With the above configuration, since the temporal change from the lying position of the head three-dimensional position of the human body on the bed is detected, for example, the start of a leaving operation such as a rising operation on the bed can be detected. . Therefore, before the human body drops his / her foot from the bed, it is possible to predict the bed leaving of the human body and detect it at an early stage. In addition, the head of the human body is usually outside the futon, and the ultrasonic signal reflected by the head of the human body is not disturbed by the futon. Therefore, it is possible to accurately detect the start of the patient's bed leaving motion by detecting the temporal change from the lying position of the human head three-dimensional position. In addition, since a transmitter and a receiver are attached to a stationary system, it is possible to avoid a situation in which a burden is imposed on a patient as in the case where a sensor is directly attached to a human body.

  In the above configuration, the determination unit uses the position calculation unit as a reference position for the three-dimensional position of the human head calculated from the reflected wave data acquired at a certain moment, and the reflected wave acquired immediately thereafter. A case where a movement vector from the reference position to the target position is calculated with the three-dimensional position of the human head calculated from data as a target position, and the magnitude of the movement vector is equal to or less than a first predetermined value. By detecting that the head of the human body has moved from the reference position to the target position based on the actual report, a temporal change from the lying position of the three-dimensional position of the human head is detected based on the actual report. It is preferable that it is comprised.

  In this way, the three-dimensional position of the human head calculated from the reflected wave data acquired at a certain moment and the three-dimensional position of the human head calculated from the reflected wave data acquired immediately thereafter are obtained. Thus, it is possible to more accurately detect a temporal change from the lying position of the three-dimensional position of the human head while correlating in time series based on the magnitude of the movement vector.

  In the above configuration, it is preferable that the determination unit is configured to increase the first predetermined value corresponding to a detection time during which the actual report is not continuously obtained. The detection time here is the detection time here, after the reflected wave data obtained by calculating the three-dimensional position as the reference position is acquired, the three-dimensional position as the target position is calculated. It means the time until the reflected wave data is acquired.

  In this way, for example, the reflected wave intensity from the human body on the bed is weak, or the 3D position of the human head cannot be calculated from the reflected wave data due to the influence of sudden noise, etc. However, the first predetermined value is increased corresponding to the detection time. Therefore, detection of a temporal change from the lying position from the three-dimensional position of the human head can be reliably continued without reducing the capture rate of the three-dimensional position of the human head.

  In the above-described configuration, the position calculating means sets a provisional head three-dimensional position when a plurality of head three-dimensional positions are calculated from one reflected wave data, A displacement vector between them is calculated, and a provisional head three-dimensional position in which the magnitude of the displacement vector is equal to or smaller than a second predetermined value is selected, and a human body is determined based on the selected provisional head three-dimensional position. It is preferable that the head three-dimensional position is set.

  Because it is difficult to transmit an ultrasonic wave as an ideal pulse wave without an amplitude decay time (a time from an amplitude decay start time (maximum amplitude time) to an amplitude decay end time) from a transmitter, In practice, an ultrasonic signal having a predetermined amplitude decay time is often transmitted. In this case, the reflected wave from the head of the same human body may be received by the receiver with a temporal width due to the relationship with the amplitude decay time of the ultrasonic signal to be transmitted. Therefore, a plurality of head three-dimensional positions indicating the same human body may be detected from one reflected wave data. Therefore, in the above configuration, when a plurality of three-dimensional positions are calculated from one reflected wave data, these are temporarily set as temporary three-dimensional positions, and displacement vectors between the temporary three-dimensional positions are calculated, and the calculation is performed. One or more provisional three-dimensional positions are selected based on the magnitude of the displacement vector. Thereby, it is possible to select a provisional head three-dimensional position that is estimated to have captured the head of the same human body from a plurality of provisional head three-dimensional positions. Then, by setting the head three-dimensional position of the human body based on the selected provisional head three-dimensional position, simplification of the arithmetic processing can be suitably realized. In addition, said 2nd predetermined value is set based on the amplitude decay time of the ultrasonic signal transmitted from a transmitter, for example.

  In this case, the position calculation means sets the temporary three-dimensional position closest to the receiver among the selected temporary three-dimensional positions as the three-dimensional position of the moving object, or the selected temporary three-dimensional position. The center of gravity position may be set to the three-dimensional position of the moving body.

  Said structure WHEREIN: It is preferable that the said receiver is an array sensor which arranged the some receiving element.

  In this way, it is possible to receive an ultrasonic signal reflected by the management area only by electronic scanning without mechanically scanning the receiver by rotating it or the like.

  The method according to the present invention, which was created to solve the above problems, continuously transmits an ultrasonic signal from a transmitter attached to a stationary system to a management area including a bed and is attached to the stationary system. A reflected wave data acquisition step of receiving the ultrasonic signal reflected in the management area by a receiver and acquiring reflected wave data corresponding to the ultrasonic signal transmitted from the transmitter every predetermined time A position calculation step for calculating momentarily the head three-dimensional position of the human body on the bed from the reflected wave data acquired in the reflected wave data acquisition step, and the human head three-dimensional from the calculation result of the position calculation step A step of detecting whether the position of the human body on the bed has started to get out of the bed based on the detection result, and a step of detecting whether the human body has left the bed Start is detected Characterized in that it comprises a notifying step of issuing a notification signal if it.

  According to the above method, the same effect as the matter described in the paragraph [0009] already described can be enjoyed.

  In the above method, in the determination step, the position calculation step sets the three-dimensional position of the human head calculated from the reflected wave data acquired at a certain moment as a reference position, and the reflected wave acquired immediately thereafter. A case where a movement vector from the reference position to the target position is calculated with the three-dimensional position of the human head calculated from data as a target position, and the magnitude of the movement vector is equal to or less than a first predetermined value. By detecting that the head of the human body has moved from the reference position to the target position based on the actual report, a temporal change from the lying position of the three-dimensional position of the human head is detected based on the actual report. It is preferable.

  In this way, it is possible to enjoy the same effects as those described in the paragraph [0011] already described.

  In the above method, it is preferable that in the determination step, the first predetermined value is increased corresponding to a detection time during which the actual report is not continuously obtained.

  In this way, the same operational effects as those described in the paragraph [0013] already described can be obtained.

  In the above method, when the plurality of head three-dimensional positions are calculated from one reflected wave data, the position calculating step sets these as the temporary head three-dimensional positions and the provisional head three-dimensional positions. A displacement vector between them is calculated, and a provisional head three-dimensional position in which the magnitude of the displacement vector is equal to or smaller than a second predetermined value is selected, and a human body is determined based on the selected provisional head three-dimensional position. It is preferable to set the head three-dimensional position.

  In this way, the same operational effects as those described in the paragraph [0015] already described can be obtained.

  As described above, according to the present invention, since the temporal change from the lying position of the head three-dimensional position of the human body on the bed is detected, for example, the start of the bed leaving operation such as the rising operation on the bed is started. Can be detected. Therefore, before the human body drops his / her foot from the bed, it is possible to predict the bed leaving of the human body and detect it at an early stage. In addition, the head of the human body is usually outside the futon, and the ultrasonic signal reflected by the head of the human body is not disturbed by the futon. Therefore, it is possible to accurately detect the start of the human body leaving motion by detecting the temporal change from the lying position of the human head three-dimensional position.

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

  FIG. 1 is a block diagram schematically illustrating a bed leaving detection apparatus according to an embodiment of the present invention, and FIG. 2 is a perspective view schematically illustrating an attachment mode thereof. As shown in the figure, the bed leaving prediction apparatus 1 includes a transmitter 2, a receiver 3, a position calculation unit 4, a determination unit 5, and a notification unit 6.

  The transmitter 2 is configured to continuously transmit ultrasonic signals to the management area 8 including the bed 7 at a predetermined interval while being attached to the ceiling. The receiver 3 is configured to receive an ultrasonic signal reflected in the management area 8 while being mounted on the ceiling. The transmitter 2 and the receiver 3 constitute a sensor unit 9.

  In this embodiment, the transmitter 2 is configured to diffuse the ultrasonic signal into the management area 8 and transmit it. On the other hand, the receiver 3 is composed of an array sensor in which a plurality of receiving elements are arranged. For example, the following configuration can be given as an example of the array sensor. That is, as the array sensor 3, as shown in FIGS. 3A and 3B, a plurality of receiving elements 3a are arranged on a single plane (substrate 3b), for example, in a lattice shape or a cross shape. The signals obtained by each receiving element 3a are delayed by a time corresponding to the incident angle of the ultrasonic signal reflected in the management area 8 and the position of each receiving element 3a, and then added. There is a configuration in which three-dimensional reflected wave data is acquired by periodic scanning. Furthermore, in this case, it is preferable to set the center-to-center distance X between adjacent receiving elements 3a to be equal to or less than a half wavelength of the ultrasonic signal transmitted from the transmitter 2. This effectively reduces the situation in which a so-called ghost component that causes an error occurs in the three-dimensional reflected wave data obtained by delay-adding the signals obtained by the plurality of receiving elements 3a. be able to.

  The position calculation means 4 determines the three-dimensional position of the head of the patient 10 on the bed 7 from the reflected wave data acquired at predetermined intervals by the receiver 3 in response to the ultrasonic signal transmitted from the transmitter 2. It is configured to operate from moment to moment.

  The determination unit 5 detects a temporal change from the recumbent position of the patient's 10 head three-dimensional position from the calculation result of the position calculation unit 4, and based on the detection result, the human body on the bed starts a bed leaving operation. Configured to determine whether or not.

  The notification unit 6 is configured to issue a notification signal when the determination unit 5 detects the start of the bed leaving operation of the patient 10.

  Next, a procedure for predicting bed leaving by the bed prediction device 1 configured as described above will be described.

  FIG. 4 is a flowchart showing the procedure for detecting getting out of bed. As shown in the figure, this bed leaving detection procedure is performed by continuously transmitting an ultrasonic signal from the transmitter 2 to the management area 8 including the bed 7 at a predetermined interval. A reflected wave data acquisition step S1 that receives an ultrasonic signal reflected from the transmitter 8 and acquires reflected wave data corresponding to the ultrasonic signal transmitted from the transmitter 2 every predetermined time, and a reflected wave data acquisition step A position calculation step S2 for calculating momentarily the head three-dimensional position of the patient 10 on the bed 7 from the reflected wave data acquired in S1, and a recumbency of the head three-dimensional position of the patient 10 from the calculation result of the position calculation step S2. A determination step S3 for detecting a temporal change from the position and determining whether or not the patient 10 on the bed 7 has started to leave the bed based on the detection result, and the determination step S3 determines whether the patient 10 has left the bed. Report when start is detected And a notification step S4, emits a signal. In this embodiment, the reflected wave data acquisition step S <b> 1 is executed by the receiver 3. In addition, the position calculation unit 4 executes a position calculation step S2. Further, the determination unit 5 executes the determination step S3. Further, the notification unit 6 executes the notification step S4.

  In the reflected wave data acquisition step S <b> 1, each time an ultrasonic signal is transmitted from the transmitter 2, three-dimensional reflected wave data is acquired from the ultrasonic signal received by the receiver 3. The reflected wave data is composed of plane data obtained by dividing the management area 8 into a plurality of planes in the height direction, and the signal intensity distribution of the reflected wave is recorded in each plane data.

  The position calculation step S2 is roughly divided into a difference processing step S10, a peak calculation step S20, and a grouping step S30.

  In the difference processing step S10, the reflected wave data in the management area 8 when the patient is absent or at bedtime, which is measured in advance, is subtracted from the reflected wave data acquired in the reflected wave data acquisition step S1. Thereby, the stationary object included in the reflected wave data is deleted in the data, and it becomes possible to clearly distinguish the stationary object and the moving object (patient 10 or the like).

  In the plane data constituting the reflected wave data that captures the head of the patient 10, when the signal intensity is taken on the vertical axis, the head of the patient 10 appears as a convex portion as shown in FIG. 5, for example. Therefore, in the peak calculation step S20, the peak value of the signal intensity and its position are detected for each of the plurality of plane data constituting the reflected wave data after the difference processing step S10. Then, the signal intensity exceeding a predetermined peak determination threshold value is stored as the head three-dimensional position. In this way, since the head three-dimensional position of the patient 10 can be defined by points, compared to the case where the head three-dimensional position of the patient 10 is defined by the entire portion where the signal intensity is a convex portion. Therefore, it is possible to simplify the arithmetic processing. The stored three-dimensional position of the head is stored as head position data in a state of being arranged in order from the one closest to the receiver 3 (sensor unit 9).

  In the present embodiment, the grouping step S30 is executed in order to determine whether or not the head three-dimensional position calculated in the peak calculation step S20 captures the head of the same patient 10. . This is for the following reason. In general, when an ultrasonic wave propagating in the air hits an object such as the head of the patient 10, it is reflected by the object and returns without going straight. However, it is difficult to transmit an ultrasonic signal to be transmitted as an ideal pulse wave having no amplitude decay time (a time from an amplitude decay start time (maximum amplitude time) to an amplitude decay end time), In practice, as shown in FIG. 6, an ultrasonic signal having a predetermined amplitude decay time ΔT is often transmitted. For this reason, the ultrasonic signal reflected by the same object may be detected with a width in time from the relationship with the amplitude attenuation time ΔT of the transmitted ultrasonic wave. In this case, among a plurality of plane data constituting the reflected wave data, a plurality of peak values due to the same object are detected in several continuous plane data. Therefore, also from the viewpoint of simplifying the arithmetic processing, it is necessary to determine which one of the plurality of peak values captures the same patient 10.

  Therefore, in the grouping step S30, when a plurality of head three-dimensional positions are calculated from one reflected wave data in the peak calculation step S20, these are temporarily set as temporary head three-dimensional positions. A displacement vector between the three-dimensional positions is calculated, and a head three-dimensional position where the magnitude of the displacement vector is equal to or smaller than a grouping threshold value (second predetermined value) is selected from the calculated displacement vector. At this time, it is determined that the selected three-dimensional position of the head captures the head of the same patient 10. Then, the head three-dimensional position (representative position) of the patient 10 is set again based on the selected head three-dimensional position.

  This grouping step S30 is executed according to the procedure shown in FIG. As shown in the figure, in the grouping step S30, first, among the head position data stored in the peak calculation step S20, the head three-dimensional position closest to the sensor unit 9 (provisional head three-dimensional) (Position) is set as a reference position, a new group with the head three-dimensional position as a representative position is registered, and the new group is set as a target group (step S31). Thereafter, it is determined whether or not the next head three-dimensional position (provisional head three-dimensional position) exists in the head three-dimensional position data (step S32).

  As a result, when the next head three-dimensional position exists, the head three-dimensional position is set as the target position (step S33). Then, a displacement vector from the reference position to the target position is calculated (step S34), and it is determined whether or not the magnitude of the displacement vector is equal to or smaller than the grouping threshold (step S35).

  As a result, if it is equal to or smaller than the grouping threshold, the target position is set as a new reference position, and additionally registered in the target group (step S36), and the process returns to step S32.

  On the other hand, if it is determined in step S35 that the grouping threshold has been exceeded, a new group with the target position as a new reference position and the next three-dimensional head position as a representative position is registered and The new group is set as a new target group (step S37), and the process returns to step S32. Thereafter, the above steps are repeated until it is determined in step S32 that the next head three-dimensional position does not exist, and all head three-dimensional positions stored in the peak calculation step S20 are classified into predetermined groups. In addition, a representative position is set for each group.

  Here, the grouping threshold is set based on the amplitude decay time ΔT of the ultrasonic signal to be transmitted. This is because it is possible to predict to what extent a signal obtained by capturing the head of the same patient 10 in advance is detected from the amplitude decay time ΔT.

In the grouping step S30 described above, the head three-dimensional positions arranged in the order of proximity to the sensor unit 9 are processed in order from the top three-dimensional position of the head, so that for each classified group The head position closest to the sensor unit 9 is set as the representative position. Therefore, what is reflected first by the object (the head of the patient 10) in time can be set as the representative position of each group. That is, even when an ultrasonic signal having a predetermined amplitude decay time is transmitted from the sensor unit 9, the same result as that obtained when an ideal pulse wave without an amplitude decay time is transmitted can be obtained.

  The processing result of the grouping step S30 processed in this way is conceptually shown in FIG. In the illustrated example, six head three-dimensional positions a1, a2, a3, b1, b2, and b3 are detected in the peak calculation step S20. As a result of the grouping step S30, the group A ( For example, the case where it classify | categorizes into the group B (for example, group which shows the patient 10) which consists of the head three-dimensional position b1-b3 and the group B which shows the third party other than the patient 10 is illustrated. In this case, the representative positions of the groups A and B are set to the head positions a1 and b1 that are closest to the sensor unit 9, respectively. The representative position of the group is not limited to the head position closest to the sensor unit 9, for example, after classifying all the head three-dimensional positions included in the head position data into a predetermined group, The barycentric position of the head three-dimensional position belonging to each group may be calculated, and the barycentric position may be set as the representative position.

  The determination step S3 is roughly divided into a movement determination step S40, an area determination step S50, and a bed leaving operation determination step S60.

  In the movement determination step S40, a movement vector between the representative position of the group detected from one already obtained reflected wave data and the representative position of the group detected from other newly obtained reflected wave data is calculated. Based on the magnitude of the displacement vector, a temporal change from the lying position of the three-dimensional position of the head of the patient 10 is detected. That is, the above-described grouping step S30 is processing within the same reflected wave data, but this movement determination step S40 compares two different reflected wave data (for example, previous reflected wave data and current reflected wave data). To process.

  This movement determination process S40 is performed in the procedure shown in FIG. As shown in the figure, in the movement determination step S40, first, it is determined whether or not the group detected in the grouping step S30 exists (step S41). As a result, if the group exists, the representative position of the group is acquired and set as the target position (step S42). Then, it is determined whether or not a tracked group already exists in the previous reflected wave data (step S43). As a result, if it is determined that it exists, the representative position of the tracked group is acquired and set as the reference position (step S44). Thereafter, a movement vector from the reference position to the target position is calculated (step S45), and it is determined whether or not the magnitude of the movement vector is equal to or smaller than a movement determination threshold value (first predetermined value) (step S46). As a result, if it is equal to or less than the movement determination threshold value, it is regarded as an actual report, and the target position is set as a new representative position of the tracked group as the determination reference position (step S47) and the process returns to step S41. That is, in this case, it is determined that the representative position (head three-dimensional position) has moved from the reference position to the target position. On the other hand, if the movement determination threshold is exceeded, the process returns to step S41 without determining that the representative position has moved from the determination position to the target position.

  If it is determined in step S43 that no tracked group exists, the target position is set as a new representative position of the newly tracked group (step S48), and the process returns to step S41.

  Then, until it is determined in step 41 that the next group does not exist, the above steps are repeated to track temporal changes in the representative position of each group.

  The movement determination threshold is set based on the movement speed of the patient 10. Specifically, the movement determination threshold is based on the maximum estimated movement amount that the patient 10 can actually move during the time from when the previous reflected wave data is acquired until the current reflected wave data is acquired. Is set.

  Further, depending on the posture of the patient 10 or the like, if the signal intensity of the ultrasonic signal reflected by the patient 10 is weak or noise is generated, the head three-dimensional position cannot be detected in the peak calculation step S20. There is. Therefore, the detection time when the head three-dimensional position cannot be detected for each group is measured, and the movement determination threshold is increased according to the detection time. Specifically, for example, the above detection time is detected by the number of reflected wave data. Then, when the movement determination threshold value used between two reflected wave data that are continuous in time series is α and the measurement number of the reflected wave data that could not be detected is n, the movement determination threshold value is, for example, α × (n + 1). It is supposed to be set.

  The processing result of the movement determination step S40 processed in this way is conceptually shown in FIG. This example shows a state where the representative positions A1 and B1 are detected in the grouping step S30 for the previous reflected wave data, and the representative positions A2 and B2 are detected in the grouping step S30 for the current reflected wave data. Yes. Then, in the movement determination step S40, the representative position A1 detected in the previous reflected wave data is moved to the representative position A2 detected in the current reflected wave data, and the representative position B1 detected in the previous reflected wave data. Shows a state in which it is determined that the head has moved to the representative position B2 detected from the current reflected wave data.

  Further, as shown in FIG. 11, the representative position C2 obtained from the current reflected wave data is within the movement determination threshold with respect to both the representative positions A1 and B1 obtained from the previous reflected wave data. Is also envisaged. Therefore, in this embodiment, when performing the above-described movement determination step S40, if the head position of the patient 10 has already been captured by the previous reflected wave data, the representative position indicating the head position of the patient 10 Is processed first, so that the movement of the patient 10 is preferentially tracked. That is, in step S43, the group that captured the patient 10 is set first. Thereby, the supplement rate of the patient 10 can be improved. Instead of processing the patient 10 preferentially, in the case as shown in FIG. 11, the processing may be performed on the assumption that the representative position near the actual distance has moved.

  In the area determination step S50, the management area 8 is defined by dividing it into a plurality of areas in advance, and it is detected in which area of the management area 8 the representative position of each group that has undergone the movement determination step S40 is located. Then, it is determined whether or not the group has captured the head of the patient 10. Here, as shown in FIGS. 12 and 13, the management area 8 is a recumbent area 11 where the head of the patient 10 lying on the bed 7 is located and a sitting position area where the head of the patient 10 sitting on the bed 7 is located. 12, a standing area 13 where the head of the patient 10 standing on the bed 7 is located, a notification area 14 formed at both ends in the width direction on the bed, and the periphery of the bed 7 outside the notification area 14 Is defined in a state of being divided into a bed leaving area 15 formed so as to surround the floor. In addition, as shown in FIG. 12, the recumbent area 11 is formed only on the pillow side of the bed 7 so as not to mistakenly recognize the foot of the patient 10 as the head.

  This area determination step S50 is executed according to the procedure shown in FIG. As shown in the figure, in the area determination step S50, it is determined whether or not there is a group that has been tracked in the movement determination step S40 (step S51). As a result, if it exists, the representative position of the tracked group is acquired and set as the target position (step S52). Next, it is detected which area of the management area 8 the target position corresponds to (step S53). If it is before capturing the patient 10 (step S54), it is determined whether or not the corresponding area is the lying area 11 of the patient 10 (step S55). As a result, when the corresponding area is equal to the recumbent area 11, the group set as the target position is regarded as the patient 10 (step S56) and the process returns to the above step S51. Further, after the patient 10 is captured (step S54) or when the corresponding area is not equal to the lying area 11 in step S55, the process returns to step S51. The above steps are repeated until it is determined in step 51 that there is no tracked group.

  In the leaving action determination step S60, after the group indicating the patient 10 is detected in the area determination step S50, the group indicating the patient 10 stays in the notification area 14 for a predetermined time or more. Determine. Since the patient 10 may stay in the notification area 14 for a predetermined time due to turning over, the temporal change in the three-dimensional position of the head of the patient 10 detected in the movement determination step S40 is changed from the lying area 11 to the sitting area. 12, when it changes to reach the notification area 14 and stay for a predetermined time or more, it is determined that the patient 10 has started getting out of bed. Thereby, it can prevent misidentifying the start of the bed leaving operation of the patient 10.

  In addition, since it is assumed that it gets up in the width direction both ends of the bed 7, the lying area 11 and the sitting area 12 are extended to the width direction both ends of the bed 7, and the head three-dimensional position of the patient 10 is extended. The notification area 14 may be formed at both ends in the width direction on the bed 7 when the temporal change from the lying position shifts from the lying area 11 to the sitting area 12.

  Further, from the viewpoint of early detection of the start of the bed leaving operation of the patient 10, the sitting area 12 may be set as a notification area. That is, when the temporal change in the three-dimensional position of the head of the patient 10 changes from the lying area 11 to the sitting area 12 so as to stay for a predetermined time, it is determined that the patient 10 has started to get out of bed. May be. In this case, the sitting area 12 and the recumbent area 11 may be extended to both ends in the width direction of the bed 7 from the viewpoint of early detection.

  Moreover, the determination method of the bed leaving movement according to the present embodiment described in the paragraph [0061] and the determination method of the bed moving operation described in the paragraphs [0062] and [0063] may be changed by, for example, a switch or the like.

  In the notification step S4, a notification signal is issued when the start of the bed leaving operation of the patient 10 is determined in the above bed movement determination step S60, and the start of the bed moving operation of the patient 10 is notified to a nurse or the like of the nurse center. Specifically, for example, the notification unit 6 is connected to a nurse call signal system, and when a notification signal is output from the notification unit 6, the nurse call is issued. In addition, a notification signal may be transmitted as a radio wave, and the notification signal may be received by a predetermined terminal installed in a specific place or a predetermined terminal (such as a mobile phone) possessed by a nurse or the like. Such a method of transmitting a notification signal using radio is effective as a means for notifying the start of a human body leaving operation in a general home where there is no nurse call.

  As described above, according to the bed leaving prediction apparatus 1 according to the present embodiment, the temporal change from the lying position of the head three-dimensional position of the patient 10 on the bed 7 is detected. The start of bed leaving movement can be detected. Therefore, before the patient 10 drops his / her foot from the bed 7, it is possible to predict the bed leaving of the patient 10 and detect it early. In addition, the head of the patient 10 is usually outside the futon, and the ultrasonic signal reflected by the head of the patient 10 is not inhibited by the duvet. Therefore, the start of the bed leaving motion of the patient 10 can be accurately detected by detecting the temporal change from the lying position of the patient's three-dimensional head position.

  In the present embodiment, the sensor unit 9 is directly attached to the ceiling 16 as shown in FIG. 12, but the present invention is not limited to this, and may be attached to the ceiling 16 via an intermediate member. In addition, the sensor unit 9 may be fixed to the ceiling 16 and may be fixed with respect to the ceiling 16 or may be adjustable in position and angle with respect to the ceiling 16.

  As another embodiment, as shown in FIG. 15, there is a bed leaving prediction apparatus in which a sensor unit 9 ′ is attached to a wall 17 via an intermediate member 18. This bed leaving prediction apparatus can be configured by adding coordinate conversion means for performing coordinate conversion to the structure of the bed leaving prediction apparatus in which the sensor unit 9 is installed on the ceiling 16. The sensor unit 9 ′ may be directly attached to the wall 17 by being embedded in the wall 17. Attachment of the sensor unit 9 ′ to the wall 17 may be fixed to the wall 17, and the position and angle with respect to the wall 17 may be adjustable.

  The above coordinate conversion will be described in detail. For example, assume that the coordinate axes for the wall-mounted sensor unit 9 'shown in FIG. 15 are shown in FIG. The Z ′ axis is a direction perpendicular to the surface of the wall-mounted sensor unit 9 ′ that transmits and receives ultrasonic waves, and is directed to the lower right of the figure. The Y ′ axis is a direction along the plane of the ultrasonic wave transmission and reception in the wall-mounted sensor unit 9 ′ and the direction along the plane of the drawing, and is the upper right direction in the figure. The X ′ axis is the direction from the back of the paper surface to the front surface in a direction perpendicular to the paper surface.

  For example, the coordinate axes for the ceiling-mounted sensor unit 9 shown in FIG. 12 are shown in FIG. The Z-axis is a direction perpendicular to the surface of the ceiling-mounted sensor unit 9 that transmits and receives ultrasonic waves, and is directed downward in the figure. The Y-axis is the direction along the plane of the sensor unit 9 that transmits and receives ultrasonic waves and the left side of the figure. The X axis is the direction from the front to the back of the paper in a direction perpendicular to the paper.

  Consider a case where a wall-mounted sensor unit 9 ′ having a coordinate axis shown in FIG. 16A is installed on a wall 17 as shown in FIG. 15. The setting ranges of the areas 11 to 15 for the area bed 7 in the bed leaving prediction apparatus using the wall-mounted sensor unit 9 'are the same as those in the above embodiment. It is assumed that the ceiling-mounted sensor unit 9 having the coordinate axes shown in FIG. 16B is installed on the ceiling 16 in the room shown in FIG. The setting ranges of the areas 11 to 15 for the area bed 7 in the bed leaving prediction apparatus using the ceiling-mounted sensor unit 9 are the same as those in the above embodiment.

  A mathematical coordinate conversion formula is created so that the coordinate value on the coordinate axis of the wall-mounted sensor unit 9 ′ for the arbitrary position in the room becomes the coordinate on the coordinate axis of the ceiling-mounted sensor unit 9. If this coordinate conversion formula is used, the algorithm in the bed prediction apparatus using the ceiling-mounted sensor unit 9 can be used in the bed prediction apparatus using the wall-mounted sensor unit 9 '. That is, by adding a coordinate conversion means for performing coordinate conversion using the coordinate conversion formula and a coordinate conversion step to the bed leaving prediction device and the bed leaving prediction method using the ceiling installation type sensor unit 9, respectively, the wall installation type sensor unit 9 The bed leaving prediction device and bed leaving prediction method using 'can be easily configured.

  Since the wall-mounted sensor unit 9 ′ is easier to change the installation work and the installation location than the ceiling-mounted sensor unit 9, the bed leaving prediction apparatus and the bed leaving prediction method using the wall-mounted sensor unit 9 ′. Improves convenience and acceptability.

  Further, the wall-mounted sensor unit 9 ′ may be attached to a base such as a tripod instead of the wall 17 and the base may be movably disposed on the floor. In this case, since it is easier to change the installation work and the installation location, the bed leaving prediction apparatus and bed leaving prediction method using the wall-mounted sensor unit 9 ′ further improve convenience and acceptability. The wall-mounted sensor unit 9 ′ may be directly attached to the table, or may be attached to the table via an intermediate member. Further, the mounting of the wall-mounted sensor unit 9 ′ on the table may be fixed to the table, or the position and angle with respect to the table may be adjustable. Further, since the base on which the wall-mounted sensor unit 9 ′ is mounted is an extendable base, a base that can be bent, or the like, the wall-mounted sensor unit 9 ′ can be adjusted in position and angle with respect to the floor. Good.

  In addition, this invention is not limited to said embodiment at all, In the range which does not deviate from the summary of this invention, it can implement with a various form. For example, in the above embodiment, the case of predicting the bed leaving motion of the patient 10 has been described. However, the present invention can be similarly applied to a person other than the patient 10 in a nursing home or a general home.

  Further, in the above embodiment, the bed leaving operation is determined by the operation on the bed. However, for example, a switch or the like is set to determine the bed moving operation at the time when the user sits on the bed or rises from the floor. May be changed by The determination of the getting-off operation can be performed by, for example, setting the notification area to the getting-off area 15 and changing the definition of the area.

  By changing the setting for getting out of bed, for example, for elderly people who are difficult to stand on their feet and may fall, if they are judged on the bed (for example, using the method of paragraph [0063]), nurses and caregivers Can respond early and prevent the elderly from falling. On the other hand, with regard to getting out of a patient with dementia who is able to walk independently but who may be jealous by changing the setting of getting out motion, for example, if it is determined that the time of getting up or getting up on the floor is a getting out motion, There is no danger, and nurses and caregivers will be in time by the day. In addition, the number of notifications is reduced and the burden on the nurse and caregiver is reduced as compared with the case where the bed leaving operation is determined by the operation on the bed. That is, by changing the setting of the bed leaving movement determination, it is possible to perform bed leaving determination that matches the needs and operational status of the nursing / nursing side with a single bed prediction apparatus.

  Note that the setting for determining when the user sits up from the state of sitting on the bed as a bed leaving operation and the setting for determining the time when standing on the floor as a bed leaving operation may be made mutually changeable by, for example, a switch or the like.

  Further, in the above embodiment, the case where only the head position of the patient 10 is tracked and detected has been described. However, in addition to the head position of the patient 10, other body part positions such as the patient's shoulder can be tracked and detected simultaneously. Thus, the start of the bed leaving operation of the patient 10 may be determined.

Furthermore, in the above-described embodiment, a case where the management area 8 including one bed 7 is managed by one sensor unit 9 (one set of transmitter 2 and receiver 3) has been described. You may make it manage using the unit 9. FIG. In this case, it is preferable that an ultrasonic signal transmitted from each sensor unit 9 does not interfere with an ultrasonic signal transmitted from another sensor unit 9. As a countermeasure, it is possible to transmit ultrasonic waves sequentially from each sensor unit 9 with a predetermined time difference so that the ultrasonic waves transmitted from each sensor unit 9 do not interfere with each other. As another countermeasure, for example, the wavelength of the ultrasonic signal transmitted from each sensor unit 9 is changed, and the received ultrasonic signal is subjected to filtering processing for each wavelength component of the ultrasonic signal transmitted from each sensor unit 9. It is possible to measure separately. Further, the management area 8 including the plurality of beds 7 may be managed by one sensor unit 9. In this case, in order to expand the management area 8, it is preferable to use an omnidirectional transmitter as the transmitter 2.

  In addition, a transmitter for transmitting an ultrasonic signal is separately attached on the bed 7 (for example, the four corners of the bed 7), and the ultrasonic signal is transmitted toward the sensor unit 9 at a predetermined timing, whereby the determination unit 5 The position of the bed 7 may be recognized.

  Furthermore, the prediction of the bed leaving operation is not limited to manual operation, and may be started automatically. When the bed leaving prediction is automatically started, for example, a separate infrared sensor is attached to the stationary system such as the ceiling 16. This infrared sensor detects infrared rays of a specific wavelength emitted from the human body such as the patient 10 from the bed 7. When infrared rays are detected over a predetermined time, a signal is output from the infrared sensor to the determination means 5 to automatically start getting out of bed. Furthermore, the bed leaving detection may be temporarily terminated when the notification means 6 issues a notification signal.

It is a block diagram which shows the bed leaving prediction apparatus which concerns on one Embodiment of this invention. It is a perspective view which shows typically the attachment aspect of the bed leaving prediction apparatus which concerns on this embodiment. (A) is a top view which shows typically an example of the receiver used for the bed leaving prediction apparatus which concerns on this embodiment, (b) is a top view which shows typically another example of a receiver. It is. It is a flowchart which shows the bed prediction procedure by the bed prediction apparatus which concerns on this embodiment. It is a graph which shows an example of reflected wave data. It is a graph which shows typically an example of the waveform of the ultrasonic signal to transmit. It is a flowchart which shows the grouping process included in the bed leaving prediction procedure of FIG. It is a figure which shows notionally the process result of a grouping process. It is a flowchart which shows the movement determination process included in the bed leaving prediction procedure of FIG. It is a figure which shows notionally the process result of a movement determination process. It is a figure which shows notionally the process result of a movement determination process. It is a side view which shows the division | segmentation aspect of the management area seen from the side of the bed. It is a side view which shows the division | segmentation aspect of the management area seen from the front of the bed. It is a flowchart which shows the area determination process included in the bed leaving prediction procedure of FIG. It is a figure which shows the bed leaving prediction apparatus which concerns on another embodiment of this invention. FIG. 6A is a diagram illustrating an example of coordinate axes of the bed leaving prediction apparatus. FIG. 6A illustrates a case where a wall-mounted sensor unit is used, and FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bed leaving prediction apparatus 2 Transmitter 3 Receiver 4 Position calculation means 5 Determination means 6 Notification means 7 Bed 8 Management area 9, 9 'Sensor unit 10 Patient S1 Reflected wave data acquisition process S2 Position calculation process S3 Determination process S4 Notification Process

Claims (9)

A transmitter that continuously transmits an ultrasonic signal to a management area including a bed while attached to a stationary system;
A receiver for receiving the ultrasonic signal reflected in the management area in a state attached to a stationary system;
Position calculating means for calculating momentarily the head three-dimensional position of the human body on the bed from the reflected wave data acquired every predetermined time by the receiver corresponding to the ultrasonic signal transmitted from the transmitter When,
A temporal change from the lying position of the human head three-dimensional position is detected from the calculation result of the position calculation means, and it is determined whether or not the human body on the bed has started leaving the bed based on the detection result. A determination means;
A bed leaving prediction device comprising: a notification unit that issues a notification signal when the determination unit detects the start of a bed leaving operation of a human body.   The determination means uses the three-dimensional head position of the human body calculated from the reflected wave data acquired at a certain moment by the position calculating means as a reference position and is calculated from the reflected wave data acquired immediately thereafter. Using the three-dimensional position of the head of the human body as the target position, the movement vector from the reference position to the target position is calculated, and the case where the magnitude of the movement vector is equal to or less than a first predetermined value is reported as It is configured to detect a temporal change from the lying position of the human head three-dimensional position by determining that the head of the human body has moved from the reference position to the target position based on actual reports. The bed leaving prediction apparatus according to claim 1, wherein   3. The bed leaving prediction apparatus according to claim 2, wherein the determination unit is configured to increase the first predetermined value corresponding to a detection time during which the actual report is not continuously obtained. .   The position calculating means sets a provisional head three-dimensional position when a plurality of head three-dimensional positions are calculated from one reflected wave data, and a displacement vector between the provisional head three-dimensional positions. Is selected, and a provisional head three-dimensional position where the magnitude of the displacement vector is equal to or smaller than a second predetermined value is selected from the above, and the head three-dimensional position of the human body is selected based on the selected provisional head three-dimensional position. The bed leaving prediction apparatus according to any one of claims 1 to 3, wherein the bed leaving prediction apparatus is configured to set the value.   The bed receiving prediction apparatus according to any one of claims 1 to 4, wherein the wave receiver is an array sensor in which a plurality of wave receiving elements are arranged. An ultrasonic signal is continuously transmitted from a transmitter attached to a stationary system to a management area including a bed, and the ultrasonic signal reflected in the management area is received by a receiver attached to the stationary system. Then, a reflected wave data acquisition step of acquiring reflected wave data corresponding to the ultrasonic signal transmitted from the transmitter every predetermined time;
A position calculating step for calculating momentarily the head three-dimensional position of the human body on the bed from the reflected wave data acquired in the reflected wave data acquiring step;
A temporal change from the lying position of the human head three-dimensional position is detected from the calculation result of the position calculation step, and it is determined whether or not the human body on the bed has started to move out of the bed based on the detection result. A determination process;
A bed leaving prediction method, comprising: a notifying step that issues a notification signal when the determination step detects the start of a bed leaving motion of a human body.   The determination step uses the three-dimensional position of the human head calculated from the reflected wave data acquired at a certain moment by the position calculating step as a reference position, and is calculated from the reflected wave data acquired immediately thereafter. Using the three-dimensional position of the head of the human body as the target position, the movement vector from the reference position to the target position is calculated, and the case where the magnitude of the movement vector is equal to or less than a first predetermined value is reported as A temporal change from the lying position of the human head three-dimensional position is detected by determining that the human head has moved from the reference position to the target position based on actual reports. The bed leaving prediction method according to claim 6.   8. The bed leaving prediction method according to claim 7, wherein the determining step increases the first predetermined value corresponding to a detection time during which the actual report is not continuously obtained.   In the position calculation step, when a plurality of head three-dimensional positions are calculated from one reflected wave data, these are set as provisional head three-dimensional positions, and displacement vectors between the provisional head three-dimensional positions. Is selected, and a provisional head three-dimensional position where the magnitude of the displacement vector is equal to or smaller than a second predetermined value is selected from the above, and the head three-dimensional position of the human body is selected based on the selected provisional head three-dimensional position. Is set, The bed leaving prediction method of any one of Claims 6-8 characterized by the above-mentioned.

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