Submergence determination system and submergence determination method

Abstract

To provide: a submergence determination system having a high measurement accuracy for a head position of a bather; and a submergence determination method.SOLUTION: A submergence determination system 1 includes: an ultrasonic transmission device 2, an ultrasonic reception device 3, and a submergence determination device 4. One of the ultrasonic transmission device 2 and the ultrasonic reception device 3 is arranged above a bath 6 in a long direction and the other of the ultrasonic transmission device 2 and the ultrasonic reception device 3 is arranged above the bath in a short direction. The ultrasonic transmission device 2 is configured to emit an ultrasonic wave obliquely downward such that the ultrasonic wave transmitted from the ultrasonic transmission device 2 reflects on a head part Q of a bather to be received by the ultrasonic reception device 3. The submergence determination device 4 acquires a water surface height of the bath 6, calculates a head position of the bather P based on the reflected wave received by the ultrasonic reception device 3, and determines whether or not the bather P is in a bathing posture with a possibility of proceeding into a submergence state based on the head position and the water surface height position.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a submersion determination system and a submersion determination method. [Background technology]

[0002] Patent Document 1 discloses a submersion determination system that detects whether or not a bather is in a bathing posture that may lead to a submerged state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-129930 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the submersion determination system disclosed in the above-mentioned Patent Document 1, the position of the bather's head is measured using ultrasonic devices installed on the ceiling. The submersion determination system disclosed in Patent Document 1 does not mention the distance from the wall surface installed in the longitudinal direction of the bathtub to each ultrasonic device. Therefore, if the distance from the longitudinal wall surface of the bathtub to each ultrasonic device is equal, the ultrasonic waves transmitted from one ultrasonic device will be reflected back by the top surface of the remote control if an object whose top surface forms a right-angle corner with the wall surface, such as a remote control, is present on the longitudinal wall surface, and will be received as high sound pressure by the other ultrasonic device. In this way, the submersion determination system disclosed in Patent Document 1 may lack the accuracy of measuring the position of the bather's head.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide a submersion determination system and a submersion determination method that can measure the bather's head position with high accuracy. [Means for solving the problem]

[0006] The submersion determination system according to the present disclosure comprises: An ultrasonic transmitting device and an ultrasonic receiving device disposed above the bathtub in the bathroom; A submersion determination device that determines whether or not the bather is in a bathing posture that may lead to a submerged state; Equipped with One of the ultrasonic transmitting device and the ultrasonic receiving device is disposed above the bathtub in a longitudinal direction, the other of the ultrasonic transmitting device and the ultrasonic receiving device is disposed above the bathtub in a short side direction, the ultrasonic transmitting device is configured to transmit ultrasonic waves obliquely downward so that the ultrasonic waves transmitted from the ultrasonic transmitting device are reflected by the head of the bather and received by the ultrasonic receiving device; The submersion determination device includes: Acquire the height position of the water surface of the bathtub; Calculating the head position of the bather based on the reflected waves received by the ultrasonic receiving device; Based on the head position and the height of the water surface, it is determined whether the bather is in a bathing posture that may lead to a submerged state.

[0007] In the submersion determination system according to the present disclosure, one of the ultrasonic transmitting device and the ultrasonic receiving device is arranged above the bathtub in the longitudinal direction, and the other of the ultrasonic transmitting device and the ultrasonic receiving device is arranged above the bathtub in the lateral direction. With this configuration, the distance from the wall surface surrounding the bathtub to each ultrasonic device is different for each surface. As a result, ultrasonic waves reflected back from an object whose upper surface forms a right-angle corner with the wall surface head in a different direction from the ultrasonic receiving device, and therefore the ultrasonic receiving device can be prevented from receiving the ultrasonic waves as high sound pressure. By preventing the reception of unnecessary ultrasonic waves, the accuracy of measuring the bather's head position can be improved.

[0008] The submersion determination method according to the present disclosure includes: A submersion determination method for determining whether a bather is in a bathing posture that may progress to a submerged state by using an ultrasonic transmitting device and an ultrasonic receiving device disposed above a bathtub in a bathroom, comprising: One of the ultrasonic transmitting device and the ultrasonic receiving device is disposed above the bathtub in a longitudinal direction, the other of the ultrasonic transmitting device and the ultrasonic receiving device is disposed above the bathtub in a short side direction, a step of transmitting ultrasonic waves obliquely downward from the ultrasonic transmitting device so that the ultrasonic waves transmitted from the ultrasonic transmitting device are reflected by the bather's head and received by the ultrasonic receiving device; Obtaining the height position of the water surface of the bathtub; calculating a head position of the bather based on the reflected waves received by the ultrasonic receiving device; A step of determining whether the bather is in a bathing posture that may progress to a submerged state based on the head position and the height position of the water surface; Includes.

[0009] In the submersion determination method according to the present disclosure, one of the ultrasonic transmitting device and the ultrasonic receiving device is arranged above the bathtub in the longitudinal direction, and the other of the ultrasonic transmitting device and the ultrasonic receiving device is arranged above the bathtub in the lateral direction. With this configuration, the distance from each wall surface around the bathtub to each ultrasonic device is different for each surface. As a result, ultrasonic waves reflected back from an object whose upper surface forms a right-angle corner with the wall surface head in a different direction from the ultrasonic receiving device, and the ultrasonic receiving device can be prevented from receiving the ultrasonic waves as high sound pressure. By preventing the reception of unnecessary ultrasonic waves, the accuracy of measuring the bather's head position can be improved. Effect of the Invention

[0010] The present disclosure makes it possible to provide a submersion determination system and a submersion determination method that can measure a bather's head position with high accuracy. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a submersion determination system according to a first embodiment. [Diagram 2] 1 is a schematic diagram of a submersion determination system according to a first embodiment. [Diagram 3] 1 is a schematic diagram of a submersion determination system according to a first embodiment. [Figure 4] 2 is a detailed block diagram of a submersion determination device of the submersion determination system according to the first embodiment. FIG. [Diagram 5] FIG. 2 is a diagram showing the arrangement of ultrasonic transmitters and ultrasonic receivers of a submersion determination system according to a comparative example and the first embodiment. [Figure 6] FIG. 1 is an explanatory diagram for explaining retroreflection. [Figure 7] FIG. 2 is an explanatory diagram for explaining transmission and reception sensitivity. [Figure 8] 13 is a diagram showing the arrangement of ultrasonic transmitting devices and ultrasonic receiving devices in a submersion determination system according to a modified example. FIG. [Figure 9] 13 is a diagram showing the arrangement of ultrasonic transmitting devices and ultrasonic receiving devices in a submersion determination system according to a modified example. FIG. [Figure 10] 13 is a diagram showing the arrangement of ultrasonic transmitting devices and ultrasonic receiving devices in a submersion determination system according to a modified example. FIG. [Figure 11] 13 is a diagram showing the arrangement of ultrasonic transmitting devices and ultrasonic receiving devices in a submersion determination system according to a modified example. FIG. [Figure 12] 4 is a diagram showing a control flow of the submersion determination system according to the first embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding elements are given the same reference numerals, and duplicated explanations are omitted as necessary for clarity of explanation. In addition, some reference numerals are omitted so as not to make the drawings complicated. It should be noted that each of the drawings below is schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each layer, etc. are different from the actual ones. Therefore, the specific thickness and dimensions should be determined with reference to the following explanation. In addition, it goes without saying that the drawings include parts in which the relationship and ratio of dimensions are different from each other.

[0013] Naturally, the right-handed xyz Cartesian coordinate system shown in each drawing is for the convenience of explaining the positional relationship of the components. Usually, the positive direction of the z axis is vertically upward, and the xy plane is a horizontal plane.

[0014] (Embodiment 1) <Submersion Judgment System> First, the configuration of a submersion determination system according to embodiment 1 will be described with reference to Figs. 1 to 3. Figs. 1 to 3 are schematic diagrams of a submersion determination system according to embodiment 1. More specifically, Fig. 1 is an xy plan view showing an outline of the submersion determination system. Fig. 2 is an xz plan view showing an outline of the submersion determination system. Fig. 3 is a yz plan view showing an outline of the submersion determination system.

[0015] 1 to 3, a submersion determination system 1 according to this embodiment includes an ultrasonic transmission device 2, an ultrasonic reception device 3, a submersion determination device 4, and an alarm device 5. In the submersion determination system 1 shown in FIG. 1, only the ultrasonic transmission device 2 and the ultrasonic reception device 3 are shown, while the submersion determination device 4 and the alarm device 5 are omitted.

[0016] <Ultrasonic transmitting device 2 and ultrasonic receiving device 3> As shown in Fig. 1, ultrasonic transmitting device 2 and ultrasonic receiving device 3 are typically arranged on the ceiling above bathtub 6 in bathroom 10, but are not limited to the ceiling. As shown in Fig. 1, bathroom 10 has walls W1 and W2.

[0017] As shown in Fig. 1, the ultrasonic receiving device 3 is disposed above the bathtub 6 in the longitudinal direction. Also, as shown in Fig. 1, the ultrasonic transmitting device 2 is disposed above the bathtub 6 in the lateral direction. In this manner, one of the ultrasonic transmitting device 2 and the ultrasonic receiving device 3 is disposed above the bathtub 6 in the longitudinal direction, and the other of the ultrasonic transmitting device 2 and the ultrasonic receiving device 3 is disposed above the bathtub 6 in the lateral direction. In other words, the ultrasonic transmitting device 2 and the ultrasonic receiving device 3 are disposed above the bathtub 6 so that a straight line connecting the center of the ultrasonic transmitting device 2 and the center of the ultrasonic receiving device 3 is not parallel to the surrounding wall surfaces W1 and W2.

[0018] 1, the ultrasonic receiving device 3 arranged at the upper part in the longitudinal direction of the bathtub 6 is arranged on the ultrasonic transmitting device 2 side from the center in the longitudinal direction of the bathtub 6. In other words, one of the ultrasonic transmitting device 2 and the ultrasonic receiving device 3 arranged at the upper part in the longitudinal direction of the bathtub 6 is arranged on the other side of the ultrasonic transmitting device 2 and the ultrasonic receiving device 3 from the center in the longitudinal direction of the bathtub 6.

[0019] As shown in Figures 2 and 3, the ultrasonic transmitting device 2 is configured to transmit ultrasonic waves diagonally downward so that the ultrasonic waves transmitted from the ultrasonic transmitting device 2 are reflected by the head Q of the bather P and received by the ultrasonic receiving device 3.

[0020] 1, ultrasonic waves transmitted from the ultrasonic transmitting device 2 are reflected by the head Q of the bather P and travel along paths L11 and L12 until they are received by the ultrasonic receiving device 3. Note that the ultrasonic transmitting device 2 may transmit and receive ultrasonic waves, and the ultrasonic receiving device 3 may further receive the ultrasonic waves transmitted by the ultrasonic transmitting device 2.

[0021] The transmission direction of the ultrasonic waves transmitted from the ultrasonic transmission device 2, that is, the angle between the direction in which the acoustic level of the ultrasonic waves transmitted from the ultrasonic transmission device 2 is maximum and the water surface 8, is hereinafter referred to as angle θ. The angle θ is one specific example of the transmission angle. In this embodiment, the angle θ is 15 degrees or more and less than 90 degrees. Preferably, the angle θ is less than 85 degrees, less than 80 degrees, or less than 75 degrees. The directional characteristics of the ultrasonic waves transmitted by the ultrasonic transmission device 2 are set so that the intensity of the ultrasonic waves transmitted directly downward from the ultrasonic transmission device 2 is as small as possible. In detail, the directional characteristics of the ultrasonic waves transmitted by the ultrasonic transmission device 2 are set so that all components within the half-value angle of the main lobe of the ultrasonic waves transmitted by the ultrasonic transmission device 2 are obliquely downward. Preferably, the ultrasonic transmission device 2 is configured not to transmit ultrasonic waves directly downward from the ultrasonic transmission device 2. By setting the directional characteristics as described above, the ultrasonic waves transmitted from the ultrasonic transmission device 2 are reflected by the water surface 8 and are less likely to be received by the ultrasonic transmission device 2.

[0022] <Submersion determination device 4> The submersion determination device 4 is a device that determines whether or not the bathing posture of the bather P may progress to a submerged state.

[0023] The submerged state of bather P is as follows: In other words, drowning in a bathtub occurs when bather P loses consciousness for some reason while immersed in the hot water of bathtub 6, or when standing up to get out of bathtub 6, a rapid drop in blood pressure causes the brain or heart to become ischemic, causing bather P's head Q to be submerged in the hot water of bathtub 6, and the hot water of bathtub 6 blocks the respiratory organs such as the nose and mouth. The submerged state of bather P is defined as the state in which bather P's head Q is submerged in the hot water of bathtub 6.

[0024] The submersion determination device 4 is connected by wire or wirelessly to the ultrasonic transmission device 2 and the ultrasonic reception device 3. As will be described later, the submersion determination device 4 determines whether or not the bathing posture of the bather P may progress to a submerged state, based on the position of the bather P's head Q and the height of the water surface 8.

[0025] <Alarm device 5> The warning device 5 is connected to the submersion determination device 4 by wire or wirelessly. The submersion determination device 4 and the warning device 5 can be installed anywhere inside or outside the bathroom. The submersion determination device 4 and the warning device 5 may be built into either the ultrasonic transmitting device 2 or the ultrasonic receiving device 3. The warning device 5 issues a warning when the submersion determination device 4 determines that the bather P is in a bathing position that may progress to a submerged state.

[0026] <Detailed Description of Submersion Judgment Device 4> The submersion determination device 4 will be described in detail below with reference to Fig. 4. Fig. 4 is a detailed block diagram of the submersion determination device of the submersion determination system according to the first embodiment. As shown in Fig. 4, the submersion determination device 4 is connected to the ultrasonic transmission device 2 and the ultrasonic reception device 3 by wire or wirelessly. As shown in Fig. 4, the submersion determination device 4 includes a pulse generation circuit 20, an oscillation circuit 21, an interruption circuit 22, and a transmission amplifier circuit 23. The submersion determination device 4 also includes a reception amplifier circuit 31, a filter circuit 32, a waveform analysis circuit 33, a head reflected wave extraction unit 28, a head distance calculation unit 29, a head height position calculation unit 30, and a water surface height position calculation unit 35. The submersion determination device 4 also includes a submersion determination unit 36.

[0027] The head reflected wave extraction unit 28, head distance calculation unit 29, head height position calculation unit 30, water surface height position calculation unit 35, and submersion determination unit 36 ​​are configured by, for example, logic circuits of a central processing unit.

[0028] The oscillator circuit 21 generates an AC signal in the ultrasonic band. The pulse generating circuit 20 generates a pulse for determining the transmission and reception time of the ultrasonic wave, and outputs it to the interrupter circuit 22 and the waveform analyzing circuit 33. The interrupter circuit 22 is controlled by the pulse from the pulse generating circuit 20, and converts the AC signal from the oscillator circuit 21 into an AC waveform having a pulsed amplitude. The transmission amplifier circuit 23 amplifies the AC signal from the interrupter circuit 22.

[0029] The receiving amplifier circuit 31 amplifies the reflected wave received by the ultrasonic receiver 3. The filter circuit 32 removes frequency components other than the frequency components of the ultrasonic waves transmitted from the ultrasonic transmitter 2 from the reflected wave received by the ultrasonic receiver 3. The output from the filter circuit 32 is input to the waveform analysis circuit 33.

[0030] The waveform analysis circuit 33 performs envelope detection on the received waveform input from the filter circuit 32, and outputs an envelope-detected waveform.

[0031] The head reflected wave extraction unit 28 extracts the reflected wave from the head Q of the bather P from the reflected waves received by the ultrasonic receiving device 3 based on the envelope detection waveform output from the waveform analysis circuit 33.

[0032] The head distance calculation unit 29 calculates the head distance D1 (see Figs. 2 and 3), which is the distance from the ultrasonic transmission device 2 to the head Q of the bather P, based on the reflected wave at the head Q of the bather P. Specifically, the head distance calculation unit 29 calculates the delay time from when the ultrasonic transmission device 2 transmits the ultrasonic wave to when the ultrasonic receiving device 3 receives the reflected wave at the head Q of the bather P, and calculates the head distance D1 by multiplying this delay time by the propagation speed of the ultrasonic wave.

[0033] Note that the distances D1, D2, D3, D4, and D11 shown in Figures 2 and 3 indicate three-dimensional distances, not two-dimensional distances. For ease of explanation, the three-dimensional distances D1, D2, D3, D4, and D11 are shown in the xz plane view in Figure 2 and the yz plane view in Figure 3.

[0034] The head height position calculation unit 30 calculates the height position of the head Q of the bather P based on the head distance D1. Specifically, the head height position calculation unit 30 calculates the vertical distance D11 between the ultrasonic receiver 3 and the head Q by a geometric means such as Pythagoras' theorem based on the head distance D1 and the known separation distance D3 between the ultrasonic transmitter 2 and the ultrasonic receiver 3. The head height position calculation unit 30 can then calculate the height position of the head Q of the bather P by subtracting the vertical distance D11 from the known height position of the ultrasonic receiver 3.

[0035] The water surface height position calculation unit 35 calculates the position of the height of the water surface 8 in the bathtub 6 by acquiring information about the water surface height in the bathtub 6. More specifically, it calculates the position of the height of the water surface 8 in the bathtub 6 by acquiring information about the water surface height from a water surface sensor (not shown) in the bathtub 6. In addition, the submersion determination device 4 can be in wireless communication with the bathtub 6, and the water surface height position calculation unit 35 may acquire information about the water surface height set in the bathtub 6 by the user, and calculate the position of the height of the water surface 8 in the bathtub 6.

[0036] The submersion determination unit 36 ​​compares the height position of the head Q of the bather P calculated by the head height position calculation unit 30 with the height position of the water surface 8 calculated by the water surface height position calculation unit 35, and determines whether the bather P is in a bathing posture that may progress to a submerged state based on the comparison result. Specifically, the submersion determination unit 36 ​​calculates the difference between the height position of the head Q of the bather P and the height position of the water surface 8, and if this difference is equal to or less than a predetermined value, determines that the bather P is in a bathing posture that may progress to a submerged state. Here, the predetermined value is set appropriately within a range of, for example, 15 cm to 30 cm, and is preferably determined according to the size of the head Q of the bather P, the position of the respiratory organs, etc. The predetermined value is set to 25 cm, for example. The predetermined value is stored in advance in a storage device (not shown) of the submersion determination device 4.

[0037] The warning device 5 issues a warning when the submersion determination unit 36 ​​determines that the bather P is in a bathing posture that may progress to a submerged state.

[0038] The water surface height position calculation unit 35 may calculate the height position of the water surface 8 based on the waves reflected by the water surface 8. In this case, the configuration is as follows. The ultrasonic transmission device 2 is configured to transmit ultrasonic waves obliquely downward so that the ultrasonic waves transmitted from the ultrasonic transmission device 2 are conformally reflected by the water surface 8 of the bathtub 6 and received by the ultrasonic receiving device 3. More specifically, as shown in FIG. 1, the ultrasonic waves transmitted from the ultrasonic transmission device 2 follow paths L21 and L22 until they are conformally reflected by the water surface 8 of the bathtub 6 and received by the ultrasonic receiving device 3.

[0039] The submersion determination device 4 includes a water surface reflected wave extraction unit. More specifically, the water surface reflected wave extraction unit extracts the reflected wave at the water surface 8 from the reflected wave received by the ultrasonic receiver 3 based on the envelope detection waveform output from the waveform analysis circuit 33. The reflected wave at the water surface 8 has an amplitude much larger than that of the reflected wave at the head Q of the bather P. Therefore, by setting a higher threshold value for the envelope detection waveform output from the waveform analysis circuit 33, the water surface reflected wave extraction unit can easily extract the reflected wave at the water surface 8 from the reflected wave received by the ultrasonic receiver 3.

[0040] The water surface height position calculation unit 35 calculates the height position of the water surface 8 based on the reflected wave from the water surface 8. Specifically, the water surface height position calculation unit 35 calculates the delay time from when the ultrasonic wave is transmitted from the ultrasonic transmission device 2 to when the reflected wave is received by the ultrasonic reception device 3, and calculates the propagation distance D2 (see Figs. 2 and 3) of the V-shaped propagation path of the ultrasonic wave conformally reflected by the water surface 8 by multiplying this delay time by the propagation speed of the ultrasonic wave.

[0041] The water surface height position calculation unit 35 calculates the vertical distance D4 between the ultrasonic receiving device 3 and the water surface 8 by a geometric means such as Pythagoras' theorem based on the propagation distance D2 and the known separation distance D3 between the ultrasonic transmitting device 2 and the ultrasonic receiving device 3. Then, the water surface height position calculation unit 35 can calculate the height position of the water surface 8 by subtracting the vertical distance D4 from the known height position of the ultrasonic receiving device 3.

[0042] <Retroreflection> Here, retroreflection will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a diagram showing the arrangement of ultrasonic transmitting devices and ultrasonic receiving devices of a submersion determination system according to a comparative example and the present embodiment 1. The upper part of Fig. 5 shows the arrangement of ultrasonic transmitting devices and ultrasonic receiving devices of a submersion determination system according to the comparative example. Moreover, the lower part of Fig. 5 shows the arrangement of ultrasonic transmitting devices and ultrasonic receiving devices of a submersion determination system according to the present embodiment 1.

[0043] Fig. 6 is an explanatory diagram for explaining retroreflection. The upper part of Fig. 6 shows an explanatory diagram in the case of the arrangement of an ultrasonic transmitter and an ultrasonic receiver of a submersion determination system according to a comparative example. The upper part of Fig. 6 is a yz plan view corresponding to the xy plan view shown in the upper part of Fig. 5. The lower part of Fig. 6 shows an explanatory diagram in the case of the arrangement of an ultrasonic transmitter and an ultrasonic receiver of a submersion determination system according to embodiment 1. The lower part of Fig. 6 is a yz plan view corresponding to the xy plan view shown in the lower part of Fig. 5.

[0044] As shown in the upper part of Fig. 5, in the submersion determination system according to the comparative example, the distance from the ultrasonic transmitter 2 to the wall W1 and the distance from the ultrasonic receiver 3 to the wall W1 are both equal, being distance D31. Therefore, as shown in the upper part of Fig. 6, in the submersion determination system according to the comparative example, ultrasonic waves transmitted from the ultrasonic transmitter 2 are reflected recursively by the right-angle corner of the remote control R1 installed on the wall W1, travel in the direction of the ultrasonic receiver 3, and are received with a high sound pressure. As a result, in the submersion determination system according to the comparative example, unnecessary reflected waves from objects such as the remote control R1 are received with a large amplitude, resulting in a lack of accuracy in measuring the bather's head position.

[0045] 5, in the submersion determination system according to the first embodiment, the distance from the ultrasonic transmission device 2 to the wall surface W1 is distance D31, whereas the distance from the ultrasonic reception device 3 to the wall surface W1 is distance D32. That is, the distance from the ultrasonic transmission device 2 to the wall surface W1 is different from the distance from the ultrasonic reception device 3 to the wall surface W1.

[0046] Therefore, as shown in the lower part of Fig. 6, in the submersion determination system according to the first embodiment, ultrasonic waves transmitted from the ultrasonic transmission device 2 are reflected retrogradely by the right-angle corner of the remote control R1 installed on the wall surface W1 and travel in the direction of the ultrasonic transmission device 2, and the sound pressure received by the ultrasonic reception device 3 is low. That is, in the submersion determination system according to the first embodiment, it is possible to prevent the ultrasonic reception device from receiving ultrasonic waves retrogradely reflected by an object having a right-angle corner with respect to the wall surface. As a result, in the submersion determination system according to the first embodiment, unnecessary reflected waves from objects such as the remote control R1 are suppressed, and the measurement accuracy of the bather's head position can be improved.

[0047] In FIG. 6, the remote control R1 is used as an example to explain retroreflection, but the present invention is not limited to this. Retroreflection also occurs on an object having a right-angle corner with respect to a wall surface, such as a window frame.

[0048] <Transmit / receive sensitivity> Next, the transmission and reception sensitivity of ultrasonic waves will be described with reference to Fig. 7. Fig. 7 is an explanatory diagram for explaining the transmission and reception sensitivity. The upper part of Fig. 7 is an xy plan view showing, by dotted lines, a range where the sensitivity is high in the submersion determination system according to the comparative example. The lower part of Fig. 7 is an xy plan view showing, by dotted lines, a range where the sensitivity is high in the submersion determination system according to the first embodiment. In Fig. 7, the sensitivity range for detecting the position of the head is shown by dotted lines.

[0049] As shown in the upper part of Fig. 7, in the submersion determination system of the comparative example, the ultrasonic transmitter 2 and ultrasonic receiver 3 are arranged at a distance in the longitudinal direction. Assuming that a bather may enter the bathtub on either of the longitudinal ends, the submersion determination system of the comparative example has a high sensitivity range near the longitudinal center of the bathtub. As shown in the upper part of Fig. 7, the position of head Q falls outside the high sensitivity range, and the sound pressure of the reflected wave from head Q becomes low, resulting in a lack of accuracy in measuring the bather's head position.

[0050] On the one hand, as shown in the lower part of FIG. 7, in the submergence determination system according to Embodiment 1, the ultrasonic receiving device 3 arranged above in the longitudinal direction of the bathtub 6 is arranged closer to the ultrasonic transmitting device 2 arranged above in the lateral direction of the bathtub 6 than the center in the longitudinal direction of the bathtub 6. This is in view of the fact that in the bathtub 6, depending on the position of the faucet and the footrest, the position of the head Q of the bather often determines to be either at both ends in the longitudinal direction of the bathtub. At this time, the range with high sensitivity is near the middle between the ultrasonic transmitting device 2 and the ultrasonic receiving device 3. And as shown in the lower part of FIG. 7, since the position of the head Q is near the center of the range with high sensitivity, the sound pressure of the reflected wave from the head Q becomes high, so that the measurement accuracy of the position of the bather's head can be improved.

[0051] In this way, in the submergence determination system 1 according to Embodiment 1, the ultrasonic receiving device 3 can be suppressed from receiving the ultrasonic wave retroreflected by an object having a right-angled corner with respect to the wall surfaces W1 and W2. Furthermore, the position of the head Q is near the center of the range with high sensitivity. Therefore, in the submergence determination system 1 according to Embodiment 1, the sound pressure of the unnecessary reflected wave from the object is suppressed low, and the sound pressure of the reflected wave from the head Q becomes high, so that the measurement accuracy of the position of the bather's head can be improved.

[0052] <Modification Example> Hereinafter, with reference to FIGS. 8 to 11, a submergence determination system according to a modification example in which the arrangement of the ultrasonic transmitting device and the ultrasonic receiving device is changed will be described. FIGS. 8 to 11 are diagrams showing the arrangement of the ultrasonic transmitting device and the ultrasonic receiving device in the submergence determination system according to the modification example. FIGS. 8 to 11 are xy plane views. In FIGS. 8 to 11, the range with high transmission and reception sensitivity is indicated by a dotted line.

[0053] <L-shaped> As shown in Fig. 8, in the submersion determination system according to the modified example, the ultrasonic receiving device 3 is arranged above the bathtub 6 in the longitudinal direction. Also, as shown in Fig. 8, in the submersion determination system according to the modified example, the ultrasonic transmitting device 2 is arranged above the bathtub 6 in the lateral direction. Furthermore, as shown in Fig. 8, in the submersion determination system according to the modified example, the ultrasonic transmitting device 2 and the ultrasonic receiving device 3 are arranged in an L-shape above the bathtub 6. They may be an integrated L-shape.

[0054] 8, the distances from the walls W1, W2 surrounding the bathtub to the ultrasonic transmitting device 2 and the ultrasonic receiving device 3 are different. Therefore, the submersion determination system according to the modified example can prevent the ultrasonic receiving device 3 from receiving ultrasonic waves retroreflected by an object having a right-angle corner with respect to the wall W1, W2.

[0055] Furthermore, as shown in Fig. 8, since the ultrasonic transmitting device 2 and the ultrasonic receiving device 3 are arranged in an L-shape, the range of high sensitivity is located near the middle between the ultrasonic transmitting device 2 and the ultrasonic receiving device 3. As shown in Fig. 8, the position of head Q is near the center of the range of high sensitivity, and the sound pressure of the reflected wave from head Q is high. Therefore, the submersion determination system according to the modified example shown in Fig. 8 can improve the accuracy of measuring the position of the bather's head.

[0056] Needless to say, the arrangement of the ultrasonic transmitting device 2 and the ultrasonic receiving device 3 is not limited to that shown in Fig. 8, and the following arrangements are also possible. The ultrasonic receiving device 3 may be arranged above the bathtub 6 in the short direction, and the ultrasonic transmitting device 2 may be arranged above the bathtub 6 in the long direction, so that the ultrasonic transmitting device 2 and the ultrasonic receiving device 3 are arranged in an L-shape. They may also be an integrated L-shape.

[0057] In the bathtub 6, the position of the bather's head Q is often determined by the position of the stopper and the position of the footrest. Therefore, it is preferable to arrange the ultrasonic transmitter 2 and the ultrasonic receiver 3 in an L-shape according to the position of the bather's head.

[0058] <Line symmetry> As shown in Fig. 9, in the submersion determination system according to the modified example, the ultrasonic transmission device 2 and the ultrasonic transmission device 12 are arranged so as to be line-symmetrical with respect to a center line C1 passing through the center in the longitudinal direction of the bathtub 6. Also, as shown in Fig. 9, in the submersion determination system according to the modified example, the ultrasonic reception device 3 and the ultrasonic reception device 13 are arranged so as to be line-symmetrical with respect to a center line C1 passing through the center in the longitudinal direction of the bathtub 6. In other words, the ultrasonic transmission devices and the ultrasonic reception devices are arranged so as to be line-symmetrical with respect to a center line passing through the center in the longitudinal direction of the bathtub.

[0059] 9, the ultrasonic transmitting device 2 is configured to transmit ultrasonic waves obliquely downward so that the ultrasonic waves transmitted from the ultrasonic transmitting device 2 are reflected by the head Q of the bather P and received by the ultrasonic receiving device 3. Moreover, the ultrasonic transmitting device 12 is configured to transmit ultrasonic waves obliquely downward so that the ultrasonic waves transmitted from the ultrasonic transmitting device 12 are reflected by the head Q of the bather P and received by the ultrasonic receiving device 13.

[0060] 9, when the head is located on the negative side of the x-axis from the central axis C1 of the bathtub 6, the position of the head Q is detected by the ultrasonic transmitting device 2 and the ultrasonic receiving device 3. On the other hand, when the head is located on the positive side of the x-axis from the central axis C1 of the bathtub 6, the position of the head Q is detected by the ultrasonic transmitting device 12 and the ultrasonic receiving device 13.

[0061] In this way, in the submersion determination system according to the modification shown in Fig. 9, a plurality of ultrasonic transmitting devices and ultrasonic receiving devices are arranged on the ceiling, and the ultrasonic transmitting devices and the ultrasonic receiving devices are arranged so as to be symmetrical with respect to the center line C1 of the bathtub 6, which passes through the center of the bathtub 6 in the longitudinal direction. As a result, the submersion determination system according to the modification shown in Fig. 9 can improve the measurement accuracy of the bather's head position regardless of which end of the bathtub 6 the head is located in the x-axis direction. Furthermore, even when two people, a child and a parent, are bathing and their respective heads are located at both ends of the bathtub 6 in the x-axis direction, the submersion determination system according to the modification shown in Fig. 9 can improve the measurement accuracy of the head positions of both people.

[0062] 9, two ultrasonic transmitters and two ultrasonic receivers are disposed at each end of the bathtub 6 in the x-axis direction, but an ultrasonic transmitter and an ultrasonic receiver may also be disposed near the central axis C1 of the bathtub 6. With this configuration, the submersion determination system according to the modified example can improve the measurement accuracy of the head position of the bather P even if the head is located in the center of the bathtub 6.

[0063] <Layout that takes into consideration reduction of retroreflection> As shown in Fig. 10, in the submersion determination system according to the modified example, the ultrasonic receiving device 3 is arranged above in the longitudinal direction of the bathtub 6. Also, as shown in Fig. 10, in the submersion determination system according to the modified example, the ultrasonic transmitting device 2 is arranged above in the transverse direction of the bathtub 6. Compared to the submersion determination system according to embodiment 1 shown in the lower part of Fig. 7, in the arrangement shown in Fig. 10, the ultrasonic receiving device 3 arranged above in the longitudinal direction of the bathtub 6 is not arranged closer to the ultrasonic transmitting device 2 than the center of the bathtub 6 in the longitudinal direction.

[0064] In the arrangement shown in FIG. 10, the range of high sensitivity is near the center of the bathtub longitudinal direction in the xy plane. Therefore, the position of the head Q is outside the range of high sensitivity, and the sound pressure of the reflected wave from the head Q is low. However, in the arrangement shown in FIG. 10, the distance from the walls W1 and W2 around the bathtub to the ultrasonic transmitter 2 is different from the distance from the walls W1 and W2 to the ultrasonic receiver 3. Therefore, the submersion determination system according to the modification shown in FIG. 10 can prevent the ultrasonic receiver 3 from receiving ultrasonic waves retroreflected by an object having a right-angle corner with respect to the walls W1 and W2. As a result, the submersion determination system according to the modification shown in FIG. 10 can improve the measurement accuracy of the bather's head position because the sound pressure of unnecessary reflected waves from the object is suppressed to a low level.

[0065] <Ceiling rail> As shown in Fig. 11, in the submersion determination system according to the modified example, the ultrasonic receiving device 3 is disposed above the bathtub 6 in the longitudinal direction. Also, as shown in Fig. 11, in the submersion determination system according to the modified example, the ultrasonic transmitting device 2 is disposed above the bathtub 6 in the lateral direction. Furthermore, the ultrasonic transmitting device 2 and the ultrasonic receiving device 3 are disposed so as to be movable on a rail ra. The rail ra is, for example, embedded in the ceiling.

[0066] More specifically, the ultrasonic transmitting device 2 and the ultrasonic receiving device 3 can move on the rail ra in the longitudinal direction of the bathtub 6. The ultrasonic transmitting device 2 and the ultrasonic receiving device 3, for example, move on the rail ra in unison by the same amount of movement. However, this is not limited to this, and the ultrasonic transmitting device 2 and the ultrasonic receiving device 3 may move on the rail ra independently by different amounts of movement. As the ultrasonic transmitting device 2 and the ultrasonic receiving device 3 move, the range of high transmission and reception sensitivity also moves.

[0067] 11, if the ultrasonic transmitting device 2 and the ultrasonic receiving device 3 cannot detect the head, they move the rail ra in the longitudinal direction of the bathtub 6. That is, the ultrasonic transmitting device 2 and the ultrasonic receiving device 3 move the rail ra in the longitudinal direction of the bathtub 6 until they can detect the head. When the head position is detected, the submersion determination device calculates the head distance.

[0068] By configuring in this manner, the submersion determination system of the modified example shown in Figure 11 can set a range of high sensitivity to match the position of the bather's head Q regardless of where the bather's head Q is located in the bathtub 6, thereby improving the measurement accuracy of the bather's head position.

[0069] Alternatively, a motion sensor may be provided in the bathtub, and the ultrasonic transmitter 2 and ultrasonic receiver 3 may move the rail ra in the longitudinal direction of the bathtub 6 to above the position detected by the motion sensor. In addition, although the rail ra is provided parallel to the longitudinal direction of the bathtub 6 in FIG. 11, the rail ra may be provided parallel to the lateral direction of the bathtub 6, and the ultrasonic transmitter 2 and ultrasonic receiver 3 may move the rail ra in the lateral direction of the bathtub 6.

[0070] <Method for determining submergence> Next, a submersion determination method using the submersion determination system 1 according to the embodiment of the present invention will be described. Fig. 12 is a diagram showing a control flow of the submersion determination system according to embodiment 1. In the following description, the reference symbols shown in Figs. 1 to 4 will be used as appropriate.

[0071] First, the ultrasonic transmitter 2 transmits ultrasonic waves obliquely downward so that the ultrasonic waves transmitted from the ultrasonic transmitter 2 are reflected by the head Q of the bather P and received by the ultrasonic receiver 3 (step ST100).

[0072] Next, the waveform analysis circuit 33 analyzes the envelope detection waveform of the reflected wave received by the ultrasonic receiving device 3 (step ST101).

[0073] Next, the head reflected wave extraction unit 28 extracts the reflected wave from the head Q of the bather P from the reflected wave received by the ultrasonic receiving device 3 based on the envelope detection waveform output from the waveform analysis circuit 33 (step ST102).

[0074] Next, the head distance calculation unit 29 calculates the head distance D1 (see Figures 2 and 3), which is the distance from the ultrasonic transmitting device 2 to the head Q of the bather P, and the height position of the head Q of the bather P, based on the reflected wave at the head Q of the bather P (step ST103).

[0075] Next, the water surface height position calculation unit 35 calculates the position of the water surface height of the bathtub 6 by acquiring information on the water surface height of the bathtub 6 (step ST104).

[0076] Next, the submersion determination unit 36 ​​calculates the difference between the height position of the head Q of the bather P and the height position of the water surface 8 (step ST105).

[0077] Next, submersion determination unit 36 ​​determines whether the difference calculated in step S105 is equal to or less than a predetermined value (step ST106). If submersion determination unit 36 ​​determines that the difference is equal to or less than the predetermined value (step ST106 YES), it determines that the bathing posture of bather P may progress to a submerged state. On the other hand, if submersion determination unit 36 ​​determines that the difference is not equal to or less than the predetermined value (step ST106 NO), it determines that the bathing posture of bather P is not one that may progress to a submerged state, and ends the process.

[0078] When the submersion determination unit 36 ​​determines that the bathing posture of the bather P may progress to a submerged state (YES in step ST106), the warning device 5 issues a warning (step ST107).

[0079] Thus, in the submersion determination method according to the first embodiment, one of the ultrasonic transmitting device and the ultrasonic receiving device is arranged above the longitudinal direction of the bathtub, and the other of the ultrasonic transmitting device and the ultrasonic receiving device is arranged above the lateral direction of the bathtub. By adopting such a configuration, the distance from the wall surface around the bathtub to each ultrasonic device is different. This makes it possible to prevent the ultrasonic receiving device from receiving ultrasonic waves reflected back by an object having a right-angle corner with respect to the wall surface, and the sound pressure of unnecessary reflected waves from the object is suppressed to be low. Therefore, in step ST102, it becomes easy to extract the reflected waves from the head Q of the bather P from the reflected waves received by the ultrasonic receiving device 3, and the detection accuracy of the bather's head position can be improved.

[0080] It should be noted that an underwater ultrasonic sensor may be provided in bathtub 6, and the presence or absence of a bather may be determined using this ultrasonic sensor prior to the submersion determination.

[0081] In addition, a part or all of the processing in the submersion determination system and the seat determination method according to the above-mentioned first embodiment and the modified example can be realized as a computer program. Such a program can be stored using various types of non-transitory computer-readable media and supplied to a computer. The non-transitory computer-readable media includes various types of tangible recording media. Examples of the non-transitory computer-readable media include magnetic recording media (e.g., flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R / Ws, and semiconductor memories (e.g., mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash ROMs, and RAMs (Random Access Memory)). The program may also be supplied to a computer by various types of temporary computer-readable media. Examples of the temporary computer-readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable media can supply the program to a computer via a wired communication path such as an electric wire and an optical fiber, or via a wireless communication path.

[0082] While the present disclosure has been described above in accordance with the above-described embodiment, the present disclosure is not limited to the configuration of the above-described embodiment, and naturally includes various modifications, alterations, and combinations that may be made by a person skilled in the art within the scope of the claims of the present application. [Explanation of symbols]

[0083] 1. Submersion Judgment System 2, 12 Ultrasonic transmitting device 3, 13 Ultrasonic receiving device 4 Submergence determination device 5 Alarm device 6. Bathtub 8 water surface 10 Bathroom 20 Pulse generating circuit 21 Oscillator Circuit 22 Intermittent Circuit 23 Transmitting amplifier circuit 28 Head reflection wave extraction section 29 Head distance calculation section 30 Head height position calculation unit 31 Receiving amplifier circuit 32 Filter Circuit 33 Waveform analysis circuit 35 Water surface height position calculation unit 36 Submergence determination section D1 Head distance D2 Propagation distance D3 Clearance D4, D11 Vertical distance P bather Q Head ra rail W1, W2 walls θ angle

Claims

1. An ultrasonic transmitting device and an ultrasonic receiving device disposed above the bathtub in the bathroom; A submersion determination device that determines whether or not the bather is in a bathing posture that may lead to a submerged state; Equipped with One of the ultrasonic transmitting device and the ultrasonic receiving device is disposed above the bathtub in a longitudinal direction, the other of the ultrasonic transmitting device and the ultrasonic receiving device is disposed above the bathtub in a short side direction, the ultrasonic transmitting device is configured to transmit ultrasonic waves obliquely downward so that the ultrasonic waves transmitted from the ultrasonic transmitting device are reflected by the head of the bather and received by the ultrasonic receiving device; The submersion determination device includes: Acquire the height position of the water surface of the bathtub; Calculating the head position of the bather based on the reflected waves received by the ultrasonic receiving device; Based on the head position and the height of the water surface, it is determined whether the bather is in a bathing posture that may progress to a submerged state. Submersion detection system.

2. The ultrasonic transmitting device and the ultrasonic receiving device are arranged in an L-shape above the bathtub. The submersion determination system according to claim 1 .

3. One of the ultrasonic transmitting device and the ultrasonic receiving device arranged above in the longitudinal direction of the bathtub is arranged on the other side of the ultrasonic transmitting device and the ultrasonic receiving device arranged above in the lateral direction of the bathtub, rather than the center in the longitudinal direction of the bathtub. The submersion determination system according to claim 1 or 2.

4. The ultrasonic transmitting device and the ultrasonic receiving device are arranged in plurality above the bathtub, The ultrasonic transmitting devices and the ultrasonic receiving devices are arranged so as to be symmetrical with respect to a center line passing through the center in the longitudinal direction of the bathtub. The submersion determination system according to claim 1 or 2.

5. A submersion determination method for determining whether a bather is in a bathing posture that may progress to a submerged state by using an ultrasonic transmitting device and an ultrasonic receiving device disposed above a bathtub in a bathroom, comprising: One of the ultrasonic transmitting device and the ultrasonic receiving device is disposed above the bathtub in a longitudinal direction, the other of the ultrasonic transmitting device and the ultrasonic receiving device is disposed above the bathtub in a short side direction, a step of transmitting ultrasonic waves obliquely downward from the ultrasonic transmitting device so that the ultrasonic waves transmitted from the ultrasonic transmitting device are reflected by the bather's head and received by the ultrasonic receiving device; calculating a head position of the bather based on the reflected waves received by the ultrasonic receiving device; Obtaining the height position of the water surface of the bathtub; A step of determining whether the bather is in a bathing posture that may progress to a submerged state based on the head position and the height position of the water surface; Including, Submergence determination method.

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