JP2005283128A - Monitoring device and distance measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a monitoring device capable of measuring accurately the position of an object or the distance thereto with simple configuration without invading privacy. <P>SOLUTION: This monitoring device is equipped with a transmitter RO for transmitting a wave propagating in a space, a receiver S41 for receiving the wave transmitted by the transmitter RO and reflected by the object 2, an amplifier S51 for amplifying the wave received by the receiver S41, a differential waveform operation means C for operating the waveform difference between the first waveform amplified by the amplifier S51 of a wave received at the first point of time T by the receiver S41 and the second waveform amplified by the amplifier S51 of a wave received at the second point of time T+ΔT different from the first point of time T, and a required time measuring means B for measuring a required time from transmission of the wave from the transmitter RO until reception thereof by the receiver S41 through reflection by the object 2 based on the waveform difference when the waveform difference is detected. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a monitoring device and a distance measuring device, and more particularly to a monitoring device and a distance measuring device that can accurately measure the position or distance of an object while having a simple configuration without fear of loss of privacy.

Conventionally, light waves are used to detect the movement and position of an object, for example, bright spots arranged in a grid are formed, and the bright spot of the picked-up image is detected based on the position change relative to the bright spot of the reference image. In general, the position information of an object moving in a three-dimensional monitoring space is measured by triangulation. In the trigonometric method, two imaging devices are used, the movement of the object is detected from temporal changes in the left and right captured images, and the position coordinates of the object are obtained from the correlation between the left and right captured images (Patent Documents 1 and 2). reference.).
JP 2002-122417 A (paragraph 0016, FIG. 1) Japanese Patent Laid-Open No. 2002-175513 (paragraphs 0034 to 0040, 0064, FIG. 4, FIG. 8)

  However, since the conventional method using the bright spots arranged in a lattice pattern uses coherent light, the apparatus scale becomes large. In addition, in the conventional trigonometry using stereo images, a high processing capacity is required in the calculation part, and the scale of the apparatus is increased, the processing time is increased, and shooting with a camera is performed. In some cases, there is a problem that privacy may be impaired.

  Therefore, an object of the present invention is to provide a monitoring device and a distance measuring device that can accurately measure the position or distance of an object while having a simple configuration without causing a risk of loss of privacy.

  In order to achieve the above object, a monitoring apparatus according to a first aspect of the present invention includes a transmitter R0 for transmitting a wave propagating in space, as shown in FIGS. 1, 5, and 7, for example; A receiver S41 that receives a wave transmitted from and reflected by the object 2; an amplifier S51 that amplifies the wave received by the receiver S41; and received at a first time T by the receiver S41. A waveform of a difference between a first waveform amplified by the amplifier S51 with a wave and a second waveform amplified by the amplifier S51 with a wave received at a second time T + ΔT different from the first time T Difference waveform calculation means C for calculating the difference; when the difference waveform is detected, the wave is transmitted from the transmitter R0 and reflected by the object 2 based on the difference waveform. Until the signal is received by the receiver S41. And a required time measuring means B for measuring a time.

  With this configuration, since the transmitter R0, the receiver S41, and the amplifier S51 are provided, the amplifier S51 is a wave transmitted from the transmitter R0 and received at the first time point T by the receiver S41. And the second waveform amplified by the amplifier S51 with the wave received at the second time point T + ΔT can be obtained. Further, when the difference waveform calculation means C and the required time measurement means B are provided, the difference waveform between the first waveform and the second waveform is calculated, and the difference waveform is detected. Based on the difference waveform, the time required for the wave to be reflected from the object 2 and received by the receiver S41 after being transmitted from the transmitter R0 can be measured. It is possible to provide a monitoring device that can accurately measure the position or distance of an object while having a simple configuration without fear of losing privacy.

  Further, as described in claim 2, the monitoring apparatus according to claim 1 includes amplifier control means A for controlling the amplification factor of the amplification by the amplifier S51; the amplifier control means A is connected to the transmitter R0. The control may be performed so that the amplification is performed at an amplification factor proportional to the n-th power of the elapsed time from the transmission time when the wave is transmitted.

  With this configuration, for example, even when the wave attenuates in proportion to the nth power of the elapsed time, the attenuation can be canceled by amplifying with an amplification factor proportional to the nth power of the elapsed time. , The detectable distance becomes longer.

  Further, as described in claim 3, in the monitoring device according to claim 1, for example, as shown in FIGS. 5 and 16, the amplifier control means A1 for controlling the amplification factor of the amplification by the amplifier S51; Waveform storage means S74 for storing the waveform of the wave received by the device S41; the amplifier control means A1 determines the amplification factor based on the waveform stored in the past by the waveform storage means S74. You may comprise.

  If comprised in this way, amplifier control means A1 will determine the amplification factor based on the waveform memorize | stored in the past, for example, and the optimal amplification factor which considered the influence of the said attenuation | damping and the distance and magnitude | size of a target object Can be set, and the detectable distance becomes longer.

  According to a fourth aspect of the present invention, in the monitoring device according to any one of the first to third aspects, the receiver S41 and the amplifier S51 may be provided in plural.

  In order to achieve the above object, a monitoring device according to a fifth aspect of the present invention includes a transmitter R0 that transmits a wave propagating in space, as shown in FIGS. 1, 5, and 19, for example; A receiver S41 that receives a wave transmitted from and reflected by the object 2; a first waveform of a wave received at a first time T by the receiver S41, and a first waveform different from the first time Difference waveform calculation means C for calculating a difference waveform from the second waveform of the wave received at time T + ΔT of 2; if the difference waveform is detected, based on the difference waveform, A time measurement means B for measuring a time required for a wave to be reflected from the object 2 and received by the receiver S41 after being transmitted from the transmitter R0; and received by the receiver S41. Waveform storage means S74 for storing the waveform of the wave; S74 on the basis of the past stored waveform by, and a transmitter control unit A2 to control the size of the waves emitted by the transmitter R0.

  With this configuration, since the transmitter R0 and the receiver S41 are provided, the first waveform of the wave transmitted from the transmitter R0 and received at the first time point T by the receiver S41, And a second waveform of the wave received at time 2 T + ΔT. Further, when the difference waveform calculation means C and the required time measurement means B are provided, the difference waveform between the first waveform and the second waveform is calculated, and the difference waveform is detected. Based on the waveform of the difference, the time required from when the wave is transmitted from the transmitter R0 to when it is reflected by the object 2 and received by the receiver S41 can be measured. Further, by providing the waveform storage means S74 and the transmitter control means A2, the waveform of the wave received by the receiver S41 is stored and transmitted by the transmitter R0 based on the stored waveform. Since the magnitude of the wave is controlled, there is no fear that the privacy is lost, and a monitoring device that can accurately measure the position or distance of the object can be provided with a simple configuration.

  In order to achieve the above object, a distance measuring device according to a sixth aspect of the present invention includes, for example, a transmitter R0 that transmits a wave propagating in space, as shown in FIGS. 22 and 24; A receiver S41 that receives the wave reflected by the object 2; an amplifier S51 that amplifies the wave received by the receiver S41; and after the amplified wave is transmitted from the transmitter R0. A required time measuring means B for measuring a time required for reflection from the object 2 and reception by the receiver S41; and a distance from the receiver S41 to the object 2 based on the required time A distance calculating means G for calculating the amplifier; and an amplifier control means A for controlling the amplification factor of the amplification by the amplifier S51; the amplifier control means A is an elapsed time from the time when the wave is transmitted from the transmitter R0. of Configured to the control so as to perform the amplification in the amplification factor proportional to the multiplication.

  With this configuration, the wave transmitted from the transmitter R0 and reflected by the object 2 can be received by the receiver S41, and the wave received by the amplifier S51 can be amplified. Further, the required time measuring means B measures the required time from when the wave amplified by the amplifier S51 is transmitted from the transmitter R0 until it is reflected by the object 2 and received by the receiver S41. Thus, the distance calculation means G can calculate the distance from the receiver S41 to the object 2 based on the required time. Further, the amplifier control means A controls the amplification by the amplifier S51 so as to perform amplification with an amplification factor proportional to the nth power of the elapsed time from the transmission time point when the wave is transmitted from the transmitter R0. It is possible to provide a distance measuring device that can accurately measure the position or distance of an object while having a simple configuration.

  In order to achieve the above object, a distance measuring device according to a seventh aspect of the present invention includes, for example, a transmitter R0 that transmits a wave propagating in space, as shown in FIGS. 22 and 25; A receiver S41 that receives the wave reflected by the object 2; an amplifier S51 that amplifies the wave received by the receiver S41; and after the amplified wave is transmitted from the transmitter R0. A required time measuring means B for measuring a time required for reflection from the object 2 and reception by the receiver S41; and a distance from the receiver S41 to the object 2 based on the required time Distance calculating means G for calculating the frequency; amplifier control means A1 for controlling the amplification factor of the amplification by the amplifier S51; waveform storage means S74 for storing the waveform of the wave received by the receiver S41; Control means A1, based on the stored waveform in the past by the waveform storage unit S74, and to determine the amplification factor.

  With this configuration, the wave transmitted from the transmitter R0 and reflected by the object 2 can be received by the receiver S41, and the wave received by the amplifier S51 can be amplified. Further, the required time measuring means B measures the required time from when the wave amplified by the amplifier S51 is transmitted from the transmitter R0 until it is reflected by the object 2 and received by the receiver S41. Thus, the distance calculation means G can calculate the distance from the receiver S41 to the object 2 based on the required time. Further, the amplifier control means A1 and the waveform storage means S74 are provided, and the amplifier control means A1 is configured to determine the amplification factor based on the waveform stored in the past by the waveform storage means S74. It is possible to provide a distance measuring device capable of accurately measuring the position or distance of an object while having a simple configuration without a risk of privacy being lost.

  In order to achieve the above object, a distance measuring device according to an eighth aspect of the present invention includes a transmitter R0 that transmits a wave propagating in space, for example, as shown in FIGS. 22 and 25; Receiver S41 that receives the wave reflected by the object 2, and after the wave is transmitted from the transmitter R0 until it is reflected by the object 2 and received by the receiver S41. A required time measuring means B for measuring a required time; a distance calculating means G for calculating a distance from the receiver S41 to the object 2 based on the required time; and a wave received by the receiver S41. Waveform storage means S74 for storing the waveform; and transmitter control means A2 for controlling the magnitude of the wave transmitted by the transmitter R0 based on the waveform stored in the past by the waveform storage means S74.

  If comprised in this way, the wave transmitted from the said transmitter R0 and reflected by the target object 2 can be received by receiver S41. Further, by measuring the required time from the time when the wave is transmitted from the transmitter R0 to the time when the wave is reflected by the object 2 and received by the receiver S41, the distance is measured by the required time measuring means B. The calculation means G can calculate the distance from the receiver S41 to the object 2 based on the required time. Furthermore, the transmitter control means A2 controls the magnitude of the wave transmitted by the transmitter R0 based on the waveform stored in the past by the waveform storage means S74. It is possible to provide a distance measuring device that can accurately measure the position or distance of an object while having a simple configuration.

  As described above, according to the present invention, a transmitter for transmitting a wave propagating in space, a receiver for receiving a wave transmitted from the transmitter and reflected by an object, and received by the receiver. An amplifier for amplifying the received wave, a first waveform amplified by the amplifier at a first time received by the receiver, and a wave received at a second time different from the first time And a difference waveform calculation means for calculating a difference waveform from the second waveform amplified by the amplifier, and when the difference waveform is detected, based on the difference waveform, the wave is Since it is provided with a required time measuring means for measuring a required time from when it is transmitted from a transmitter until it is reflected by the object and received by the receiver, privacy is not impaired, and a simple configuration is provided. Exactly the position or distance of the object It can provide a measurement can monitor.

  Further, according to the present invention, a transmitter for transmitting a wave propagating in space, a receiver for receiving a wave transmitted from the transmitter and reflected by an object, and a wave received by the receiver. An amplifier for amplifying, a required time measuring means for measuring a required time from when the amplified wave is transmitted from the transmitter to when it is reflected by the object and received by the receiver; A distance calculating means for calculating a distance from the receiver to the object based on time; and an amplifier control means for controlling an amplification factor of the amplification by the amplifier. The amplifier control means includes: Since the control is performed so that the amplification is performed at an amplification factor proportional to the n-th power of the elapsed time from the transmission time when the wave is transmitted, there is no possibility that privacy is lost, and the configuration is simple. , Positive Possible to provide a distance measuring device capable of measuring the position or distance of the object.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the mutually same or equivalent member, and the overlapping description is abbreviate | omitted.

Below, the monitoring apparatus 1 which is the 1st Embodiment of this invention is demonstrated based on drawing.
FIG. 1 schematically shows the arrangement state of the apparatus in order to explain the measurement principle of the present embodiment. The wave propagating in space includes sound waves (for example, ultrasonic waves, audible sound waves), radio waves (for example, radio waves, microwaves), and light (for example, infrared rays, visible light, and ultraviolet rays). The case where the wave propagating in the space is an ultrasonic wave will be described. In this way, a highly accurate and inexpensive device can be configured. In this embodiment, there are a plurality of receivers and amplifiers. Further, the receiver and the amplifier are integrally formed to form ultrasonic receiving parts R1 to R3. That is, there are a plurality of ultrasonic receiving units. Here, three ultrasonic wave receivers are configured. If it does in this way, the three-dimensional position coordinate of the target object 2 can be calculated | required. The receiver and the amplifier will be described later with reference to FIG.

  Here, in FIG. 1, the ultrasonic waves transmitted from the ultrasonic transmitter R0 are irradiated and reflected on the object 2 such as a person in the monitoring space, and reflected by a plurality of ultrasonic receivers R1 to R3. Received. W0 is an incident wave from the ultrasonic transmitter R0 to the object 2, and W1 to W3 are reflected waves from the object 2 to the ultrasonic receiving units R1 to R3.

The position coordinates of the ultrasonic transmitter R0 in the three-dimensional space are P (0, 0, 0), and the position coordinates of the ultrasonic receivers R1 to R3 are P (x1, y1, z1) and P (x2, y2), respectively. , Z2), P (x3, y3, z3), the position coordinates of the object 2 is P (x, y, z), and an ultrasonic wave transmitted from the ultrasonic transmitter R0 is transmitted to the object 2. Assuming that the time until irradiation is t0, the time until reception by the ultrasonic receivers R1 to R3 is t1, t2, t3, and the ultrasonic velocity is v, the position P (x, y of the object 2 , Z) is obtained from (Expression 1) to (Expression 4).

(X−x1) ² + (y−y1) ² + (z−z1) ² = (v × (t1−t0)) ²
... (Formula 1)

(X−x2) ² + (y−y2) ² + (z−z2) ² = (v × (t2−t0)) ²
... (Formula 2)

(X−x3) ² + (y−y3) ² + (z−z3) ² = (v × (t3−t0)) ²
... (Formula 3)

x ² + y ² + z ² = (v × t0) ² (Expression 4)

  That is, in (Expression 1) to (Expression 4), the positions of P (0,0,0), P (x1, y1, z1), P (x2, y2, z2), and P (x3, y3, z3) Is fixed, and if t1, t2, and t3 are measured, the unknowns are only x, y, z, and t0, and the unknown can be obtained by solving the simultaneous equations.

  As shown in FIG. 2, the monitoring apparatus 1 may be arranged such that any one of the plurality of ultrasonic receiving units R1 to R3 is adjacent to the ultrasonic transmitter R0. In this way, the unknown part of the distance to be measured or the unknown part of the time to be measured can be shortened, and the measurement accuracy can be improved.

  More specifically, for example, one of the three ultrasonic receivers R1 to R3 in FIG. 1 is disposed adjacent to the transmitter R0. The time t0 when the ultrasonic wave W0 transmitted from the ultrasonic transmitter R0 reaches the object 2 is the time t1 until the ultrasonic wave W0 transmitted from the ultrasonic transmitter R0 is received by the ultrasonic receiver R1. Since t2 and t3 are replaced with t2 ′ and t3 ′ using (Expression 5) and (Expression 6), (Expression 1) to (Expression 3) are replaced with (Expression 7). It can be substituted with (Formula 9). The unknown measurement distance or the unknown measurement time is halved, and the measurement accuracy can be improved. That is, the measurement error of t2 and t3 can be halved.

t2 '= t2-t1 / 2 (Formula 5)

t3 '= t3-t1 / 2 (Formula 6)

(X−x1) ² + (y−y1) ² + z ² = (v × t1 / 2) ² (Expression 7)

(X−x2) ² + (y−y2) ² + (z−z2) ² = (v × t2 ′) ² (Expression 8)

(X−x3) ² + (y−y3) ² + (z−z3) ² = (v × t3 ′) ² (Equation 9)

FIG. 3 schematically shows a configuration in which the ultrasonic transmitter R0 and the three ultrasonic receivers R1 to R3 are combined into one module M. The configuration of the first embodiment is as follows. Three ultrasonic receivers R1 to R3 are arranged radially around the ultrasonic transmitter R0 at an angle of approximately 120 degrees. In this case, the z-coordinates of the ultrasonic receivers R1 to R3 are 0 and constant, and the time until the ultrasonic wave reaches each ultrasonic receiver Ri (i = 1 to 3) from the object 2 (person) is as follows. , Ti / 2, (Expression 1) to (Expression 3) can be displayed as (Expression 10) to (Expression 12), and the position P (x, y, z) of the object 2 is 3 Obtained by the former simultaneous equations. In this way, the distance between the transmitter R0 and the receivers R1 to R3 is fixed, which is convenient for obtaining the position coordinates, and facilitates transportation and attachment.

(X−x1) ² + (y−y1) ² + z ² = (v × t1 / 2) ² (Expression 10)

(X−x2) ² + (y−y2) ² + z ² = (v × t2 / 2) ² (Expression 11)

(X−x3) ² + (y−y3) ² + z ² = (v × t3 / 2) ² (Expression 12)

  As shown in the schematic perspective view of FIG. 4, the module M is installed on the ceiling of the room in order to monitor whether there is an abnormality in the person 2 in the room that cannot be seen by others such as a toilet. And In the figure, the module M is arranged near the center of the ceiling. Thus, although this Embodiment demonstrates the monitoring apparatus 1 in the case of monitoring a toilet room, it can be used also in open spaces, such as the outdoors other than closed spaces, such as a toilet.

  In other words, when the module M, in other words, the ultrasonic transmitter R0 and the ultrasonic receivers R1 to R3 are installed on the ceiling of the room and the object 2 is a person, first, a reflected wave from the top of the head is first detected, Sequentially, reflected waves from the shoulders, hands, torso, and feet are detected. Furthermore, there are reflected waves from surrounding stationary objects, and the reflected waves from the floor are particularly strong. Since the velocity v of the ultrasonic wave in the atmosphere is about 340 m / sec, if the traveling distance from the transmission of the ultrasonic wave to the object 2 being reflected and received is about 2 to 6 m, t1 to t3. Is about 6-18 msec. The distance from the top of the head to the back of the foot in an upright state is usually 1 to 2 m, and is about 1 m even when sitting on a chair (toilet seat) etc., for example, the installation height of the module M (distance from the floor to the ceiling) Is 2.5 m, the detection time of the reflected wave has a spread of about 3 to 15 msec in the standing position and about 9 to 15 msec in the sitting position. In a closed space such as a toilet, the detection time of the wave reflected by the object 2 by the ultrasonic receivers R1 to R3 is reflected until the wave is reflected and received at the farthest distance in the monitoring space. Time. Here, since the object at the farthest distance is the floor, the detection time may be 15 msec. In other words, the sampling time of the received wave may be 15 msec. Here, the detection interval (sampling interval) corresponds to a later-described time ΔT (for example, see FIG. 10).

  FIG. 5 shows an example of the circuit configuration of the monitoring device 1. The ultrasonic transmitter R0 includes a transmission pulse generator S1, a transmission drive circuit S2, and a transmission element S3. In the ultrasonic transmitter R0, the transmission drive circuit S2 is driven by a pulse generated (oscillated) by the transmission pulse generator S1, and an ultrasonic pulse is transmitted from the transmission element S3. The ultrasonic receivers R1 to R3 are received by the receiving elements S41 to S43 as a plurality of receivers that receive the waves transmitted from the ultrasonic transmitter R0 and reflected by the object 2, and received by the receiving elements S41 to S43. The signal amplifying circuits S51 to S53 as a plurality of amplifiers for amplifying the generated wave and the detecting circuits S61 to S63 are configured. In the ultrasonic receivers R1 to R3, the reflected waves of the ultrasonic waves are received by the receiving elements S41 to S43, the direct current component is cut, and then amplified by the signal amplification circuits S51 to S53. For example, a negative feedback type differential operational amplifier amplifier circuit is used as the signal amplifier circuits S51 to S53, and the amplification is performed with an amplification factor of about 1000 times (60 dB), for example. Here, the amplification factors of the signal amplification circuits S51 to S53 can be changed by an amplifier control means described later. Or it is variable. The amplified signal is subjected to half-wave rectification and envelope detection processing in the detection circuits S61 to S63. Half-wave rectification is performed using, for example, two Schottky barrier diodes, and envelope detection is performed using, for example, an RC delay circuit. Outputs of the detection circuits S61 to S63 of the reception units R1 to R3 are guided to the reception waveform measuring device S7. The received waveform measuring device S7 will be described in detail later. The envelope detection process will be described with reference to FIG.

  As the ultrasonic transmitting element S3 and the ultrasonic receiving elements S41 to S43, a ceramic piezoelectric element such as PZT (lead zirconate titanate) or a polymer piezoelectric element such as PVDF (polyvinylidene fluoride) is used. Can do.

  The monitoring device 1 includes a received waveform measuring device S7. In the received waveform measuring device S7, the output from the detection circuits S61 to S63 is sequentially switched by the switch circuit S71 and led to the A / D conversion circuit S72, and the analog / digital conversion is performed by the A / D conversion circuit S72. (CPU) Guide to S73. In the central processing unit S73, ultrasonic waveform data, measurement data, and calculation data are stored using the storage circuit S74, and various calculations are performed using the calculation circuit S75. The measurement result and the calculation result are output from the external output circuit S76 under the control of the central processing unit S73. The storage circuit S74 is also a waveform storage unit that stores the waveforms of the waves received by the receiving elements S41 to S43. The arithmetic circuit S75 and the storage circuit S74 of the received waveform measuring device S7 will be described later with reference to FIGS.

  The monitoring device 1 further includes a temperature sensor S8 that measures the temperature of the medium existing in the space. Here, the medium is the atmosphere (air). The ultrasonic velocity v in the atmosphere is about 340 m / sec when the atmospheric temperature is 14 ° C., but varies depending on the temperature. By measuring the atmospheric temperature with the temperature sensor S8, an accurate ultrasonic velocity v corresponding to the measured temperature can be used, for example, for the position coordinates described above. That is, accurate position coordinates can be calculated.

  FIG. 6 shows an example of the configuration of the arithmetic circuit S75 of the received waveform measuring apparatus S7 in the present embodiment. The arithmetic circuit S75 is an amplifier control means A that controls the amplification factor of the amplification by the signal amplification circuits S51 to S53, and a wave received at the first time T as the first time point by the ultrasonic wave reception units R1 to R3. Amplified by the signal amplification circuits S51 to S53 with the first waveform amplified by the signal amplification circuits S51 to S53 and the wave received at the second time T + ΔT as a second time point different from the first time T Difference waveform calculation means C for calculating a difference waveform from the second waveform, and when the difference waveform is detected, the wave is transmitted from the ultrasonic transmitter R0 based on the difference waveform. The required time measuring means B for measuring the required times t1 to t3 from being reflected by the object 2 and being received by the ultrasonic receivers R1 to R3, and the waveform of the difference between the ultrasonic receivers R1 to R3 When object 2 is detected, object 2 moves From the simultaneous determination equation D indicating the relationship between the required times t1 to t3 measured by the ultrasonic receivers R1 to R3 and the position coordinates P (x, y, z) of the object 2, the object 2 The position calculation means E for obtaining the position coordinates P (x, y, z) of the object 2 and the movement amount ΔP (dx, dy, dz of the object 2 from the time change of the position coordinates P (x, y, z) of the object 2 ) And movement information calculation means F for determining movement speed U (dx / ΔT, dy / ΔT, dz / ΔT). In addition, a determination means determines with the target object 2 having moved, when the waveform of the said difference is detected in any ultrasonic receiving part Ri among ultrasonic receiving part R1-R3. The determination means D determines that the object 2 has moved when the absolute value of the difference in the difference waveform exceeds a predetermined threshold at an arbitrary time. In this way, erroneous measurement due to noise can be prevented.

  Note that the case where a difference waveform is detected means, for example, a case where the value (for example, amplitude) of the difference waveform between the first waveform and the second waveform is equal to or greater than a threshold value. In this way, erroneous measurement due to noise can be prevented. The amplifier control means A is configured to control the amplification factor so that the amplification is performed at an amplification factor proportional to the nth power of the elapsed time from the transmission time point when the wave is transmitted from the ultrasonic transmitter R0. Here, the nth power is, for example, a square or a fourth power. Here, the case where n-th power is square is described. This is because a wave (ultrasonic wave) traveling in the atmosphere attenuates in proportion to the square of the elapsed time (also referred to as a moving distance). By doing so, for example, attenuation of ultrasonic waves received from the ultrasonic wave receiving units R1 to R3 can be canceled out, so that an accurate waveform can be obtained. Moreover, the detectable distance becomes long. In other words, it is easy to obtain a waveform reflected by an object located further away.

  The nth power may be the fourth power. This is because, in addition to the above attenuation, the amount of ultrasonic waves reflected by the object 2 becomes smaller in proportion to the square of the distance from the ultrasonic receivers R1 to R3 (also referred to as the ultrasonic moving distance). Because. In other words, the amount of ultrasonic waves reflected by the object 2 decreases in proportion to the square of the elapsed time from the transmission time point when the wave is transmitted from the ultrasonic transmitter R0. That is, the ultrasonic waves received from the ultrasonic wave receivers R1 to R3 are attenuated in proportion to the fourth power of the elapsed time from the transmission time point when the wave is transmitted from the ultrasonic wave transmitter R0. By doing so, for example, a more accurate waveform of the ultrasonic wave reflected by the object 2 can be easily obtained. Amplification by the amplifier control means is performed for a period from a transmission time point when a wave is transmitted from the ultrasonic transmitter R0 to a transmission time point when the ultrasonic transmitter R0 transmits a next wave. In other words, the period is from the first time T to the second time T + ΔT.

  FIG. 7 shows an example of the configuration of the memory circuit S74 of the received waveform measuring apparatus S7 in the present embodiment. The memory circuit S74 includes memories M0 to M9. M0 corresponds to the amplification factor a1 set by the amplifier control means, M1 corresponds to the first waveform corresponding to the wave received at the first time T, and M2 corresponds to the wave received at the second time T + ΔT. The second waveform, M3, the difference waveform between the first waveform and the second waveform, and M4, the ultrasonic wave receiving unit R1 after the ultrasonic wave is transmitted from the ultrasonic wave transmitter R0 at the first time T. M5 is the required time t1 until the ultrasonic wave is received at M2, and M5 is the required time t1 + Δt1 from when the ultrasonic wave is transmitted from the transmitter R0 at the second time T + ΔT until it is received by the ultrasonic wave receiving unit R1, M6 is the first time M7 represents the position coordinate P (x, y, z) of the object 2 measured by the position calculation means E at time T, and M7 represents the object 2 measured by the position calculation means E at the second time T + ΔT. The position coordinate P (x + dx, y + dy, z + dz) is expressed as M8 from time T to T + ΔT. M9 is the moving speed U (dx / ΔT, dy / ΔT, dz / ΔT) at which the object has moved between time T and T + ΔT. Is stored.

  The amplifier control means A, the required time measurement means B, the difference waveform calculation means C, the determination means D, and the memories M0 to M5 described above are provided for each ultrasonic receiving unit R1 to R3. One calculating means F and memories M6 to M9 are provided in the monitoring device.

  FIG. 8 schematically shows an ultrasonic transmission signal from the ultrasonic transmitter R0. For example, if the frequency is 40 kHz, 40 cycles are transmitted per 1 msec. If the pulse width is 1 msec, 40 pulses of carrier wave are included in one pulse, and it propagates in the air as a wave packet having a length of about 34 cm.

  FIG. 9 schematically shows a received signal at the ultrasonic wave receiving unit R1. Hereinafter, the ultrasonic receivers R1 to R3 will be described as representative of the receiver R1, but the same applies to the ultrasonic receivers R2 and R3. In the drawing, the reflected wave is detected after time t1 from the transmission of the ultrasonic wave. However, the transmitted wave W0 and the reflected waves W1 to W3 spread three-dimensionally, and further, since the reflection position of the object 2 has a spread, the detection intensity becomes weak and the waveform of the detection wave becomes broad. Here, the waveform is represented by a change with time when a received wave is detected by electric power or potential. That is, the first waveform and the second waveform are also expressed by changes over time when the amplified wave is detected by power or potential. 8 and 9 are different in scale on the horizontal axis (time axis). FIG. 9 shows a larger scale than FIG.

Next, FIG. 10 schematically shows an amplified signal in the signal amplifier circuit S51. Here, a period from a transmission time point (first time T) when the wave W0-1 is transmitted from the ultrasonic transmitter R0 to a transmission time point (second time T + ΔT) when the next wave W0-2 is transmitted is shown. As shown in the figure, the detection intensity of the received signal at the receiving element S41 of the ultrasonic wave receiving unit R1 becomes weaker in proportion to the square of the elapsed time (indicated by a two-dot chain line in the figure). The amplifier control means A amplifies the received signal at an amplification factor a1 (= f (t ² )) proportional to the square of the elapsed time from the transmission time point (time T) at which the wave is transmitted from the ultrasonic transmitter R0. By controlling the amplification factor in this way, an accurate waveform can be obtained even if the elapsed time, in other words, the detection distance becomes long. That is, the detectable range (distance) is expanded.

  FIG. 11 schematically shows an example of the received signal after the envelope detection processing by the detection circuit S61. The signal after the envelope detection process is indicated by a dotted line. The ultrasonic wave transmitted from the ultrasonic transmitter R0 is detected between the time t1 and the detection end time te by the receiving element S41 of the ultrasonic receiving unit R1, and further amplified by the signal amplification circuit S51. Although the actual waveform is not as beautiful as the schematic diagram due to the spread of the reflected wave, a broad envelope waveform as shown in the figure is obtained.

  If the object 2 does not move, the shape of the received wave shown in FIG. 11 does not change. By the way, it is assumed that the object 2 moves from time T to T + ΔT. For example, it is assumed that the object 2 stands up from a toilet seat. Since the top of the head approaches both the ultrasonic transmitter R0 and the ultrasonic receiver R1, the time required from transmission to reception is shorter than t1. Also, assuming that the head is lying down and lying down, the top of the head is far from the ultrasonic transmitter R0 and the ultrasonic receiver R1, and therefore the time required from transmission to reception is longer than t1. If the top of the head becomes 10 cm higher during ΔT (for example, 0.1 sec) at the time of standing up, the reciprocating distance of the ultrasonic wave is shortened by about 20 cm, so that it is accelerated by Δt1 (about 0.6 msec). Therefore, the reception start time is shifted by Δt1 toward the shorter side. On the other hand, if the top of the head becomes 10 cm lower during ΔT (for example, 0.1 sec) when the body falls down, the reciprocating distance of the ultrasonic wave becomes about 20 cm longer, so the reception start time is Δt1 (about 0.6 msec). Shift to the slower one. For the time interval ΔT, for example, a time interval that can detect a change in the object 2 (such as a person) and that the change is a minute amount and that follows the change may be selected.

  Here, the required time t1 is preferably the first time when the waveform exceeds a predetermined threshold. However, in this case, for example, when an object that is a background exists at a position higher than the object (position close to the ultrasonic wave receiving unit), it is necessary to consider it. For example, the background at a position closer to the object may be grasped in advance, and the first time that exceeds a predetermined threshold with a waveform ignoring the portion corresponding to the background may be used. In this way, for example, the time required for the ultrasonic wave transmitted from the ultrasonic transmitter to be reflected by the head of the person who is the target and received by the ultrasonic receiver, in other words, the shortest distance to the target It is easy to measure the required time corresponding to.

  FIG. 12 schematically shows a reception waveform (first waveform) of the ultrasonic wave transmitted from the ultrasonic transmitter R0 at the first time T at the ultrasonic receiving unit R1. The signal after the envelope detection process is indicated by a dotted line.

  FIG. 13 schematically shows a reception waveform (second waveform) of the ultrasonic wave transmitted from the ultrasonic transmitter R0 at the ultrasonic wave receiving unit R1 at the second time T + ΔT. The signal after the envelope detection process is indicated by a dotted line. Generally speaking, there is a shift from the first waveform toward Δt1 later.

  FIG. 14 schematically shows a difference waveform between the two waveforms detected in FIGS. 12 and 13. Since the second waveform is shifted toward the time when the reception start time is delayed by Δt1 compared to the first waveform, a negative waveform appears from time t1 to t1 + α1, and the time is positive from time t1 + α1 to t1 + α1 + α2. The waveform appears. Here, α1 and α2 are values reflecting the moving distance of the object.

FIG. 15 shows an example of a processing flow of detection and position measurement of the object 2 in the present embodiment. First, the amplification factor a1 = f (t ² ) stored in the memory M0 by the amplifier control means A is set in the signal amplification circuit S51 (step S101). Then, ultrasonic wave W0-1 is transmitted at the first time T by the ultrasonic transmitter R0 (step S103). The ultrasonic wave transmitted at the first time T is received by the receiving element S41 of the ultrasonic receiving unit R1, amplified by the signal amplifying circuit S51 with the amplification factor a1 = f (t ² ), and then the first waveform. Is stored in the memory M1 (step S105). Next, the ultrasonic wave W0-2 is transmitted by the ultrasonic transmitter R0 at the second time T + ΔT (step S107). The ultrasonic wave transmitted at the second time T + ΔT is received by the receiving element S41, amplified by the signal amplification circuit S51 with the amplification factor a1 = f (t ² ), and then the second waveform is stored in the memory M2. (Step S109). Next, the difference waveform calculation means C compares the first waveform with the second waveform, and the difference waveform is calculated and stored in the memory M3 (step S115). Thus, by taking the difference between the first waveform and the second waveform, the object having no movement disappears with the waveform canceled. As a result, only the reflected wave from the moving object remains. Thereby, the required time t1 can be detected efficiently. In addition, the required time t1 can be easily detected. When the difference waveform is detected, the required time measuring means B detects the required time t1 from when the ultrasonic wave is transmitted until it is received from the first waveform, and stores it in the memory M4 (step S1). S111), the required time t1 + Δt1 from when the ultrasonic wave is transmitted until it is received is detected from the second waveform and stored in the memory M5 (step S113).

  As described above, as long as the object 2 is stationary, the first waveform and the second waveform are the same, and the difference waveform is not detected. When the object 2 moves, a difference occurs between the first waveform and the second waveform, and the difference waveform is detected. The determination unit D monitors the detection of the difference waveform, and determines that the object 2 has moved when detected (step S117). At the time of detection, a threshold is set. For example, in the difference waveform, it is determined that the object 2 has moved when the absolute value of the difference exceeds a predetermined threshold at an arbitrary time (Yes in step S117). Thereby, erroneous measurement due to noise can be prevented.

  When the movement of the object 2 is not detected (No at Step S117), the pulse transmission is resumed (return to Step S103), and the receiving element S41 continues to receive the ultrasonic wave at ΔT intervals. From the ultrasonic transmitter R0, ultrasonic pulses are transmitted at intervals of ΔT (for example, 0.1 sec), and the pulse width Pw is, for example, 1 msec. For 1 msec, 40 cycles of 40 kHz ultrasonic dense waves are included. For the time interval ΔT, for example, a time interval that can detect a change in the object 2 (such as a person) and that the change is a minute amount and that follows the change may be selected. A reception waveform is detected by the reception element S41 at every time interval ΔT.

  Note that a new ultrasonic wave is further received after ΔT from the second time T + ΔT, the previously received second waveform is set as a new first waveform, and the newly received waveform is set as a new second waveform. As a result, a difference waveform between the first waveform and the second waveform is calculated, and a new first waveform, a new second waveform, and a new difference waveform are stored in the memories M1 to M3, respectively. The required times t1 and t1 + Δt1 from when the ultrasonic wave is transmitted until it is received are also detected from the first waveform and the second waveform and stored in the memories M4 and M5, respectively. If the data in the memory M2 is moved to the memory M1 and a new second waveform is taken into the memory M1, the difference waveform is always calculated between the data in the memory M2 and the data in the memory M1. Just do it. If the data in the memory M5 is moved to the memory M4 and the new required time t1 + Δt1 is taken into the memory M5, the required time t1 is always stored in the memory M4 and the required time t1 + Δt1 is stored in the memory M5. Thereafter, reception of the waveform, calculation of the difference waveform, and detection of the required time are repeated at each time interval ΔT. In addition, transmission of ultrasonic waves by the ultrasonic transmitter R0 is continuously performed one after another at regular intervals. That is, the reception of the waveform, the calculation of the difference waveform, and the detection of the required time are continuously performed at regular intervals for each time interval ΔT.

  Although the ultrasonic reception unit R1 has been described so far, the steps S101 to S117 are repeated in the ultrasonic reception unit R2 and the ultrasonic reception unit R3. Therefore, with respect to the receiving unit R2 and the receiving unit R3, the reception waveform at time T, the reception waveform at T + ΔT, the waveform of the difference between these, and the time required for the ultrasonic wave to be received by the receiving unit R2 after being transmitted at time T and T + ΔT Times t2 and t2 + Δt2, and the required times t3 and t3 + Δt3 from when the ultrasonic waves are transmitted at the times T and T + ΔT until they are received by the receiving unit R3 are recorded in the memories M4 and M5. If no difference waveform is detected by the receiving unit R1 from time T to T + ΔT, the difference waveform is not normally detected by the receiving unit R2 and the receiving unit R3, and the difference waveform is detected by the receiving unit R1. In such a case, the difference waveform is usually detected also in the receiving unit R2 and the receiving unit R3.

  If there is a movement of the object 2 between time T and T + ΔT, a difference waveform is detected, and if it is determined in step S117 that the object 2 has moved by the determination means D, the position of the object 2 is measured. If it is determined that the object 2 has moved by the determination unit D related to the reception unit R1 (Yes in step S117), it is usually determined that the determination unit D related to the reception unit R2 and the reception unit R3 also moved.

  Next, when the required times t1, t2, and t3 are extracted from the memory M4 related to the receiving units R1 to R3 and substituted into (Expression 10) to (Expression 12), the position P (x , Y, z) can be calculated. The position calculation means E can determine the position coordinates P (x, y, z) of the object 2 at time T, and the obtained position coordinates P (x, y, z) are stored in the memory M6 (step S1). S119). Further, when the required times t1 + Δt1, t2 + Δt2, t3 + Δt3 are extracted from the memory M5 related to the receiving units R1 to R3 and substituted into (Expression 10) to (Expression 12), the position P (x + dx, y + dx, z + dz) can be calculated. The position calculation means E can determine the position coordinates P (x + dx, y + dx, z + dz) of the object 2 at time T + ΔT, and the calculated P (x + dx, y + dy, z + dz) is stored in the memory M7 (step S121). .

  Furthermore, the movement information calculation means F calculates the object from the difference between the position coordinates P (x, y, z) of the object 2 at time T and the position coordinates P (x + dx, y + dx, z + dz) of the object 2 at time T + ΔT. Movement amount ΔP (dx, dy, dz) can be obtained, and the obtained movement amount ΔP (dx, dy, dz) is recorded in the memory M8 (step S123). Further, the movement speed U (dx / ΔT, dy / ΔT, dz / ΔT) can be obtained by dividing the movement amount ΔP (dx, dy, dz) by the time ΔT, and the obtained movement speed U (dx / ΔT, dy / ΔT, dz / ΔT) is stored in the memory M9 (step S125). In this way, a series of processing is performed, but returning to the start again, the ultrasonic receiving unit R1 repeats reception of ultrasonic waves every ΔT.

  While the object 2 continues to move, the difference waveform continues to be detected. In such a case, the first waveform data stored in the memory M1 and the difference waveform data stored in the memory M3 are not erased when a new wave is received at ΔT intervals, but the capacity is reduced. If the data can be moved to different memories M1'M3 'which can store a large number of waveforms, the waveform data when there is a motion and the waveform data of the difference can be sequentially stored. Further, the data of the required time t1 stored in the memory M4 at the time T is not deleted when receiving a new wave at ΔT intervals, but is stored in another memory M4 ′ having a large capacity and capable of storing a large number of data. If it is possible to move, data of required time when there is a movement can be sequentially stored.

  Further, regarding the position coordinate data, while the object 2 is moving, the position coordinates P (x, y, z) of the object 2 stored in the memory M6 at the time T are expressed in ΔT intervals and the capacity is increased. Move to another memory M6 ′ that can store a large amount of data, and move the position coordinate P (x + dx, y + dy, z + dy) of the object 2 at time T + ΔT stored in the memory M7 from the memory M7 to the memory M6. The position coordinates P (x + dx, y + dy, z + dy) of the object 2 newly calculated and stored are stored in the memory M7, and the movement amount ΔP (dx, dy, stored in the memories M8 and M9 at time T is stored. dz) and moving speed U (dx / ΔT, dy / ΔT, dz / ΔT) can be moved to other memories M8 ′ and M9 ′ capable of storing a large number of data at intervals of ΔT, respectively. Position coordinate data and the movement data can be sequentially accumulated. And the movement locus | trajectory of the target object 2 can be followed from the accumulated position coordinate data and movement data.

  In the above description, the detection of the required time has been described in the case where the required time t1 (t1 + Δt1) is detected from each of the first waveform and the second waveform, but is not limited thereto. For example, the required time may be the time when the difference waveform (or the absolute value of the difference waveform) calculated by the difference waveform calculating means C first exceeds a predetermined threshold. In this case, the predetermined threshold is set in consideration of the influence of noise and the like. In this way, the required time is detected from the waveform of the moving object with the background removed, which is suitable for detecting the position (distance) of the moving object.

  Further, for example, when the first waveform is subtracted from the second waveform in the calculation of the difference waveform, attention is paid to the positive waveform among the difference waveforms, and the time when the positive waveform first exceeds the predetermined threshold is determined as the required time. It is good. However, in this case, when the object approaches, the value reflects the shortest distance to the current object, but when the object moves away, the value reflects the shortest distance to the current object. (However, if there is a movement more than the thickness of the object within the sampling interval (ΔT), the value reflects the shortest distance).

  As another method, the average position of the current (time T + ΔT) and the position immediately before (time T) is obtained. The average position of two peaks from the larger difference waveform, for example, one positive peak and 1 The time corresponding to the average position with two negative peaks may be the required time. Alternatively, an average of the shortest time and the longest time when the absolute value of the difference waveform exceeds a predetermined threshold may be used as the required time.

  Thus, according to the present embodiment, when the object 2 moves, the movement can be known, and the movement immediately in an emergency such as when a person falls in an unreachable toilet etc. Can be detected. In addition, with ultrasonic waves, it is not necessary to detect the face and appearance of an object, and privacy is not infringed.

Hereinafter, a monitoring device 1 ′ according to a second embodiment of the present invention will be described with reference to the drawings.
The configuration of the monitoring apparatus 1 ′ of the second embodiment is basically the same as that of the monitoring apparatus 1 of the first embodiment. For example, instead of the amplifier control means A, an amplifier control means A1 described later is provided. Is different. The monitoring apparatus 1 ′ will be described below, but the configuration common to the monitoring apparatus 1 of the first embodiment will be omitted as much as possible.

  FIG. 16 shows an example of the configuration of the arithmetic circuit S75 (see FIG. 5) and the storage circuit S74 (see FIG. 5) of the received waveform measuring apparatus S7 in the second embodiment. The amplifier control means A1 is configured to determine the amplification factor based on the waveform stored in the past by the storage circuit S74 as the waveform storage means. The waveform memorize | stored in the past is a waveform acquired previously, for example. Specifically, when viewed from the second time, the waveform stored in the past is the waveform of the first time. Furthermore, the waveform is stored in the memory M1. As described above in the first embodiment, the ultrasonic wave traveling in the atmosphere attenuates in proportion to the square of the elapsed time. In addition, the amount of ultrasonic waves reflected by the object 2 decreases in proportion to the square of the distance from the ultrasonic receiving units R1 to R3. For this reason, it is difficult to obtain an appropriate level waveform. The amplifier control means A1 determines the amplification factor based on the waveform acquired immediately before, so that, for example, an amplification factor that can amplify the previous wave to an appropriate level can be adopted as the current amplification factor. The amplification factor can be set. By doing in this way, since a waveform of an appropriate level can be obtained, it becomes difficult to be influenced by, for example, the distance and size of the object. That is, an accurate waveform can be obtained. Amplification by the amplifier control means A1 is performed for a period from a transmission time point when a wave is transmitted from the ultrasonic transmitter R0 to a transmission time point when the ultrasonic transmitter R0 transmits a next wave. In other words, the period is from the first time T to the second time T + ΔT. The memory M0 of the storage circuit S74 is configured to store the amplification factor a2 set by the amplifier control means A1. The amplifier control means A1 and the memory M0 described above are provided for each of the ultrasonic wave receiving units R1 to R3.

  The required time measurement means B, difference waveform calculation means C, determination means D, position calculation means E, and movement information calculation means F are the same as the calculation circuit S75 of the received waveform measurement device S7 of the first embodiment. is there. Further, the memories M1 to M9 are the same as the memory circuit S74 of the first embodiment.

  Next, FIG. 17 schematically shows an amplified signal in the signal amplifier circuit S51. Here, the period from the transmission time point (first time T) at which the wave W0-1 is transmitted from the ultrasonic transmitter R0 to the transmission time point (second time T + ΔT) at which the next wave W0-2 is transmitted, and the wave A period from a transmission time point (second time T + ΔT) for transmitting W0-2 to a transmission time point (third time T + 2ΔT) for transmitting the next wave W0-3 will be described.

  As shown in the figure, the received signal of the ultrasonic wave W0-1 transmitted at the first time point T at the receiving element S41 is amplified by the signal amplifying circuit S51 with the amplification factor a2 'to form the first waveform. The amplification factor a2 'is determined based on the previous waveform (before ΔT) or set in advance (for example, when there is no previous waveform). When the peak of the first waveform is lower than the allowable reception level, the amplification factor a2 is determined so that the peak of the first waveform is, for example, about 70 to 95%, more preferably about 80%. Good. Further, the amplification factor a2 is determined so that the peak of the first waveform is, for example, 70 to 95%, more preferably about 80% even when the peak of the first waveform is higher than the allowable reception level. To do. The received signal at the receiving element S41 of the ultrasonic wave W0-2 transmitted at the second time T + ΔT is amplified by the signal amplification circuit S51 with the determined amplification factor a2 to form a second waveform. That is, the second waveform has a proper level. In this way, for example, by determining an appropriate amplification factor of the second waveform based on the level of the first waveform, an amplification factor that does not exceed the allowable reception level (does not cause saturation) is obtained. Can be set. Further, it is possible to set an amplification factor that is not significantly lower than the allowable reception level (for example, 20% or less of the allowable reception level). In other words, an accurate waveform can be obtained efficiently.

  The calculation of the difference waveform between the first waveform and the second waveform by the difference waveform calculation means C is based on the amplification factor a2 ′ in the first waveform and the amplification factor a2 in the second waveform. To do. In other words, the first waveform amplified at the first amplification factor a2 ′ by the signal amplification circuit S51 and received at the second time T + ΔT by the wave received at the first time T by the ultrasonic receiving unit R1. The difference waveform from the second waveform amplified by the signal amplification circuit S51 at the second amplification factor a2 is calculated based on the first amplification factor a2 ′ and the second amplification factor a2. Like that. Specifically, for example, the waveform of the difference is calculated using a waveform obtained by further amplifying the first waveform with an amplification factor (for example, a2 / a2 ') that has the same amplification factor as the amplification factor a2. That is, the difference waveform is calculated with the same amplification factor. Conversely, the difference waveform may be calculated by aligning the second waveform with the first waveform.

  Further, the amplification factor may be determined based on the state of the object 2. For example, when there is no object in the monitoring space (a vacant state in the case of a toilet), the amplification factor may be set to a level that is approximately half of the permissible reception level. Further, the amplification factor is set so that the reception signal relating to the object 2 does not exceed the reception allowable level. For example, if the object is a person, the position of the head (height of the back) can be estimated, so if the amplification factor is determined by paying attention to the level of the received signal indicating the height around the position of the head Good. In other words, a received signal indicating a position higher or lower than the vicinity of the head position is treated as the background.

  FIG. 18 shows an example of a processing flow of detection and position measurement of the object 2 in the second embodiment. First, the amplification factor a2 'stored in the memory M0 is set in the signal amplification circuit S51 by the amplifier control means A1 (step S131). Then, the ultrasonic wave W0-1 is transmitted at the first time T by the ultrasonic wave transmitter R0 (step S133). The ultrasonic wave transmitted at the first time T is received by the receiving element S41 of the ultrasonic receiving unit R1, amplified by the signal amplifying circuit S51 with the amplification factor a2 ′, and then the first waveform is stored in the memory M1. (Step S135). The amplifier control means A1 determines the amplification factor a2 based on the first waveform stored in the memory M1, and stores it in the memory M0. Then, the amplification factor a2 stored in the memory M0 is set in the signal amplification circuit S51 (step S136).

  Next, the ultrasonic wave W0-2 is transmitted by the ultrasonic transmitter R0 at the second time T + ΔT (step S137). The ultrasonic wave transmitted at the second time T + ΔT is received by the receiving element S41, amplified by the signal amplification circuit S51 with the amplification factor a2, and then the second waveform is stored in the memory M2 (step S139). Next, the difference waveform calculation means C compares the amplification factor a2 ′ in the first waveform with the amplification factor a2 in the second waveform, calculates the difference waveform, and stores it in the memory M3 (step S145). ). When the difference waveform is detected, the required time measuring means B detects the required time t1 from when the ultrasonic wave is transmitted until it is received from the first waveform, and stores it in the memory M4 (step S1). S141) The required time t1 + Δt1 from when the ultrasonic wave is transmitted until it is received is detected from the second waveform and stored in the memory M5 (step S143). The following processing is the same as that of the first embodiment (see description of FIG. 15).

Hereinafter, a monitoring device 1 ″ according to a third embodiment of the present invention will be described with reference to the drawings.
The configuration of the monitoring apparatus 1 ″ of the third embodiment is basically the same as that of the monitoring apparatus 1 of the first embodiment. For example, instead of the amplifier control means A, a transmitter control means A2 described later is used. The monitoring apparatus 1 ″ will be described below, but the configuration common to the monitoring apparatus 1 of the first embodiment will be omitted as much as possible.

  FIG. 19 shows an example of the configuration of the arithmetic circuit S75 (see FIG. 5) and the storage circuit S74 (see FIG. 5) of the received waveform measuring apparatus S7 in the third embodiment. The transmitter control unit A2 is configured to control the magnitude of the wave transmitted by the ultrasonic transmitter R0 based on the waveform stored in the past by the storage circuit S74 as the waveform storage unit. Specifically, the transmitter control unit A2 controls the transmission drive circuit S2 (see FIG. 5) of the ultrasonic transmitter R0 to vary the size of the transmitted ultrasonic wave. It is difficult to obtain a waveform having an appropriate level for the reason described above in the second embodiment. The transmitter control means A2 can receive, for example, the previous (preceding) wave at an appropriate level, for example, by determining the magnitude of the wave, that is, the output level of the ultrasonic wave based on the previously acquired waveform. Since an ultrasonic wave can be output, a reception waveform at an optimum level can be obtained. By doing in this way, since a waveform of an appropriate level can be obtained, it becomes difficult to be influenced by, for example, the distance and size of the object. That is, an accurate waveform can be obtained. The memory M0 of the storage circuit S74 is configured to store the ultrasonic output level Pa set by the transmitter control means A2. The transmitter control means A2 and the memory M0 described above are provided for each of the ultrasonic receiving units R1 to R3.

  The required time measurement means B, difference waveform calculation means C, determination means D, position calculation means E, and movement information calculation means F are the same as the calculation circuit S75 of the received waveform measurement device S7 of the first embodiment. is there. Further, the memories M1 to M9 are the same as the memory circuit S74 of the first embodiment.

  Next, FIG. 20 schematically shows an output level of an ultrasonic wave transmitted by the ultrasonic transmitter R0 and an amplified signal in the signal amplifier circuit S51. Here, the period from the transmission time point (first time T) at which the wave W0-1 is transmitted from the ultrasonic transmitter R0 to the transmission time point (second time T + ΔT) at which the next wave W0-2 is transmitted, and the wave A period from a transmission time point (second time T + ΔT) for transmitting W0-2 to a transmission time point (third time T + 2ΔT) for transmitting the next wave W0-3 will be described.

  As shown in the figure, the received signal at the receiving element S41 of the ultrasonic wave W0-1 transmitted at the output level Pa1 at the first time point T is amplified by the signal amplifying circuit S51 to form a first waveform. The ultrasonic output level Pa1 is determined based on the previous waveform (before ΔT) or set in advance (for example, when there is no previous waveform). When the peak of the first waveform is lower than the reception allowable level, the transmitter control means A2 is such that the peak of the first waveform is, for example, 70 to 95%, more preferably about 80%. The sound wave output level Pa2 may be determined. Further, the received signal at the receiving element S41 of the ultrasonic wave W0-2 transmitted at the second time T + ΔT is amplified by the signal amplifier circuit S51 to form a second waveform. By doing so, the second waveform becomes a waveform of an appropriate level.

  The calculation of the difference waveform between the first waveform and the second waveform by the difference waveform calculation means C is performed for the output level Pa1 of the ultrasonic wave in the first waveform and the output of the ultrasonic wave in the second waveform. This is performed based on the level Pa2. In other words, the first waveform corresponding to the ultrasonic wave W0-1 transmitted at the first output level Pa1 at the first time T by the ultrasonic transmitter R0 and the second output level at the second time T + ΔT. The calculation of the difference waveform from the second waveform corresponding to the ultrasonic wave W0-2 transmitted at Pa2 is performed based on the first output level Pa1 and the second output level Pa2. Specifically, for example, an amplification factor (for example, the same as when the first waveform corresponding to the ultrasonic wave W0-1 transmitted at the first output level Pa1 is transmitted at the second output level Pa2 (for example, The waveform of the difference is calculated using the waveform further amplified by Pa2 / Pa1). That is, the difference waveform is calculated by amplifying the signal level of the first waveform so as to be equivalent to the case where the ultrasonic wave is transmitted at the same output level as the second output level Pa2. In other words, the difference waveform is calculated by aligning the signal level of the first waveform with the signal level of the second waveform. Conversely, the difference waveform may be calculated by aligning the second waveform with the first waveform.

  FIG. 21 shows an example of a processing flow of detection and position measurement of the object 2 in the third embodiment. First, at the output level Pa1 stored in the memory M0 by the transmitter control means A2, the ultrasonic wave W0-1 is transmitted at the first time T by the ultrasonic transmitter R0 (step S153). The ultrasonic wave transmitted at the first time T is received by the receiving element S41 of the ultrasonic receiving unit R1, amplified by the signal amplifying circuit S51, and then the first waveform is stored in the memory M1 (step S155). ). Then, the transmitter control means A2 determines the ultrasonic output level Pa2 based on the first waveform stored in the memory M1, and stores it in the memory M0.

  Next, the ultrasonic wave transmitter R0 transmits the ultrasonic wave W0-2 at the output level Pa2 at the second time T + ΔT (step S157). The ultrasonic wave transmitted at the second time T + ΔT is received by the receiving element S41, amplified by the signal amplification circuit S51, and then the second waveform is stored in the memory M2 (step S159). Next, the difference waveform calculation means C compares the ultrasonic output level Pa1 of the first waveform with the ultrasonic output level Pa2 of the second waveform, calculates the difference waveform, and stores the memory M3. (Step S155). When the difference waveform is detected, the required time measuring means B detects the required time t1 from when the ultrasonic wave is transmitted until it is received from the first waveform, and stores it in the memory M4 (step S1). S161) The required time t1 + Δt1 from when the ultrasonic wave is transmitted until it is received is detected from the second waveform and stored in the memory M5 (step S163). The following processing is the same as that of the first embodiment (see description of FIG. 15).

  In the above description, the case where the signal amplifier circuit S51 is provided has been described. In this case, the difference waveform calculation means C receives the first waveform of the wave received at the first time point by the ultrasonic receiver R1 and the wave received at the second time point different from the first time point. It may be configured to calculate a waveform of a difference from the second waveform. The monitoring apparatus 1 ″ may further include the amplifier control unit A described in the first embodiment or the amplifier control unit A1 described in the second embodiment.

The monitoring device according to the embodiment of the present invention has been described above. However, the embodiment is not limited thereto, and it is obvious that various changes can be made without departing from the spirit of the present invention.
For example, the number of ultrasonic receiving units may be four or more. In this case, if three of the four or more ultrasonic receivers are selected, the position and movement of the object can be detected as in the case of three ultrasonic receivers. Also, several combinations of three may be formed (one may belong to a plurality of groups), and the most relevant data may be selected from the measurement results of these position coordinates and movement distances. These average values may be calculated. Further, for example, an integrated value of the difference waveform (absolute value) may be used as a threshold in the detection of the difference waveform. Further, the number of ultrasonic receiving units may be one. In this case, the distance from the ultrasonic wave receiving unit to the target object is calculated from the required time from the transmission from the ultrasonic wave transmitter to being reflected by the target object and received by the ultrasonic wave receiving unit. Good. Since both the ultrasonic transmitter and the ultrasonic receiver have directivity and almost no sensitivity to the side, it is possible to estimate the position of the object from the distance to the object.

  Moreover, it is not necessary to install all the ultrasonic receiving units on the ceiling, and they may be installed on a wall or a stand. Also, the wave to be used can be selected from sound waves, ultrasonic waves, radio waves, microwaves, infrared rays, visible light, ultraviolet rays, and the like, and the frequency can be changed. Various changes can be made to the pulse period (time difference), the pulse width, the circuit configuration of the transmitting element, the receiving element, and the receiving unit. Further, both the amplifier control means A of the first embodiment and the amplifier control means A1 of the second embodiment may be provided. In other words, the amplification factor is controlled so that the amplification is performed at an amplification factor proportional to the n-th power of the elapsed time from the transmission time when the wave is transmitted from the ultrasonic transmitter R0, and further stored in the past by the waveform storage unit. The amplifier control means may be configured to determine the amplification factor based on the waveform.

  As described above, according to the present invention, it is possible to provide a monitoring device that can measure the movement and position of an object accurately, for example, while having a simple configuration without the risk of losing privacy.

  Below, the distance measuring device 100 which is the 4th Embodiment of this invention is demonstrated based on drawing. The configuration of the distance measuring apparatus 100 according to the fourth embodiment is common to the monitoring apparatus 1 according to the first embodiment in many parts. For example, the difference waveform calculating means C, the determining means D, and the position calculating means E are used. The movement information calculation means F is not provided, but the distance calculation means G described later is provided. Another difference is that one ultrasonic receiving unit is provided. The monitoring device 1 ″ will be described below, but the configuration common to the monitoring device 1 of the first embodiment will be omitted as much as possible.

  FIG. 22 schematically shows the arrangement state of the apparatus in order to explain the measurement principle of the present embodiment. Here, for example, the ultrasonic wave transmitted from the ultrasonic transmitter R0 is applied to the object 2 such as a person in the monitoring space, reflected, and received by the ultrasonic receiver R1. W0 is an incident wave from the ultrasonic transmitter R0 to the object 2, and W1 is a reflected wave from the object 2 to the ultrasonic receiver R1.

  FIG. 23 shows an example of the configuration of the arithmetic circuit S75 of the received waveform measuring apparatus S7 in the fourth embodiment. The arithmetic circuit S75 includes the amplifier control means A that controls the amplification factor of the amplification by the signal amplifier circuit S51 (see FIG. 5) and the object 2 after the amplified wave is transmitted from the ultrasonic transmitter R0. The required time measuring means B that measures the required times t1 to t3 until it is reflected and received by the ultrasonic receivers R1 to R3, and the distance from the ultrasonic receiver R1 to the object 2 based on the required times And a distance calculating means G for calculating. The distance calculation means G is a distance from the ultrasonic receiver R1 to the object 2 based on the required time measured by the required time measuring means B and the velocity v of ultrasonic waves in the atmosphere (340 m / sec at 14 ° C.). Can be calculated.

  Next, FIG. 24 shows an example of the configuration of the memory circuit S74 of the received waveform measuring apparatus S7 in the present embodiment. The storage circuit S74 includes memories M0 to M3. M0 is the amplification factor a1 set by the amplifier control means, M1 is the first waveform corresponding to the wave received at the first time T, and M2 is the ultrasonic transmitter at the first time T. M3 stores the required time t1 from the transmission from R0 to the reception by the ultrasonic receiving unit R1, and M3 stores the distance from the ultrasonic receiving unit R1 to the object 2 calculated based on the required time t1.

  By configuring as described above, the distance measuring apparatus 100 can cancel the attenuation of the ultrasonic wave received from the ultrasonic wave receiving unit R1, for example, and thus the detectable distance becomes long. In other words, it is possible to measure the distance to a farther object.

  In the above description, the amplifier control unit A is used. However, as shown in FIG. 25A, the amplifier control unit A1 of the second embodiment may be used. That is, instead of the amplifier control means A, the amplifier control means A1 configured to determine the amplification factor based on the waveform stored in the past by the storage circuit S74 as the waveform storage means may be provided. Further, as shown in FIG. 25 (b), instead of the amplifier control means A, the transmitter control means A2 described in the third embodiment may be used. That is, instead of the amplifier control means A, the size of the wave transmitted by the ultrasonic transmitter R0 is controlled based on the waveform stored in the past by the storage circuit S74 as the waveform storage means. You may make it provide transmitter control means A2.

The distance measuring device according to the embodiment of the present invention has been described above. However, the embodiment is not limited thereto, and it is obvious that various modifications can be made without departing from the spirit of the present invention. .
For example, the number of ultrasonic receiving units may be two or more. In this case, the most relevant data may be selected from the detection results of the distances of the respective ultrasonic receivers, and the average value of these may be calculated. Further, for example, in the case of 4 or more, the position and movement of the object can be detected in the same manner as in the case of 3 receiving units by selecting 3 out of 4 or more receiving units.

  As described above, according to the present invention, it is possible to provide a distance measuring device that can accurately measure the distance of an object, for example, while having a simple configuration without a risk of loss of privacy.

It is a figure which shows typically the arrangement | positioning state of the apparatus in 1st Embodiment. It is a figure which shows typically the arrangement | positioning state different from FIG. 1 of the apparatus in 1st Embodiment. In 1st Embodiment, it is a figure which shows the example which comprised the transmitter and the three receiving parts collectively in one module. It is a perspective view which shows the example which has arrange | positioned the module in FIG. 3 to a toilet. It is a block diagram which shows the circuit structure of the monitoring apparatus in 1st Embodiment. It is a block diagram which shows the structure of the arithmetic circuit in FIG. FIG. 6 is a block diagram illustrating a configuration of a memory circuit in FIG. 5. It is a figure which shows typically the transmission signal from the transmitter in 1st Embodiment. It is a figure which shows typically the received signal in the receiving part in 1st Embodiment. It is a figure which shows typically the amplified signal in the signal amplifier circuit in 1st Embodiment. It is a figure which shows typically the received signal after the envelope detection process in 1st Embodiment. It is a figure which shows typically the receiving waveform in the receiving part of the ultrasonic wave transmitted in 1st time from the transmitter in 1st Embodiment. It is a figure which shows typically the receiving waveform in the receiving part of the ultrasonic wave transmitted in 2nd time from the transmitter in 1st Embodiment. It is a figure which shows typically the waveform of the difference of two received waveforms. It is a figure which shows the example of the processing flow of the detection of the motion of the target object in 1st Embodiment, and a position measurement. It is a block diagram which shows the structure of the arithmetic circuit and memory circuit in 2nd Embodiment. It is a figure which shows typically the amplified signal in the signal amplifier circuit in 2nd Embodiment. It is a figure which shows the example of the processing flow of the detection of the motion of the target object in 2nd Embodiment, and a position measurement. It is a block diagram which shows the structure of the arithmetic circuit and memory circuit in 3rd Embodiment. It is a figure which shows typically the amplified signal in the signal amplifier circuit in 3rd Embodiment. It is a figure which shows the example of the processing flow of the detection of the motion of the target object in 3rd Embodiment, and a position measurement. It is a figure which shows typically the arrangement | positioning state of the distance measuring device in 4th Embodiment. It is a block diagram which shows the structure of the arithmetic circuit in 4th Embodiment. It is a block diagram which shows the structure of the memory circuit in 4th Embodiment. It is a block diagram which shows another structural example of the distance measuring device in 4th Embodiment.

Explanation of symbols

1: Monitoring device 100: Distance measuring device 2: Object A, A1: Amplifier control means A2: Transmitter control means B: Required time measuring means C: Difference waveform calculating means D: Determination means E: Position calculating means F: Movement Information calculation means G: Distance calculation means M: Modules M1 to M9: Memory P ₀ (0, _0, 0): Transmitter position coordinates P ₁ (x1, y1, z1) to P ₃ (x3, y3, z3) : Position coordinates P (x, y, z) of the receiving part: Position coordinates ΔP (dx, dy, dz) of the object: Movement amount Pw of the object: Pulse width R0: Transmitters R1 to R3: Reception part S1: Transmission pulse generator S2: Transmission drive circuit S3: Oscillation elements S4, S41 to S43: Reception elements S51 to S53: Signal amplification circuits S61 to S63: Detection circuit S7: Reception waveform measuring device S71: Switch circuit S72: A D conversion circuit S73: Central processing unit (CPU)
S74: Memory circuit S75: Arithmetic circuit S76: External output circuit T: First time ΔT: Pulse interval T + ΔT: Second time t1 to t3: After the ultrasonic wave transmitted from the transmitter R0 is transmitted, the receiving unit Required times Δt1 to Δt3 until the signals are received by R1 to R3: Changes in the required time in the receiving units R1 to R3 te: Detection end time U: Moving speed of the object v: Ultrasonic speed W0: To the object Incident waves W1 to W3: Reflected waves from the object a1 to a2: Amplification factors Pa1 to Pa2: Output level of ultrasonic waves

Claims (8)

A transmitter that transmits waves propagating in space;
A receiver for receiving a wave transmitted from the transmitter and reflected by an object;
An amplifier for amplifying the wave received by the receiver;
A first waveform amplified by the amplifier with a wave received at a first time by the receiver, and a first waveform amplified by the amplifier with a wave received at a second time different from the first time. Difference waveform calculating means for calculating a difference waveform from the waveform of 2;
If the waveform of the difference is detected, the required time from when the wave is transmitted from the transmitter to when it is reflected by the object and received by the receiver based on the waveform of the difference A time measuring means for measuring time;
Monitoring device. An amplifier control means for controlling an amplification factor of amplification by the amplifier;
The amplifier control means is configured to perform the control so that the amplification is performed at an amplification factor proportional to the n-th power of an elapsed time from a transmission time point when the wave is transmitted from the transmitter;
The monitoring device according to claim 1. Amplifier control means for controlling an amplification factor of amplification by the amplifier;
Waveform storage means for storing the waveform of the wave received by the receiver;
The amplifier control means is configured to determine the amplification factor based on waveforms previously stored by the waveform storage means;
The monitoring device according to claim 1. A plurality of receivers and a plurality of amplifiers each;
The monitoring apparatus according to any one of claims 1 to 3. A transmitter that transmits waves propagating in space;
A receiver for receiving a wave transmitted from the transmitter and reflected by an object;
A difference for calculating a waveform of a difference between a first waveform of a wave received at a first time point by the receiver and a second waveform of a wave received at a second time point different from the first time point. Waveform calculation means;
If the waveform of the difference is detected, the required time from when the wave is transmitted from the transmitter to when it is reflected by the object and received by the receiver based on the waveform of the difference A time measuring means for measuring time;
Waveform storage means for storing the waveform of the wave received by the receiver;
Transmitter control means for controlling the magnitude of the wave transmitted by the transmitter based on the waveform stored in the past by the waveform storage means;
Monitoring device. A transmitter that transmits waves propagating in space;
A receiver for receiving a wave transmitted from the transmitter and reflected by an object;
An amplifier for amplifying the wave received by the receiver;
Required time measuring means for measuring a required time from when the amplified wave is transmitted from the transmitter to when it is reflected by the object and received by the receiver;
Distance calculating means for calculating a distance from the receiver to the object based on the required time;
Amplifier control means for controlling the amplification factor of amplification by the amplifier;
The amplifier control means is configured to perform the control so that the amplification is performed at an amplification factor proportional to the n-th power of an elapsed time from a transmission time point when the wave is transmitted from the transmitter;
Distance measuring device. A transmitter that transmits waves propagating in space;
A receiver for receiving a wave transmitted from the transmitter and reflected by an object;
An amplifier for amplifying the wave received by the receiver;
Required time measuring means for measuring a required time from when the amplified wave is transmitted from the transmitter to when it is reflected by the object and received by the receiver;
Distance calculating means for calculating a distance from the receiver to the object based on the required time;
Amplifier control means for controlling an amplification factor of amplification by the amplifier;
Waveform storage means for storing the waveform of the wave received by the receiver;
The amplifier control means is configured to determine the amplification factor based on waveforms previously stored by the waveform storage means;
Distance measuring device. A transmitter that transmits waves propagating in space;
A receiver for receiving a wave transmitted from the transmitter and reflected by an object;
Required time measuring means for measuring a required time from when the wave is transmitted from the transmitter to when the wave is reflected by the object and received by the receiver;
Distance calculating means for calculating a distance from the receiver to the object based on the required time;
Waveform storage means for storing the waveform of the wave received by the receiver;
Transmitter control means for controlling the magnitude of the wave transmitted by the transmitter based on the waveform stored in the past by the waveform storage means;
Distance measuring device.

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