JP2002054999A - Sound wave generation detecting device, environmental state measuring device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly accurately measure propagation time of a sound wave in a measuring object space. SOLUTION: A large number of nodes are arranged over the whole periphery in a peripheral edge part of the measuring object space, and the respective nodes have a loudspeaker arranged toward the inside of the measuring object space, a first microphone arranged toward the loudspeaker in front of the loudspeaker and a second microphone arranged toward the inside of the measuring object space in front of the loudspeaker. The nodes of a sound wave generating object convert sound wave data (see (A)) into an analog signal, supply the analog signal to the loudspeaker, generate the sound wave, and acquire comparing sound wave measuring data (see (B)) by detecting the sound wave by the first microphone. The other nodes acquire sound wave measuring data (see (C)) by detecting the sound wave by the second microphone. The propagation time of the sound wave is arithmetically operated by determining the correlation between a waveform of the comparing sound wave measuring data and a waveform of the sound wave measuring data (see (D)).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sound wave generation detecting device,
The present invention relates to an environmental state measuring apparatus and method, and in particular, an acoustic state detecting apparatus usable for measuring an environmental state, an environmental state measuring method for measuring an environmental state such as a temperature distribution in a space using the acoustic state detecting apparatus, and The present invention relates to an environmental condition measuring apparatus to which the environmental condition measuring method can be applied.

[0002]

2. Description of the Related Art In order to control the temperature and humidity in a space to be air-conditioned to desired values, it is necessary to measure the temperature and humidity in the space to be air-conditioned.
Humidity is rarely constant. Particularly in a closed large space such as a dome stadium or a theater, the temperature and humidity at each point in the space often vary greatly. For this reason, for example, when performing air conditioning that satisfies both comfort and energy saving in a large space such as a dome stadium or a theater, or when precisely controlling indoor temperature and humidity to desired values, the air-conditioned space It is necessary to measure the distribution of temperature and humidity inside.

However, in order to directly measure the distribution of temperature and humidity using a temperature sensor and a humidity sensor, it is necessary to arrange a large number of sensors in a matrix in the space to be air-conditioned including the vicinity of the center of the space to be air-conditioned. However, it is not practical to arrange a large number of sensors as described above because the cost is increased, the landscape is impaired, and the use of the space to be measured is limited. In a dome stadium, a theater, etc., the temperature of the peripheral portion is measured by a sensor attached to a peripheral portion (for example, a wall body) of the measured space, and the sensor is lifted by a balloon or the like so that the central portion of the measured space can be measured. Although it is conceivable to measure the temperature and the like, it is impossible with this method to measure the distribution of temperature and humidity while an event such as baseball is being performed in the measured space.

On the other hand, in the field of medicine, a human body is irradiated with X-rays from multiple directions, the X-ray dose transmitted through the human body is measured by a high-sensitivity sensor, and based on the measured X-ray dose, a cross section of the human body is formed. Computed Tomography (CT) technology, which calculates the amount of X-ray absorption of body tissue at each position along the computer and reconstructs it as a two-dimensional image and displays it on a monitor as a cross-sectional image of the human body, is widely used. ing. According to this CT technique, it is possible to measure a state inside a measurement target (in this case, a human body) in a non-contact manner. Therefore, it has been proposed to obtain a temperature distribution in a measured space using this CT technique. I have.

Specifically, instead of X-rays, sound waves whose propagation time (velocity) changes depending on the temperature of the medium are used, and speakers, for example, are provided at a large number of places on a wall partitioning the measured space.
A microphone and a temperature sensor are provided, and a propagation time of the sound wave between the plurality of locations is measured by a speaker and a microphone. From the propagation time of the sound wave between the plurality of locations in the measured space, a temperature distribution in the measured space is calculated. It is calculated by calculation.

[0006]

More specifically, in measuring the propagation time of a sound wave, a sound wave is generated from a speaker by supplying digital original sound data to the speaker via a D / A converter, and the measured space is measured. The sound signal output from the microphone when the propagated sound wave reaches the microphone arrangement position is converted into digital detected sound data by an A / D converter, and the waveform of the detected sound data and the waveform of the original sound data are converted into time. This is performed by calculating the correlation while shifting the position, and using the time difference when the correlation becomes the highest as the propagation time of the sound wave.

However, the loudspeaker has a structure that emits a sound by vibrating the diaphragm according to the audio signal, and the microphone has a structure that converts the vibration of the diaphragm generated according to the surrounding sound into the audio signal. Due to the influence of the mass of the diaphragm, both the waveform of the sound emitted from the speaker and the waveform of the audio signal output from the microphone are duller than the original waveform, and the vibration of the diaphragm increases as the frequency increases. Is unable to follow, thereby cutting high-frequency components higher than a predetermined frequency. Also, the sound pressure level of the sound handled by the speaker is different from that of the microphone, and the diaphragm of the speaker handling sound with a higher sound pressure level requires a correspondingly high strength and therefore has a large mass. More prominent.

[0008] For this reason, the waveform of the audio signal obtained by detecting the sound emitted from the speaker with the microphone is different from the waveform of the original audio data due to the influence of the speaker and the microphone (particularly, the speaker).
This causes a decrease in measurement accuracy in the measurement of the propagation time, and also causes a decrease in measurement accuracy of the temperature distribution. In addition, a speaker with poor response of the vibration of the diaphragm to the audio signal is used to promote dulling of the waveform of the audio signal output from the microphone, which leads to a further decrease in the measurement accuracy of the propagation time and the temperature distribution. There was also a problem that it could not be done.

Further, the diaphragm of the speaker has a three-dimensional shape such as a cone type or a dome type (a flat type has a drawback that waveform reproducibility is inferior), and a sound is actually emitted on the diaphragm. Since the position of the point (sound generation point) differs depending on the frequency of the sound emitted from the speaker due to the divided vibration of the diaphragm, the distance between the sound generation point of the speaker and the microphone slightly changes depending on the frequency of the sound emitted from the speaker. Since the change in the distance between the sounding point of the speaker and the microphone has a nonnegligible effect on the measurement of the propagation time and temperature distribution especially in a narrow space,
The sound emitted from the loudspeaker for measuring the propagation time and the temperature distribution has been limited to, for example, a simple sound of a single frequency or a sound close thereto.

Although a calibration method such as a three-speaker method for measuring the position of a sound generation point using three speakers and a microphone has been proposed, there has been a problem that the measurement accuracy is not sufficient.

The present invention has been made in view of the above facts, and provides a sound wave generator capable of improving the accuracy of measuring the propagation time of sound waves and the accuracy of measuring environmental conditions such as temperature distribution in the space to be measured. It is a first object to obtain a detection device.

It is a second object of the present invention to provide an environmental condition measuring method and an environmental condition measuring device capable of measuring environmental conditions such as temperature distribution in a measured space with high accuracy.

[0013]

According to a first aspect of the present invention, there is provided a sound wave generating and detecting apparatus which is disposed on a sound wave emitting side of a sound wave generator.
First sound wave detecting means for detecting a sound wave radiated from the sound wave generator at a position separated from the sound wave generator by a predetermined distance; and a sound wave arranged on the sound wave emitting side of the sound wave generator and arriving from the side opposite to the sound wave generator side. Second sound wave detecting means for detecting the sound wave at a position separated from the sound wave generator by a predetermined distance, and light which is arranged on the sound wave emitting side of the sound wave generator and which arrives from the side opposite to the sound wave generator side at a predetermined distance from the sound wave generator. A light reflecting plate that reflects light at a position
It is comprised including.

The first aspect of the present invention includes a sound wave generator. As the sound wave generator, for example, a speaker can be used. More specifically, various speakers such as an electrodynamic type (for example, a dynamic speaker), an electromagnetic type (for example, a magnetic speaker), and an electrostatic type (for example, a condenser speaker) are used. However, the sound wave generated by the sound wave generator may be a sound wave having a frequency outside the audible range,
For example, it is possible to use a wave transmitter that emits an ultrasonic wave as a sound wave generator.

Further, a first sound wave detecting means is arranged on the sound wave emitting side of the sound wave generator, and the sound wave emitted from the sound wave generator is separated by a predetermined distance from the sound wave generator by the first sound wave detecting means. Is detected. A second sound wave detecting means is also provided on the sound wave emitting side of the sound wave generator, and the sound wave arriving from the side opposite to the sound wave generator side is separated by a predetermined distance from the sound wave generator by the second sound wave detecting means. Is detected.

As the first sound wave detecting means and the second sound wave detecting means, for example, a microphone can be used. More specifically, an electrodynamic type (for example, a dynamic microphone or a ribbon microphone), an electrostatic type (for example, a condenser microphone), or a piezoelectric type A sound wave detector such as various microphones such as a crystal microphone can be applied. If the sound wave generated by the sound wave generator is an ultrasonic wave, for example, a sound wave detector such as a receiver for detecting the ultrasonic wave Can also be used.

Also, the first sound wave detecting means and the second sound wave detecting means need not be separate sound wave detectors. That is, since the first sound wave detecting means and the second sound wave detecting means have the directions of arrival of the sound waves to be detected in approximately opposite directions, for example, the first sound wave detecting means and the second sound wave detecting means It is also possible to configure by a sound wave detector. Further, when the first sound wave detecting means and the second sound wave detecting means are respectively constituted by independent unidirectional sound wave detectors, the sound wave detector corresponding to the first sound wave detecting means has a sound wave detecting direction of the sound wave generation. The sound wave detector corresponding to the second sound wave detector may be arranged so that the sound wave detection direction is opposite to the sound wave generator.

As described above, the sound wave generation detecting device according to the first aspect of the present invention includes the sound wave generator, the first sound wave detecting means, and the second sound wave detecting means. Such sound wave generation detecting devices are arranged at both ends of a section where the propagation time of a sound wave is to be measured, and the sound wave generation device of one of the sound wave generation detecting devices (referred to as “first sound wave generation detecting device” for convenience). When a sound wave is generated, the generated sound wave is transmitted to a predetermined position of the end of the section on the sound wave generator side by the first sound wave detecting means of the first sound wave generation detecting device (specifically, the sound wave generator At a position separated by a predetermined distance from: a first position for convenience, and a second sound detection means of the other sound generation detection device (for convenience, referred to as "second sound generation detection device"). By the above-mentioned sound wave generator across the section It is possible to detect at a predetermined position of the opposite end (conveniently referred to as a "second position").

Here, for example, the sound wave generator is configured to generate a sound wave according to an input sound signal, and the generated sound wave has a waveform that changes from the sound signal waveform (eg, the waveform becomes dull). The first sound wave detection means of the first sound wave generation detection device and the second sound wave detection means of the second sound wave generation detection device for detecting sound waves generated by the sound wave generator. Since the sound wave emitted from the vessel (the sound wave whose waveform has been changed by the sound wave generator) is detected, the waveform of the sound wave detected by the first sound wave detecting means and the wave form of the sound wave detected by the second sound wave detecting means are Match with high precision.

Further, the position of the sound generation point when the sound wave generator generates a sound wave changes according to the frequency of the sound wave generated by the sound wave generator. The sound wave affects the detection of the sound wave by the second sound wave detecting means of the detecting device, and is generated by the sound wave generator of the first sound wave generating and detecting device and detected by the second sound wave detecting means of the second sound wave generating and detecting device. The propagation distance of the sound wave changes in accordance with the change in the position of the sound generation point, and the propagation time of the sound wave also changes with the change in the propagation distance of the sound wave.

However, the first sound wave detecting means of the first sound wave generation detecting device detects the same sound wave as the second sound wave detecting means of the second sound wave generation detecting device. The same effect is exerted on the detection of sound waves by the first sound wave detecting means of the first sound wave generation and detection device, and the first sound wave generation and detection device generated by the sound wave generator of the first sound wave generation and detection device The propagation distance and propagation time of the sound wave detected by the first sound wave detecting means vary in the same manner as the sound wave detection by the second sound wave detecting means of the second sound wave generation detecting device.

Therefore, the waveform of the sound wave detected by the first sound wave detecting means of the first sound wave generation detecting device is compared with the waveform of the sound wave detected by the second sound wave detecting means of the second sound wave generation detecting device. The sound wave generated by the sound wave generator reaches the first sound wave detecting means of the first sound wave generation detecting device as the sound wave propagation time of the section where the propagation time is to be measured (for example, calculating the correlation). From the time until the sound wave reaches the second sound wave detecting means of the second sound wave generating and detecting device, that is, the first sound wave detecting means of the first sound wave generating and detecting device and the second sound wave detecting device of the second sound wave generating and detecting device. By determining the propagation time of the sound wave between the two sound wave detecting means, the propagation time of the sound wave can be measured with high accuracy without being affected by the characteristics of the sound wave generator or the movement of the position of the sound generation point.

In measuring environmental conditions such as temperature distribution by measuring the propagation time of sound waves in a plurality of sections, it is important to accurately grasp the distance of the section in which the propagation time is measured. When the section from the sound wave generator to the sound wave detector is used as the measurement section, if the position of the sounding point changes, the actual propagation distance of the sound wave changes, so it is difficult to accurately grasp the distance in the propagation time measurement section. It is. On the other hand, in the measurement of the propagation time of the sound wave using the sound wave generation detecting device according to the first aspect of the present invention, the first sound wave detecting means of the first sound wave generation detecting device and the second sound wave generation detecting device of the second sound wave generation detecting device are used. Since the section between the two sound wave detecting means is the propagation time measuring section, the actual propagation distance of the sound wave does not change even if the position of the sound generation point changes.

Further, according to the first aspect of the present invention, there is provided a sound wave generation detecting device for detecting light arriving from a side opposite to a sound wave generator side.
A light reflecting plate is provided which reflects the first sound wave detecting means and the second sound wave detecting means at a position where the distance from the sound wave generator is equal (a position separated by a predetermined distance from the sound wave generator). This light reflection plate can be constituted by, for example, a total reflection mirror arranged so that the light reflection surface faces the opposite side to the sound wave generator. By using this light reflection plate, the distance of the propagation time measurement section can be easily and accurately measured by, for example, a laser distance meter, and the measurement result of the sound wave propagation time and the measurement of the distance of the propagation time measurement section Based on the result,
Environmental conditions such as temperature distribution can be accurately measured.

As described above, according to the first aspect of the present invention, by using the sound wave generation and detection device according to the first aspect of the present invention, the accuracy of measuring the propagation time of the sound wave can be improved, and the temperature in the space to be measured can be improved. The accuracy of measurement of environmental conditions such as distribution can be improved.

According to the first aspect of the present invention, as described in the second aspect, the first sound wave detecting means, the second sound wave detecting means, and the light are provided on a bracket connected to the sound wave generator. It is preferable that the reflector is integrally mounted.
Thereby, when installing the sound wave generation detecting device, the first sound wave detecting means and the second sound wave
There is no need to adjust the relative positions of the sound wave detection means and the light reflection plate, and the sound wave generation detection device can be easily installed, and the first sound wave detection means, the second sound wave detection means and A change in the relative position of the light reflection plate can be suppressed.

In the first sound wave detecting means according to the first aspect of the present invention, since the sound wave generator for generating the sound wave to be detected is located at a relatively close position, the sound pressure level of the sound wave to be detected can be improved. And the waveform of the sound wave detected by the first sound wave detecting means may be distorted or saturated. In consideration of this, it is preferable that an attenuating means for attenuating the incoming sound wave is disposed on the sound wave arrival side of the sound wave detection position by the first sound wave detecting means. In addition, as the attenuation means, for example, a sound absorbing material or the like can be used. This can prevent the waveform of the sound wave detected by the first sound wave detecting means from being distorted or saturated.

Further, the waveform of the sound wave detected by the sound wave detecting means changes slightly (eg, becomes dull) with respect to the waveform of the incoming sound wave. In consideration of this, as described in claim 4, the first sound wave detecting means and the second sound wave detecting means may be configured to detect sound waves by at least a sound wave detector of a similar kind (preferably the same kind). preferable. Thereby, the waveform detected by the first sound wave detecting means and the waveform detected by the second sound wave detecting means show the same change with respect to the waveform of the arriving sound wave.

Accordingly, in a mode in which the sound wave generation detecting device according to the present invention is arranged at both ends of the section where the propagation time of the sound wave is to be measured, the first sound wave generation detecting device for generating a sound wave from the sound wave generator is provided. The waveform of the sound wave detected by the first sound wave detecting means and the second sound wave of the second sound wave
The waveforms of the sound waves detected by the sound wave detecting means can be matched with high accuracy, and the sound wave propagation time can be measured more accurately.

In order to achieve the second object, the environmental condition measuring apparatus according to the present invention is arranged at both ends of a plurality of propagation time measuring sections crossing the space to be measured. A sound wave is output from the sound wave generator of one of the sound wave generation detection devices according to any one of claims 4 to 4, and one of a pair of sound wave generation detection devices disposed at both ends of the propagation time measurement section. Generating the generated sound waves by the first sound wave detection means of the one sound wave generation detection device and the second sound wave detection means of the other sound wave generation detection device; A control unit for performing each of the measurement sections, and a waveform of a sound wave detected by the second sound wave detection unit is compared with a waveform of a sound wave detected by the first sound wave detection unit, and the sound generated by the first sound wave detection unit Calculating the propagation time of the sound wave propagating from the detection position to the detection position of the sound wave by the second sound wave detection means for each of the plurality of propagation time measurement sections, and the propagation time measurement means Environmental state calculating means for calculating an environmental state in the measured space based on the measured values of the propagation times of the sound waves in the plurality of measurement sections.

According to a fifth aspect of the present invention, the sound wave generation and detection device according to any one of the first to fourth aspects is arranged at both ends of a plurality of propagation time measurement sections that cross the space to be measured. The control means generates a sound wave from the sound wave generator of one of the sound wave generation detection devices of the pair of sound wave generation detection devices disposed at both ends of the propagation time measurement section, and generates the generated sound wave on one side. The detection by the first sound wave detecting means of the sound wave generation detecting device and the second sound wave detecting means of the other sound wave generation detecting device is performed for each of the plurality of propagation time measurement sections.

Further, the propagation time calculating means compares the waveform of the sound wave detected by the second sound wave detecting means with the waveform of the sound wave detected by the first sound wave detecting means, and determines the position of the sound wave detected by the first sound wave detecting means. The calculation of the propagation time of the sound wave propagating to the detection position of the sound wave by the second sound wave detection means is performed for each of the plurality of propagation time measurement sections. Thereby, as described above, the propagation time of the sound wave can be accurately determined for each of the plurality of propagation time measurement sections without being affected by the characteristics of the sound wave generator or the position of the sounding point being moved. Can be measured.

Since the measurement accuracy of the propagation time of the sound wave is not affected by the movement of the sounding point position as described above, any sound wave (for example, a sound wave corresponding to a natural sound) can be used as the sound wave generated by the sound wave generator. ) Can be used. Thus, even when a person is present in the measured space, it is possible to avoid giving a feeling of strangeness or discomfort to a person present in the measured space when measuring the propagation time.

The environmental condition calculating means calculates the environmental condition in the space to be measured based on the measured values of the propagation times of the sound waves in the plurality of travel time measuring sections measured by the propagation time measuring means. Environmental conditions such as temperature distribution in the space can be measured with high accuracy.

The calculation of the environmental state in the space to be measured by the environmental state calculating means is performed, for example, by dividing the measured space into a number of small areas, and using the sound velocity in each of the small areas as a variable.
A number of simultaneous equations are used to represent the propagation time of a sound wave propagating along a propagation path from a certain sound wave generator to a certain sound wave detector as the sum of the transit times of sound waves in each of the small regions existing on the propagation path. It can also be realized by substituting the generated and measured propagation time of the sound wave into the simultaneous equations and solving it.
It is preferable to calculate as follows.

That is, a plurality of virtual paths of the same length, which penetrate the space to be measured at different positions along different directions, are set in a plurality of different directions, respectively. The propagation time of the sound wave in the measurement section on the virtual path corresponding to the first sound wave detecting means of the first sound wave generation detecting device and the second sound wave detecting means of the second sound wave generation detecting device is actually calculated as the sound wave. Propagating and measuring, and estimating the propagation time of the sound wave in the section outside the measurement section on the virtual path assuming that the outside of the measured space is filled with a medium of a constant temperature, the sound wave on the virtual path Calculating an estimated value of the propagation time of the sound wave when propagating, and obtaining projection data of the propagation time of the sound wave in the predetermined direction based on the estimated value of the propagation time of each sound wave in a plurality of virtual paths along the predetermined direction. To It performed each for the serial a plurality of directions,
It is preferable to calculate an environmental state in the measured space based on projection data of the propagation time of the sound wave in each of the plurality of directions.

In the above description, since the projection data of the sound wave propagation time can be obtained by virtually matching the lengths of the propagation time measurement paths, a calculation method (Fourier domain reconstruction method, filter (A back projection method of processing data, a two-dimensional filtering method, etc.) can be applied, and the calculation time can be shortened and the configuration of the device for measuring the propagation time can be simplified.

The method for measuring an environmental condition according to the invention according to claim 6, wherein the sound wave generation detection device according to any one of claims 1 to 4, is provided at both ends of a plurality of propagation time measurement sections crossing the space to be measured. Are arranged, and a sound wave is generated from the sound wave generator of one of the sound wave generation detection devices of the pair of sound wave generation detection devices disposed at both ends of the propagation time measurement section, and the generated sound wave is generated by the one of The first sound wave detecting means of the sound wave generation detecting device and the second sound wave detecting means of the other sound wave generating detecting device perform the detection for each of the plurality of propagation time measurement sections, The waveform of the sound wave detected by the means is compared with the waveform of the sound wave detected by the first sound wave detecting means, and the position of the sound wave detected by the first sound wave detecting means is used by the second sound wave detecting means. Calculating the propagation time of the sound wave propagating to the wave detection position is performed for each of the plurality of propagation time measurement sections, and in the measurement target space based on the measurement value of the sound wave propagation time of the plurality of propagation time measurement sections. Is calculated, the environmental condition such as the temperature distribution in the space to be measured can be measured with high accuracy, similarly to the fifth aspect of the present invention.

According to a seventh aspect of the present invention, in the sixth aspect of the present invention, light is applied to a pair of light reflection plates of a pair of sound wave generation and detection devices respectively disposed at both ends of the propagation time measuring section. Measuring the distance between the pair of light reflecting plates with respect to each of the plurality of propagation time measurement sections, and calculating the environmental state in the measured space using the pair of light beams in each of the plurality of propagation time measurement sections. It is characterized in that the measurement is performed in consideration of the measurement result of the distance between the reflectors.

According to the present invention, the distance between the pair of light reflecting plates is measured by irradiating light to each of the pair of light reflecting plates of the pair of sound wave generation detecting devices disposed at both ends of the propagation time measuring section. I do. For example, a laser distance meter can be used for this distance measurement, and the distance between the pair of light reflection plates, that is, the distance between the propagation time measurement sections can be easily and accurately measured by irradiating the light reflection plate with laser light. can do.

According to the seventh aspect of the present invention, the distance measurement is periodically performed for each of the plurality of propagation time measurement sections, and the measurement result of the distance between the pair of light reflecting plates in each of the plurality of propagation time measurement sections. In consideration of the above, the calculation of the environmental state in the space to be measured is performed, so that even if the distance of the propagation time measurement section changes due to environmental temperature changes due to seasonal changes or temporal changes, for example, the change in distance changes. It is possible to accurately measure the environmental state in the measured space without being affected.

[0042]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an environmental condition measuring apparatus 10 to which the environmental condition measuring method is applied. The environmental condition measuring device 10 includes a number of nodes 12A, 1
2B, 12C,... And a host computer 14, which are connected to each other via a transmission medium 18.

The host computer 14 has a CPU 14
A, ROM 14B, RAM 14C, input / output port 14D
Which are connected to each other via a bus 14E. The input / output port 14D is connected to a transmission medium 18 via a network transmission unit 16. The input / output port 14D is connected to a display 20 for displaying various information and a keyboard 22 for the operator to input various data and commands.

On the other hand, a large number of nodes 12 are arranged on the periphery of the space to be measured at substantially constant intervals over the entire periphery of the periphery. As an example, FIG. 2 illustrates a case where an environmental state in a dome-shaped measured space 24 (for example, a dome stadium or the like) which is defined by a cylindrical wall 22 and whose upper part is closed by a roof (not shown) is measured. The arrangement of each node 12 is shown. Note that the number and intervals of the nodes 12 are not limited to the example shown in FIG. 2, but it is desirable that the number of nodes 12 is an even number. In order to identify each node 12, each node is given a node number for convenience.

Since the nodes 12A, 12B, 12C,... Have the same configuration, the node 12A will be described below. The node 12A includes a speaker 30 as a sound wave generator arranged toward the inside of the measured space 24, a first microphone 32 as first sound wave detecting means arranged toward the speaker 30, and And a second microphone 34 as a second sound wave detecting means arranged toward the camera. The speaker 30 is embedded in the wall 22 (not shown), and is connected to a data processing unit 40 via an amplifier 36 and a D / A converter 38.

As shown in FIG. 3A, a base of an arm 54 bent in a U-shape is attached to the speaker 30 so that an intermediate portion projects toward the space to be measured 24. As shown in FIG. 3B, a hole 54 </ b> A is formed in an intermediate portion of the arm 54 on a surface facing the speaker 30, and the first microphone 32 transmits a sound wave emitted from the speaker 30 to the speaker 30. It is buried inside the hole 54A so that it is detected at a predetermined distance from the hole 54A. Hereinafter, the arrangement position of the first microphone 32 is referred to as a “first position”.

Since the first microphone 32 detects a sound wave emitted from the speaker 30 of its own node, the distance from the sound source (speaker 30) is short, and the sound pressure level of the sound wave to be detected is relatively high. Therefore, the first microphone 3
Reference numeral 2 is disposed on the bottom side of the hole 54A, and a sound absorbing material 56 is provided on the near side of the hole 54A (between the first microphone 32 and the speaker 30). This prevents the signal level of the audio signal output from the first microphone 32 from being distorted or saturated. The sound absorbing material 56 corresponds to the damping means according to the third aspect.

Also, as shown in FIG.
In the middle part of No. 4, holes 54B and 54 are formed on the surface opposite to the surface on which hole 54A is formed (the surface facing the space under measurement 24).
C are drilled, and the second microphone 34 is
The hole 5 is so detected that a sound wave emitted from the speaker 30 of another node is detected at a position separated from the speaker 30 by a predetermined distance.
It is buried inside 4B. Hereinafter, the arrangement position of the second microphone 34 is referred to as a “second position”.
Since the second microphone 34 detects the sound wave emitted from the speaker 30 of the other node, the distance from the sound source is large and the sound pressure level of the sound wave to be detected is relatively small.
No sound absorbing material is provided in 4B.

In this embodiment, microphones of the same model are used as the first microphone 32 and the second microphone 34, and the first microphone 32 and the second microphone 34 are described in claim 4. Vessel ". On the other hand, a light reflecting plate 58 is attached to the bottom of the hole 54C so as to reflect light arriving from the side opposite to the speaker 30 at a position separated from the speaker 30 by a predetermined distance. The light reflecting plate 58 is connected to each node 12.
Is used when measuring the distance between the arms 54 with a laser distance meter or the like.

The above-described speaker 30 and arm 5
4, first microphone 32, second microphone 34
The light reflection plate 58 corresponds to the sound wave generation and detection device described in claim 1 (specifically, claim 2).

The first microphone 32 is connected to a data processing section 40 via a filter / amplifier 42 and an A / D converter 44, and the second microphone 34 is connected to a filter / amplifier 42.
Data processing unit 4 via amplifier 46 and A / D converter 48
Connected to 0. The data processing unit 40 includes a microcomputer and the like, and is connected to the transmission medium 18 via the network transmission unit 50.

Next, the operation of the present embodiment will be described. In the present embodiment, as shown in FIG. 4, for example, a large number of virtual paths are set in advance as paths for estimating the propagation time of a sound wave in a temperature distribution calculation process described later. Although FIG. 4 shows only a virtual path along a certain direction, in practice, as shown in FIG. 6B, for example, as shown in FIG. For each direction, a number of virtual routes are set in advance.

The virtual path is composed of a virtual speaker located on a virtual speaker row arranged perpendicular to a predetermined direction outside the measured space 24 and a virtual speaker row opposite to the virtual speaker row with the measured space 24 interposed therebetween. A fixed distance L outside the measured space 24
₀ (see FIG. 5) is defined as a path connecting the virtual microphones located on the virtual microphone row arranged in parallel with the virtual speaker row with the virtual speaker row and the virtual speaker row being separated from each other. However, the positions on the virtual speaker row and the virtual microphone row are determined so as to intersect the wall 22 and penetrate the measured space 24 at positions where the different nodes 12 are arranged along the predetermined direction and respectively. I have. Therefore, the lengths of the virtual paths are equal to each other.

In each of the virtual paths, a section between a pair of nodes 12 located on the same virtual path (a section to be measured indicated by a solid line in FIG. 4; specifically, a section of each arm 54 of the pair of nodes 12). In the section (between), the propagation time of the sound wave is measured by actually propagating the sound wave. In the section between the virtual speaker and the node 12 and between the node 12 and the virtual microphone (the propagation time estimation section), However, the propagation time of the sound wave cannot be measured. Therefore, the length of the propagation time estimation section is stored in the ROM 14B of the host computer 14 corresponding to each virtual route.

In this embodiment, as shown in FIG. 5, an orthogonal coordinate system x having the center O of the measured space 24 as the origin O is used.
-Y, each of the virtual paths is defined as a length X (distance X) of a straight line S orthogonal to the virtual route and passing through the origin O, and the straight line S
And the x-axis make an identification (referred to as a virtual route (X, θ)).

Next, with reference to the flowchart of FIG. 7, a description will be given of a temperature distribution calculation process executed by the host computer 14 when obtaining the environmental state (temperature distribution in the present embodiment) in the measured space 24.

In the present embodiment, sound wave data (a sound wave converted into an analog signal and further converted into digital data) used for measuring the propagation time is stored in the R of the host computer 14.
In step 100, the sound data is transferred to all the nodes 12 via the transmission medium 18. The sound wave data transferred to each node 12 is stored in a built-in memory or the like of the data processing unit 40 of each node 12.

As the sound wave data, sound wave data representing an arbitrary sound can be used. For example, sound wave data representing music, a message, a natural sound (birdsong, door opening / closing sound, etc.) can be used. . In addition, as the size of the measured space 24 increases (that is, as the distance between the opposing nodes 12 across the center of the measured space 12 increases), the frequency band of the sound wave shifts toward the lower frequency side. May be selected.

In the next step 102, 1 is substituted for the count value m representing the node number of the node 12 for generating a sound wave. In step 104, the sound generation time from the sound generation target node m is determined, and in the next step 106, the determined sound generation time and the node number of the sound generation target node 12 are notified to all the nodes 12. In the next step 108, it is determined whether or not the sound wave generation timing has arrived, and the process waits until the determination is affirmed. When the sound wave generation timing has arrived, the determination in step 108 is affirmed, and the process proceeds to step 110.
An instruction is issued to generate a sound wave using the sound wave data transferred earlier.

Data processing unit 4 of node m for which a sound wave is to be generated
At 0, the sound wave generation processing shown in FIG. 8A is performed. This sound wave generation processing is performed based on the node number of the sound wave generation target node 12 notified from the host computer 14.
The process is executed when the own node recognizes that the node is the sound wave generation target node 12. First, in step 150, it is determined whether or not the sound wave generation timing has arrived, and the process waits until the determination is affirmed.

Transmission medium 18 and network transmission unit 48
When the generation of a sound wave is instructed from the host computer 14 via the CPU, the determination in step 150 is affirmed, and the process proceeds to step 152 to output the sound wave data transferred earlier to the D / A converter 38. The sound wave data output from the data processing unit 40 is converted into an analog sound signal by the D / A converter 38, amplified by the amplifier 36 at a predetermined amplification rate, and supplied to the speaker 30. Thereby, the temperature distribution calculation processing (FIG. 7) is performed from the speaker 30 of the node m.
At the sound wave generation timing determined in step 104 of
A sound wave represented by the sound wave data is emitted at a predetermined volume.

The sound wave generated by the speaker 30 of the node m to be generated is detected by the first microphone 32 of the node m, and an analog sound signal is output from the first microphone 32 of the node m. Step 1
At 52, the A / D converter 44 is operated for a predetermined time (for example, several seconds) in parallel with the process of generating a sound wave from the speaker 30, and the first microphone 32 detects the sound wave and outputs the sound from the first microphone 32. The sampling of the audio signal is executed for a predetermined time.

As a result, the audio signal output from the first microphone 32 is amplified by the filter / amplifier 42 for a predetermined period of time after the noise is removed, and then the A / D converter 44 outputs the audio signal at a constant sampling cycle. It is sampled and converted into digital sound wave data, and the sound wave measurement data for comparison for a predetermined time (the amplitude of the sound wave detected by the first microphone 32 is changed over a predetermined time (t _WAVE = 0 to t _WAVE )
_LAST : refer to FIG. 9 (B)), and are sequentially input to the data processing unit 40 as time series data at time intervals corresponding to the sampling period of the A / D converter 42). The data processing unit 40 stores the comparison sound wave measurement data sequentially input in a memory or the like.

In step 154, the comparison sound wave measurement data for the predetermined time obtained by the above processing is transferred to each node 12 other than the own node, and the sound wave generation processing ends.

As an example, FIG. 9A shows an example of a waveform of a sound wave represented by sound wave data used for generating a sound wave from the node 12 to be sound-generated, and FIG. 9B shows comparison sound wave measurement data. Each shows an example of the waveform of the sound wave represented by. Since the comparison sound wave measurement data represents the result of detecting the sound wave emitted from the speaker 30 by the first microphone 32, it is clear from the comparison between the waveform of FIG. 9A and the waveform of FIG. 9C. In this manner, the waveform of the sound wave represented by the comparative sound wave measurement data is slightly changed (distorted) from the waveform of the sound wave represented by the original sound wave data due to the influence of the characteristics of the speaker 30 and the first microphone 32. There).

On the other hand, the data processing units 40 of the nodes 12 (the measurement target nodes 12) other than the sound wave generation target node 12
Then, the propagation time calculation processing shown in FIG. 8B is performed.
This propagation time calculation processing is executed when it is recognized that the own node is not the sound wave generation target node 12 based on the node number of the sound wave generation target node 12 notified from the host computer 14. First, at step 160, the host computer 14 stores the sound wave generation time notified together with the node number. In the next step 162, it is determined whether or not the sound wave generation timing has arrived by comparing the stored sound wave generation time with the current time, and the process stands by until the determination is affirmed. When the sound wave generation time has arrived, the above determination is affirmed, and the routine proceeds to step 164.

As described above, when the sound wave generation time arrives, a sound wave is emitted from the speaker of the node 12 to be subjected to sound wave generation. Twelve second microphones 34 are respectively detected, and analog sound signals are output from the second microphones 34 of the nodes 12 to be subjected to sound wave measurement. In step 164, the A / D converter 48 is operated for a predetermined time (for example, several seconds), and the second microphone 34 detects a sound wave to execute sampling of an audio signal output from the second microphone 34 for a predetermined time.

Thus, the audio signal output from the second microphone 32 is amplified by the filter / amplifier 46 for a predetermined period of time after the noise is removed, and then the A / D converter 48 outputs the audio signal at a constant sampling period. It is sampled and converted into digital sound wave data, and the sound wave measurement data for a predetermined time (the amplitude of the sound wave detected by the second microphone 32 is converted into a time corresponding to the sampling period of the A / D converter 42 over a predetermined time) The data is sequentially input to the data processing unit 40 as data represented in time series at intervals. The data processing unit 40 stores the sequentially input sound wave measurement data in a memory or the like. In order to reduce the data amount of the sound wave measurement data, the sampling of the sound signal is performed after a certain time (slightly shorter than the propagation time of the sound wave from the sound wave generation target node 12) from the arrival of the sound wave generation time. May be started.

In the next step 166, it is determined whether or not the comparison sound wave measurement data has been received from the node 12 as the sound wave generation target, and the process waits until the judgment is affirmed. When the comparison sound wave measurement data is received, the determination in step 166 is affirmed, and the process proceeds to step 168, where the correlation between the waveform represented by the sound wave measurement data and the waveform represented by the comparison sound wave measurement data received from the node 12 to be subjected to sound wave generation. Calculate gender.

The waveform represented by the sound wave measurement data and the sound wave
The correlation with the waveform represented by the constant data is
Position of the first microphone 32 of the microphone 12 (first position)
Based on the timing at which the sound wave to be measured arrives at
From this reference timing, the second
The measurement pair is placed at the position (second position) where the microphone 34 is disposed.
The time it takes for the elephant sound wave to arrive (the propagation time of the sound wave)
Value t_XAnd t _WAVEIs a predetermined value (the initial value is t_WAVE=
0: amplitude value at the reference timing (see FIG. 9B))
Is obtained from the comparative sound wave measurement data.
At the corresponding timing (t_X+ T
_WAVEData representing the amplitude value at the elapsed timing)
From the sound wave measurement data and multiply the two
And t_WAVE0 to t_LASTIterating while changing in order until
And multiplying the result of multiplication.

The value of the correlation obtained by the above calculation is
Arrangement position of the arm 54 of the sound wave generation target node 12 when the measured sound wave time after reaching t _X (first arrangement position of the microphone 32) has passed, the arm 54 of the node 12 to be measured Arrangement position (second microphone 3
(Arrangement position 4) indicates the likelihood that the sound wave to be measured has reached (the more positive the correlation value has a positive sign and the greater the absolute value, the higher the likelihood can be considered). Is repeated while gradually changing the value of the time t _X , as shown in FIG. 9D, for example, the correlation between the waveform represented by the sound wave measurement data and the waveform represented by the comparison sound wave measurement data. It is possible to obtain data representing the transition of the gender value along the time axis.

In the next step 170, step 168
The value of the time t _X when the value of the correlation becomes maximum is obtained based on the calculation result of the correlation in the above, and the measurement target sound wave from the sound wave generation target node 12 to the measurement target node 12 (own node) is obtained. As the propagation time (specifically, the propagation time of the sound wave to be measured from the first position of the node 12 to be subjected to the sound wave generation to the second position of the node 12 to be measured), the time t _X when the correlation value is the maximum. , And set the propagation time,
The sound wave is transmitted from the node m to the node n as propagation time data tmn to the host computer 14, and the propagation time calculation processing is completed.

As an example, FIG. 9C shows an example of the waveform of the sound wave represented by the sound wave measurement data. The sound wave measurement data is obtained by converting the sound wave emitted from the speaker 30 to the second microphone 3.
FIG. 9 (A) shows the result of detection by FIG.
9C and the waveform of FIG. 9C, the waveform of the sound wave represented by the sound wave measurement data is
In addition, the waveform of the sound wave represented by the original sound wave data slightly changes (is distorted) due to the influence of the characteristics of the second microphone 34.

However, the comparison sound wave measurement data is
Since the sound wave emitted from the same speaker 30 is detected by the first microphone 32 of the same model as the second microphone 34 (that is, the microphone having the same characteristics as the second microphone 34), the sound wave measurement data 9B and the waveform of the sound wave represented by the comparative sound wave measurement data are the waveform of FIG. 9B and the waveform of FIG.
As is clear from the comparison of the waveforms of the waveforms, the waveform changes similarly with respect to the waveform of the sound wave represented by the original sound wave data, and the degree of correlation of the waveform is dramatically improved.

Accordingly, the correlation value obtained by the calculation in step 168 becomes positive when the value of the time t _X coincides with the propagation time of the sound wave to be measured from the node 12 to be measured to the node 12 to be measured. Although the absolute value of the correlation value is slightly larger when the value of the time t _{X is} a value before and after the time t _X , when the value of the time t _{X is} a value significantly different from the propagation time, the correlation value is The absolute value is a very small value. Thus, the propagation time can be measured and set with high accuracy without being affected by the characteristics of the speaker 30 and the second microphone 34. In addition, each node 12
Between the arms 54 is a measurement target section of the propagation velocity, the measurement result of the sound wave propagation time of the measurement target section fluctuates under the influence of the change of the sounding point position accompanying the frequency change of the sound wave emitted from the speaker 30. Nothing to do. In addition,
Steps 168 and 170 correspond to the propagation time calculating means.

The above-described propagation time calculation processing is performed for each node 12 (the node 1 to be measured) other than the node 12 to be subjected to the sound wave generation.
2), the measurement target section between the sound wave generation target node 12 and the other nodes 12 (for example, in FIG. 6 (A), the measurement target section is superimposed on a single measurement target space). (Measurement section corresponding to the radiated line), the propagation time of the sound wave from the node 12 to be measured to the node 12 to be measured is calculated, and the calculated propagation time is transferred to the host computer 14. become.

On the other hand, in the temperature distribution calculation process (FIG. 7), when the generation of a sound wave is instructed to the node 12 to be generated (step 110), the process proceeds to step 112 to calculate the propagation times of all the measurement target sections. Is completed, and every time the propagation time of the sound wave is received from the node 12 to be measured, the process of storing the propagation time of the received sound wave in the RAM 14C or the like is repeated until the determination is affirmed. .

When the propagation time of the sound wave is received from all the nodes 12 to be measured, the determination at step 112 is affirmed, and the routine goes to step 114, where the value of the counter m is set to the node 1
2 that is equal to the total number _mMAX of all the sound waves, that is, all the nodes 12 are regarded as the sound wave generation target nodes 12 (the sound wave generation processing is performed from the sound wave generation target node 12 and the measurement target is measured from the sound wave generation target node 12). To calculate the propagation time of the sound wave to the node 12). If the determination is negative, the value of the counter m is incremented by 1 in step 116, and
Return to 04.

Thus, until the determination at step 114 is affirmed, the nodes 12 to be subjected to sound wave generation are sequentially switched, and steps 104 to 114 are repeated (so-called fan beam measurement: see FIG. 6A). The propagation times of the sound waves in all the measurement target sections are measured and calculated in both directions.

If the determination in step 114 is affirmative, the process proceeds to step 118, and the temperature distribution in the measured space 24 is calculated in step 118 and thereafter. That is, step 11
8, all measurement target sections corresponding to a number of virtual paths parallel to a predetermined direction (all virtual paths having the same inclination θ) (in FIG. 6B), each of the measurement target sections is overlapped with a single measurement target section. The data of the propagation time of the section corresponding to the parallel line) is fetched.

When an air flow (wind) is generated in the space where the sound wave propagates, the propagation time of the sound wave depends on the influence of the air flow (specifically, the flow velocity of the air flow component in a direction parallel to the sound wave propagation direction). Changes). In this embodiment,
In order to avoid a decrease in the measurement accuracy of the temperature distribution due to the effect of the air flow generated in the measured space 24, the propagation times of the sound waves in all the measurement target sections are measured in both directions. In step 120, based on the data of the propagation time fetched in step 118, calculating the average value for each of the data of the propagation time in both directions corresponding to the single measurement target section is performed for all the parallel data in the predetermined direction. This is performed for the measurement target section.

For example, as the data of the propagation time of the measurement target section corresponding to the virtual route passing through each of the nodes m and n, the data of the propagation time tmn of the sound wave from the node m to the node n and the data of the propagation time tmn from the node n to the node m Sound wave propagation time t
nm data, and these average values tm-n (=
(Tmn + tnm) ÷ 2) is calculated. As described later, in the present embodiment, the temperature distribution is calculated using the average value tm-n, so that the change in the propagation time due to the influence of the air flow can be corrected.

When the fan beam measurement is performed as in the present embodiment, the measurement of the propagation time of the sound wave in both directions is performed at intervals in some measurement target sections. If the air flow generated in the measured space 24 is mainly caused by air conditioning or the like, the direction and intensity of the air flow are almost constant over time, and the propagation time in both directions is measured. The effect is small even if the time is spent. However, when the direction and intensity of the airflow generated in the measured space 24 change greatly with time, the propagation time in one direction is measured before the propagation time in the other direction is measured. If the direction and strength of the air flow change before this, the accuracy of correction for changes in the propagation time due to the influence of the air flow may be insufficient.

In the above case, if the propagation time in one direction is measured for a single measurement target section instead of performing the fan beam measurement, the propagation time in the other direction is immediately measured. , Is preferably performed sequentially for all measurement target sections. As a result, although it takes longer time to perform the measurement as compared with the fan beam measurement, the measurement target space 24 is not affected by the time-dependent changes in the direction and intensity of the airflow generated in the measurement target space 24. The temperature distribution in the inside can be obtained with high accuracy.

In the next step 122, the difference (tmn-tnm) between the propagation times of the sound waves in both directions is calculated for all the measurement sections for which the average value tm-n has been calculated, and the calculation result is calculated in each measurement section. RAM 14 as airflow data
Store it in C or the like. The airflow data may be displayed together with the calculation result of the temperature distribution (described later).

At step 124, the ROM
14B (the virtual speaker and the node 12 (specifically, the arm 5 of the node 12)
The length L _SN between 4), and the node 12 (details length L _NM between the virtual microphone arm 54) of the node 12), taking each of all the virtual paths parallel to the predetermined direction. Note that the distance of the measurement target section (each node 1
The distance between the two arms 54) can be accurately measured by a laser distance meter using the light reflecting plate 58. Therefore, the length L _SN and the length L _NM are also measured with respect to the distance of the measurement target section. It can be determined accurately based on the result.

At step 126, assuming that the outside of the section to be measured is filled with a medium (air) having a predetermined temperature, the propagation time of the sound wave is calculated for all virtual paths (X, θ) parallel to the predetermined direction. Each of the estimated values t (X, θ) is calculated. The estimated value of the propagation time t (X, θ) can be obtained by the following equation (1).

T (X, θ) = (L _SN ÷ v ₀ ) + tm-n + (L _NM … v ₀ ) (1) where v ₀ is the sound velocity when the air is at a predetermined temperature, and tm−
n, L _SN and L _NM are values corresponding to the virtual route (X, θ). The first and third terms in the equation (1) are a section outside the measured section on the virtual path (propagation time estimation section) when it is assumed that the outside of the measured section is filled with a medium having a constant temperature. Corresponding to the estimated value of the propagation time of the sound wave.

At step 128, the estimated value t of the propagation time of the sound wave of all virtual paths (X, θ) parallel to the predetermined direction
The projection data p (X, θ) is calculated based on (X, θ). The projection data p (X, θ) can be obtained by the following equation (2).

P (X, θ) = t (X, θ) − (L ₀ ÷ v ₀ ) (2) Here, the sound velocity at the position (x, y) is represented by v (x, y), and the sound velocity distribution f (x, y) (temperature distribution is sound velocity distribution f
(X, y) can be easily calculated from), f (x, y) = (1 / v (x, y)) - (1 / v 0) ... (3) above (3) defined by the equation ( That is, f (x, y) = 0 outside the measurement target section), the X-axis is a direction along the straight line S (see FIG. 5), and the Y-axis is a direction along the virtual path. When Y (a coordinate system obtained by rotating the orthogonal coordinate system xy around the origin O by an angle θ) is defined, the relationship between the projection data p (X, θ) and the sound velocity distribution f (x, y) is as follows.
The virtual path (X, θ) becomes an integration section,

[0091]

(Equation 1)

Is obtained. As shown in Expression (4), the projection data p (X, θ) is obtained by projecting a sound velocity distribution f (x, y) along the virtual path (X, θ). In the above-described step 110, the calculation of the expression (2) is performed for all the virtual paths (X, θ) parallel to the predetermined direction (that is, all the virtual paths having different distances X and equal inclinations θ). Are obtained as a set (parallel projection data) of the same projection data p (X, θ).

In the next step 130, it is determined whether or not the projection data p (X, θ) has been calculated for all directions.
If the determination is negative, the process returns to step 118, and steps 118 to 130 are repeated until the determination in step 130 is affirmed. When the calculation of the projection data p (X, θ) of the virtual path (X, θ) is completed for all directions (the projection data p (X, θ) of the virtual path (X, θ) is calculated for all directions). This is generally called a Radon transform), and based on these projection data (X, θ), a short-time method such as a Fourier domain reconstruction method, a back projection method of filtered data, and a two-dimensional filtering method. By applying a calculation method that can be calculated by the above, it is possible to calculate the temperature distribution in the measured space 24.

Therefore, if the determination in step 130 is affirmative, the process proceeds to step 132, where the projection data p (X,
Based on θ), the temperature distribution in the measured space 24 is calculated. This step 132 corresponds to the environmental state calculation means. Hereinafter, a Fourier domain reconstruction method will be described as an example of a calculation method for calculating a temperature distribution based on projection data.

If the two-dimensional Fourier transform of the sound velocity distribution f (x, y) is F (u, v),

[0096]

(Equation 2)

The Fourier transform is defined by the above equation (5). The two-dimensional inverse Fourier transform from F (u, v) is

[0098]

(Equation 3)

This is defined by the above equation (6).

On the other hand, a rectangular coordinate system xy and a rectangular coordinate system X-
The relationship of the following equation (7) is established with Y.

X = Xcos θ−Ysin θ y = Xsin θ + Ycos θ (7) From Expression (7), the sound velocity distribution f (x, y) can be expressed by the following Expression (8).

F (x, y) = f (Xcos θ−Ysin θ, Xsin θ + Ycos θ) = f ′ (X, Y) (8) where f ′ (X, Y) is f (x, y) around the origin O. Is a function obtained by rotating by the angle −θ. (8)
When the definition of the Fourier transform of the equation (5) is transformed into a variable using the equation,

[0103]

(Equation 4)

Is obtained.

Also in the spatial frequency domain, similarly to the real domain, the angle θ around the origin with respect to the coordinate system (u, v) is
The coordinate system obtained by rotating only the coordinate system (U,
V), u = Ucosθ−Vsinθ v = Usinθ + Vcosθ (10) and U = ucosθ + Vsinθ V = −usinθ + vcosθ (11), as in the above equation (7). (U, v) can be expressed as follows: F (u, v) = F (Ucos θ−Vsin θ, Usin θ + Vcos θ) = F ′ (U, V) (12) By substituting these equations into equation (9), the following equation (13) can be obtained.

[0106]

(Equation 5)

From the equation (13), the spectrum of the object rotated in the real region (in this case, the sound velocity distribution f (x, y)) is
It can be seen that the spectrum of the original object is the same as the one rotated by the same angle.

According to the equations (7) and (8), the equation (4) relating to the projection data p (X, θ) can be expressed as the following equation (14).

[0109]

(Equation 6)

Note that in equation (14), the sound velocity distribution f (x,
Since y), that is, f ′ (x, y) is 0 outside the measurement target section, the integration section is expanded to ± ∞. The Fourier transform of the projection data p (X, θ) with respect to the X axis can be expressed by the following equation (15).

[0111]

(Equation 7)

By substituting equation (14) into equation (15), the following equation (16) is obtained.

[0113]

(Equation 8)

Since equation (16) matches the equation when V = 0 in equation (13), P (U, θ) = F ′ (U, 0) holds.

As described above, the projection data P (X, θ) of all the virtual paths having the same inclination θ are subjected to the Fourier transform (one-dimensional Fourier transform) on the X axis according to the equation (15). (U, θ) is 2 of the sound velocity distribution f (x, y).
Is equal to the component in the θ direction of the four-dimensional Fourier transform F (u, v) (a value on a straight line (ie, U axis) inclined by an angle θ with respect to the u axis of the Fourier transform F (u, v)) The fault theorem (projection slice theorem)).

Accordingly, the Fourier transform is performed on the projection data obtained in each direction to obtain the coordinate system (u,
v) If arranged radially on top, 2 of the sound velocity distribution f (x, y)
A dimensional Fourier transform F (u, v) can be obtained. Then, by performing an inverse two-dimensional Fourier transform on this F (u, v) according to the above equation (6), the sound velocity distribution f
(X, y) can be obtained.

In step 132, the projection data p is first applied by applying an arithmetic method which can be operated in a short time, such as the above-described Fourier domain reconstruction method or the well-known back-projection method or two-dimensional filtering method of filtered data. A sound velocity distribution f (x, y) is obtained from (X, θ). Next, based on the obtained sound velocity distribution f (x, y), the measured space 24
Calculates the sound speed v (x, y) at each position within
The temperature distribution T (x, y) in the measured space 24 is calculated based on the following equation (17), which represents the relationship between the temperature and the temperature T of the medium (air) through which the sound wave propagates.

V = 331.45 + 0.607 · T [m / sec] (17) In the next step 134, the temperature distribution in the measured space 24 obtained as described above is taken as an example using the contour map shown in FIG. The information is displayed on the display 20 in the form, and the process ends. Instead of the display on the display 20, data representing the temperature distribution and the humidity distribution in the measured space 24 may be output to an air conditioner that performs air conditioning in the air-conditioned space 24. Thereby, the air conditioner can perform air conditioning that satisfies both comfort and energy saving on the measured space 24, for example.

In the present embodiment, a number of nodes 12 are provided on the peripheral edge of the space to be measured 24, and a section to be measured between a pair of nodes 12 on the virtual path (a section between each arm 54 of the pair of nodes 12). Section), the sound wave is actually propagated in both directions, and the propagation time tmn and the propagation time tnm
Is measured, and the average value tm-n of the propagation time is obtained, and the section outside the section to be measured (the section for estimating the propagation time between the virtual speaker and the node 12 and between the node 12 and the virtual microphone)
As for, assuming that the air temperature is a predetermined temperature, the propagation time of the sound wave is estimated using the sound velocity v ₀ when the air is at the predetermined temperature, and the estimated value t (X, θ) of the propagation time is calculated. Therefore, the projection data p (X, θ) can be obtained without providing a large number of nodes 12 outside the measured space 24. Based on the projection data p (X, θ), the Fourier domain reconstruction method and the filter processing data It is possible to calculate the environmental state in the space to be measured by applying a calculation method that can be calculated in a short time, such as the back projection method and the two-dimensional filtering method. Therefore, the configuration of the environmental condition measuring apparatus 10 can be simplified, and the time required for calculating the temperature distribution can be reduced.

In the above description, the case where the sound wave arriving at the first position is detected by the first microphone 32 has been described. However, sound wave data for generating sound waves from the speaker 30 of the node 12 of the sound wave generation target is fixed in advance. A sound wave is generated from the speaker 30 using the sound wave data, the sound wave reaching the first position is detected by a microphone, and sound wave measurement data for comparison is obtained, and the ROM 14B of the host computer 14 or Stored in the internal memory of the data processing unit 40 of each node 12,
It is also possible to read out and use the comparison sound wave data when calculating the propagation time.

In the above description, microphones of the same model (microphones having the same characteristics) are used as the first microphone 32 and the second microphone 34. However, the present invention is not limited to this. (Microphones having similar characteristics such as the same detection principle) are suitable for use as the first microphone 32 and the second microphone 34.

In the above description, the temperature distribution is calculated from the projection data of the sound wave propagation time. However, the present invention is not limited to this. For example, the temperature near the wall surface of the wall 22 is measured by a temperature sensor, and The temperature distribution may be corrected based on a measured value of a nearby temperature.

Further, in the above, a virtual route is set so as to penetrate the measured space 24, and a propagation time of a sound wave is estimated for a section of the virtual path outside the section to be measured.
Although the temperature distribution is obtained by obtaining the propagation time of the sound wave propagating on the virtual path, the present invention is not limited to this. For example, the measured space is virtually divided into a number of regions (voxels), When a sound wave propagates between a certain pair of places, the distance that the sound wave traverses each region existing between the pair of places is determined, and the propagation time of the sound wave between the pair of places,
The relationship with the propagation speed when a sound wave traverses each region is expressed by a mathematical expression using the distance at which the sound wave traverses each region. The propagation time of the sound wave during the period is substituted into the simultaneous equations, the propagation speed when the sound wave crosses the region where the propagation speed is unknown is calculated, and the temperature distribution is calculated by calculating the temperature of each region from the propagation speed. You may.

In the above description, the case where the environmental condition in the measurement space 24 having a circular floor surface, such as a dome stadium, is measured has been described. However, according to the present invention, the sound wave generator and the sound wave detecting means are used. The temperature distribution in the space to be measured can be obtained by providing at the periphery of the space to be measured.Therefore, a space having an arbitrary shape is adopted as the space to be measured, and the temperature distribution in the space having an arbitrary shape is obtained. Can be.

Further, the case where only the temperature distribution is calculated as the environmental state has been described above as an example. However, the present invention is not limited to this case. , The humidity distribution in the measured space may be calculated together, or other environmental conditions may be calculated.

[0126]

As described above, according to the first aspect of the present invention, there is provided a sound wave generator, a first sound wave detecting means for detecting a sound wave radiated from the sound wave generator at a predetermined distance from the sound wave generator, and a sound wave generator. Second sound wave detecting means for detecting a sound wave arriving from the side opposite to the sound generator at a predetermined distance from the sound wave generator; and light arriving from the side opposite to the sound wave generator at a predetermined distance from the sound wave generator. Includes a light reflection plate that reflects light at a different position, improving the accuracy of measuring the propagation time of sound waves,
There is an excellent effect that measurement accuracy of environmental conditions such as temperature distribution in the measured space can be improved.

According to a second aspect of the present invention, in the first aspect, the first sound wave detecting means, the second sound wave detecting means, and the light reflecting plate are integrally mounted on a bracket connected to the sound wave generator. In addition to the above effects, the installation of the sound wave generation detection device can be easily performed, and the change in the relative positions of the first sound wave detection means, the second sound wave detection means, and the light reflection plate due to the change in the ambient temperature is suppressed. Has the effect of being able to

According to the third aspect of the present invention, in the first aspect of the present invention, the attenuating means for attenuating the arriving sound wave is disposed on the sound wave arrival side of the sound wave detecting position by the first sound wave detecting means. In addition, the waveform of the sound wave detected by the first sound wave detecting means can be prevented from being distorted or saturated.

According to a fourth aspect of the present invention, in the first aspect of the present invention, since the first sound wave detecting means and the second sound wave detecting means detect sound waves by at least a sound wave detector of a similar kind, the sound wave propagation time can be reduced. This has the effect that measurement can be performed with high accuracy.

According to the fifth and sixth aspects of the present invention, the sound wave generation and detection devices according to any one of the first to fourth aspects are arranged at both ends of a plurality of propagation time measurement sections that cross the space to be measured. Then, a sound wave is generated from the sound wave generator of the one sound wave generation detecting device, and the generated sound wave is used as the first sound wave detecting means of the one sound wave generation detecting device and the second sound wave detecting means of the other sound wave generation detecting device. That each is detected by
It is performed for each of the plurality of propagation time measurement sections, the waveform of the detected sound wave is collated, and the propagation time of the sound wave propagating from the detection position of the sound wave by the first sound wave detection unit to the detection position of the sound wave by the second sound wave detection unit is calculated. Is performed for each of the plurality of propagation time measurement sections, and the environmental state in the measured space is calculated based on the measured values of the propagation times of the sound waves in the plurality of propagation time measurement sections. And the like can be measured with high accuracy.

According to a seventh aspect of the present invention, in the sixth aspect of the present invention, a distance is measured by irradiating light to a pair of light reflecting plates of a pair of sound wave generation detecting devices at both ends of a propagation time measuring section. Doing that periodically for each of the plurality of propagation time measurement sections, calculating the environmental state in the measured space, taking into account the measurement results of the distance between the pair of light reflectors in each of the plurality of propagation time measurement sections Therefore, in addition to the above effects, the effect that the environmental state in the measured space can be accurately measured without being affected by the change in the distance of the propagation time measurement section due to a change in the environmental temperature or a change over time. Have.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of an environmental condition measuring apparatus according to an embodiment.

FIG. 2 is a plan view of a measured space showing an arrangement of nodes.

FIG. 3A is a side view showing an arrangement of a speaker and a microphone in a single node, and FIG. 3B is an enlarged view around a microphone arrangement position in FIG.

FIG. 4 is a conceptual diagram showing a virtual path composed of a measurement target section and a propagation time estimation section superimposed on a plan view of a measured space.

FIG. 5 is a diagram showing a rectangular coordinate system x- set for a measured space;
FIG. 6 is a conceptual diagram showing a distance X and a slope θ of a straight line S for identifying each virtual route.

FIGS. 6A and 6B are conceptual diagrams showing the relationship between the measurement order of propagation time data and the processing order of propagation time data.

FIG. 7 is a flowchart showing the contents of a temperature distribution calculation process executed by the host computer.

FIG. 8 is a flowchart showing the contents of a sound wave generation process and a propagation time calculation process executed at each node to be measured.

9A is an example of a waveform of a sound wave represented by sound wave data, FIG. 9B is an example of a waveform of a sound wave represented by comparative sound wave measurement data, FIG. 9C is an example of a waveform of a sound wave represented by sound wave measurement data, (D) is a diagram showing each example of the correlation operation result.

FIG. 10 is an image diagram showing a display example of a temperature distribution in a measured space.

[Explanation of symbols]

 Reference Signs List 10 environmental condition measuring device 12 node 14 host computer 24 measured space 30 speaker 32 first microphone 34 first microphone

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yukio Ishikawa 1-5-1, Otsuka, Inzai City, Chiba Prefecture Inside Takenaka Corporation Technical Research Institute (72) Inventor Mikio Takahashi 1-5-1, Otsuka, Inzai City, Chiba Prefecture Inside Takenaka Corporation Technical Research Institute (72) Inventor Kiyotaka Iwamoto 1-5-1, Otsuka, Inzai City, Chiba Prefecture Inside Takenaka Corporation Technical Research Institute (72) Inventor Masayoshi Maruyama 2 Tayuhamamachi, Niigata City, Niigata Prefecture 140-chome Inside Cyprus Co., Ltd. (72) Koichi Mizutani Inventor 1-1-1 Tennodai, Tsukuba, Ibaraki Pref. 5J083 AA04 AB20 AC28 AD22 AF01 AG20 BE08 CA10 CA31

Claims (7)

[Claims] A first sound wave generator disposed on a sound wave emitting side of the sound wave generator and detecting a sound wave emitted from the sound wave generator at a position separated from the sound wave generator by a predetermined distance; A second sound wave detecting means disposed on the sound wave emitting side of the sound wave generator and detecting a sound wave arriving from a side opposite to the sound wave generator side at a position separated by a predetermined distance from the sound wave generator; A light reflector that is arranged and reflects light arriving from a side opposite to the sound wave generator side at a position separated by a predetermined distance from the sound wave generator. 2. The sound wave according to claim 1, wherein the first sound wave detecting means, the second sound wave detecting means, and the light reflecting plate are integrally mounted on a bracket connected to the sound wave generator. Occurrence detection device. 3. The sound wave generation and detection device according to claim 1, further comprising an attenuating means disposed on a sound wave arrival side of a sound wave detection position of said first sound wave detecting means and attenuating the arriving sound wave. 4. The sound wave generation and detection device according to claim 1, wherein the first sound wave detection means and the second sound wave detection means detect sound waves by at least a sound wave detector of a similar kind. 5. The sound wave generation and detection device according to claim 1, which is disposed at both ends of a plurality of propagation time measurement sections that traverse the space to be measured, and both ends of the propagation time measurement section. A sound wave is generated from a sound wave generator of one of the sound wave generation detection devices of the pair of sound wave generation detection devices disposed in the section, and the generated sound wave is the first sound wave detection means of the one sound wave generation detection device And control means for performing the detection by the second sound wave detecting means of the other sound wave generation detecting apparatus for each of the plurality of propagation time measurement sections, and the waveform of the sound wave detected by the second sound wave detecting means. The transmission of the sound wave propagating from the detection position of the sound wave by the first sound wave detection unit to the detection position of the sound wave by the second sound wave detection unit is compared with the waveform of the sound wave detected by the first sound wave detection unit. Calculating a time, for each of the plurality of propagation time measurement sections, a propagation time calculation means, based on a measured value of the propagation time of the sound wave in the plurality of propagation time measurement sections measured by the propagation time measurement means. An environmental condition calculating means for calculating an environmental condition in the measured space; 6. The sound-wave generation detecting device according to claim 1, which is disposed at both ends of a plurality of propagation time measurement sections traversing the space to be measured. A sound wave is generated from a sound wave generator of one of the pair of sound wave generation detection devices disposed at both ends, and the generated sound wave is generated by the first sound wave detection means of the one sound wave generation detection device. And performing the detection by the second sound wave detecting means of the other sound wave generation detecting apparatus for each of the plurality of propagation time measurement sections, and converting the waveform of the sound wave detected by the second sound wave detecting means to the first sound wave. The waveform is compared with the waveform of the sound wave detected by the sound wave detecting means, and the propagation time of the sound wave propagating from the detection position of the sound wave by the first sound wave detecting means to the detection position of the sound wave by the second sound wave detecting means is calculated. Each performed, environmental condition measuring method for calculating the environmental conditions of the measurement space based on the measurement of the propagation time of the sound wave of the plurality of propagation time measuring section for a plurality of propagation time measurement period to. 7. A method of irradiating light to a pair of light reflectors of a pair of sound wave generation detectors respectively disposed at both ends of a propagation time measurement section to measure a distance between the pair of light reflectors.
Each of the plurality of propagation time measurement sections is periodically performed, and the calculation of the environmental state in the measured space is performed in consideration of the measurement result of the distance between the pair of light reflecting plates in each of the plurality of propagation time measurement sections. 7. The method for measuring an environmental condition according to claim 6, wherein: