Space monitoring system and space monitoring method using sound signal

Abstract

The invention relates to a space monitoring system and a space monitoring method using sound signals. The invention discloses a technology which can compare frequency response spectrums of each measurement period of a monitored object space by taking a single frequency as a unit or taking a frequency period as a unit, and can simply, quickly and accurately judge the condition of the monitored object space by analyzing the change degree and the change mode of the difference value of the frequency response spectrums.

Description

Technical Field

[0001] The present invention relates to a space monitoring system and a space monitoring method using sound signals. The present invention proposes a technology that can compare the frequency response spectra of each measurement cycle of the monitored space in units of single frequency or frequency time period, and analyze the change degree and change pattern of the difference to simply, quickly and accurately judge the physical state of the monitored space. Background Art

[0002] A space condition monitoring sensor technology is being proposed that uses sound signals to sense various conditions such as intrusion of outsiders, fire, gas leakage, etc. in indoor spaces.

[0003] Conventional technology involves emitting sounds of multiple frequencies to the sensing target space for each measurement cycle, receiving the sounds and obtaining the sound pressure spectrum of the received sounds. The sound pressure spectrum thus measured is compared with a specific reference sound pressure spectrum, and the condition of the target space is determined based on the degree of change in the spectrum and the pattern of the change.

[0004] If the measured sound pressure spectrum changes to a value above the reference value, it can be determined that some event has occurred in the monitored space. However, in order to understand the type of event that has occurred in the monitored space, for example, whether it is the movement of an object or a change in temperature, it is necessary to observe the change pattern of the sound pressure spectrum.

[0005] To explain what is needed to accurately observe the change pattern of the sound pressure spectrum, let's take an infrared sensor as an example. For example, an infrared sensor installed in an automatic door only needs to detect whether there is a warm object in front of the door. In this case, the infrared sensor only needs to measure the amount of infrared light flowing into the sensor or the amount of change. In other words, in order to confirm whether an event has occurred, only one pixel of the infrared sensor is enough.

[0006] However, when the infrared sensor has only one pixel, the fact that an event has occurred can be known, but the type of event may not be distinguished. For example, it is impossible to distinguish whether the warm object in front of the door is a person or an animal. However, in the case of a military infrared camera, it is necessary to distinguish whether the warm object that appears at night is a person or an animal. At this time, two requirements are required. First, the number of pixels must be large enough. Second, the resolution must be high enough, and for this, the area of ​​the monitored object sensed by one pixel must be small. If one pixel senses an area of ​​1m*1m, it may not be able to distinguish between people and animals. If one pixel senses an area of ​​1cm*1cm, it can distinguish between people and animals.

[0007] The same is true for sound sensors. In order to understand whether an event has occurred, the sound sensor only needs to understand the "whether" or "degree" of change in the sound pressure spectrum. Therefore, measuring the sound pressure spectrum 2 to 3 times may be sufficient. However, in order to understand whether the type of event is movement or temperature change, it is necessary to observe the "pattern" of the change of the spectrum over time. In order to clearly observe the "pattern", two requirements are necessary. First, the number of times the spectrum is measured must be sufficient, and second, the time interval between spectrum measurements must be narrow enough.

[0008] Taking the case where the sound pressure spectrum is measured once in the monitored object space with a measurement period of 5 seconds using the conventional technology, for example, in order to observe the variation pattern of the spectrum, if 20 to 30 measurement points are required, the time required for this is 100 to 150 seconds, and therefore the measurement speed is slowed down accordingly.

[0009] On the other hand, if the spectrum is measured every 5 seconds, the time interval between the measurement points is too large, so it is difficult to accurately determine the type of event. In other words, the resolution is too low in terms of appropriately expressing the change pattern of the spectrum over time. For example, if an intruder moves at a speed of 2 meters per second, if the fact of the change of the spectrum is to be expressed every time the position of the intruder changes by 10 cm, then according to the conventional technology, the spectrum must be measured 20 times per second. However, it is impossible to measure the spectrum every 0.05 seconds in reality.

[0010] In summary, the spatial condition monitoring sensors based on the prior art can sense the fact that an event has occurred. However, in order to distinguish the type of event, such as the movement of an object or a temperature change, it will inevitably take a long time, and the resolution is low, and there is a problem that the accuracy of event type distinction cannot be guaranteed. Summary of the invention

[0011] In the case of conventional space monitoring sensors using sound, the fact that an event has occurred can be sensed, but there are problems such as difficulty in distinguishing the type of event and requiring a lot of time.

[0012] The present invention is made to solve the above-mentioned problems of the conventional technology, and proposes a technology that can distinguish the types of events occurring in a monitoring target space more quickly, more accurately and more simply while observing the change pattern of the spectrum.

[0013] The objects of the present invention are not limited to the above-mentioned ones, and other objects and advantages of the present invention which are not mentioned can be understood from the following description.

[0014] It can be that an embodiment of the space monitoring method using sound signals according to the present invention includes: a frequency response measuring step, transmitting and receiving sound signals to the monitored object space according to the measurement period to obtain a frequency response spectrum according to the measurement period; a difference calculating step, comparing the frequency response spectrum of a specific period with the frequency response spectrum of a comparison object in units of single frequencies or in units of frequency time periods, thereby calculating the difference for each single frequency unit or frequency time period unit; a difference saving step, matching the difference to any one or more of the corresponding frequencies or corresponding measurement times to save it in a database; and a space status judging step, judging the status of the monitored object space based on the degree of change or the change pattern of the difference according to the frequency or measurement time.

[0015] Preferably, the difference calculating step may compare the frequency response spectrum of the specific period with the frequency response spectrum of at least one other measurement period, and the difference saving step may save the difference by matching the difference with the corresponding frequency or the corresponding measurement time, the measurement time period of the frequency response spectrum of the specific period, and the measurement time period of the frequency response spectrum of other measurement periods.

[0016] As an example, the frequency response measuring step may transmit a single-tone sound signal whose frequency changes continuously or in stages over time to the monitored object space, and when the degree of scattering of the difference during the first frequency period or the first time period remains less than the first benchmark and then the degree of scattering of the difference during the second frequency period or the second time period exceeds the second benchmark, the space condition judging step judges that there is a change in the physical shape of the monitored object space in the second frequency period or the second time period.

[0017] As an example, when the dispersion of the difference during a third frequency period or a third time period exceeds a third benchmark, the space condition judgment step determines that there is a change in the physical shape of the monitored object space during the third frequency period or the third time period.

[0018] As an example, when the dispersion of the difference during a fourth frequency period or a fourth time period exceeds a fourth benchmark, and the dispersion of the difference during a fifth frequency period or a fifth time period included in the fourth frequency period or the fourth time period is less than the fifth benchmark, the spatial condition judgment step judges that there is a temperature change in the monitored object space in the fourth frequency period or the fourth time period.

[0019] In addition, one embodiment of a space monitoring system using sound signals according to the present invention includes: a frequency response measuring component, which transmits sound signals to the monitored object space according to a measurement period and receives sound signals to measure the frequency response spectrum according to the measurement period, and compares the frequency response spectrum of a specific period with the frequency response spectrum of a comparison object in units of single frequencies or in units of frequency time periods, thereby calculating a difference for each single frequency unit or frequency time period unit; a database building component, which matches the difference to any one or more of the corresponding frequencies or corresponding measurement times and stores it in a database; and a space status judgment component, which judges the status of the monitored object space based on the degree of change or the change pattern of the difference according to the frequency or measurement time.

[0020] Preferably, the frequency response measuring component compares the frequency response spectrum of a specific period with the frequency response spectrum of at least one other measuring period, and the database building component matches the difference with the corresponding frequency or the corresponding measuring time, the measuring time period of the frequency response spectrum of the specific period and the measuring time period of the frequency response spectrum of other measuring periods for storage.

[0021] As an example, the frequency response measuring component may transmit a single-tone sound signal whose frequency changes continuously or in stages over time to the monitored object space, and when the dispersion of the difference during a first frequency period or a first time period remains less than a first benchmark and then the dispersion of the difference during a second frequency period or a second time period exceeds a second benchmark, the space condition judging component judges that there is a change in the physical shape of the monitored object space in the second frequency period or the second time period.

[0022] As an example, when the dispersion of the difference during a third frequency period or a third time period exceeds a third benchmark, the space condition determination component determines that there is a change in the physical shape of the monitored space during the third frequency period or the third time period.

[0023] As an example, when the dispersion of the difference during a fourth frequency period or a fourth time period exceeds a fourth benchmark, and the dispersion of the difference during a fifth frequency period or a fifth time period included in the fourth frequency period or the fourth time period is less than the fifth benchmark, the space condition judgment component judges that there is a temperature change in the monitored object space in the fourth frequency period or the fourth time period.

[0024] According to the present invention, the frequency response spectra of each measurement cycle of the monitored object space are compared in detail in units of single frequency or frequency period, and the degree of change and change pattern of the difference are analyzed. In the present invention, since the time interval or frequency interval of the calculated difference is narrow enough, the types of events such as movement and temperature change occurring in the monitored object space can be quickly and accurately distinguished.

[0025] The effects of the present invention are not limited to the above-mentioned contents, and a person having ordinary knowledge in the technical field to which the present invention belongs can clearly understand other technical problems not mentioned from the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A configuration diagram of an embodiment of a space monitoring system according to the present invention is shown.

[0027] Figure 2 A diagram showing the structure of an embodiment of a frequency response measuring means for a space monitoring system according to the present invention.

[0028] Figure 3 A diagram showing the structure of an embodiment of a database building component for a space monitoring system according to the present invention.

[0029] Figure 4 A diagram showing the structure of an embodiment of a space situation determination component of a space monitoring system according to the present invention.

[0030] Figure 5 A flow chart of an embodiment of a spatial monitoring method according to the present invention is shown.

[0031] Figure 6 An example of obtaining a frequency response spectrum in the present invention is shown.

[0032] Figure 7 An example of extracting a measurement value in units of a single frequency or in units of a frequency period in the present invention is shown.

[0033] Figure 8 An example of extracting a difference by comparing each frequency between frequency response spectra in the present invention is shown.

[0034] Fig. 9 An example of a multidimensional data table for differences in the present invention is shown.

[0035] Fig.10 An example of the degree of change and the change pattern of the difference value for each different event type in the present invention is shown.

[0036] Figures 11 to 14 An example of determining a movement event of an object in a monitoring target space in the present invention is shown.

[0037] Fig.15 An example of determining a temperature change event in a monitoring target space in the present invention is shown.

[0038] Figures 16 to 18 An example of determining an event in a monitoring target space using a multidimensional data table for differences in the present invention is shown. DETAILED DESCRIPTION

[0039] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings; however, the present invention is not limited to or restricted by the embodiments.

[0040] In order to illustrate the present invention and the advantages thereof in operation and the objects attained by the implementation of the present invention, preferred embodiments of the present invention are illustrated below and viewed with reference thereto.

[0041] First, the terms used in this application are only used to illustrate specific embodiments and are not intended to limit the present invention. As long as the context does not clearly indicate otherwise, singular expressions may include plural expressions. In addition, it should be understood that in this application, terms such as "including" or "having" refer to the existence of features, numbers, steps, operations, constituent elements, accessories, or combinations thereof recorded in the specification, and do not exclude in advance the existence or additional possibility of one or more other features or numbers, steps, operations, constituent elements, accessories, or combinations thereof.

[0042] When describing the present invention, if it is determined that the detailed description of the relevant well-known structure or function may obscure the purpose of the present invention, the detailed description will be omitted.

[0043] The frequency response (FR) of a space mentioned in the present invention refers to the sound pressure or phase of each frequency measured by receiving a sound signal after transmitting a single-tone sound signal whose frequency changes with time or a composite sound including multiple frequency components whose frequency does not change with time to the monitored space in each measurement cycle. The sound pressure or phase measured during one measurement cycle is represented in a graph according to the frequency, which is called a frequency response spectrum (Frequency Response Spectrum, FRS).

[0044] This frequency response spectrum can be measured and the events occurring in the monitored object space can be grasped through its degree of change and change pattern. The present invention proposes a technology that can more accurately grasp the fact that an event occurred and the type of event in a faster time.

[0045] In the present invention, the frequency response spectrum measured in the monitored object space at a specific measurement period can be compared with the frequency response spectrum of the comparison object in units of single frequency or in units of frequency time periods, and the difference between each frequency can be extracted. The event status of the monitored object space can be judged based on the frequency of the difference or according to the degree of change over time and the change pattern.

[0046] Figure 1 A configuration diagram of an embodiment of a space monitoring system using sound signals according to the present invention is shown.

[0047] The space monitoring system may include a frequency response measuring component 100, a database building component 200, a space status judging component 300, and the like.

[0048] The frequency response measuring means 100 can measure the frequency response of the monitored space for each measurement period and obtain a frequency response spectrum thereof.

[0049] In addition, the frequency response measuring component 100 may compare the frequency response spectrum of a specific period with the frequency response spectrum of a comparison object to calculate the difference in a single frequency unit or a frequency period unit.

[0050] As an example, the measured value of a single frequency unit or a frequency time period unit extracted from a frequency response spectrum of a specific period can be compared with the measured value of a single frequency unit or a frequency time period unit extracted from a frequency response spectrum of another period or a reference frequency response spectrum to calculate the difference in each frequency of the sound pressure or phase. That is, in the present invention, two frequency spectra can be compared for each corresponding frequency and the difference in each frequency of the sound pressure or phase can be calculated.

[0051] The database construction means 200 can organize and process the measurement values ​​of each frequency in each measurement period extracted by the frequency response measurement means 100 and store them.

[0052] In addition, the database construction means 200 can organize and process the difference values ​​of each frequency calculated by the frequency response measurement means 100 and store them.

[0053] As an example, the database construction component 200 may store each difference by matching it with the corresponding frequency or corresponding measurement time, the measurement time period of the frequency response spectrum of a specific cycle, and the measurement time period of the frequency response spectrum of other measurement cycles. That is, the database construction component 200 may generate a multidimensional data table for the difference and store it. The database construction component 200 may construct the database by updating the multidimensional data table with the difference calculated for each new measurement cycle.

[0054] The space status determination component 300 can determine the status of the monitored space based on the measured value or difference value generated by the frequency response measurement component 100. At this time, the space status determination component 300 can accurately distinguish the types of events occurring in the monitored space in a faster time by using the measured value information and difference value information stored in the database construction component 200 to determine the status of the monitored space. As an example, the space status determination component 300 can determine the event status of the monitored space based on the degree of change and change pattern of the difference value during the selected frequency period or time period.

[0055] Hereinafter, each configuration of the space monitoring system according to the present invention will be examined through embodiments.

[0056] Figure 2 A diagram showing the structure of an embodiment of a frequency response measuring means for a space monitoring system according to the present invention.

[0057] The frequency response measuring means 100 may include a frequency response measuring unit 110 , a measurement value extracting unit 130 , a difference calculating unit 150 , and the like.

[0058] As an example, the frequency response measuring unit 110 may include a sound signal transmitter 111, a sound signal processor 113, a sound signal receiver 115, etc. to measure the frequency response of the space to be monitored through the sound signal. The frequency response measuring unit 110 may transmit the sound signal to the space to be monitored and receive the sound signal for each measurement period to measure the frequency response of the space in each measurement period.

[0059] The sound signal transmitter 111 may include a speaker or other components for transmitting sound signals to transmit sound signals to the monitored object space. Here, the sound signal transmitter 111 may transmit sound signals in various forms.

[0060] As an example, the sound signal transmitter 111 may transmit only one frequency tone at a specific time, and transmit a single tone sound signal whose frequency changes continuously or periodically over time, or may transmit a complex tone sound signal including multiple frequency components whose frequency does not change over time.

[0061] The sound signal receiver 115 may include various measuring components such as a microphone capable of measuring sound pressure, sound intensity, and the like.

[0062] The sound signal transmitter 111 and the sound signal receiver 115 may be configured as one device and disposed at the same location, or the sound signal transmitter 111 and the sound signal receiver 115 may be configured as different devices and be separated from each other and disposed at different locations.

[0063] The sound signal processor 113 may provide the sound signal to be transmitted to the monitored space to the sound signal transmitter 111. In addition, the sound signal processor 113 may measure the frequency response of the space based on the sound signal received by the sound signal receiver 115.

[0064] For example, when the sound signal is a composite sound composed of a plurality of frequency components, the sound signal processor 113 may transform the received sound signal into the frequency domain by Fourier transform (FT) or fast Fourier transform (FFT) to measure the frequency response of the space and thereby obtain a frequency response spectrum.

[0065] As another example, when the sound signal is a single tone whose frequency changes continuously or in stages over time, the sound pressure or phase value that changes over time can be measured to replace it with the sound pressure or phase value that changes with frequency. In this case, the sound signal processor 113 can directly measure the frequency response of the space without performing a Fourier transform process on the received sound signal. Moreover, the frequency response spectrum can be obtained thereby.

[0066] The measurement value extractor 130 may extract the measurement value for the sound pressure or phase from the frequency response spectrum in units of single frequencies or in units of frequency periods. The measurement value extracted in each measurement cycle by the measurement value extractor 130 may be transmitted to the database construction means 200 and organized and stored.

[0067] The difference calculation unit 150 may calculate the difference by comparing the frequency response spectrum of a specific period with the frequency response spectrum of the comparison object in units of a single frequency or in units of a frequency period.

[0068] Here, the comparison target frequency response spectrum may be a frequency response spectrum of another period or a reference frequency response spectrum. The reference frequency response spectrum may be a frequency response spectrum measured in a stable state where no significant event occurs in the monitoring target space.

[0069] As an example, the difference calculation unit 150 may calculate the difference by comparing the measured value extracted from the frequency response spectrum of a specific period with the measured value extracted from the frequency response spectrum of another period or the reference frequency response spectrum in units of respective corresponding single frequencies or in units of respective corresponding frequency time periods.

[0070] As an example, the difference calculation unit 150 may compare the frequency response spectrum of a specific cycle with the frequency response spectra of multiple other measurement cycles to calculate the difference. For example, the frequency response spectrum of the current cycle may be compared with the frequency response spectrum of multiple previous cycles such as the frequency response spectrum of the previous cycle, the frequency response spectrum of the previous two cycles, etc. to calculate the difference.

[0071] The difference values ​​calculated by the difference value calculation unit 150 may be organized and stored in the database construction means 200 .

[0072] Figure 3 A diagram showing the structure of an embodiment of a database building component for a space monitoring system according to the present invention.

[0073] The database construction component 200 may include a measurement value information processing unit 210, a difference value information processing unit 220, a data management unit 230, a database 250, etc. The database 250 may be composed of a single integrated storage medium or a storage medium separated into a measurement value information storage unit 260 and a difference value information storage unit 270. In addition, the database 250 may be composed of a permanent storage medium such as a hard disk or a temporary storage medium such as a buffer, either selectively or together.

[0074] The measurement value information processing unit 210 can work in conjunction with the frequency response measuring means 100 to organize the measurement values ​​extracted from the frequency response spectrum of each measurement period in a single frequency order or a measurement time order and store them in the database 250. Preferably, the measurement value information processing unit 210 can store the measurement value information in the measurement value information storage unit 260 in correspondence with the corresponding frequency or the corresponding measurement time.

[0075] The difference information processing unit 220 may work in conjunction with the frequency response measuring unit 100 to receive the difference information, organize and process the difference information, and store the difference information in the difference information storage unit 270 .

[0076] As an example, the difference information processing unit 220 may store each difference by matching the corresponding frequency or the corresponding measurement time, the measurement time period of the frequency response spectrum of the specific measurement period to be compared, and the measurement time period of the frequency response spectrum of other measurement periods to be compared.

[0077] Furthermore, when new difference information is obtained or when an update cycle arrives, the difference information processing unit 230 can update the database by reflecting the new difference information.

[0078] The data management unit 230 can maintain and manage the data stored in the measurement value information storage unit 260 and the difference value information storage unit 270 .

[0079] As an example, when the number of measurement value information stored in the measurement value information storage unit 260 exceeds a preset holding number or the holding time of the stored measurement value information exceeds a preset holding time, the data management unit 230 can remove measurement value information with a longer measurement period from the measurement value information storage unit 260 in sequence.

[0080] As an example, when the number of difference information stored in the difference information storage unit 270 exceeds a preset holding number or the holding time of the stored difference information exceeds a preset holding time, the data management unit 230 can remove the difference information with a longer measurement period from the difference information storage unit 260 in sequence.

[0081] As described above, the database construction means 200 can include the above-described configuration to organize and process the measurement value information and the difference value information, thereby accumulating and storing them and providing the stored data when determining the status of the monitoring target space.

[0082] Figure 4 A diagram showing the structure of an embodiment of a space situation determination component of a space monitoring system according to the present invention.

[0083] The space status judgment component 300 may include a data analysis unit 310, an event status judgment unit 330, a status information providing unit 350, and the like.

[0084] The data analysis unit 310 may receive difference information calculated by comparing a plurality of frequency response spectra from the database construction component 200. Furthermore, the data analysis unit 310 may analyze the degree of change and the change pattern of the difference.

[0085] The event status determination unit 330 may determine the status of the target space based on the analysis result of the data analysis unit 310 .

[0086] As an example, the event situation determination unit 330 may compare the analysis results such as the degree of change and the change pattern of the difference with the determination reference information to determine the situation of the monitored space.

[0087] The data analysis unit 310 analyzes the difference, and based on this, the event status determination unit 330 determines the status of the monitored space. The specific content will be described in detail through the embodiments described later.

[0088] The state information providing unit 350 may provide the state information of the monitoring target space determined by the event state determining unit 330 to the user or the manager.

[0089] The status information provided by the status information providing unit 350 may include various event status information such as intrusion, fire, etc. into the monitored space. In addition, the status information providing unit may provide a multidimensional data table image that visually expresses the status of the current monitored space.

[0090] In addition, the present invention proposes a space monitoring method using sound signals. Hereinafter, the space monitoring method according to the present invention will be reviewed together with the embodiment of the space monitoring system according to the present invention described above.

[0091] In order to know the specific events that occurred in the monitored space, it is necessary to observe the change pattern of the frequency response spectrum. However, in the conventional technology, in order to check the change pattern of the spectrum, the newly measured spectrum is compared with the spectrum that serves as the reference each time the spectrum is measured. Therefore, if the spectrum is measured every 5 seconds, the change pattern of the spectrum can be observed at intervals of 5 seconds.

[0092] However, as described above, in order to quickly and accurately determine the type of event occurring in the monitoring target space, it is necessary to observe the variation pattern of the spectrum more quickly, for example, at intervals of 0.05 seconds. However, it is actually impossible to measure the spectrum at intervals of 0.05 seconds.

[0093] However, in the present invention, when comparing the measured spectrum with the comparison target spectrum, the comparison is performed in units of frequencies constituting the spectrum, not in units of spectrum.

[0094] For example, suppose a spectrum is composed of 100 points representing sound pressure in units of 1 Hz from 1001 Hz to 1100 Hz. In the past, the technology was to compare the spectrum composed of 100 points with the comparison target spectrum composed of 100 points to calculate a difference. For example, when the two spectra differ by 2.4%, a difference of 2.4% is extracted.

[0095] However, in the present invention, each of the sound pressure values ​​for 100 frequencies constituting one spectrum is compared with the corresponding sound pressure values ​​for 100 frequencies of the comparison target spectrum to extract 100 difference values. Therefore, if the time for measuring the spectrum consisting of 100 points is 5 seconds, the sound pressure value corresponding to one frequency is extracted every 0.05 seconds, and therefore, according to the present invention, one difference value is calculated at intervals of 0.05 seconds.

[0096] In the prior art, a difference is generated at intervals of 5 seconds, while in the present invention, a difference is generated at intervals of 0.05 seconds, so the type of event occurring in the monitored object space can be identified more quickly and accurately. How this is achieved will be described below.

[0097] Figure 5 A flow chart of an embodiment of a spatial monitoring method according to the present invention is shown.

[0098] The frequency response measuring means 100 can measure the frequency response of the space to be monitored ( S110 ) and obtain a frequency response spectrum based on the frequency response ( S120 ).

[0099] As an example, the frequency response measuring means 100 may transmit and receive a sound signal to the monitored space for each measurement period. Here, as described above, the sound signal may be a complex sound signal composed of multiple frequency components whose frequency does not change over time, or a single sound signal whose frequency changes continuously or stepwise over time.

[0100] The frequency response measuring means 100 can measure the spatial frequency response of each measurement period based on the received sound signal, and obtain a frequency response spectrum of the sound pressure or phase for each measurement period based on the spatial frequency response.

[0101] In the present invention, as an example of obtaining a frequency response spectrum, refer to Figure 6 View. Figure 6 It is the case of obtaining a frequency response spectrum using a sound signal whose frequency changes continuously over time.

[0102] The frequency response measuring component 100, as described Figure 6 As shown in (a), it can be S to E During the measurement period, the transmission sound 411 whose frequency continuously changes from fmin to fmax is transmitted to the monitored object space.

[0103] At this time, as described Figure 6 As shown in (b), the sound pressure of the sound emitted by the frequency response measuring means 100 to the monitored space changes from time t S to E During the measurement cycle, at a frequency that continuously changes from fmin to fmax, its size 413 can be set identically.

[0104] Moreover, the Figure 6 (c) shows a frequency response spectrum 415 measured by the frequency response measuring means 100 receiving sound in the monitoring target space. However, from the measurement period t S to E During this period, the frequency of the transmitted sound changes continuously from fmin to fmax. Therefore, it can be S to E During the measurement period, the frequency response spectrum 415 is measured by changing the sound pressure of the received sound from fmin to fmax corresponding to the frequency.

[0105] The sound signal received by the sound signal receiver 115 of the frequency response measurement member 100 is the sum of many signals that enter the receiver after being reflected or refracted in various parts of the monitored space, and therefore the received sound signal is affected by the physical environment of the monitored space. Therefore, although the magnitude of the transmitted sound 411 emitted by the frequency response measurement member 100 to the monitored space is the same for each frequency 413, the magnitude of the frequency response spectrum 415 obtained by the frequency response measurement member 100 in the monitored space is different for each frequency.

[0106] The frequency response measuring means 100 can extract the measured value of the sound pressure or phase value in the frequency response spectrum obtained in each measurement cycle in units of a single frequency or in units of a frequency period (S130). As an example of extracting the measured value in units of a single frequency or in units of a frequency period in the frequency response spectrum, refer to Figure 7 Provide explanation.

[0107] Said Figure 7 (a) is a case where the frequency response measuring means 100 transmits a single tone sound signal 421 whose frequency changes stepwise from f1 to f6 to the monitored space during the measuring period from time t1 to t7, and obtains a frequency response spectrum 423 using the received sound received in the monitored space.

[0108] The frequency response measuring means 100 can extract the sound pressure value measurement value 424 in the frequency response spectrum 423 in units of single frequencies. At this time, the frequency of the emitted sound 421 changes stepwise from f1 to f6 during the measurement period from time t1 to t7, and therefore, each measurement value 424 for each single frequency unit f1 to f6 can be extracted from the frequency response spectrum 423 corresponding to this.

[0109] Said Figure 7 (b) is a case where the frequency response measuring means 100 transmits a single tone sound signal 425 whose frequency continuously changes from fmin to fmax to the monitored space during the measuring period from time t1 to t7, and obtains a frequency response spectrum 427 using the received sound received in the monitored space.

[0110] The frequency response measuring means 100 may divide the frequency response spectrum 427 into frequency segments and calculate an average value or a representative value of the sound pressure value for each frequency segment ( f1 to f2 , f2 to f3 , etc.) to extract a measurement value 428 for each frequency segment.

[0111] Alternatively, the frequency response measuring component 100 provides the extracted measurement values ​​to the database constructing component 200, and the database constructing component 200 organizes and processes the measurement values ​​and stores the measurement values ​​by matching them to corresponding frequencies or corresponding measurement times according to each measurement cycle.

[0112] The frequency response measuring component 100 may compare the frequency response spectrum of the specific period with the comparison target frequency response spectrum in units of single frequency or frequency time periods to calculate a difference for each single frequency unit or frequency time period unit ( S140 ).

[0113] As an example, the frequency response measurement component 100 can extract measurement values ​​in single frequency units or frequency time period units from the frequency response spectrum of a specific period, and compare them with the measurement values ​​of single frequency units or frequency time period units extracted from the frequency response spectra of one or more other periods stored in the database construction component 200 to calculate the difference for each single frequency unit or frequency time period unit.

[0114] As another example, the frequency response measuring means 100 may extract a measurement value in a frequency response spectrum of a specific period in a single frequency unit or a frequency period unit, and compare it with the measurement value of the reference frequency response spectrum for the single frequency unit or the frequency period unit to calculate a difference for each single frequency unit or the frequency period unit. Here, the reference frequency response spectrum may be a frequency response spectrum that can be measured in a stable state where no event occurs in the monitored object space.

[0115] As an example of comparing frequency response spectra to calculate the difference, refer to Figure 8 Check.

[0116] As stated Figure 8 As shown in (a), the difference d between the measurement values ​​432 and 434 can be calculated by matching the measurement value 432 extracted in the frequency response spectrum 431 of the current measurement cycle in units of each single frequency with the measurement value 434 extracted in the frequency response spectrum 433 of the previous measurement cycle in units of each single frequency according to the number of each single frequency unit.

[0117] As mentioned above, it is possible to Figure 8 (b) obtains the difference calculated by comparing the frequency response spectrum 431 of the current measurement cycle with the frequency response spectrum 433 of the previous measurement cycle in units of single frequency. Similar to this process, the frequency response spectrum of a specific measurement cycle can be compared with the reference frequency response spectrum to calculate the difference.

[0118] Furthermore, the calculated difference may be provided to the database construction component 200, and the database construction component 200 may process and organize the difference and save it (S150).

[0119] As an example, the database construction component 200 may match the difference with the corresponding frequency or the corresponding measurement time, the measurement time period of the frequency response spectrum of the specific measurement period for comparison, and the measurement time period of the frequency response spectrum of other measurement periods for comparison, and store them. Furthermore, the database construction component 200 may generate a multidimensional data table for the difference and store it.

[0120] Fig. 9 An example of a multidimensional data table for difference values ​​in the present invention is shown. Fig. 9 The frequency response of the space is measured using a single tone emission sound with a frequency continuously changing from 3098 Hz to 4078 Hz in a measurement period of 6 seconds, and the difference is calculated by comparing the frequency response spectra in units of frequency time segments at intervals of 0.3 seconds. Data tables 510 and 520 are shown for the difference calculated by comparing the frequency response spectrum of the current period with the frequency spectra up to the previous 10 measurement periods in units of single frequency time segments.

[0121] In the data tables 510 and 520, the b value 511 indicates a single frequency from 4000 Hz to 4076 Hz as the center frequency of each frequency time period unit, and the single frequency can also be replaced by the measurement time for the corresponding frequency in the current measurement cycle. Alternatively, the b value 511 can also be implemented as a data table by matching the corresponding measurement time to the corresponding frequency.

[0122] Furthermore, the a value 513 indicates the measurement time interval related to the measurement time of the frequency response spectrum of other measurement periods, which is compared with the measurement time of the frequency response spectrum of a specific period. That is, it indicates the frequency response measurement time of the previous period, that is, 6 seconds ago, from the current period, and sequentially indicates the frequency response measurement time of the previous 10 periods, that is, 60 seconds ago.

[0123] Said Fig. 9 (a) is an example of a data table 510 showing difference values ​​by color distinction. Fig. 9 (b) is an example of a data table 520 showing differences by column height.

[0124] The difference 515, 525 between the measured values ​​of each frequency in a specific measurement cycle and the measured values ​​of each frequency in the measurement cycle 6 seconds ago can be represented by color differentiation or column height differentiation. As mentioned above, the difference from the current cycle to the cycle 60 seconds ago can be realized as a multidimensional data table by color differentiation or column height differentiation.

[0125] Furthermore, the Fig. 9 A data table showing the difference between the frequency response spectrum of a specific measurement period and the frequency response spectrum of a plurality of other measurement periods can be generated by generating one such data table for each measurement period to generate a higher-dimensional data table. Fig. 9Although not shown in the figure, a data table can be generated with each of the multiple measurement cycles as a specific cycle, and a higher-dimensional data table can be generated by applying the c value to each specific cycle as another axis. Furthermore, the database construction component 200 can update the multidimensional data table to reflect the difference obtained for each new measurement cycle.

[0126] The space status determination unit 300 can grasp the degree of change or change pattern of the difference based on the difference of the frequency response spectra of each measurement period stored in the database (S160) and determine the event status occurring in the monitored space based on it (S170).

[0127] Preferably, the space status determination component 300 can grasp the variation degree or variation pattern of the difference value during the selected frequency period or time period to instantly determine the occurrence of an event in the monitored object space and also determine the type of event.

[0128] Hereinafter, a method of distinguishing the types of events occurring in a monitoring target space based on the degree of change or change pattern of a difference value in the present invention will be reviewed with reference to various embodiments.

[0129] Fig.10 An example of the degree of change and change pattern of the difference value for each different event type in the present invention is shown. Fig.10 This is a case where a frequency response spectrum for a monitored space is measured using a single-tone sound signal whose frequency changes with time for each measurement cycle, and the frequency response spectrum of the current measurement cycle is compared with the frequency response spectrum of other measurement cycles to calculate a difference.

[0130] Said Fig.10 (a) represents the difference between the frequency response spectrum of the current measurement cycle and the frequency response spectrum of the cycle 6 seconds ago. Fig.10 (b) represents the difference between the frequency response spectrum of the current measurement cycle and the frequency response spectrum of the cycle 30 seconds ago. Fig.10 (c) shows the difference between the frequency response spectrum of the current measurement cycle and the frequency response spectrum of the cycle 60 seconds ago.

[0131] In the Fig.10The left-center graph shows the degree of change and change pattern of the difference when there is no movement in the monitored space for the past 60 seconds and a sudden movement occurs at the current time point. There was no movement 6 seconds ago, 30 seconds ago, and 60 seconds ago, so the spectra measured at this time are similar to each other. Therefore, when the currently measured spectrum is compared with the spectrum 6 seconds ago, 30 seconds ago, and 60 seconds ago, the shape of the difference will also be similar. For example, when an intrusion occurs in the monitored space and the intruder moves in the monitored space, the difference appears as a sharp change or fluctuation within the G1 range as a whole.

[0132] In the Fig.10 The middle right graph shows the degree of change and change pattern of the difference when a fire started 60 seconds ago in the monitored space and the temperature continues to rise. In the case of a fire, the temperature does not change much in a period of time close to 6 seconds, so the difference calculated by comparing the current time point with 6 seconds ago does not change much as a whole and changes at a constant level within the G2 range. However, in the case of a fire, the temperature continues to rise over time, so the longer the measurement time interval of the compared spectrum is, the greater the temperature difference between the two time points. Therefore, the difference calculated by comparing the current time point with 30 seconds ago shows a larger change as a whole and changes in a form similar to a sine curve within the G3 range, and the difference calculated by comparing the current time point with 60 seconds ago shows a considerable change as a whole and changes in a form similar to a sine curve within the G4 range.

[0133] If the temperature of the monitored space changes, the frequency response spectrum measured in the monitored space shifts to the left (in the case of cooling) or the right (in the case of heating) in proportion to the temperature change. When the temperature change is negligible, the frequency shift is also negligible, so the frequency unit difference d of the two spectra is also small by 650. However, the greater the temperature change, the greater the frequency shift is proportionally, so not only the frequency unit difference d of the two spectra also increases, but also because the frequency shift is necessarily negative in some frequency domains and d is necessarily positive in other frequency domains, when the overall spectrum period is viewed, d presents a form of alternating negative and positive periods similar to a sine curve 670. At this time, the period in which the difference d fluctuates once similar to a sine curve becomes similar to the period of the frequency response spectrum. That is, if the shape of the frequency response spectrum is the same as that of a sine curve, the shape of the difference d that appears when the frequency shift occurs also becomes a sine curve, and its period becomes the same as the period of the frequency response curve.

[0134] As described above, the change pattern of the spectrum difference is unique depending on whether the event occurring in the monitored object space is a temperature change or a physical shape change. Therefore, according to the present invention, the type of event occurring in the monitored object space can be determined very quickly and accurately.

[0135] First, an event judgment related to the movement of an object in the monitoring target space is referred to Figures 11 to 14 Provide explanation.

[0136] Assume that Fig.11 For ease of explanation, the difference is calculated as shown in FIG. Fig.11 The difference is represented by a line, but in fact, as described Fig.12 To the Fig.14 As shown, the difference is represented by points corresponding to each frequency.

[0137] In addition, the Figures 11 to 14 The corresponding difference and the corresponding measurement time are represented in correspondence, and the corresponding measurement time can be replaced by the corresponding frequency. As described above, the difference can be matched to one or more of the corresponding frequency or the corresponding measurement time to be stored in the database. If the specific measurement period and the corresponding frequency are known, the corresponding measurement time corresponding to the corresponding frequency can be known. Conversely, if the corresponding measurement time is known, the specific measurement period and the corresponding frequency can be known.

[0138] In the Fig.11 A is a stable state where no meaningful situation occurs in the monitored object space. Fig.12 The viewing space status determination component 300 determines the status of the monitored space.

[0139] The data analysis unit 310 of the space condition determination component 300 can analyze the change degree and change pattern of the difference value 720 while scanning the difference value in time sequence. Fig.12 In this case, the data analysis unit 310 of the space condition determination component 300 can scan the difference in time sequence while grasping whether the difference exists within the first reference range S1 during the constant time period P1.

[0140] As described above, according to the inherent physical characteristics of the monitored object space, the difference value will change below a constant level when the corresponding monitored object space is in a stable state. Therefore, when the corresponding monitored object space is in a stable state, the degree of change of the difference value can be grasped to set the first reference range S1. The first reference range S1 can be set differently to reflect the status of the monitored object space.

[0141] exist Fig.12In this case, the data analysis unit 310 of the space status judgment component 300 can judge that each difference 721 exists within the first reference range S1 during the first time period P1, so that the corresponding monitored object space is in a stable state during this first time period P1.

[0142] Here, the first time period P1 can be selected as a long time period that can be used to judge that the monitored object space is in a stable state. For example, even if the difference measured in the monitored object space does not change significantly for 1 second, it is difficult to hastily judge that the space is in a stable state. This is because if the intruder stops for a few seconds after moving in the monitored object space, even if the monitored object space is not in a stable state, the difference between the seconds may remain within the reference range. On the other hand, if the measured difference does not change significantly for more than 5 minutes, it can be judged that the monitored object space is in a stable state without movement. As described above, the boundary conditions that can be judged as a state without movement in the monitored object space can be appropriately set according to the characteristics of the monitored object space. The boundary conditions at this time need to meet two benchmarks. (1) During a constant period of time, (2) the change in the difference should be kept below a constant level.

[0143] The first time period P1 may also be a relatively long time, for example, more than 10 seconds. If one measurement cycle of the spectrum is 6 seconds, the first time period P1 may be a long time equivalent to multiple measurement cycles. Such a first time period P1 may be appropriately set according to the conditions of the monitored space.

[0144] As an example, the data analysis unit 310 of the space condition determination component 300 may calculate the degree of scattering of the difference during the first time period P1 and analyze the degree of change and the change pattern of the difference based on the degree of scattering.

[0145] As an index expressing dispersion, for example, standard deviation, variance, absolute deviation, range, interquartile range, etc. are often used. However, in the present invention, as one of the indexes expressing dispersion, the root mean square error (Root Mean Square Deviation or Root Mean Square Error) used in linear regression analysis is included. If the root mean square error is used as an index of dispersion, especially when the temperature changes in the monitored object space, the accuracy of sensing can be improved.

[0146] The data analysis unit 310 of the space condition determination component 300 may calculate the dispersion of the difference 721 during the first time period P1, and analyze whether the dispersion of the difference remains smaller than the first reference.

[0147] If the dispersion of the difference values ​​calculated in a stable state where no significant event occurs in the corresponding monitoring target space is referred to as D0, the first reference may be, for example, a value 1.1 to 3 times D0.

[0148] Including the first benchmark, the various benchmarks described below will be described at what threshold values, which may vary greatly depending on the user or the purpose of use. If you want to reduce the false positives of a certain sensor, you can set the threshold high. In this case, the probability of false negatives will inevitably increase. On the contrary, if you want to reduce the probability of false negatives, you can set the threshold low. In this case, the probability of false alarms will inevitably increase. However, for example, under specific purposes of use, false alarms are not a big problem, but false negatives may lead to fatal consequences. On the contrary, for some users, false alarms may become a very troublesome problem. Therefore, specifically, the degree to which the threshold is preferred will inevitably vary according to the characteristics of the monitored object space and the user, the purpose of sensor use, and the severity of false alarms and false negatives.

[0149] exist Fig.12 In the example, when the dispersion of the difference value during the first reference time P1 is less than the first reference, the event state determination unit 330 of the space state determination component 300 can determine that the monitored space is currently in a stable state. At this time, as for how long P1 is set or how large the first reference of the dispersion is set, as described above, it can be appropriately set according to the purpose of use of the sensor and the state of the space.

[0150] In the Fig.11 B in the figure shows the state where the first intrusion occurs after the monitored space remains stable. Fig.13 The viewing space status determination component 300 determines the status of the monitored space.

[0151] The data analysis unit 310 of the space condition judgment component 300 can grasp the situation that the difference becomes larger in the second time period P2 which is continuous with the first time period after the difference is not large during the first time period P1 in the process of scanning the difference in time sequence. Here, the first time period P1 should be set to what, as described above. On the other hand, the second time period P2 should be set to a time interval suitable for judging "whether the intrusion occurs initially" according to its purpose, so a time period of, for example, 0.1 seconds to 5 seconds can be selected according to the condition of the space or the purpose of sensing.

[0152] In the Fig.13In the case of, if the dispersion of the difference value 731 during the first time period P1 is less than the first reference, and on the other hand, the dispersion of the difference value during the second time period P2 exceeds the second reference, it can be determined that the movement occurs for the first time in the second time period P2 in the monitored object space. At this time, the second reference can be set to a value equal to or greater than the first reference.

[0153] On the other hand, in order to set a criterion for judging the fact that the initial movement occurs in the monitored object space, various indices or various concepts may be used. However, as described above, even if various judgment criteria are applied, such a judgment method may be included as a judgment method using dispersion. For example, Fig.13 In the above, if the absolute value of the difference d remains within the range of S1 and then exceeds the range of S2 at a specific time point, it can be determined that the initial movement occurs at that time point. However, the judgment method described above can be called a kind of "judgment method based on dispersion". For example, if the "absolute value of the difference d" is used as an index representing dispersion and the width of the second time interval P2 is minimized, the two expressions become exactly the same.

[0154] refer to Fig.13 By checking, it can be seen that the present invention is different from the prior art in two aspects. First, in the prior art, the difference between the currently measured spectrum and the spectrum measured at other times is calculated in units of spectrum. Therefore, it can only be known that a certain event occurred during the time period of measuring the current spectrum, but it is impossible to know what type of event it is. Second, in the prior art, it can only be inferred that the time point of a certain event is a certain time point within the time period of measuring the current spectrum, but it is impossible to know exactly when the event occurred. Different from this, in the present invention, it can be known that the event first occurred in the second time period P2, and further, it can be known that the type of event is an intrusion.

[0155] In the Fig.11 In the middle, C is a difference change pattern that can be judged as a movement in the monitored object space, although it cannot be said that the movement occurred initially. Fig.11 In case B, when the movement first occurs, the stable state and the state when the movement first occurs are in sharp contrast, so the second benchmark can be set relatively low. However, it is preferred that the third benchmark used as a benchmark for judging whether to maintain the current intrusion is greater than the second benchmark. Obviously, the third benchmark can also be made the same as the second benchmark.

[0156] When the monitored space is stable, the dispersion of the difference is necessarily small, while on the other hand, when there is movement, the dispersion of the difference is necessarily high. However, the appropriate dispersion to issue an alarm requires different settings depending on the monitored space and the characteristics of the user, the purpose of use, the severity of false alarms and missed alarms, etc.

[0157] Fig.14 The variation of the difference according to the measurement time is shown. At this time, the measurement time can be replaced by the corresponding frequency, as described above. Fig.14 The data analysis unit 310 of the space condition determination component 300 can check the third time period P3 in which the difference value exceeds the third reference range S3 and changes in an upward and downward manner. The data analysis unit 310 of the space condition determination component 300 can analyze the degree of change and the change pattern of the difference value 740 during the third time period (or frequency period) P3.

[0158] As an example, the data analysis unit 310 of the space condition determination component 300 calculates the dispersion related to the difference 741 during the third time (frequency) period P3. If the dispersion of the difference exceeds the third reference, it can be determined that there is movement in the monitored object space. At this time, the third reference can be set to, for example, a value slightly larger than the second reference, as described above.

[0159] How to set the third time (frequency) period P3 appropriately can be evaluated from two aspects.

[0160] First, in order to distinguish between the situation where there is movement in the monitored object space and the situation where there is a temperature change, the third time (frequency) period P3 should be narrower than the width of the period in which the difference may change due to temperature change. That is, a narrow period is set, and even if there is a temperature change, the difference cannot change significantly. If the difference change is measured in this narrow period, it can be determined that there is movement in the monitored object space. However, when there is a temperature change, the width of the period in which the difference may change significantly is proportional to the width of the peak in the frequency response spectrum. Therefore, the third time (frequency) period P3 should be smaller than the width of the peak of the frequency response spectrum, and preferably, should be smaller than 20% of the peak width.

[0161] Second, if the time interval between the two spectra being compared is narrow enough, it can be reasonably assumed that the temperature of the monitored space does not change much during the time period when the two spectra are measured. In this case, the change in the difference due to the temperature change can be ignored, and only the change in the difference due to movement can be considered. Therefore, when the time interval between the two spectra being compared is narrow enough, the third time period P3 can be set to the time required for the intruder to move to a certain extent, for example, about 0.1 to 5 seconds.

[0162] On the other hand, in order to set a criterion for judging the existence of movement, various indexes or various concepts may be introduced. However, as described above, even if various judgment criteria are applied, this judgment method may be included as a judgment method using dispersion. For example, in the Fig.14 In this case, the data analysis unit 310 of the space status judgment component 300 can grasp the difference 741 changing from a negative value to a positive value M1 and from a positive value to a negative value M2 while the absolute value of the difference 741 during the third time period P3 exceeds the first average reference AVE1 on average. If the frequency exceeds a certain reference, it can also be judged that movement has occurred in the monitored object space.

[0163] The Fig.11 To the Fig.14 The difference value based on the corresponding measurement time is used for illustration and explanation, but the corresponding measurement time can be changed to the corresponding frequency. That is, as described above, the corresponding frequency in each measurement cycle can be matched to the measurement time corresponding to the corresponding frequency in the corresponding measurement cycle, so the corresponding measurement time can also be changed to the corresponding frequency to express the change of the difference value as needed.

[0164] Next, refer to Fig.15 The event determination regarding the occurrence of a temperature change in the monitored space will be described.

[0165] As described above with reference to Fig.10 As described above, the temperature change caused by a fire or the like in the monitored space changes with time, and the difference changes in a form similar to a sine curve, and the temperature changes greatly as a whole.

[0166] Said Fig.15 This is the case where the difference of 750 is calculated by comparing the frequency response spectrum at the current time point after the fire occurs and the frequency response spectrum before the fire occurs. Fig.15 The change in the difference according to the measurement time is shown, but it is seen above that the respective measurement times can be replaced by the corresponding frequencies.

[0167] The data analysis unit 310 of the space condition judgment component 300 can scan the difference while grasping the fourth time (or frequency) period P4 in which the change of the difference changes similarly to the sine curve as a whole. Here, preferably, the fourth time (frequency) period P4 is selected as a period that can confirm the degree to which the difference changes in a form similar to the sine curve. For example, the overall time (frequency) period that constitutes a spectrum can be selected. Alternatively, it can be set at an interval of 1 to 5 times the peak width at the frequency point where the peak of the frequency response spectrum exists.

[0168] As an example, the data analysis unit 310 of the space status determination component 300 calculates the dispersion related to the difference 750 during the fourth time (frequency) period P4, and analyzes whether the dispersion of the difference during the fourth time (frequency) period P4 exceeds the fourth reference. Here, the fourth reference must indicate what event occurs in the monitored space, and therefore, for example, may have a value similar to the third reference.

[0169] At the same time, the data analysis unit 310 of the space status judgment component 300 can calculate the dispersion related to the difference during the fifth time (frequency) period P5 included in the fourth time (frequency) period, and analyze whether the dispersion of the difference during the fifth time (frequency) period P5 is less than the fifth benchmark.

[0170] Here, the fifth time (frequency) period P5 is a time (frequency) period suitable for observing sharp changes without differences. For example, at the frequency point where there is a peak in the frequency response spectrum, the P5 period should be smaller than the width of the peak, preferably, less than 20% of the peak width.

[0171] Furthermore, the fifth criterion is a criterion that requires judging that the variation range of the difference is not large compared with the case of intrusion, and therefore, it is preferably set to a level similar to or slightly larger than the first criterion, for example.

[0172] On the other hand, when the fifth reference is set and the dispersion is calculated, if the root mean square error is used as an index to express the dispersion, the accuracy of the temperature change judgment can be improved. The reason is that the dispersion in the fifth time (frequency) period is such that even if the "distance from the average of each difference" is relatively large, if the "distance from the regression line of each difference" is small, the change pattern of the difference d is close to the sine curve, and therefore, it can be judged that there is a temperature change. Therefore, for example, when measuring the dispersion in other time periods or frequency periods, the standard deviation is used, and when evaluating the dispersion in the fifth time (frequency) period, the root mean square error used in the linear regression analysis is used.

[0173] As described above, if the dispersion of the difference during the fourth time (frequency) period P4 exceeds the fourth benchmark and the dispersion of the difference during the fifth time (frequency) period P5 is less than the fifth benchmark, then in this case, it means that the difference has a sinusoidal change pattern. Therefore, the data analysis unit 310 of the space condition judgment component 300 can determine that there is a temperature change in the monitored object space.

[0174] In order to set a criterion for judging the existence of temperature change, various indexes or various concepts may be introduced. However, as described above, even if various judgment criteria are applied, this judgment method may also be included as a judgment method using dispersion. For example, in the Fig.15In the case of, the data analysis unit 310 of the space condition judgment component 300 can calculate the average and the average of the absolute value related to the difference 751 during the fourth time (frequency) period P4, and analyze whether the average of the absolute value of the difference exceeds the second average reference AVE2 and the average of the difference is less than the third average reference AVE3. In addition, it is possible to grasp M1 where the difference 751 changes from a negative value to a positive value and M2 where it changes from a positive value to a negative value to analyze that its frequency is less than the second frequency reference. If this condition is met, the difference becomes a form similar to a sine curve as a whole, and therefore, the fact of temperature change can be identified.

[0175] Furthermore, in the present invention, the status of the monitoring target space can be determined using a multidimensional data table for the difference values. Fig. 9 as well as Figures 16 to 18 An example of using a multidimensional data table for difference values ​​in the present invention to determine an event in the monitoring object space is shown. Fig.16 To the Fig.18 For matters such as multidimensional data tables and storage, refer to the above Fig. 9 etc., and therefore, the detailed description will be omitted.

[0176] In the Fig.16 To the Fig.18 In (a), yellow indicates the difference d is close to 0, red indicates a large positive difference, and blue indicates a large negative difference. Fig. 9 In the case of , it can be seen that there is no overall difference between the spectrum measured in the current measurement cycle and the spectrum measured in the past measurement cycle. That is, it is a state where a stable state without movement or temperature change is maintained in the monitored object space.

[0177] Said Fig.16 The multidimensional data tables 810 and 820 shown have differences that are disordered and change significantly from 60 seconds before the current time point. According to the previous embodiment, if the spatial condition judgment component 300 is used to judge the event process, it can be judged that there is a change in the physical shape in the monitored object space. More specifically, it can be judged that there is a continuous movement of an object. For example, it can be a situation where a person continues to move in the monitored object space.

[0178] Said Fig.17The multidimensional data tables 830 and 840 shown show a pattern 835 in which the difference value changes slightly at a constant level in the previous period at 4036 Hz, then starts to change significantly from 4036 Hz, and changes significantly until 4076 Hz. According to the previous embodiment, if the spatial condition judgment component 300 is used to judge the process of the event, it can be judged that there is a change in the physical shape of the monitored object space. More specifically, it can be judged that after maintaining a stable state in the previous period at 4036 Hz, the movement of an object occurs for the first time in the measured monitored object space near the frequency of 4036 Hz. For example, it may be a situation where an intruder enters the monitored object space.

[0179] Said Fig.18 The multidimensional data tables 850 and 860 shown are in the form 870 of a sine curve similar to the difference calculated by comparing the current measurement cycle and the measurement cycle 60 seconds ago. Moreover, the difference calculated by comparing the measurement cycle 60 seconds ago gradually approaching the current measurement cycle with the current measurement cycle is observed to present a pattern 851, 852, 853, 861, 862, 863 in which the change in the difference gradually decreases. With respect to the degree of change and change pattern of such a difference, through the previous embodiment, if the process of judging an event by the space condition judging component 300 is applied, it can be judged that there is a temperature change in the monitored object space. More specifically, it can be judged that a fire occurred 60 seconds ago and the current fire is actively ongoing.

[0180] In the past, the only focus was on the difference between the currently measured spectrum and the spectrum measured in the past. Therefore, based on the fact that the two spectra are different, it is possible to understand the fact that there has been a change between the time when the two spectra were measured, but it is impossible to know what specific event has occurred.

[0181] However, in the present invention, in addition to measuring how much the spectrum currently measured differs from the spectrum measured in the past, the specific differences are also observed in detail. As a result, the time when the intrusion first occurred in the monitored space can be accurately known (for example, Fig.13 Moreover, if, for example, a relatively narrow time (frequency) period (e.g., Fig.14 If the dispersion of the difference is high in P3), it can be judged that it is moving. On the contrary, if it is in a relatively narrow time (frequency) period (for example, Fig.15 If the dispersion of the difference in P5) is low, it can be judged that a temperature change has occurred.

[0182] As described above, according to the present invention, the frequency response spectra of each measurement cycle of the monitored object space are compared in units of a single frequency or in units of a frequency period and the degree of change and the change pattern of the difference are analyzed. Based on this, the change of the physical condition of the monitored object space can be sensed more quickly and accurately. Furthermore, in the present invention, the change pattern of the difference is made into a visual data table to be provided so that non-experts can also grasp it intuitively and simply.

[0183] The above description is only an example of the technical concept of the present invention. Anyone with common knowledge in the technical field to which the present invention belongs can make various modifications and deformations without departing from the essential characteristics of the present invention. Therefore, the embodiments described in the present invention are not intended to limit the technical concept of the present invention, but to illustrate the technical concept of the present invention, and the technical concept of the present invention is not limited to these embodiments. The protection scope of the present invention should be interpreted by the attached claims, and all technical concepts within the scope equivalent to them should be interpreted as included in the scope of rights of the present invention.

Claims

1. A method for spatial monitoring using sound signals, characterized in that: include: A frequency response measuring step of transmitting a sound signal to a monitored space and receiving the sound signal according to a measuring period to obtain a frequency response spectrum according to the measuring period; a difference calculation step, comparing the frequency response spectrum of the specific period with the frequency response spectrum of the comparison object in units of single frequency or frequency time period, thereby calculating the difference for each single frequency unit or frequency time period unit; A difference saving step, matching the difference to one or more of the corresponding frequency or the corresponding measurement time and saving the difference in a database; as well as The space state judgment step judges the state of the monitored space based on the degree of change or the change pattern according to the difference in frequency or measurement time.

2. The method for spatial monitoring using sound signals according to claim 1, characterized in that: The difference calculation step compares the frequency response spectrum of the specific period with the frequency response spectrum of at least one other measured period, The difference value saving step saves the difference value by matching it with the corresponding frequency or the corresponding measurement time, the measurement time period of the frequency response spectrum of a specific cycle, and the measurement time periods of the frequency response spectrum of other measurement cycles.

3. The space monitoring method using sound signals according to claim 1, characterized in that: The frequency response measurement step transmits a single-tone sound signal whose frequency changes continuously or step by step over time to the monitored space. When the dispersion of the difference during the first frequency period or the first time period remains less than the first benchmark and then the dispersion of the difference during the second frequency period or the second time period exceeds the second benchmark, the spatial status judgment step judges that there is a change in the physical shape of the monitored object space in the second frequency period or the second time period.

4. The method for spatial monitoring using sound signals according to claim 1, characterized in that: When the dispersion of the difference during a third frequency period or a third time period exceeds a third reference, the space condition judgment step judges that there is a change in the physical shape of the monitored object space during the third frequency period or the third time period.

5. The space monitoring method using sound signals according to claim 1, characterized in that: When the dispersion of the difference during the fourth frequency period or the fourth time period exceeds the fourth benchmark, and the dispersion of the difference during the fifth frequency period or the fifth time period included in the fourth frequency period or the fourth time period is less than the fifth benchmark, the spatial condition judgment step judges that there is a temperature change in the monitored object space in the fourth frequency period or the fourth time period.

6. A space monitoring system using sound signals, characterized in that: include: A frequency response measuring component, which transmits a sound signal to a monitored space and receives the sound signal according to a measuring period to measure a frequency response spectrum according to the measuring period, and compares the frequency response spectrum of a specific period with the frequency response spectrum of a comparison object in units of single frequency or in units of frequency time periods, thereby calculating a difference for each single frequency unit or frequency time period unit; A database construction component matches the difference to one or more of the corresponding frequency or the corresponding measurement time to store the difference in a database; as well as The space state determination means determines the state of the monitored space based on the degree of change or the change pattern according to the difference in frequency or measurement time.

7. The space monitoring system using sound signals according to claim 6, characterized in that: The frequency response determination means compares the frequency response spectrum of a specific period with the frequency response spectrum of at least one other determination period, The database construction component matches the difference with the corresponding frequency or the corresponding measurement time, the measurement time period of the frequency response spectrum of a specific cycle, and the measurement time periods of the frequency response spectrum of other measurement cycles to store them.

8. The space monitoring system using sound signals according to claim 6, characterized in that: The frequency response measuring means transmits a single tone sound signal whose frequency changes continuously or step by step over time to the monitored space. When the dispersion of the difference during the first frequency period or the first time period remains less than the first benchmark and then the dispersion of the difference during the second frequency period or the second time period exceeds the second benchmark, the spatial condition judgment component judges that there is a change in the physical shape of the monitored object space in the second frequency period or the second time period.

9. The space monitoring system using sound signals according to claim 6, characterized in that: When the dispersion of the difference exceeds a third reference during a third frequency period or a third time period, the space condition determination means determines that there is a change in the physical shape of the monitoring target space during the third frequency period or the third time period.

10. The space monitoring system using sound signals according to claim 6, characterized in that: When the dispersion of the difference during the fourth frequency period or the fourth time period exceeds the fourth benchmark, and the dispersion of the difference during the fifth frequency period or the fifth time period included in the fourth frequency period or the fourth time period is less than the fifth benchmark, the space condition judgment component judges that there is a temperature change in the monitored object space in the fourth frequency period or the fourth time period.

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