Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
  • G01H3/00—Measuring characteristics of vibrations by using a detector in a fluid
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
  • G01H3/00—Measuring characteristics of vibrations by using a detector in a fluid
  • G01H3/10—Amplitude; Power
  • G01H3/12—Amplitude; Power by electric means
  • G01H3/125—Amplitude; Power by electric means for representing acoustic field distribution
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
  • G01H3/00—Measuring characteristics of vibrations by using a detector in a fluid
  • G01H3/10—Amplitude; Power
  • G01H3/14—Measuring mean amplitude; Measuring mean power; Measuring time integral of power

Definitions

• the present invention relates to acoustic monitoring of an environment, especially continuously.
• the present invention relates to an acoustic monitoring device, powered independently, and the corresponding global monitoring system, for monitoring an industrial or urban environment.
• different noise or acoustic indicators are used such as, for example, night noise level indicators L N expressed in decibels, dB, and A-weighted to take into account the sensitivity of the human ear.
• An acoustic monitoring can also, in an urban environment, continuously monitor the noise nuisance caused by a construction site for example, in order to limit nuisance and avoid complaints from residents.
• monitoring the sound signal emitted by an industrial equipment for example a machine
• acoustic signals there are two ways to analyze acoustic signals: a sound level measurement (energy measurement only) or an analysis of the signal waveform (digital audio signal corresponding to the sound pressure).
• the first way is used in environmental acoustics, especially for monitoring large transport infrastructure, such as highways, high-speed railways or airports.
• the sound wave is then picked up by a microphone and then integrated to determine its energy.
• the integration time was set on the analog sonometers by the operator to facilitate the reading of the sound level. Three integration times were used: long (ls), short (125ms) and pulse (10ms).
• L p in decibel (dB) thus measured are then combined to determine an equivalent sound level, q, T (dB), corresponding to an average energy over an observation time T.
• the external sound environments are usually quantified by the weighted equivalent sound level A, Z. Aeq (dB).
• Sound level meters are used in different contexts: spot measurement or measurement station in the context of observatories of the sound environment. These observatories have a maximum of a few tens of sound level meters to monitor the entire territory of a large metropolis. Measurements are used to qualify the sound environment: for example, they are used to determine the black spots of the noise (place where the noise level is higher than the regulation). However, these indicators are not very correlated with the noise discomfort perceived by local residents or the pleasantness of sound environments.
• the sound meters used in a timely manner are powered by a battery allowing a measurement of a few days. For longer measurements, it is necessary to feed them via an external network.
• the second way is based on more complex analysis tools.
• the acoustic wave is picked up by a microphone and digitized before being processed by an algorithm.
• the sound signal thus obtained contains detailed information making it possible to determine numerous acoustic indicators. These thus qualify the evaluated product: fundamental frequency (F 0 ), linear prediction coefficients, spectral center of gravity, perceived sound level, etc.
• F 0 fundamental frequency
• linear prediction coefficients linear prediction coefficients
• spectral center of gravity spectral center of gravity
• perceived sound level etc.
• the energy consumption of an acoustic measurement depends on the consumption of the microphone, the processing unit and the transmission of the analysis between the processing unit and the storage unit. It is possible to reduce the energy consumption for each element separately.
• the current tools for measuring the sound environment are based on continuous measurement. Thus, despite the development of sensors and low-power processing tools, the continuous processing of a signal remains the primary source of energy consumption of communicating objects.
• the present invention aims to solve the various technical problems mentioned above.
• the present invention aims to provide a continuous acoustic monitoring device to optimize the power supply of the device so as to obtain a longer monitoring period.
• the present invention also aims to provide an acoustic monitoring device for providing substantial information on the surrounding acoustic environment, so as to allow a subsequent more refined analysis from complex acoustic indicators for example.
• a device for monitoring, or measuring, a continuous acoustic signal the monitoring device being fed autonomously and comprising:
• an acoustic transducer receiving an activation signal, and configured to provide, when activated, an electrical signal corresponding to the measured acoustic pressure of the acoustic signal
• control means supplying the activation signal
• an analysis means receiving as input the electrical signal supplied by the acoustic transducer and outputting successive values of one or more acoustic indicators representative of the acoustic signal over a determined period of time
• a means of communication for example wireless, receiving the successive values of the acoustic indicator or indicators supplied by the analysis means, and configured to transmit, at a first time interval, one or more several values of the acoustic indicator (s) to a reception means, or transmission-reception means, remote from the monitoring device.
• control means is configured to activate the acoustic transducer for a fraction of said determined duration
• analysis means is configured to determine each value of the acoustic indicator (s) from the electrical signal corresponding to the acoustic signal. during said fraction of said determined duration.
• the measurement and analysis of signals measured on a fraction only of the determined duration made it possible to obtain values of acoustic indicators close to those obtained from signals measured during the whole determined duration.
• the invention makes it possible to carry out a supervised and thus optimized temporal discretization of the measurement, in particular to limit the electrical consumption of the monitoring device and thus to have, for the same given energy source, a running time longer.
• the fraction of determined duration is chosen in particular so as to obtain values of acoustic indicators whose uncertainty due to time discretization is lower than that due to the rest of the monitoring device.
• the determined duration can be equal to 1 second and the fraction of fixed duration can be equal to 100 ms, which makes it possible to reduce the total duration and / or the total number of acoustic measurements by a factor 10.
• the first time interval can be 10 seconds.
• the monitoring device can send ten values of acoustic indicators determined over ten fractions of a second. This reduces the duration of analysis of the acoustic environment and thus the power consumption of the monitoring device, while obtaining values of relevant acoustic indicators.
• the monitoring device is powered independently.
• the monitoring device may comprise a battery or an accumulator for supplying the various elements of the monitoring device with electrical energy.
• control means is configured to activate once, at a second time interval or during a second time interval, the acoustic transducer for a fraction of said determined duration.
• analysis means is configured to determine, at each second time interval, each value of the acoustic indicator (s) from the electrical signal corresponding to the acoustic signal during said fraction of said determined duration.
• the first and second time intervals are repeated time intervals, i.e. the actions that are performed are periodically performed, even if the duration of said time intervals can be changed during the operation of the monitoring device. .
• the second time interval is thus equal to the determined duration or to a multiple of the determined duration.
• the second time interval may be equal, for example, to 1 or 4 seconds.
• the monitoring device analyzes the acoustic environment at each determined duration, during a fraction of it.
• the monitoring device analyzes the acoustic environment every multiple of the determined duration, during a fraction thereof. The frequency of measurement and analysis of the acoustic environment is therefore reduced, to take account of the small variations thereof, in order to further limit the electrical consumption of the monitoring device.
• control means also receives as input the successive values of the acoustic indicator (s) provided by the analysis means, and is configured to modify the second time interval and / or the fraction of the determined duration, as a function of the variation of said successive values of the acoustic indicator or indicators.
• the temporal discretization factor varies (active process) according to the environment to be measured and the acoustic indicators obtained (controlled feedback).
• the temporal discretization factor varies according to the variations of the acoustic indicators with respect to the previous measurements.
• Acoustic indicator values are then obtained that are still relevant, while having a reduced total number of acoustic measurements.
• the variation of the second time interval makes it possible to guarantee values of acoustic indicators that are representative while reducing the measurement time and the energy consumption.
• the invention provides a significant advantage over existing devices since it allows the automatic and adapted adjustment of the various parameters involved (first and / or second time interval, fraction of the determined duration, temporal discretization factor). %) depending on the intended application.
• This adjustment which takes into account all or part of the measurement history, therefore impacts not only the time of sleep and / or extinction of the device (s) according to the invention but also the s) actual measurement time (fraction of the determined duration %) for which the acoustic indicator (s) determined will be (are) representative) d a longer duration (fixed term ).
• the invention thus has an energy and metrological efficiency that is naturally superior to that which could be obtained by means of a system based on the optimization of said sleep times, and in which the measurement (s) ( s) is (are) carried out throughout the period of activity.
• the device is able to adapt on the one hand to the study of an urban environment by studying low frequencies between 100 and 5000 Hz and affecting a determined fraction "long" to listen to these low frequencies , as well as the study of acoustic emissions of industrial equipment for the prediction of upstream damage by favoring in this case the ultrasound, ie the frequencies beyond 20 000 Hz and by affecting a determined fraction "Short" filtering the low frequencies.
• the analysis means and / or possibly the acoustic transducer and / or possibly the control means are fed at least (stand-by mode, one or more standby levels being conceivable), and even more preferably are extinguished, that is to say are not powered, outside the fraction of determined duration during which the acoustic signal is measured to determine the value of the acoustic indicator (s).
• the different elements of the monitoring device are put to sleep or more preferably extinguished in order to reduce their electrical consumption, outside the periods of measurement and analysis.
• the analysis means and / or possibly the acoustic transducer and / or possibly the control means are fed at least (stand-by mode, one or more standby levels being conceivable), and even more preferably are extinguished, that is to say are not powered, outside the duration D MT required for measurement and / or sending and / or analysis (treatment, determination) the acoustic signal and / or the value of the acoustic indicator (s).
• Said duration D MT necessary for measuring and / or sending and / or analyzing the acoustic signal and / or the value of the acoustic indicator or indicators is between the duration of the fraction of determined duration F D and the duration of the second time interval I 2 : F D ⁇ D MT £ h-
• the duration D MT is between the duration of the fraction of time fixed duration F D and the determined duration D.
• the duration D MT can begin during the duration of the fraction of fixed duration F D or after.
• the acoustic indicator (s) are representative of the energy value of the acoustic signal over the determined duration, for example the weighted equivalent sound level AL Aeqis in decibel.
• the acoustic indicators are chosen according to the information sought, and can be selected from among several types of acoustic indicators, for example:
• the analysis means comprises in particular an analog / digital converter receiving as input the electrical signal supplied by the acoustic transducer, and outputting a digital signal corresponding to said electrical signal.
• the analysis means thus makes it possible, by converting the analog signal into a digital signal, to allow a more complete analysis of the signal measured by the transducer, in particular by allowing the application of different digital processes.
• the analysis means also comprises an integration means receiving as input the digital signal supplied by the analog / digital converter, and outputting the acoustic indicator (s).
• the integration means is one of the conventional data processing used to obtain acoustic indicators from a signal representative of the sound signal. The integration means can thus perform the processing numerically, within the analysis means.
• the analysis means also comprises a means for aggregating successive values of the acoustic indicator (s), to obtain values of one or more global acoustic indicators, such as: the sum, the average, the median or the value maximum of said acoustic indicators.
• the global acoustic indicators allow the monitoring device, or a global control means, to evaluate the variations of the acoustic environment, and more particularly the duration of variation thereof. This makes it possible, in particular, to adapt the frequency of measurements and analyzes carried out by the monitoring device, that is to say to adapt the temporal discretization implemented by the monitoring device, in order to optimize the energy consumption of the said device. monitoring device.
• the invention also relates to an acoustic signal monitoring system, comprising several monitoring devices as described above, for example arranged in networks, and a reception or transmission-reception means, configured to receive the values of the acoustic indicators transmitted by the communication means of said monitoring devices.
• the monitoring system makes it possible to apply the principle of monitoring devices to a wider environment, thanks to a network arrangement of several monitoring devices whose transmitted values are centralized by a single means of reception, or transmission-reception .
• the monitoring system also comprises a global control means of the monitoring devices, receiving as input the values of the acoustic indicators provided by the monitoring devices, and configured to modify, according to said values of the acoustic indicators, the second interval of time of each monitoring device and / or the fraction of the determined duration, and to provide, by means of control of the monitoring devices, the modified value of the second time interval and / or the fraction of the determined duration.
• the temporal discretization performed by each monitoring device is determined and decided centrally for all the monitoring devices, from the information they have transmitted. This decision-making and the corresponding analysis are then performed by an element that can be connected to an electrical network, which further reduces the power consumption of each monitoring device.
• the temporal discretization that is to say the choice of the second time interval and / or the fraction of determined duration, is performed locally, by each monitoring device.
• each device determines and decides by and for itself at least one parameter such as: fraction of determined duration, second time interval,
• At least one device is capable of determining and deciding, by and for itself and for at least one other device, at least one parameter such as: fraction of determined duration, second time interval.
• an analysis signal is provided with an electrical signal corresponding to the measured acoustic pressure of the acoustic signal
• the electrical signal is processed to obtain successive values of one or more acoustic indicators representative of the acoustic signal over a determined period
• the electrical signal supplied corresponds to the measured acoustic pressure of the acoustic signal during a fraction of said determined duration.
• the acoustic signal is measured, and an electrical signal is provided by means of analysis only during a fraction of said determined duration.
• step a) by means of analysis only once, at a second time interval or during a second time interval, the electrical signal corresponding to the measured acoustic pressure of the acoustic signal during a fraction of said specified period.
• we measure the signal acoustically and an electrical signal is provided by means of analysis only once at each second time interval or during each second time interval, and only during a fraction of said determined period of time.
• the method comprises a step d) during which the successive values of the acoustic indicator (s) provided in step b) are input, and the second time interval and / or the fraction of the determined duration are modified, in function of the variation of said successive values of the acoustic indicator or indicators.
• the acoustic indicator (s) are representative of the energy value of the acoustic signal over the determined duration, for example the weighted equivalent sound level AL Aeqis in decibel.
• the acoustic indicators are chosen according to the information sought, and can be selected from among several types of acoustic indicators, for example:
• step b) comprises a step b1) of analog / digital conversion of the electrical signal provided by step a), into a digital signal.
• step b) comprises a step b2) of integrating the digital signal obtained by step b1) into the acoustic indicator or indicators.
• step b) comprises a step b3) aggregating successive values of the acoustic indicator or indicators obtained in step b2), to obtain values of one or more global acoustic indicators.
• FIG. 1 schematically illustrates an acoustic monitoring system according to the invention
• FIG. 2 is a temporal representation of the various successive actions performed by the acoustic monitoring device illustrated in FIG. 1, and - Figure 3 shows an example of dispersion of Z. Aeqis over a period of day,
• FIG. 4 shows an example of dispersion of the Z. Aeqis over a period of night
• FIG. 5 shows an example of dispersion of the Z. Aeqi oo ms over a day period
• FIG. 6 shows an example of dispersion of the Z. Aeqi oo ms over a period of night
• FIG. 7 is a flowchart of an exemplary mode of implementation of the method according to the invention.
• FIG. 1 schematically illustrates a monitoring system 10 according to the present invention.
• the monitoring system 10 includes in particular several monitoring devices 1, distributed in a network, that is to say regularly, in the geographical area to be monitored, and only one of which is shown and detailed in FIG.
• the monitoring device 1 aims to continuously monitor an acoustic signal S a , while being powered independently.
• the monitoring device 1 thus comprises in particular an acoustic transducer 2, an analysis means 4, a control means 6, a communication means 8 and a power supply 12, for example a battery, an accumulator or even a solar panel or a wind turbine.
• the acoustic transducer 2 senses the acoustic signal S has to be monitored, and outputs an electric signal S E corresponding to the measured acoustic pressure of the acoustic signal S a.
• the acoustic transducer 2 may comprise one or more microphones of the MEMS type, allowing the transduction of the acoustic pressure into an electrical signal.
• the acoustic transducer 2 is also electrically powered by the power supply 12 of the monitoring device 1. Moreover, the acoustic transducer 2 and / or the analysis means 4 receives an activation signal from the control means 6.
• the activation signal makes it possible to control the acoustic transducer 2 by indicating to it when it has to measure the acoustic signal S a and to supply an electrical signal S e .
• the activation signal thus makes it possible to activate the acoustic transducer 2, which is preferably the rest of the time, in stand-by, in order to limit its electrical consumption.
• the acoustic transducer 2 is activated for only a fraction of the determined duration, for which one or more representative acoustic indicators are desired. It is through the activation signal that the acoustic transducer 2 is activated for only said duration fractions, to measure the acoustic signal and to provide an electrical signal.
• the representative acoustic indicators are determined at each monitoring device 1, that is to say for each acoustic transducer 2 (acoustic sensor) and analysis means 4.
• the monitoring device 1 also comprises the analysis means 4.
• the analysis means 4 receives as input the electrical signal Se supplied by the acoustic transducer 2, and outputs one or more acoustic indicators corresponding to the measured acoustic signal.
• the analysis means 4 can thus firstly comprise an analog / digital converter 41 receiving as input the electrical signal Se and outputting a corresponding digital signal.
• the converter 41 may also include an audio encoder, so that the analog-to-digital converter 41 is capable of quantizing the electrical signal into a 16 or 24-bit digital signal and sampled at a frequency of at least 16 kHz. This faithfully reproduces the acoustic signal while increasing the signal-to-noise ratio.
• analog / digital converter 41 can be integrated in the acoustic transducer 2, so that it directly provides a digital signal corresponding to the acoustic signal Sa measured, instead of having in the means of analysis 4.
• the analysis means 4 further comprises digital processing means for processing the digital signal corresponding to the acoustic signal.
• the analysis means 4 can comprise an integration means 42 receiving as input the digital signal and outputting the values of the acoustic indicator or indicators.
• the integration means 42 is a means for digital processing of the digital signal, and can therefore be performed by a computer program whose parameters make it possible to choose the desired acoustic indicator (s) at the output.
• the analysis means 4 can then supply the values of the acoustic indicator (s) to the communication means 8 so that it transmits them to an element collecting the values provided by the various monitoring devices 1 of the system 10.
• the analysis means 4 can provide the values at time intervals, by example at a first time interval II which may be equal to or be a multiple of a fixed duration D (see Figure 2).
• the values provided by the analysis means 4 can be transmitted in real time to the communication means 8 which transmits them together only at time intervals II.
• Such a group sending of the values obtained by the monitoring device 1 optimizes the transmission between the communication means and the collecting element of the system 10, which saves energy the rest of the time.
• the integration means 42 makes it possible to determine values of one or more acoustic indicators representative of a determined duration D (see FIG. 2), for example 1 second, from a digital signal corresponding to the measurement of the acoustic signal during a fraction F D only of said determined duration D.
• the integration means 42 is configured to provide values of acoustic indicators representative of the acoustic signal over a determined duration of 1 second, starting from a measurement of said acoustic signal during, for example, a fraction F D of 100ms.
• the characterization of certain acoustic signals over a given period of time could be obtained from a measurement of the acoustic signal for only a fraction of the said determined duration.
• the uncertainty introduced by the measurement of the acoustic signal on only a fraction of the determined duration may be less than that obtained at the end of the measured signal processing steps, so that the values obtained for the indicator or indicators Acoustics on the basis of the fraction of fixed duration remain relevant to characterize the acoustic signal over the determined duration. It is thus possible to put the acoustic transducer 2 and the analysis means 4 on standby for the remainder of the determined duration, and thus save the energy of the power supply.
• the analysis means 4 may also comprise an aggregation means 43 configured to provide values of one or more global acoustic indicators.
• the aggregation means 43 may, for example, aggregate the successive values of the acoustic indicator or indicators supplied by the integration means 42, to provide the values of a more global acoustic indicator, or may simply directly process the digital signal provided. by the analog / digital converter 41 to determine said global acoustic indicator values.
• the global acoustic indicator or indicators are intended to allow a more general analysis of the monitored acoustic signal, in particular on its short or long term temporal evolution. More precisely, such indicators are intended to make it possible to adapt the frequency of the measurements made by the monitoring device, in order to limit unnecessary and redundant measurements whose analysis would lead to unnecessary electricity consumption.
• the measurements of the acoustic signal by the acoustic transducer 2 may be further spaced to take account of a low variation of the acoustic signal over long periods, in order to further reduce the energy consumption of the monitoring device 1.
• the measurements the acoustic signal by the acoustic transducer 2 may for example be made only at a second time interval 12 (see Figure 2) longer than the determined duration D and smaller than the first time interval II.
• the first time interval II may thus be equal to the second time interval 12 or to a multiple of the second time interval 12.
• the acoustic transducer 2 no longer measures the acoustic signal during a fraction F D at all the determined durations D, but only at each second time interval 12.
• the energy consumption of the monitoring device is further reduced by limiting the phases measurement and analysis of the acoustic signal.
• the second time interval 12 may be modified, for example shortened or lengthened, and / or the fraction of the determined duration may be modified, so that the values provided by the monitoring device remain relevant.
• the values of the acoustic indicator or indicators determined by the analysis means 4 can be provided by the control means 6.
• the control means 6 makes it possible in particular to activate the acoustic transducer 2, via the activation signal, in order to indicate to him when he must measure the acoustic signal Sa.
• the control means 6 can determine the second time interval 12 from the acoustic indicators and / or global indicators, and control the acoustic transducer 2 and / or the means Analysis 4 accordingly.
• the second time interval 12 can be globally determined by the system 10 for all or only some of the monitoring devices 1, depending on the values of acoustic indicators, possibly global, which are collected by the system 10. In this case, the values of the second time interval 12 are transmitted to the communication means 8 of the monitoring devices 1 and then transmitted by these to the control means 6.
• the communication means 8 may be a wireless communication means, for example Wifi type or wireless telephony technology, such as 3G or 4G, Zigbee, 802.15.4, LoRa, 6I0WPAN.
• the communication means 8 may be connected to a wired connection, for example to an internet connection.
• the communication means 8 makes it possible to send the values obtained by the communication device 1 to a reception or remote transmission-reception means 14.
• the means of reception, or emission-reception, 14 makes it possible to recover the different values measured and calculated by the different monitoring devices, in one and the same place.
• the reception means 14 When the reception means 14 is of the transmission-reception type, it is also able to transmit the received values to a global control means 16 configured to determine a second time interval value that can be applied by all or some monitoring devices 1
• the global control means 16 makes it possible to determine the value of the second time interval centrally, in order to limit the power consumption of each monitoring device 1.
• the value of the second time interval is determined by the global control means 16, it is sent back, via the transceiver means 14, to the communication means 8 of the different monitoring devices 1, to be transmitted to the control means 6.
• the reception means 14 and the global control means 16 may be installed in a centralizer 18 for example, which will collect information from the monitoring network 1 and allow recovery of this information via the Internet for example, via a server that can also apply processing on the information collected.
• a centralizer 18 which may be equipped with: among other things, a reception means 14 and a global control means 16, or, inter alia, a transceiver means 14 and a receiver. global control means 16.
• the system 10 described above can operate as follows: at a time t, all the monitoring devices 1 of the system are waking at the same time to perform an acoustic measurement for a fraction of a fixed duration F D. The measured signal is then processed by each monitoring device 1 and then transmitted to the centralizer 18 before the monitoring devices 1 do not go back to sleep at the same time.
• the waking frequency (second time interval) of the devices 1 may vary, but it can be expected that after a day or after a preset time, the frequency returns to a initial value by default.
• Figures 3 and 4 show the results of a first discretization (which will be called "wide" discretization) over several time periods of the same audio recording.
• the audio recording is an audio recording of 24 hours.
• a first time period (for example a day period) is analyzed in Figure 3, while a second time period (for example a night period) is analyzed in Figure 4.
• the reference measurement 50, 51 represents the average of Z. Aeqis calculated over the entire period (audio recording) of 24 hours.
• each point represents the measurement of Z. Aeq averaged over a second (Z. Aeqis ) and therefore represents the "condensed" information of a sound sample of one second,
• each beam 60 to 64 of the discretizations has an amplitude of between 0.5 dB (A) and 4 dB (A),
• each beam 65 to 69 of the discretizations has an amplitude of between 4 dB (A) and 11 dB (A).
• the calculation of the standard deviation of the different points for each discretization gives a maximum of 2.5 dB.
• FIGS. 3 and 4 makes it possible to observe that it is necessary to adjust the level of discretization as a function of the time period (of the audio recording) analyzed in order to maintain a relevant level of information.
• Figures 5 and 6 show the results of the application of a second discretization (which will be called “refined” discretization) to the same audio recording and the same time periods respectively as in Figures 3 and 4.
• the first time period (for example a day period) is analyzed in Figure 5, while the second time period (for example a night period) is analyzed in Figure 6.
• the reference measurement 50, 51 always represents the average of Z. Aeqis calculated over the entire period (audio recording) of 24 hours.
• each point represents the measurement of Z.
• Aeq averaged over one hundred milliseconds eqi oo ms ) and therefore represents the "condensed" information of a sound sample of one hundred milliseconds
• each beam 70 to 74 of the discretizations has an amplitude of between 1 dB (A) and 5.1 dB (A),
• FIGS. 5 and 6 makes it possible to observe that it is necessary to adjust the level of discretization as a function of the time period (of the audio recording) analyzed in order to maintain a relevant level of information.
• the measurements corresponding to the beam 70 provide an approximation closer to the real reference level (reference measurement 50) than those corresponding to the beam 63. It is indeed noted that the measurements of the Z. Aeqi oo ms (beam 70) deviate from the reference Z. Aeqis 50 (over the entire 24 hour audio recording) by approximately 0.5dB (A), while the Z ⁇ qis measurements (beam 63) deviate by approximately 2 dB (A).
• the standard deviation values obtained are very satisfactory compared to the sensitivity of the acoustic transducer (s) used. (s) for the measurement, the influence of the measuring chain (state of the transducer, supply voltage %) and the context of the measurement (temperature, hygrometry, %), which reinforces the principle of the invention.
• FIG. 7 illustrates a flowchart of a monitoring method 100 according to the present invention.
• the monitoring method 100 comprises a first step 110 in which the analysis means 4 provides an electrical signal S e corresponding to the measured acoustic pressure of the acoustic signal.
• an electrical signal S is supplied to a means of analysis 4 only once, at a second time interval or during a second time interval. e corresponding to the measured acoustic pressure of the acoustic signal during a fraction F D of a determined duration D.
• a second step 120 the electrical signal is processed to obtain successive values of one or more acoustic indicators representative of the acoustic signal over a predetermined period.
• the second step 120 may comprise at least one substep in the following logical order:
• the second step 120 then provides (by means of communication 8) values of one or more acoustic indicators, in particular global indicators.
• a third step 130 one or more values of the acoustic indicator or indicators are transmitted to a remote wireless reception means at a first time interval.
• a fourth step 140 distinct from the third step and possibly simultaneous, the second time interval of the first step 110 and / or the fraction of the determined duration are modified as a function of the variation of said successive values of the acoustic indicators.
• This provides an acoustic monitoring method to reduce power consumption, while providing reliable acoustic indicator values.
• the acoustic system described previously allows to obtain more robust results, to be able to diagnose the source of the anomalies thanks to the richness of the acoustic information, to be able to be modulated by displacement of certain devices network, and to be low cost thanks to inexpensive sensors compared to other sensors, for example chemical.
• the described system allows detection of abnormality by acoustics, use can be used in many environments and can determine the origin of the problem.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Acoustics & Sound (AREA)
• Radar, Positioning & Navigation (AREA)
• Remote Sensing (AREA)
• Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
• Selective Calling Equipment (AREA)

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• 2017
  • 2017-11-27 FR FR1761208A patent/FR3074290B1/fr active Active
• 2018
  • 2018-11-27 WO PCT/FR2018/053003 patent/WO2019102167A1/fr not_active Ceased
  • 2018-11-27 EP EP18826766.0A patent/EP3717876A1/de not_active Withdrawn

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