Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S3/00—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received
  • G01S3/80—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received using ultrasonic, sonic or infrasonic waves
  • G01S3/802—Systems for determining direction or deviation from predetermined direction
  • G01S3/808—Systems for determining direction or deviation from predetermined direction using transducers spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems
  • G01S3/8083—Systems for determining direction or deviation from predetermined direction using transducers spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems determining direction of source
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
  • G01S5/18—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using ultrasonic, sonic, or infrasonic waves
  • G01S5/22—Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements

Definitions

• the present invention relates to the field of monitoring and localization of sound sources and more particularly of noise pollution.
• Transport-related noise nuisances particularly those affecting people living near the traffic lanes, are a major concern, most often associated with urban and peri-urban contexts.
• the diagnosis or the prediction of a sound environment requires a knowledge of the emission of vehicles, in real traffic conditions.
• the noise suffered is a source of stress and deterioration of health causing numerous complaints from residents in urban or industrial areas, whose objectivity and relevance should be verified.
• noise maps are also a source of pollution indices or environmental health problems.
• the measurement is made by a sound level meter intended to measure the sound pressure level and to provide a level expressed in decibels at a given point and at a given time.
• the microphones network is an acoustic antenna for locating and identifying noisy sources in near or far-field, or locating buried objects, monitoring acoustic emission structures, acoustic avalanche detection, detection seismic and underwater location.
• the measurement microphones consist for example of four omnidirectional capsules placed at the same distance from each other, forming a pyramidal structure. This geometrical configuration is at the base of the triangulation technique which makes it possible to locate each source very precisely, both on the horizontal plane and on the vertical plane.
• Each of the four capsules is attached to the end of thin tubes, for example brass to avoid diffraction. They form a tetrahedron constituting a geometrical configuration adapted to identify at the same time the distance, the azimuth and the elevation.
• all the responses of the capsules are recursively analyzed and compared in order to find the best torque and reach a spatial resolution under +/- 2 ° in all directions.
• acoustic wave acquisition means comprising a plurality of elementary sensors distributed in space, and each delivering a measurement signal; and processing means by the application, to said measurement signals, of filtering combinations representative of structural characteristics of said acquisition means for delivering a plurality of acoustic signals each associated with a predetermined general restitution direction with respect to a given point space, all of said acoustic signals forming a representation of said acoustic field.
• the elementary sensors are spatially distributed in a substantially non-regular manner and in that said filtering combinations are representative of this distribution.
• the monitoring stations comprising a sound level measuring device, a calculation unit and a communication unit;
• European Patent EP 1108994 discloses a method and a device for simultaneously estimating the respective directions of a plurality of sound sources and for detecting the individual sound levels of the respective moving sound sources.
• a waveform extraction means for influencing the respective microphone output signals produced from a network of M microphones, where M is an integer greater than one, in order to extract from each said microphone output signals, a microphone signal portion during each respective time window, and thereby obtaining successive sets of M parts of microphone signals, said sets corresponding to respective ones of said time windows, frequency analyzer means for applying a frequency analysis to each of said sets of microphone signal portions to separate each said microphone signal portion into a plurality of components corresponding to respectively different frequencies of a fixed set of frequencies, and
• processing means for acting on said components corresponding to each said set of signal portions of M microphones so as to obtain, for each frequency of said fixed set of frequencies, and data expressing an estimated direction of said sound source with respect to a position in said microphone array,
• European Patent EP 1273927 describes an environmental noise monitoring method which comprises the following steps:
• European Patent EP 1811346 discloses a device for locating acoustic sources and measuring their intensity, comprising
• an antenna comprising at least two sub-antennas each sub-antenna comprising at least two branches arranged in a cross or in a star, each branch being equipped with a plurality of microphones, and
• This device of the prior art is arranged to establish, for a frequency greater than a determined value fc, a hologram of the acoustic sources, that is to say a distribution of the acoustic pressures or intensities in different calculation points of the same surface, by performing, for each calculation point of the hologram, the sum of the acoustic pressures measured by the microphones of the same sub-antenna taking into account the delay of the acoustic pressures corresponding to the time of the path between the calculation point and a microphone, the device being characterized in that for each calculation point of the hologram, the pressure values obtained by adding the acoustic pressures measured by the microphones of the different sub-antennas are multiplied between they.
• Some of the solutions propose to build a sound card at first, to allow a later exploitation, for example to note a posteriori a sound source whose sound intensity exceeds a threshold value.
• the present invention relates to a signaling system for exceeding a sound intensity threshold of a source comprising an acoustic antenna, at least one image sensor and an electronic circuit performing a location processing. at least one sound source from the signals delivered by said acoustic antenna, characterized in that said circuit controls the orientation and / or the triggering of the timestamped recording of the images provided by the sound sensor.
• the system comprises one or more additional technical characteristics, taken alone or in combination:
• said acoustic antenna is constituted by a group of microphones forming a tetrahedron
• the system includes a camera separated from the group of microphones
• said group of microphones and said camera are mounted on a mobile platform, the movement of which is controlled by the coordinates of a sound source determined by the processing of digitized acoustic signals
• said group of microphones and said camera are mounted on a mobile platform, the movement of which is controlled by the coordinates of a sound source determined by the processing of digitized acoustic signals
• said digitized acoustic signals are processed to eliminate unwanted noise such as engine noises or air noise
• said sound antenna consists of four microphones forming a tetrahedron, and an electrical signal processing circuit for calculating information representative of the direction of the sound source with respect to said antenna, said acoustic antenna further comprising at least one means of imaging whose optical axis coincides with the geometric center of said antenna
• the system comprises means for controlling the recording of a sequence of time-stamped digital data series comprising, for each series, a digital datum of time stamp, data corresponding to the sound intensity measured by said acoustic antenna, the angular position of the sound source, and the image acquired by the imaging means.
• the system comprises a telecommunication means for the transmission of said data sequences after the output of a sound source of intensity greater than the threshold value of the detection field.
• the invention also relates to a signaling system for exceeding a sound intensity threshold of a source according to the preceding claim, characterized in that it comprises a telecommunication means for the transmission of said data sequences after the output of a sound source of intensity greater than the threshold value of the detection field.
• FIG. 1 represents a schematic view of a system according to the invention
• FIG. 2 represents a perspective view of a sound antenna according to the invention
• FIG. 3 represents a perspective view of a microphone support
• FIGS. 4 and 5 show perspective views of three quarter front and three quarter rear of the microphone cover
• FIG. 6 represents a schematic view of a display screen
• FIG. 7 shows the block diagram of an electronic circuit for the implementation of the invention.
• the sound nuisance localization system consists of a sound antenna (100) formed by a group of microphones (110, 120, 130, 140) forming a tetrahedron.
• the microphone support (110, 120, 130, 140) includes a camera (200) disposed at the geometric center of the aforementioned tetrahedron.
• the sound signals picked up by the group of microphones (110, 120, 130, 140) are digitized and processed by an electronic circuit to determine the coordinates of the origin of the detected sound events.
• a processing controls the orientation of the camera (200) in a direction calculated according to the trajectory of the identified sound source and the recording of a video sequence correlated to the sound recording.
• the trajectory of the source is calculated according to the evolution of the coordinates of the source of the most intense sound event on the one hand, and a prerecorded model of the possible trajectories.
• the initial orientation is determined according to the point of entry of the sound source in the monitored area, and then controlled according to the evolution of the coordinates of the sound source.
• the camera (200) disposed at the center of the group of microphones (110, 120, 130, 140) can be supplemented by an additional camera (300) fixed or adjustable, for recording a video sequence of the monitored area, correlated with the sound recording.
• the detection of an exceeding of the sound intensity threshold controls the activation of a light source (680) illuminating the monitored area.
• the antenna according to the exemplary embodiment described is constituted by a rigid core (1) formed by a metal sphere having a coupling sleeve (2) for connection to a support rod (3).
• This rigid core (1) is extended by four arms (10, 20, 30, 40) directed downwards, defining a tetrahedron where four vertices carry a microphone supported by a support respectively (11, 21, 31, 41).
• the central arm (40) is directed downward in a substantially vertical direction.
• the other three arms (10, 20, 30) are also directed downwards and form with the vertical axis an angle of about 109 °.
• the central arm (40) has a plate (45) for mounting an optical sensor (46).
• the position of the optical center of the optical sensor (46) coincides with the geometric center of the tetrahedron.
• Each sound capture head is constituted by a support (11, 21, 31, 41) in which is housed a microphone MEMS (acronym for "Micro Electro Mechanical System”).
• MEMS Micro Electro Mechanical System
• Each sound capture head is constituted by a MEMS microphone housed in a polyimide (imide-based polymer) assembly, for example Kapton (trade name) formed by a support (11, 21, 31, 41) and a cap (12, 22, 32,
• the rigidity and manufacturing accuracy of MEMS membranes significantly reduce the distance between the membrane and the backplate; the microphone can thus operate with a very efficient 10 volt load, maintained by a single charge pump instead of the high capacity electret material.
• the MEMS microphone is in the form of a parallelepiped shaped component.
• the microphone holder (11, 21, 31, 41) is made by molding a polymer, preferably Kapton (trade name), to form a part having a parallelepiped base (50), of square section, of which distal end has a housing (51) complementary section to the cross section of the microphone.
• a polymer preferably Kapton (trade name)
• the microphone holder (11, 21, 31, 41) also includes an annular skirt (53) extended by a proximal connector (54) for connection to an arm (10, 20, 30, 40).
• the skirt (53) has a frustoconical shape, with, at its distal end, an inner section greater than the outer section of the base (50).
• the base (50) extends forward of the skirt (53).
• a rib (54) is provided to allow passage of the MEMS microphone lead wires.
• Figures 3 and 4 show views of the cap (21, 22, 32, 42). It has a general shape cylindrical flare, with a distal section greater than the proximal section.
• the front portion (60) has a frustoconical longitudinal channel (61) of circular section opening into a hole (62) corresponding to the microphone vent.
• the rear portion (63) has a longitudinal square section channel (64) complementary to the outer section of the base (50) of the microphone holder.
• the cap is slid on the base (50) after positioning the microphone, to form an assembly protecting the microphone from the weather and allowing a connection with the rod (10, 20, 30, 40).
• the operation of the signals delivered by the four microphones is carried out in a known manner.
• the processing is based on the estimation of the time offsets between the sound signals received by pairs of microphones (TDOA, for “Time Difference Of Arrival", that is to say “time difference of 'arrival'). These estimates are used, together with the knowledge of microphone positions, to compute hyperbolic curves whose intersection gives the position of the source.
• Time offsets can notably be estimated by the so-called PHAT-GCC ("PHAse Transform - Generalized Cross-Correlation”) method, which exploits the calculation of an intercorrelation - or cross-correlation - between previously "bleached” signals by filtering.
• PHAT-GCC PHAse Transform - Generalized Cross-Correlation
• the treatment can also combine the synthesis of an orientable acoustic beam and the generalized cross-correlation with phase transformation. This method is called SRP-PHAT (for "Steered Response Power - PHAse Transform” or “Directed Response Power - Phase Transformation”).
• the information resulting from the analysis of the signals generated by the sound antenna is represented in the form of graphic objects superimposed on the image acquired by the optical sensor (46), for example in the form of an animated sequence or a fixed card. of accumulation of sound intensities.
• the graphical representation comprises the image (510) captured by the camera (200, 300), on which is superimposed a graphic symbol (500) whose position relative to the image (510) is determined by the calculation of direction of the sound source.
• This representation is completed by a sound level display (520), and optionally additional information such as the time stamp of the sequence.
• the graphic objects (500) are, for example, geometric zones superimposed on the image, whose color is calculated as a function of the instantaneous or cumulative intensity, and the size is representative of the spatial spread of the sound source.
• the signals transmitted by the microphones are digitized to allow the execution of a computer program for calculating PHAT-GCC time offsets.
• This treatment provides the angle between a reference axis passing through the geometric center of the four microphones and the source or sources, as well as the measured loudness of each of these sources.
• the data delivered by the signal processing circuit generated by the microphones are stored in a permanent memory or buffer in the form of packets whose frame includes for each identified source:
• a particular variant embodiment relates to a mobile platform, for example an airship
• the processing circuit has inputs (610 to 613) for receiving the electrical signals from the microphones (110, 120, 130, 140). These signals are pretreated by a card (620), pre-amplifying, digitizing and filtering each of the signals. The signals thus pretreated are exploited by a calculator (630) calculating:
• a circuit (640) performs event detection processing from the data provided by the calculator (630) by a logical combination of criteria relating to these data, or possibly a neural network.
• the detection of an event also triggers an action such as the video recording of the images provided by the sensors (200, 300), the data coming from the computer (630) and the qualification of the events as well as the date and time. , and optionally the recording of the sound files, by a recorder (660).
• the circuit further comprises a predictive model (650) estimating the evolution of the position of the source to optimize the capture of a fixed reference image, for example an image of the license plate by one of the cameras ( 200, 300), possibly associated with a light source (670).
• a predictive model 650 estimating the evolution of the position of the source to optimize the capture of a fixed reference image, for example an image of the license plate by one of the cameras ( 200, 300), possibly associated with a light source (670).
• the system can also be supplemented by a speedometer for determining the speed of the mobile source support, for example by a Doppler radar or by telemetry of the reflected wave train coupled to a measurement of time.
• a speedometer for determining the speed of the mobile source support, for example by a Doppler radar or by telemetry of the reflected wave train coupled to a measurement of time.
• the system controls the orientation of a camera and / or the triggering of an alarm based on the detection of abnormal noise, to a central monitoring.

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• General Physics & Mathematics (AREA)
• Radar, Positioning & Navigation (AREA)
• Remote Sensing (AREA)
• Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)

Applications Claiming Priority (2)

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• 2018
  • 2018-02-13 FR FR1851193A patent/FR3077886B1/fr active Active
• 2019
  • 2019-02-08 WO PCT/FR2019/050279 patent/WO2019158839A1/fr unknown
  • 2019-02-08 EP EP19710042.3A patent/EP3752849A1/de active Pending

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