Device for localizing acoustic sources and measuring their intensities
View Patent ↗The invention relates to a device for localizing acoustic sources and measuring their intensity comprising an antenna having at least two sub-antennas, each sub-antenna having at least two branches disposed in a cross or star shape, each branch being equipped with a plurality of microphones, and a system for processing the signals coming from the microphones, the device being designed to establish, for a frequency higher than a given value f c , an acoustic source hologram, i.e. a distribution of acoustic pressures or intensities at different computation points on a given surface.
1. A device for localizing acoustic sources and measuring their intensities, comprising:
an antenna having at least two sub-antennas, each sub-antenna having at least two branches disposed in a cross shape or star shape, each branch being equipped with a plurality of microphones, and
a signal processing unit that processes signals coming from the plurality of microphones; to establish, for a frequency higher than a given value f c , an acoustic source hologram, the acoustic source hologram representing a distribution of acoustic pressures or intensities at different computation points on a given surface, the signal processing unit including;
a calculation unit that calculates, for each computation point in the hologram, a sum of acoustic pressures measured by the plurality of microphones in a given sub-antenna, and taking into account a lag in acoustic pressures corresponding to a travel time between the calculation point and the plurality of microphones, multiplying the pressure values obtained by adding the acoustic pressures measured by the microphones of the various sub-antennas for each calculation point of the hologram.
2. The device according to claim 1 , wherein the sub-antennas are disposed in parallel planes and are offset angularly.
3. The device according to claim 1 , wherein the signal processing unit establishes an acoustic source hologram, for a frequency less than the value determined f c , the calculation unit calculating, for each computation point of the hologram, the sum of the acoustic pressures measured by the antenna microphones, taking the lag in acoustic pressures into account.
4. The device according to claim 1 , wherein the frequency value determined f c is equal to (c×D)/(p×l) where c is the speed of sound, D is the distance between the object and the antenna, p is the distance between two microphones, and 1 is the length of the object to be analyzed.
5. The device according to claim 1 , wherein the branches of a given sub-antenna have a regular angular distribution and that the sub-antennas are offset by an angle corresponding to a fraction of the angle between two branches.
6. The device according to claim 1 , wherein the sub-antennas are offset by an angle corresponding to half the angle between two branches.
7. The device according to claim 1 , wherein the signal processing unit is designed to process signals emitted by moving sources.
8. The device according to claim 1 , wherein the branches of the sub-antennas are straight.
9. The device according to claim 1 , wherein each branch has 7 to 30 microphones.
10. The device according to claim 1 , wherein each branch is between 1 m and 20 m long.
11. The device according to claim 1 , wherein the microphones are regularly distributed.
12. The device according to claim 1 , wherein the microphones are identical.