Sound source location and quantification using arrays of vector probes

Abstract

Method and apparatus for locating and quantifying sound sources using an array of acoustic vector probes (200). Signals received at the probes are converted to digital form and fed into a digital signal processor (400) which computes the sound pressure and the sound-intensity vector at each probe. The set of sound-intensity vectors measured by the array provides a set of directions to a sound source (100) whose approximate spatial coordinates are determined using a least-squares triangulation formula. The sound-intensity vectors also determine sound-power flow from the source. In addition sound pressure measured by the probes can be phased to form a sensitivity beam (250) for scanning a source. Sound-intensity measurements made concurrently can be used to determine the spatial coordinates of the part being scanned and the sound power radiated by that part. Results are displayed on a computer screen or other device (500) permitting an operator to interact with and control the apparatus. Additional related features and methods are disclosed.

Description

[0001] THIS APPLICATION IS A CONTINUATION-IN-PART OF U.S. PATENT APPLICATION ENTITLED “ACOUSTIC MEASUREMENT METHOD AND APPARATUS” Ser. No. 10 / 396,541, FILED 2003, MAR. 25, AND ALSO OF A CONTINUATION—IN-PART ENTITLED “METHOD AND APPARATUS FOR ACOUSTIC DETECTION OF BURIED OBJECTS” Ser. No. 10 / 658,076, FILED 2003 SEPT. 9, BOTH SUBMITTED BY ROBERT HICKLING, THE PRESENT INVENTOR.TECHNICAL FIELD [0002] The invention relates to methods and means of remotely locating and quantifying sound sources, using arrays of recently-developed acoustic vector probes (AVPs). BACKGROUND OF THE INVENTION Acoustic Vector Probes [0003] Recently a patent application was filed for a new acoustic instrument, the acoustic vector probe (AVP). [0004] 1. R. Hickling 2003, “Acoustic Measurement Method and Apparatus”, Patent Application to the United States Patent and Trademark Office, Ser. No. 10 / 396,541, Filing Date Mar. 25, 2003. The technical information contained in this application is hereby incorporated her...

AI Technical Summary

Benefits of technology

[0031] The present invention includes and utilizes arrays of acoustic vector probes (AVPs) with the object of remotely locating and quantifying sound sources. AVPs are small, rugged and inexpensive and can easily be formed into an array.

[0034] There is an important case when an array surrounds a source either totally or combined with rigid surfaces. Integration over the array of the component of the intensity vector perpendicular to the array then determines the sound power of the source. Previously two-microphone probes were used for this purpose. However such probes are cumbersome and expensive and it is difficult to use a sufficient number of them to make simultaneous measurements at all points in the surrounding array. AVPs, on the other hand, are more compact and less expensive and can make the required simultaneous measurements. This speeds up the sound power measurement, and also makes it possible to investigate the sound power of a non-steady source. It also makes it possible to measure the sound power of a source in a noisy environment, provided the background noise is not overwhelming compared to that of the source. In addition, the techniques of this invention can be used to investigate the characteristics of the source. These improvements make it possible to use an array of AVPs for quality control in manufacturing.

[0037] AVPs simultaneously measure the three fundamental quantities of acoustics, namely intensity, velocity and pressure. Using these quantities as input for computational methods of source location and quantification will improve the accuracy of these methods and save time and effort by avoiding having to make measurements with parallel arrays of individual microphones.

Problems solved by technology

Elementary thinking would position the source where the directions intersect However because of experimental error and the finite size of the source the directions determined by AVPs generally do not intersect.

However such probes are cumbersome and expensive and it is difficult to use a sufficient number of them to make simultaneous measurements at all points in the surrounding array.

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