Data processing: measuring – calibrating – or testing – Measurement system – Measured signal processing
Patent
1998-07-08
1999-08-24
Barlow, John
Data processing: measuring, calibrating, or testing
Measurement system
Measured signal processing
702190, 702195, 702103, 73 182, 73612, H04R 1904
Patent
active
059436417
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to the extraction of a useful acoustic signal from a composite acoustic signal comprising nuisance components.
It finds an application in the processing of a composite acoustic signal comprising a useful acoustic signal, for example the voice which it is desired to record, and nuisance components originating from some source of noise (noise from a machine or vehicle, etc.), the said nuisance components being capable of disturbing the recording of the voice.
DESCRIPTION OF RELATED ART
It is already known to cancel nuisance components contained in a composite acoustic signal.
For example, the Patent GB-A-2273359 describes a device for processing a useful acoustic signal so as to relieve if of its nuisance component. Two geophones pick up the same composite signal consisting of a useful signal and of its nuisance components. A delay which depends on the nature of the useful signal and on the distance between the two sensors is imparted to one of the signals thus picked up and the signals, are next subtracted in order to extract the useful signal relieved of its nuisance components.
Such a device is complicated and of limited use on account of the delay to be imparted to the propagation of the signals, geometric constraints related to the siting of the sensors and filtering limitations related to the nature of the useful signal to be processed.
It is also known to use characteristics relating to the nuisance components to be canceled (spectral density and bandwidth for example), as well as to the useful acoustic signal to be processed (periodicity and distribution).
However, access to all these characteristics is expensive and difficult to set in place, and may sometimes even be impossible when the nuisance noise is random, liable to vary over time, in terms of level and frequency, and/or stretches over a wide band of frequencies and when, additionally, there is no a priori knowledge regarding the characteristics of the useful acoustic signal.
SUMMARY OF THE INVENTION
The present invention provides a solution to precisely this problem.
It aims to provide an extractor of a useful acoustic signal from a composite acoustic signal comprising nuisance components, which may be of any type, even random and broadband, and which are liable to disturb the processing of the useful acoustic signal in respect of which no a priori knowledge is available.
It pertains to the device for extracting a useful acoustic signal from a composite acoustic signal comprising nuisance components, including: able to pick up the composite acoustic signal, according to a predetermined geometric relationship with the first location, and are able to pick up, in real time, a reference acoustic signal which is substantially correlated with the nuisance components of the composite acoustic signal and is capable of propagating from the said second location to the said first location, the second sensor means, a second input and an output, and a second input linked to the output of the adaptive filtering means, and an output linked to the second input of the adaptive filtering means.
According to a general definition of the invention, the second location is chosen so that the reference acoustic signal contains no information related to the useful signal and the filtering means are able to minimize the energy of the composite acoustic signal as a function of the energy of the reference acoustic signal, by adapting at least some of the filtering coefficients in real time, until the signal leaving the output of the extraction means corresponds substantially to the useful acoustic signal selectively rid of the nuisance components.
The subject of the invention is also a process for extracting a useful acoustic signal relieved of its nuisance components, implemented by the abovementioned extraction devica, in which the process comprises the following steps: location and are able to pick up the composite acoustic signal, chosen according to a predetermined geometric relationship with the first lo
REFERENCES:
patent: 4433435 (1984-02-01), David
patent: 4630304 (1986-12-01), Borth et al.
patent: 5040156 (1991-08-01), Foller
patent: 5402669 (1995-04-01), Pla et al.
patent: 5463893 (1995-11-01), Pla et al.
patent: 5471195 (1995-11-01), Rickman
patent: 5479813 (1996-01-01), Pla et al.
Carme Christian E.
Roure Alain R.
Barlow John
Bui Bryan
Technofirst
LandOfFree
Method and device for recovering a wanted acoustic signal from a does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and device for recovering a wanted acoustic signal from a, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and device for recovering a wanted acoustic signal from a will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-476672