Abstract:
The present invention relates to a system for localizing at least one sound source, comprising a set of spatially spaced apart sound sensors to detect sound from the at least one sound source and produce corresponding sound signals, and a frequency-domain beamformer responsive to the sound signals from the sound sensors and steered in a range of directions to localize, in a single step, the at least one sound source. The present invention is also concerned with a system for tracking a plurality of sound sources, comprising a set of spatially spaced apart sound sensors to detect sound from the sound sources and produce corresponding sound signals, and a sound source particle filtering tracker responsive to the sound signals from the sound sensors for simultaneously tracking the plurality of sound sources. The invention still further relates to a system for localizing and tracking a plurality of sound sources, comprising a set of spatially spaced apart sound sensors to detect sound from the sound sources and produce corresponding sound signals; a sound source detector responsive to the sound signals from the sound sensors and steered in a range of directions to localize the sound sources, and a particle filtering tracker connected to the sound source detector for simultaneously tracking the plurality of sound sources.
Abstract:
Apparatus and a corresponding method for processing speech signals in a noisy reverberant environment, such as an automobile. An array of microphones (10) receives speech signals from a relatively fixed source (12) and noise signals from multiple sources (32) reverberated over multiple paths. One of the microphones is designated a reference microphone and the processing system includes adaptive frequency impulse response (FIR) filters (24) enabled by speech detection circuitry (21) and coupled to the other microphones to align their output signals with the reference microphone output signal. The filtered signals are then combined in a summation circuit (18). Signal components derived from the speech signal combine coherently in the summation circuit, while noise signal components combine incoherently, resulting in composite output signal with an improved signal-to-noise ratio. The composite output signal is further processed in a speech conditioning circuit (20) to reduce the effects of reverberation.
Abstract:
In order to record and to process audio signals with a good useful-signal to noise-signal ratio in acoustic noise conditions and with a good ratio between the direct sound and the reflected sound in an environment which in particular has no reverberation electrical signals produced by conversion of audio signals recorded by a predetermined microphone arrangement are processed in such a manner that, if the sound pressure levels at the microphones in the microphone arrangement are the same, electrical signals which are produced by these microphones but are of different intensity—different sensitivities of the microphones—are automatically matched, without any manual matching procedures needed to be carried out individually and separately. A microphone arrangement is based on combining the characteristics of an array of microphones with those of a method for matching the sensitivity of microphones.
Abstract:
Determining a time delay between a first signal received at a first sensor and a second signal received at a second sensor is described. The first signal is analyzed to derive a plurality of first signal channels at different frequencies and the second signal is analyzed to derive a plurality of second signal channels at different frequencies. A first feature detected that occurs at a first time in one of the first signal channels. A second feature is detected that occurs at a second time in one of the second signal channels. The first feature is matched with the second feature and the first time is compared to the second time to determine the time delay.
Abstract:
The present invention relates to a receiving system for a multi-sensor antenna and comprising: at least one set of channel filters (310i, 710k; inull1 . . . N) filtering the signals Xi(t, f) received by the different antenna sensors, where these signals may include a desired signal (Si(t, f)); a summer (350, 720) summing the filtered signals nullVi(t, f)null, where inull1 . . . N, by means of the channel filters and emitting an antenna output signal Y(t,f), at least one calculating module (320, 720) receiving either the sensor signals and aligning them in phase or the signals filtered by the channel filters, said module estimating the transfer function V(t, f), W k(t, f)) of an optimum filter in a manner to minimize the square difference between the antenna output signals filtered by said filter and the desired signal characterized in that it furthermore comprises at least one statistical analysis module (330, 730) operating on the frequency values of the transfer function.
Abstract:
An apparatus and method for processing sound, suitable for use in association with a hearing aid, cochlear implant prosthesis or the like. Coupled to an array of microphones (1) are a pair of fixed array processors (2,4) each having different characteristic signal-to-noise performances and internal noise parameters in different levels of ambient noise. Based upon an ambient noise estimate derived from noise floor detector (8) a control circuit (5) controls the gain of a pair of VCA's (7,9) coupled to the fixed array processors (2,4) in order to produce an output signal from summer (16) which maximises the signal-to-noise ratio of a signal emanating from a source in an on-beam direction relative to the microphone array (10).
Abstract:
A directional microphone system is disclosed, which comprises circuitry for low pass filtering a first order signal, and circuitry for high pass filtering a second order signal. The system further comprises circuitry for summing the low pass filtered first order signal and the high pass filtered second order signal. A method of determining whether a plurality of microphones have sufficiently matched frequency response characteristics to be used in a multi-order directional microphone array is also disclosed. For a microphone array having at least three microphones, wherein one of the microphones is disposed between the other of the microphones, a method of determining the arrangement of the microphones in the array is also disclosed.
Abstract:
Determining a time delay between a first signal received at a first sensor and a second signal received at a second sensor is described. The first signal is analyzed to derive a plurality of first signal channels at different frequencies and the second signal is analyzed to derive a plurality of second signal channels at different frequencies. A first feature detected that occurs at a first time in one of the first signal channels. A second feature is detected that occurs at a second time in one of the second signal channels. The first feature is matched with the second feature and the first time is compared to the second time to determine the time delay.
Abstract:
A sound reinforcement system (1) comprises at least one microphone (2), adaptive echo compensation (EC) means (4) coupled to said microphone (2) for generating a microphone signal, and one or more loudspeakers (3) coupled to the EC means (4). In addition it comprises a dynamic echo suppressor (DES 7) coupled between the adaptive EC means (4) and said at least one loudspeaker (3) for suppressing remaining echoes by using a time delay between the amplitudes of a microphones signal frequency component and the same remaining echo frequency component. Echo emanating from a room wherein the listener resides is effectively removed, and even a fine tuned model can effectively be made in cases wherein the speaker(s) move. The sound reinforcement system (1), which may be a hands-free system is embodied as a public address system, a congress system, a conferencing system, or a communication system such as a passenger communication system for a vehicle such as a car, aeroplane or the like.
Abstract:
A pickup section 11 transduces sounds to audio signals. A zoom control section 12 outputs a zoom position signal corresponding to a zoom position. A directivity control section 13 alters the directivity characteristics under telescopic operation so as to mainly pickup sounds coming from a frontal direction with an enhancement which is in accordance with the zoom position signal, thereby outputting an R channel audio signal and an L channel audio signal. In accordance with the zoom position signal, a noise suppression section 14 applies a greater degree of suppression to the background noise contained in the respective channel audio signals under telescopic operation than under wide-angle operation. As a result, a target sound from a remote location can be picked up with a sufficient enhancement in accordance with the zoom position under telescopic operation.