Method and apparatus for processing signals to extract narrow bandwidth features
First Claim
1. A method for processing a set of input signals, including the steps of:
- generating an array of input pixels from the input signals, wherein each of the input pixels has a time coordinate and a column coordinate; and
processing the input pixels to generate a classification pixel array of classification pixels corresponding to the input pixels, wherein the classification pixels identify a first subset of the input pixels representing narrow-band energy and a second subset of the input pixels representing broad-band energy.
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Abstract
A method and apparatus for processing a set of signals to identify narrow bandwidth features of the signals, and optionally to process the signals further to extract information about the identified narrow-band features. The invention processes a set of input signal frames (a two-dimensional pixel array) to generate a narrow-band feature signal (also a two-dimensional pixel array) from which narrow-band features of the input signal frames can be efficiently, automatically, and unambiguously identified. In a class of preferred embodiments, the input signal frames are the power spectra of a set of sequentially measured signals. Thus, the set of input signal frames is a "spectrogram," comprising rows and columns of pixels (with row indices representing time, and column indices representing frequency). Alternatively, the input signal frames represent a data array of another type, such as a correlogram or a sequence of images. In a class of embodiments, the input signal frames are processed to identify narrow-band pixels (the subset of input signal frame pixels which represent narrow-band energy, or narrow-band processes). Then, the identified narrow-band pixels (which can be displayed as a narrow-band pixel array) undergo "feature extraction" processing to generate the output narrow-band feature signal (which can be displayed as the output image). The narrow-band feature signal can be further processed to determine the center frequency, bandwidth, and amplitude of one or more of its narrow-band features.
26 Citations
34 Claims
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1. A method for processing a set of input signals, including the steps of:
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generating an array of input pixels from the input signals, wherein each of the input pixels has a time coordinate and a column coordinate; and processing the input pixels to generate a classification pixel array of classification pixels corresponding to the input pixels, wherein the classification pixels identify a first subset of the input pixels representing narrow-band energy and a second subset of the input pixels representing broad-band energy. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for processing a set of input signals, including the steps of:
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generating the input signals at an acoustic receiver, in response to reception of acoustic waves; digitizing each of the input signals to generate digital data, and generating power spectra of the digital data; generating an array of input pixels from the power spectra, wherein each of the input pixels has a time coordinate and a frequency coordinate; and processing the input pixels to generate a classification pixel array of classification pixels corresponding to the input pixels, wherein the classification pixels identify a first subset of the input pixels representing narrow-band energy and a second subset of the input pixels representing broad-band energy. - View Dependent Claims (18, 19, 34)
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20. A method for processing a set of input signals, including the steps of:
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generating the input signals at at least one hydrophone, in response to reception of sonar signals; digitizing each of the input signals to generate digital data, and performing a correlation operation on the digital data to generate correlation data for each of the input signals; generating an array of input pixels from the correlation data, wherein each of the input pixels has a time coordinate and a time interval coordinate; and processing the input pixels to generate a classification pixel array of classification pixels corresponding to the input pixels, wherein the classification pixels identify a first subset of the input pixels representing narrow-band energy and a second subset of the input pixels representing broad-band energy. - View Dependent Claims (21, 22)
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23. An apparatus for processing a set of input signals, including:
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means for generating an array of input pixels from the input signals, wherein each of the input pixels has a time coordinate and a column coordinate; and means for processing the input pixels to generate a classification pixel array of classification pixels corresponding to the input pixels, wherein the classification pixels identify a first subset of the input pixels representing narrow-band energy and a second subset of the input pixels representing broad-band energy. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31)
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32. An apparatus for processing a set of input signals, including:
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an acoustic receiver for generating the input signals in response to reception of acoustic waves; means for digitizing each of the input signals to generate digital data; means for generating power spectra of the digital data; means for generating an array of input pixels from the power spectra, wherein each of the input pixels has a time coordinate and a frequency coordinate; and means for processing the input pixels to generate a classification pixel array of classification pixels corresponding to the input pixels, wherein the classification pixels identify a first subset of the input pixels representing narrow-band energy and a second subset of the input pixels representing broad-band energy.
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33. An apparatus for processing a set of input signals, including:
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a set of one or more acoustic receivers for generating the input signals response to reception of acoustic waves; means for digitizing each of the input signals to generate digital data; means for performing a correlation operation on the digital data to generate correlation data for each of the input signals; means for generating an array of input pixels from the correlation data, wherein each of the input pixels has a time coordinate and a time interval coordinate; and means for processing the input pixels to generate a classification pixel array of classification pixels corresponding to the input pixels, wherein the classification pixels identify a first subset of the input pixels representing narrow-band energy and a second subset of the input pixels representing broad-band energy.
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Specification