Sparse reduced (spare) filter
First Claim
1. A method for selecting a subset of hyperspectral imaging scene spectral covariance matrix principal components to detect a material of interest or specific target in a scene, the method comprising:
- in a filtering engine provided with a set of whitened principal component coefficients of a spectral reference vector, the spectral reference vector representative of a material of interest or specific target;
computing a signal-to-clutter ratio (SCR) of the spectral reference vector based on the set of whitened principal component coefficients of the spectral reference vector;
ranking the contribution of each whitened principal component coefficient to the total SCR;
selecting, based on the ranking, a subset of whitened principal component coefficients from the set of whitened principal component coefficients of the spectral reference vector;
for each of a plurality of scene pixels in the scene, computing a sparse detection filter score for a subject scene pixel based on the selected subset of whitened principal component coefficients of the spectral reference vector and a respective subset of whitened principal component coefficients of the subject scene pixel having the same indices; and
determining, based on the sparse detection filter score, whether the material of interest or specific target is present in the subject scene pixel.
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Abstract
The disclosure provides a filtering engine for selecting sparse filter components used to detect a material of interest (or specific target) in a hyperspectral imaging scene and applying the sparse filter to a plurality of pixels in the scene. The filtering engine transforms a spectral reference representing the material of interest to principal components space using the eigenvectors of the scene. It then ranks sparse filter components based on each transformed component of the spectral reference. The filtering engine selects sparse filter components based on their ranks. The filtering engine performs the subset selection quickly because the computations are minimized; it processes only the spectral reference vector and covariance matrix of the scene to do the subset selection rather than process a plurality of pixels in the scene, as is typically done. The spectral filter scores for the plurality of pixels are calculated efficiently using the sparse filter.
9 Citations
13 Claims
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1. A method for selecting a subset of hyperspectral imaging scene spectral covariance matrix principal components to detect a material of interest or specific target in a scene, the method comprising:
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in a filtering engine provided with a set of whitened principal component coefficients of a spectral reference vector, the spectral reference vector representative of a material of interest or specific target; computing a signal-to-clutter ratio (SCR) of the spectral reference vector based on the set of whitened principal component coefficients of the spectral reference vector; ranking the contribution of each whitened principal component coefficient to the total SCR; selecting, based on the ranking, a subset of whitened principal component coefficients from the set of whitened principal component coefficients of the spectral reference vector; for each of a plurality of scene pixels in the scene, computing a sparse detection filter score for a subject scene pixel based on the selected subset of whitened principal component coefficients of the spectral reference vector and a respective subset of whitened principal component coefficients of the subject scene pixel having the same indices; and determining, based on the sparse detection filter score, whether the material of interest or specific target is present in the subject scene pixel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A system for selecting a subset of hyperspectral imaging scene spectral covariance matrix principal components to detect a material of interest or specific target in a scene, the system comprising:
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a memory having computer executable instructions thereupon; at least one interface receiving a set of whitened principal component coefficients of a spectral reference vector, the spectral reference vector representative of a material of interest or specific target; a filtering engine coupled to the memory and the at least one interface, the computer executable instructions when executed by the filtering engine cause the filtering engine to; compute a signal-to-clutter ratio (SCR) of the spectral reference vector based on the set of whitened principal component coefficients of the spectral reference vector; rank the contribution of each whitened principal component coefficient to the total SCR; select, based on rank, a subset of whitened principal component coefficients from the set of whitened principal component coefficients of the spectral reference vector; and for each of a plurality of scene pixels in the scene, compute a sparse detection filter score for a subject scene pixel based on the selected subset of whitened principal component coefficients of the spectral reference vector and a respective subset of whitened principal component coefficients of the subject scene pixel having the same indices; and determine, based on the sparse detection filter score, whether the material of interest or specific target is present in the subject scene pixel.
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13. A tangible non-transitory computer-readable storage medium having computer readable instructions stored therein for selecting a subset of hyperspectral imaging scene spectral covariance matrix principal components to detect a material of interest or specific target in a scene, which when executed by one or more processors provided with a set of whitened principal component coefficients of a spectral reference vector, the spectral reference vector representative of a material of interest or specific target:
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compute a signal-to-clutter ratio (SCR) of the spectral reference vector based on the set of whitened principal component coefficients of the spectral reference vector; rank the contribution of each whitened principal component coefficient to the total SCR; select, based on rank, a subset of whitened principal component coefficients from the set of whitened principal component coefficients of the spectral reference vector; and for each of a plurality of scene pixels in the scene, compute a sparse detection filter score for a subject scene pixel based on the selected subset of whitened principal component coefficients of the spectral reference vector and a respective subset of whitened principal component coefficients of the subject scene pixel having the same indices; and determine, based on the sparse detection filter score, whether the material of interest or specific target is present in the subject scene pixel.
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Specification