Linear phase FIR biorthogonal wavelet filters with complementarity for image noise reduction
AssigneeAvago Technolgies General IP (Singapore) Pte. Ltd.
InventorDiego Pinto DeGarrido
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Abstract
In described embodiments, Linear Phase, Finite Impulse Response, filters incorporate a power complementarity property into a perfect reconstruction filter bank. Non-linear constraints for type A and type B filters are included in the Sequential Quadratic Programming design of the filters. An initial Quadrature Mirror Filter includes perfect reconstruction constraints, which might be optimized through iterative design techniques. Embodiments might be employed in noise reduction applications related to, for example, signal processing of images.
Claims20
Apparatus for filtering a signal with a bi-orthogonal wavelet filter bank, the apparatus comprising:
- a decomposition bank configured to decompose a signal into high-pass and low-pass signal components using corresponding high-pass and low-pass filter decomposition kernels;
- a filtering processor configured to apply noise filtering to the high-pass and low-pass signal components, wherein noise filtering includes applying paired filters to a block generated by segmenting an image into vertically and horizontally symmetrical sub-bands in a subsequent dimension;
- and
- a synthesis bank configured to reconstruct a processed signal from the noise-filtered high-pass and low-pass signal components using corresponding high-pass and low-pass filter synthesis kernels,
- wherein the filter parameters defining the high-pass and low-pass filter decomposition kernels and the high-pass and low-pass filter synthesis kernels are generated with power complimentarity and perfect reconstruction restraints.
A method of filtering a signal with a bi-orthogonal wavelet filter bank, the method comprising:
- decomposing, with a decomposition bank, a signal into high-pass and low-pass signal components using corresponding high-pass and low-pass filter decomposition kernels;
- applying, with a filtering processor, noise filtering to the high-pass and low-pass signal components, wherein noise filtering includes applying paired filters to a block generated by segmenting an image into two-dimensionally symmetrical sub-bands in a subsequent dimension;
- and
- reconstructing, with a synthesis bank, a processed signal from the noise- filtered high-pass and low-pass signal components using corresponding high-pass and low-pass filter synthesis kernels,
- wherein the filter parameters defining the high-pass and low-pass filter decomposition kernels and the high-pass and low-pass filter synthesis kernels are generated by applying power complimentarity and perfect reconstruction restraints.
A non-transitory machine-readable storage medium, having encoded thereon program code, wherein, when the program code is executed by a machine, the machine implements a method for filtering a signal with a bi-orthogonal wavelet filter bank, comprising the steps of:
- decomposing, with a decomposition bank, a signal into high-pass and low pass signal components using corresponding high-pass and low-pass filter decomposition kernels;
- applying, with a filtering processor, noise filtering to the high-pass and low-pass signal components, wherein noise filtering includes applying paired filters to a block generated by symmetrically segmenting an image in sub-bands across a vertical direction and a horizontal direction, wherein segmenting is performed in a subsequent dimension;
- and
- reconstructing, with a synthesis bank, a processed signal from the noise-filtered high-pass and low-pass signal components using corresponding high-pass and low-pass filter synthesis kernels,
- wherein the filter parameters defining the high-pass and low-pass filter decomposition kernels and the high-pass and low-pass filter synthesis kernels are generated by applying power complimentarity and perfect reconstruction restraints.
Dependencies are inferred from the claim text.