IMAGE PROCESSING APPARATUS AND METHOD FOR REDUCING EDGE-INDUCED ARTEFACTS
First Claim
1. An image processing unit (100) comprisinga wavelet decomposition unit (110) configured to apply a wavelet decomposition on an input data signal descriptive for an image, wherein at least one approximation and at least one detail signal are generated;
- a discontinuity detection unit (120) configured to detect discontinuities in at least one evaluation signal selected from the approximation and detail signals, the discontinuities comprising image edges and block boundaries; and
an artefact reduction unit (140) configured to reduce edge-induced artefacts by equalizing pixel values in image areas identified by the detected discontinuities in at least one of the approximation and detail signals to obtain at least one corrected approximation or detail signal.
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Abstract
The present invention relates to image processing. A wavelet decomposition unit (110) applies a wavelet decomposition on an image or video data signal and generates approximation and detail signals. A discontinuity detection unit (120) detects discontinuities like block boundaries and/or image contour lines in an evaluation signal selected from the approximation and detail signals. An artefact reduction unit (140) reduces edge-induced artefacts by equalizing pixel values in image areas identified by the detected discontinuities in one or more of the approximation and detail signals to obtain at least one corrected approximation or detail signal. The corrected approximation and detail signals support a reconstruction of the image data signal, wherein the reconstructed image shows reduced blocking and ringing artefacts.
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19 Claims
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1. An image processing unit (100) comprising
a wavelet decomposition unit (110) configured to apply a wavelet decomposition on an input data signal descriptive for an image, wherein at least one approximation and at least one detail signal are generated; -
a discontinuity detection unit (120) configured to detect discontinuities in at least one evaluation signal selected from the approximation and detail signals, the discontinuities comprising image edges and block boundaries; and an artefact reduction unit (140) configured to reduce edge-induced artefacts by equalizing pixel values in image areas identified by the detected discontinuities in at least one of the approximation and detail signals to obtain at least one corrected approximation or detail signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of operating an image processing unit, the method comprising
decomposing, by a wavelet decomposition scheme, an input data signal descriptive for an image into at least one approximation and one detail signal, detecting discontinuities in at least one evaluation signal selected from the approximation and detail signals, and equalizing energy of areas identified by the detected discontinuities with energy of neighbouring areas to obtain at least one corrected detail or approximation signal.
Specification