Koninklijke Philips Corporation N.v.

Estelle Lesellier

Carolina Miro Sorolla

Jorge Caviedes

Vincent Ruol

The present invention relates to a method of processing a sequence of digital images, intended to detect, in a dynamical manner, a grid comprising blocking artefacts. Said method comprises the steps of, a) detecting () a current spatial grid (SG(t)) within a portion of the image constituted by a current field (FLD(t)), b) determining () a current reference grid (RG(t)) from a current spatial grid (SG(t)) and a preceding reference grid (RG(t-)) supplied by a memory MEM (), the current reference grid (RG(t)) being subsequently stored temporarily in the memory MEM (), and c) correcting COR () blocking artefacts which are present in the current field (FLD(t)) from the preceding reference grid (RG(t-)) so as to supply a processed field (PPP(t)).

Dynamic detection of blocking artifacts

Blocking artifacts within a sequence of digital images are detected by detecting a grid corresponding to the blocking artifacts. A portion of a digital image is high-pass filtered to supply a set of discontinuity pixels. Blocking artifacts are detected in the set, and rows within the portion are searched for a grid row having a density of blocking artifacts that is substantially larger than that of its neighboring rows.

Method of detecting blocking artifacts

A method of post-processing digital images frequency transforming a set of the pixels to a set of transformed coefficients; extracting original low-frequency coefficients and original high-frequency coefficients from the set of transformed coefficients; correcting the original low-frequency coefficients and the original high-frequency coefficients for delivering a set of corrected transformed coefficients including corrected low-frequency coefficients and corrected high-frequency coefficients; and combining the set of corrected transformed coefficients and the original high-frequency coefficients for delivering a set of combined transformed coefficients. The set of combined transformed coefficients are inverse frequency transformed for delivering a processed set of pixels that are ready for display on a screen.

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Boulogne, France

Estelle Lesellier