Koninklijke Philips Corporation N.v.

Sandra Del Corso

Pierre Gautier

Vincent Ruol

Isabelle Lemaguet

A method of reducing noise in images formed by uniform regions and textures delimited by edges, comprises a step of filtering these images, a step of detecting edges in these images, a sub-step of re-assigning or no re-assigning each image pixel to an edge or a texture in accordance with the result of a connectivity test, this sub-step taking place at the end of the step of detecting edges and textures and a selection step of eliminating or applying this filtering to each image pixel according to whether this image pixel is associated or not associated with an edge or a texture.

Noise reduction method

The invention relates to the processing of video signals prior to encoding or other compression operations, and, more particularly, to a method for encoding video signals corresponding to a sequence of frames each of which consists of two fields Fand F. The proposed method comprises the steps of receiving successive frames of an input video signal and delaying them with at least a 'two fields' duration delay, and detecting any dominance change and adjusting said delay. When a change from an Fdominance to an Fdominance is detected, the first field of the first Fdominant frame is suppressed, and said delay is decreased by a quantity equal to 'one field' duration; when a change from an Fdominance to an Fdominance is detected, the last field of the last Fdominant frame is repeated, and the delay is further increased by a quantity equal to &#x201c;one field&#x201d; duration. The invention also relates to a method for encoding a sequence of frames including either video-type images or film-type images, and to an encoding system that carries out said method by incorporating the first solution hereinabove presented. If a sequence of film-type is detected, the inverse 3:2 pull-down technique is applied on the input frames, while in the opposite case, said technique is de-activated and replaced by said first solution: preprocessing according to the type of dominance change.

Method and device for encoding video signal

The invention relates to a method for encoding video signals corresponding to a sequence of frames constituted either from video-type images or film-type images. These film-type images are obtained by means of the 3:2 pull-down technique involving a subdivision of each film frame into two fields and a duplication of two fields within each group of four subdivided frames. The encoding step of the signals is preceded by a preprocessing step that includes thresholding the eight absolute values of the successive pixel-to-pixel differences between fields of the same parity. Measuring the density of '1' (resp. '0') per block of m&#xd7;n pixels of the field structure leading to mark each pixel as 1 or 0. Detecting in any group of ten successive fields within the preprocessed signals thus obtained, the film pattern formed by the duplicated fields. Switching the preprocessed signals from a first encoding mode to a second one, when the film pattern is detected, or from the second one to the first one, when it is not detected.

Encoding method and device including thresholding pixel-to-pixel differences

A method and a decoder for processing a digital video signal representing a sequence of images includes

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Clamart, France

Sandra Del Corso