U.S. Philips Corporation

Detlef Gotting

Achim Ibenthal

Rolf-Rainer Grigat

In a method of data reduction of a luminance and/or chrominance signal of a digital picture signal by means of fractal image coding, in which method each image of the luminance/chrominance signal is divided into range blocks of n.times.n pixels each, in which a domain block is searched for each range block, which domain block is imageable on the range block with a minimal deviation while using a transformation function, which domain blocks have a larger size than the range blocks, and in which information on the transformation functions is transmitted, from which information the image data are regained at the receiver end in an iterative process, the search is facilitated in that a digital search tree strategy is employed in the search for that domain block which is imageable on a range block with a minimal deviation while using a transformation function.

Method of data reduction by means of fractal image coding

In a method of data reduction of a luminance and/or chrominance signal of a digital picture signal by means of fractal image coding, in which method each image of the luminance/chrominance signal is divided into range blocks of n.times.n pixels each, in which a domain block is searched for each range block, which domain block is imageable on the range block with a minimal deviation while using a transformation function, which domain blocks have twice the size of the range blocks, and in which information on the transformation functions is transmitted, from which information the image data are regained at the receiver end in an iterative process, the search for appropriate domain blocks is facilitated in that the data of each range block are examined on geometrical basis functions which are possibly satisfactory approximations of the data structure of the range block, in that a difference value is computed from the basis function found for the best approximation of the data structure of the range block and the data of the range block, which difference value represents a residual roughness, in that the data of the domain blocks are examined on geometrical basis functions which are possibly satisfactory approximations of the data structure of the domain block, in that a difference value is computed from the basis function found for the best approximation of the data structure of the domain block and the data of the domain block, which difference value represents a residual roughness, in that the search for the domain block which is imageable on a range block with a minimal deviation, and the associated transformation function is performed with reference to the computed difference values of the range block and the computed difference values of the domain blocks, and in that information on the mutually balanced basis functions of this block and of the most favorable domain block, as well as the transformation function, by means of which the most favorable domain block is imageable on the range block, is transmitted for each range block as a data-reduced data current instead of the luminance/chrominance signal.

Method of data reduction by means of a fractal image coding and encoder

To achieve an enhanced data reduction, a method of fractal image coding, in which method an image to be encoded is divided into range blocks which do not overlap and jointly cover the image contents completely, in which domain blocks comprising areas of the image contents in their original form or in a transformed form are generated from the image contents, and all areas of the image contents are covered by at least one domain block, for each range block the domain block most similar to the range block being searched, and the addresses of the domain blocks found as the most similar and possibly the transform functions used for their generation being transmitted instead of the data of the range blocks, is characterized in that, in a sequence of images, the fractal image coding performed exclusively within the images is only performed with basic images comprised in the image sequence at selectable time intervals, in that, for intermediate images provided between the basic images, the same range and domain block division is used as for the basic images, and in that, individually for each range block in a search area, that domain block is searched in an intermediate image which was found as the most similar in the previous image for the range block of the same position, and in that, if said domain block is found in the search area, the displacement vectors of this block relative to the domain block found as the most similar in the previous image are transmitted instead of the address and possibly the transform function.

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Hamburg, Germany

Detlef Gotting