France Telecom

Telediffusion De France

France Telecom and Telediffusion De France

Patrick M Lechat

Nathalie Laurent-Chatenet

The invention relates to a method for coding an image that is to be coded, characterized in that said method comprises the following steps: definition of a hierarchical mesh structure having at least two levels of interconnected meshing formed from mesh units which are defined by peaks; determination, for each of said mesh units, of information concerning an error between the image which is to be coded and an interpolated image obtained from the peaks of the mesh units pertaining to the level of the meshing of the mesh unit in question; termination () of the refinement of mesh units having error information below a first predetermined threshold; implementation of a specific coding () for the mesh units having error information above a second predetermined threshold; continuation () of the refinement of mesh units having error information above the first predetermined threshold and below the second predetermined threshold.

Variable transformation hierarchical image coding

An image coding method for a domain corresponding to at least one portion of an image. A minimal triangular partition covering the domain is defined. A square matrix is associated with each of the source triangles by a first reversible transformation so that each matrix represents a specific source triangle. A second reversible decorrelation transformation is applied to each square matrix, resulting in transformed matrixes. The method may be used in isolation, or as a supplement to another coding of the hierarchic type. A corresponding decoding method is also provided.

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Prades le Lez, France

Patrick M Lechat