	US 7,346,219 B2
	Methods and devices for encoding and decoding images using nested meshes, programme, signal and corresponding uses
Laurent Demaret, Rennes (France); and Nathalie Laurent-Chatenet, Vignoc (France)
Assigned to France Telecom, Paris (France)
Appl. No. 10/479,904 PCT Filed Jun. 06, 2002, PCT No. PCT/FR02/01937 § 371(c)(1), (2), (4) Date Jun. 29, 2004, PCT Pub. No. WO02/100111, PCT Pub. Date Dec. 12, 2002.
Claims priority of application No. 01 07406 (FR), filed on Jun. 06, 2001.
Prior Publication US 2004/0218824 A1, Nov. 04, 2004
Int. Cl. G06K 9/36 (2006.01)

U.S. Cl. 382—248 [382/232; 382/240; 382/241; 375/240; 375/240.04]

25 Claims

1. A method for the encoding of at least one source image implementing a hierarchical mesh defining at least two nested spaces, each corresponding to a level of decomposition of the mesh, comprising:

a preliminary step for associating a mathematical space of representation of an image V_nsuch that V_n=V_n−1⊕W_n−1, with at least one decomposition level n other than the first level of decomposition, where:

V_n−1is the space associated with the decomposition level n−1; and

W_n−1is a space orthogonal to V_n−1;

a preliminary step for obtaining orthogonal bases, delivering a base of piecewise affine functions (φ_n−1of said space V_n−1and a base of functions of pre-wavelets ψ_n−1of said space W_n−1forming two orthogonal bases, such that, with space V_nthere is associated, firstly, a base of piecewise affine functions φ_n, and, secondly, a base formed by the combination of said two orthogonal bases; and

a step for determining, at said decomposition level n other than the first level of decomposition, image coefficients expressed only in the base of pre-wavelet functions ψ_n−1defined in said space W_n−1orthogonal to said space V_n−1corresponding to the decomposition level n−1, the pre-wavelet functions being selected so that the image coefficients enable the optimizing, for said decomposition level n, of the information already transmitted for a preceding decomposition level n−1;

so as to enable the production of a reconstructed image, representing the at least one source image, with a quality of restoration optimized for said decomposition level n.