Abstract: In a particular implementation, a codebook C can be used for quantizing a feature vector of a database image into a quantization index, and then a different codebook (B) can be used to approximate the feature vector based on the quantization index. The codebooks B and C can have different sizes. Before performing image search, a lookup table can be built offline to include distances between the feature vector for a query image and codevectors in codebook B to speed up the image search. Using triplet constraints wherein a first image and a second image are indicated as a matching pair and the first image and a third image as non-matching, the codebooks B and C can be trained for the task of image search. The present principles can be applied to regular vector quantization, product quantization, and residual quantization.

Abstract: The present disclosure relates to a method, adapted to be implemented in an electronic device, for selecting a content, during a backup operation, amongst a plurality of contents coding audiovisual data and being accessible by the electronic device. According to one embodiment, the method includes obtaining, for each accessible content, one audiovisual descriptor derived from the audiovisual data, and selecting the accessible content according to one backup rule taking into account the obtained audiovisual descriptor. The present disclosure also relates to corresponding electronic device, system, computer readable program product and computer readable storage medium.