Abstract: A method for detecting differences between two digital images includes the steps of: transforming the images by resizing the images in order to get identical image sizes, by aligning pixels of the images and by normalizing colors of the images; determining plural binary masks from the pixels of the transformed images, each binary mask being composed of one element per couple of pixels of the transformed images having same coordinates; determining plural energy functions, each energy function being the sum of a first term representative of transformed images and of one binary mask and of a second term which is only dependent on said one binary mask; minimizing the energy function over other plural energy functions; and selecting the binary mask corresponding to the minimized energy function.

Abstract: The present invention concerns a method for deriving from an arbitrary local image descriptor a descriptor that is invariant under arbitrary mirror symmetries. For a point of interest, pi, for which the descriptor is to be determined a direction, ODi is determined. The local patch from which the descriptor is to be extracted is mirrored along ODi if a “smaller than” relation does not hold a feature extracted from the left half of the local image patch, in regard of ODi, compared to the right half of the local image patch. Thereby, the local patch is brought into a normalized intrinsic orientation. Thereafter, the descriptor is extracted. Examples include a mirror symmetry invariant version of Lowe's SIFT.

Abstract: The present invention pertains to a method and a system for identifying a specific image within a flow of images. The system calculates a reference index of the specific image, and current indexes of the current images of said flow. The index has the form of an ordered and finite set of values encoding the content of the current image. The system also compares the reference index with the current index of the current image of the monitored flow. It is thus possible to detect a specific image within a flow with great precision and extremely fast while being robust during major photometric alterations.

Abstract: A process for presenting information in a multimedia file from a query implemented by a user on an open computer network including a multiplicity of computer terminals enabling transmission of graphical data displayed in multimedia files, the process including selecting at least one image comprising an object to be retrieved, adaptively analyzing a global image to isolate a zone of interest comprising a graphical element which is an object of a query and calculating a set of visual signatures for each object, comparing visual signatures of extracted objects and images contained in the multimedia files to find similar objects stored in the multimedia files, and constructing a file including a set of responses resulting from the comparison.