Method and a system for indexing and searching for video documents

A system for indexing and searching for a query video document in a set of preexisting video documents, characterized in that it comprises a first indexing module comprising a sub-module for constructing a time-space video slice of a video document, for extracting a video fingerprint of each of the preexisting video documents and of each of the query video documents, a second indexing module for indexing video fingerprints extracted from preexisting video documents to create a database of video fingerprints of preexisting video documents, a search module for searching the video fingerprints database of the preexisting video documents for candidate video fingerprints close to a video fingerprint of a query video document, a comparison module for comparing a video fingerprint of a query video document to each of the candidate video fingerprints fingerprint by fingerprint, and a module for selecting pertinent video fingerprints from the candidate video fingerprints as a function of the results supplied by the comparison module.

A method of indexing a video document, comprising the following steps:

• (a) representing the video document in the form of a parallelepipedal volume obtained by juxtaposing on a time axis (t) K successive frames constituting the video document, each frame being represented by a matrix of pixels in a two-dimensional space (x, y);
• and
• (b) constructing a space-time video slice (STVSα) of the video document by extracting a set of pixels for each frame of the video document in the same line defined relative to a first direction (x) of the frames, juxtaposing the K lines of pixels corresponding to the K frames on a time axis (t) to form a space-time video slice (STVSα) of length (WSTVSα) defined by the K juxtaposed lines of pixels and of height (HSTVSα) equal to the length of the lines extracted from each of the frames, which length is a function of the dimension of the frames in the second direction (y) and the orientation of the lines, and initializing the calorimetric values of the pixels of the K lines of the space-time video slice (STVSα) on the basis of the content of the lines extracted from the K frames of the video document.