10. A method for generating a concept database respective of a plurality of multimedia data elements (MMDEs) comprising: generating a plurality of items from a received MMDE of the plurality of MMDEs; determining the items that are of interest for signature generation; generating at least one signature responsive to at least one item of interest of the received MMDE of the plurality of MMDEs; clustering a plurality of signatures received from the signature generator responsive of the plurality of MMDEs, wherein the clustering of the plurality of signatures includes: generating a clustering score for each signature of an MMDE of the plurality of MMDEs versus all other MMDEs of the plurality of MMDEs; determining a size of a diagonal matrix having a size corresponding to the number of the plurality of MMDEs; placing the clustering score in a diagonal matrix in storage, one clustering score for each pair of MMDEs; creating a new cluster element for each two cluster elements in the diagonal matrix having a clustering score that exceeds a threshold; and repeating the process at the newly created cluster element level each time using the new cluster elements generated as the plurality of cluster elements for the subsequent sequence, until a single cluster is reached or it is determined that a single cluster cannot be reached; reducing the number of signatures in each cluster to a create a signature reduced cluster (SRC) of the cluster; associating metadata with the SRC to a concept structure comprised of a plurality of SRCs and their associated metadata; and generating at least one index for mapping the received MMDE to at least one concept structure, wherein the concept database includes concept structures and the generated indices for the plurality of MMDEs.
11. The method of claim 10 , wherein generating the plurality of items further comprising: extracting items in the form of patches from the received MMDE by a patch AP (PAP).