1. A method of extracting universal scene descriptors (USDs) from a scene, comprising: providing a sequence of one or more unsegmented images of a scene; unsupervised decomposition of the scene captured in each said image into at least one region of interest (ROI), the scene in at least one said image decomposed into a plurality of ROIs; extracting multiple classes of biologically-inspired hierarchical visual features from each scene for each of the one or more ROI; assembling the visual features from the plurality of classes into a universal feature vector for each said ROI, each said universal feature vector providing a USD for the scene; for each ROI in each image, processing the corresponding universal feature vector to construct metadata at multiple semantic levels; converting the metadata into a structured description for each said ROI; and assembling the structured descriptions for all ROI in a scene into a single structured description.