1. An apparatus for generating feature vectors and sending them to a server for information retrieval, the apparatus comprising: a feature extraction module having an input and output, for extracting features from an input signal, the input of the feature extraction module coupled to receive the input signal; a grouping module having input and output for assigning the extracted features into one or more groups, the input of the grouping module coupled to the output of the feature extraction module; and a sending module having an input and output for transmitting groups of feature vectors, the input of the sending module coupled to the output of the grouping module, and the output of the sending module coupled to the server.