1. A computer implemented method of encoding a feature vector, the method comprising: retrieving a feature vector, the feature vector representing a target media object; generating a permutation, the permutation comprising a vector of ordinals, wherein the dimensionality of the permutation vector is equivalent to the dimensionality of the feature vector; permuting the feature vector with the generated permutation; truncating the permuted feature vector according to a selected window size; identifying the index of the maximum value of the truncated permuted feature vector; and producing a sparse binary vector, the sparse binary vector comprising the identified index encoded using one-hot encoding.