Patent ID: 8316011

Claim:
A method, comprising: computing two or more values for a feature in an instance of query content; comparing each of the two or more computed query feature values to at least one threshold value that corresponds to at least one of the two or more computed query feature values; based on the comparisons, determining at least a first bit and a second bit in a hash value that is derived from the query content feature; computing a first conditional probability value for the likelihood that a quantized bit value of the first query feature value equals a quantized bit value of a target or a reference feature value; computing a second conditional probability value for the likelihood that a quantized bit value of the second query feature value equals a quantized bit value of a target or reference feature value; comparing the computed first conditional probability value and second conditional probability value; based on the comparison, determining a relative strength of the first bit and the second bit, wherein the relative bit strength directly corresponds to the computed conditional probability; selecting the first bit as a weakbit if its bit strength is lower than that of the second bit; or selecting the second bit as the weakbit if its bit strength is lower than that of the first bit; toggling the value of the weakbit, wherein a variation of the hash value, which is derived from the query content feature, is generated; and extending the query using the generated hash value variation.