A method for creating a weighted compressed representation of an audio or image dataset, the method comprising the steps of: a) computing a compressed representation of the dataset; the method being further characterised by: b) deleting a first number of elements from the dataset to create a modified dataset; c) after step (b), computing another compressed representation of the dataset; d) repeating steps (b) and (c) a plurality of times to create a plurality of compressed representations; and e) combining the plurality of compressed representations into a weighted compressed representation, where each weight in the weighted compressed representation is computed as a function of elements in the plurality of compressed representations, wherein said function computes said each weight as a correlation coefficient of the elements in said plurality of compressed representations, wherein said correlation coefficient is computed as follows: 1) if an element is below a first predetermined threshold in a first predetermined number of said plurality of compressed representations, set the correlation coefficient to a first value; 2) if an element is above a second predetermined threshold in a second predetermined number of said plurality of compressed representations, set the correlation coefficient to a second value; 3) otherwise set the correlation coefficient to a third value. a) computing a compressed representation of the dataset; the method being further characterised by: b) deleting a first number of elements from the dataset to create a modified dataset; c) after step (b), computing another compressed representation of the dataset; d) repeating steps (b) and (c) a plurality of times to create a plurality of compressed representations; and e) combining the plurality of compressed representations into a weighted compressed representation, where each weight in the weighted compressed representation is computed as a function of elements in the plurality of compressed representations, wherein said function computes said each weight as a correlation coefficient of the elements in said plurality of compressed representations, wherein said correlation coefficient is computed as follows: 1) if an element is below a first predetermined threshold in a first predetermined number of said plurality of compressed representations, set the correlation coefficient to a first value; 2) if an element is above a second predetermined threshold in a second predetermined number of said plurality of compressed representations, set the correlation coefficient to a second value; 3) otherwise set the correlation coefficient to a third value. b) deleting a first number of elements from the dataset to create a modified dataset; c) after step (b), computing another compressed representation of the dataset; d) repeating steps (b) and (c) a plurality of times to create a plurality of compressed representations; and e) combining the plurality of compressed representations into a weighted compressed representation, where each weight in the weighted compressed representation is computed as a function of elements in the plurality of compressed representations, wherein said function computes said each weight as a correlation coefficient of the elements in said plurality of compressed representations, wherein said correlation coefficient is computed as follows: 1) if an element is below a first predetermined threshold in a first predetermined number of said plurality of compressed representations, set the correlation coefficient to a first value; 2) if an element is above a second predetermined threshold in a second predetermined number of said plurality of compressed representations, set the correlation coefficient to a second value; 3) otherwise set the correlation coefficient to a third value. 1) if an element is below a first predetermined threshold in a first predetermined number of said plurality of compressed representations, set the correlation coefficient to a first value; 2) if an element is above a second predetermined threshold in a second predetermined number of said plurality of compressed representations, set the correlation coefficient to a second value; 3) otherwise set the correlation coefficient to a third value.