Patent ID: 8443025

Claim:
A method for operating an apparatus to selectively reduce noise in a digital signal having a first range of values, the method comprising steps of: decomposing, via the apparatus, the digital signal to a plurality of frequency sub-bands using integer arithmetic and wavelet transform, and expanding, via the apparatus, the digital signal or at least one of the frequency sub-bands by one or more bits before, during or after the step of decomposing, wherein at least one expanded frequency sub-band having a higher range of integer values than the first range of integer values is obtained, and wherein the expanding is achieved either by adding one or more bits at a least significant bit (LSB) position and setting the added bit or bits to a value that is obtained from the digital signal, or by omitting a division operation for at least one frequency sub-band during the step of decomposing, and wherein, in the case of the expanding being achieved by adding one or more bits at the least significant bit (LSB) position, the value that is obtained from the digital signal is obtained from the most significant bits (MSBs) of the digital signal; automatically reducing or removing in at least one expanded frequency sub-band values that are below a threshold; and reconstructing from the frequency sub-bands, via the apparatus and after the step of reducing or removing in the at least one expanded frequency sub-band the values that are below a threshold, an output signal having the first range of values, wherein the at least one expanded frequency sub-band or the reconstructed output signal is de-expanded and wherein integer arithmetic is used.