Patent ID: 8620979

Claim:
A filter bank for subband decomposition of an input signal into a number K of subband components for processing, comprising a filtering module for transforming the input signal into 2 d components including a low-frequency component and 2 d âˆ’1 higher-frequency components, d being an integer at least equal to 1 representing a dimension of the input signal, wherein said 2 d âˆ’1 higher-frequency components are oversampled compared to said low-frequency component, wherein each filtering module is made of 2 d âˆ’1 filtering units arranged in a binary tree having d levels, wherein, for 1â‰¦ iâ‰¦d , the i-th level in the tree has 2 iâˆ’1 filtering units each receiving a respective input signal and producing a respective output low-frequency signal and a respective output high-frequency signal oversampled compared to said respective output low-frequency signal, wherein the input signal of said filtering module is the input signal of the filtering unit of the first level in the tree, wherein, for any i >1, the output low-frequency and high-frequency signals from the 2 iâˆ’2 filtering units of the (iâˆ’1)-th level in the tree are the respective input signals of the 2 iâˆ’1 filtering units of the i-th level in the tree, and wherein the 2 d respective components from said filtering module are the output low-frequency and high-frequency signals from the 2 dâˆ’1 filtering units of the d-th level in the tree, and wherein each filtering unit has: a first branch, comprising a high-pass filter, for transforming the respective input signal of the filtering unit into the respective output high-frequency signal; and a second branch, comprising one of a polyphase low-pass filtering arrangement and a low-pass filter followed by a downsampler, for transforming the respective input signal of the filtering unit into the respective output low-frequency signal downsampled by a factor of two compared to the respective input signal and the respective output high-frequency signal.