Patent ID: 8359195

Claim:
A method for processing signals representing speech or audio via a plurality of filters that approximate behaviors of basilar membrane in human cochlea, comprising: providing a processor configured to: providing a first signal representing said speech or said audio to the plurality of filters, wherein said first signal is a digital signal; and filtering the first signal with the plurality of filters, each of the plurality of filters producing one of a plurality of filtered signals; wherein each of the plurality of filters is formed from a base function via a dilation and a shift in time, wherein the base function is a digital filter representing an impulse response at a point on the basilar membrane to a corresponding frequency and the each of the plurality of filters is a digital filter formed from the base function via a dilation and a shift in time; wherein the first signal is filtered according to: T ⁡ [ a i , b ] = ∑ n = 0 N ⁢ f ⁡ [ n ] ⁢ 1  a i  ⁢ ψ ⁡ [ n - b a i ] , and wherein for the shift of b and a dilation of a i , the each of the plurality of digital filters is determined according to: ψ a i , b ⁡ ( n ) = 1  a i  ⁢ ( n - b a i ) α ⁢ exp ⁡ [ - 2 ⁢ ⁢ π ⁢ ⁢ f L ⁢ β ⁡ ( n - b a ) ] ⁢ cos ⁡ [ 2 ⁢ ⁢ π ⁢ ⁢ f L ⁡ ( n - b a i ) + θ ] ⁢ u ⁡ ( n ) , wherein n=1, . . . , N, are discrete time instances, u(n) is a step function, and α, β, θ, and ƒ L are constants; and wherein the impulse response of the base function at a particular frequency band is similar to an impulse response of the basilar membrane at a corresponding frequency band in the human cochlea when: value of α>0, value of β>0, value of θ is selected to equate ∫ - ∞ ∞ ⁢ ψ ai , b ⁡ ( n ) ⁢ ⁢ ⅆ n = 0 , u(n) =1 for n >=0, and a>0, b>=0, ƒ L >0.