Patent ID: 7409065

Claim:
An apparatus for detecting sound direction, comprising: a plurality of sound source detecting units, each receiving a sound signal from a sound source, amplifying and filtering the sound signal for generating a amplified sound signal, and then transforming the amplified sound signal to a pulses signal; and a processing unit, coupled to the sound source detecting units, respectively, for sampling the pulse signals outputted from the sound source detecting units to generate a plurality of sampling signal sequences, and then performing a maximum likelihood method on the sampling signal sequences to obtain a plurality time differences, thereby detecting a position of the sound source via a table look-up method based on the time differences; wherein the sampling signal sequences are represented as {right arrow over (χ)} 1 , {right arrow over (χ)} 2 , {right arrow over (χ)} 3 ∈{1,0}, the sampling length of the sampling signal sequence sampled by the processing unit is L, and the time differences are represented as Δ 1 , Δ 2 , Δ 3 , where Δ 1 is the time difference between {right arrow over (χ)} 1 and {right arrow over (χ)} 2 , Δ 2 is the time difference between {right arrow over (χ)} 2 and {right arrow over (χ)} 3 , Δ 3 is the time difference between {right arrow over (χ)} 3 and {right arrow over (χ)} 1 ; and the maximum likelihood method is performed as follows: L(a|x)=f(x|a) for a in A and x in S, if a=Δ 1 , then x={right arrow over (χ)} 1 (n)·{right arrow over (χ)} 2 (n+Δ 1 ), if a=Δ 2 , then x={right arrow over (χ)} 2 (n)·{right arrow over (χ)} 3 (n+Δ 2 ), if a=Δ 3 , then x={right arrow over (χ)} 3 (n)·{right arrow over (χ)} 1 (n+Δ 3 ), where A is a possible time difference (A∈{0,Δ possible max }) and S∈{1,0}, thereby computing the time differences and maximizing the corresponding L(a|x)=f(x|a).