next up previous
Next: Simulations of segregation Up: Calculation of physical parameters Previous: Calculation of input phase

Segregation algorithm

The theorem for segregation is obtained from previous lemma as follows.

Theorem 1 (Segregation algorithm)  

For the problem of segregating two acoustic sources where $\theta_{1k}(t)=0$ and $\theta_k(t)=\theta_{2k}(t)$, the input phase $\theta_k(t)$ can be determined using physical constraints 1-3 from Eqs. ([*]) and ([*]). Therefore, this problem can be solved using the amplitude envelope Sk(t) and the output phase $\phi_k(t)$ from Eqs. ([*])-([*]).

Proof. Refer to Lemma 1 and 2. $\Box$

Segregation algorithm based on Theorem 1 is shown in Fig. [*]. When the problem of segregating two acoustic sources is to be solved using Theorem 1, signal duration which two signals exist in the same time region must be known. In Section 2, we assumed that when localized f1(t) is added to f2(t), the signal duration can be detected using onset and offset of f1(t). By focusing on the temporal deviation of Sk(t) and $\phi_k(t)$, onset and offset of f1(t) can be determined as follows:

1.
Onset $T_{\rm {on}}$ is determined by the nearest maximum point of $\vert d\phi_k(t)/dt\vert$ (within 25 ms) to the maximum point of |dSk(t)/dt|.
2.
Offset $T_{\rm {on}}$ is determined by the nearest maximum point of $\vert d\phi_k(t)/dt\vert$ (within 25 ms) to the minimum point of |dSk(t)/dt|.
Therefore, the segregated duration is $t_{\rm {on}} \leq t \leq
t_{\rm {off}}$.


next up previous
Next: Simulations of segregation Up: Calculation of physical parameters Previous: Calculation of input phase
Masashi Unoki
2000-10-26