| In hearing aids application, it is difficult to localize sound source accurately and quickly in the noisy and reverberant environment. In order to solve this question, many researchers have presented efficient approaches. The steered response power-phase transform weighted (SRP-PHAT) source localization algorithm has been proved robust, however, it requires high computation cost for searching the peak of steered response power in a large location space. Thus, an improved SRP-PHAT method using an orthogonal linear array was presented, which reduced a two-dimension searching space into a couple of one-dimension ones. Then the parameters of direction of arrival (DOA) were separated, and computed respectively in the one-dimension searching space with coarse-fine strategies of hierarchical search. This algorithm was based on the observation that the wavelengths of the sound from a speech source are comparable to the dimensions of the space being searched and that the source was broadband. A systematic series of comparisons with previous algorithms were made basing on MATLAB. Simulations show that the main computational load of SRP-PHAT algorithms has been greatly cut down, and there is no loss in accuracy in the proposed method. The algorithm presented can localize sound source very rapidly.Loudness compensation is a key function of hearing aids. Because hearing loss is commonly more severe for high-frequency signal than low-frequency signal, the gain of the loudness compensation should be modified with the frequency of the signal. A new six-channel loudness compensation method was proposed based on human auditory, especially on presbycusis. The filter-band designed for sub-band loudness compensation was given by using quadrature mirror filter bank (QMFB). The signal at senile hearing loss was simulated and used for loudness compensation. Results of simulation by MATLAB and experiments show that, the energy loss in high bands of hearing loss patients on presbycusis is well compensated. |
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