SIGNAL PROCESSING METHODS AND SYSTEMS FOR MULTI-FOCUS BEAM-FORMING

A method and apparatus are provided for generating a directional output signal from sound received by at least two microphones arranged as microphone array. The directional output signal has one or more Beam Focus Directions. The method includes transforming sound received by each microphone into a corresponding complex valued frequency-domain microphone. For any Beam Focus Direction a Beam Focus Spectrum is calculated, consisting, for each of the plurality of frequency components, of time-dependent, real-valued attenuation factors being calculated based on the plurality of microphone signals. For each of the plurality of frequency components, the maximum amongst those attenuation factors of different Beam Focus Spectra is selected and multiplied with the frequency component of the complex-valued frequency-domain signal of one microphone, forming a frequency-domain multi-focus directional output signal, from which by means of inverse transformation a time-domain signal can be synthesized.