FIRST-ORDER DIFFERENTIAL BEAMFORMING AND JOINT-PROCESS ESTIMATION FOR SPATIAL SOURCE SEPARATION
Pedro Gómez‐Vilda, Victor M. Garca Nieto, Agustín Álvarez-Marquina, R. Martínez, Francisco Rodríguez, F.A. Díaz, V. Rodellar · 2003
Speech Enhancement is a technique required to grant the success of speech recognition systems working under strong noisy conditions, and to grant understandability in speech transmission and coding. Array beamforming has been traditionally used to produce improvements in the signal-to-noise ratio. Two-sensor systems based on First-Order Differential Beamformers (FODB) have been proposed as a promising alternative [G. Elko, 1996]. Nevertheless null beamformers are not sufficient to grant enough separation levels. Through this paper FODB’s and Joint-Process Estimators (JPE’s) are combined to grant speech source separation. Results for superposed sinusoidal sources are presented. where the parameter β is the steering factor of the FODB controlling the DOA (see [1], [3], [4] for further details) (see Figure 2). The output of the filter will be defined in general as: y = xF( ϕ) (2) i x being the equivalent input to the FODB, which may be evaluated from the signals arriving to each sensor. Therefore, the output of the FODB will contain information coming from any DOA except from ϕi. sjk si sik sjm sj 1.