1. Method for audio signal processing, comprising detecting an audio signal from a microphone array to obtain communication signals; processing the communication signals by a beamformer to obtain a beamformed signal; processing the communication signals through a blocking matrix to obtain power densities of noise contributions of each of the communication signals; processing the power densities of noise contributions of each of the communication signals to obtain an short-time power density from the power densities of noise contributions of each of the communication signals; estimating the power density of a noise contribution of the beamformed signal based on the short-time power density obtained from the power densities of noise contributions of each of the communication signals; and post-filtering the beamformed signal based on the estimated power density of the noise contribution of the beamformed signal to obtain an enhanced beamformed signal.