1. A computer-readable medium having computer executable instructions stored thereon for generating an adaptive post-filter for use in improving a signal to noise ratio (SNR) of a target signal, said computer executable instructions comprising: receiving a set of frequency domain transform coefficients corresponding to overlapping frames of an input signal for each of a plurality of sensors comprising a sensor array; using the frequency domain transform coefficients to compute instantaneous direction of arrival (IDOA) vectors corresponding to inter-sensor phase differences for each of a plurality of non-repeating sensor pairs; using a set of pre-computed IDOA prior distributions to estimate a probabilistic direction from which each IDOA vector originated; applying a beamformer to the frequency domain transform coefficients to produce a beamformer signal corresponding to a target channel; constructing a probabilistic model of a spatial and spectral signal field corresponding to a working space of the sensor array from the IDOA vectors, the probabilistic direction of each IDOA vector, and the beamformer signal; for each frame of the input signal, estimating signal and noise variances from the probabilistic model and updating parameters of the probabilistic model, and constructing an adaptive post-filter from the estimated signal and noise variances and the beamformer output signal.