Principal angles approach to time-domain filter design for target cancelation

We consider the design of a pair of time-domain filters to achieve target signal cancelation in a multi-source environment. The problem is formulated as a minimization of a sum squared error cost function with respect to the pair of finite impulse response cancelation filters. Direct minimization is achieved through an alternating gradient descent based method, whereas a novel method based on the method of principal angles is proposed which exploits the singular value decomposition. Simulation studies show that the gradient descent method suffers from slow convergence but this is overcome by the method based on principal angles which also achieves a lower cost than the gradient descent approach. The cancelation filters are then combined with an adaptive filtering scheme to address a video-informed audio source separation problem and preliminary results suggest good performance in terms of objective measures.