Impulse Response Interpolation Using Optimal Transport

The spatial impulse response (IR) interpolation problem is of general interest, e.g. for imaging of subsurface structures based on seismic waves, rendering of audio and radar IRs, as well as for numerous spatial audio applications. A commonly used model represents the occurring reflections as equivalent source positions, often being determined using a sparse re-construction framework employing spatial dictionaries. How-ever, in the presence of calibration errors, such spatial dictionaries tend to inaccurately represent the actual propagation, limiting these methods from being used in practice. In-stead of explicitly assuming an equivalent source model, we here introduce a trade-off between minimizing the distance to an equivalent source model and fitting the data by means of a multi-marginal optimal transport problem. The proposed method is evaluated on real acoustic IRs illustrating its prefer-able performance.