Extrapolation of Spatial Transfer Functions for Primary Reflections with Equivalent Sources

The spatial transfer function (STF) is important for many acoustic technologies. However, it is not easy to measure STFs at multiple points. We propose a method of estimating the sound field using a small number of microphones to make it easier to measure STFs. By using equivalent sources, STFs are modeled to extrapolate the sound field including primary reflections. We investigated the effect of the arrangement of the microphone array configuration and the robustness to noise for the proposed method. It was found by simulation that the proposed method provided better estimation accuracy, especially extrapolation, than linear interpolation.