Continuous measurement of impulse responses on a circle using a uniformly moving microphone

We propose a continuous measurement technique which can be used to capture a large number of impulse responses within short time. The response of an acoustic system is continuously captured by a moving microphone, and the instantaneous impulse responses are computed by post-processing. The time-variance due to the movement of the microphone is compensated by employing a recently proposed system identification method. In this method, each sample of the captured signal is interpreted as the orthogonal expansion coefficient of the instantaneous impulse response. The impulse responses are computed from the interpolated orthogonal coefficients. This method is applied to the measurement on a circle. Based on the modal bandwidth of the spatio-temporal impulse response, the relation among the length of the impulse response, the angular speed of the microphone, and the effective number of measurements is revealed. The presented measurement technique was used to measure a large number of room impulse responses, and the results were compared with a conventional sequential measurement technique.