同期加算とスペクトル減算に基づく雑音環境に頑健な音響測距法

概要

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In many engineering fields, distance to targets is very important. General distance measurement method uses a time delay between transmitted and reflected waves, but it is difficult to estimate the short distance. On the other hand, the method using phase interference to measure the short distance has been known in the field of microwave radar. Therefore, we have proposed the distance estimation method based on interference between transmitted and reflected audible sound, which can measure the distance between microphone and target with one microphone and one loudspeaker. However, the distance measurement performance of the proposed method was degraded by additional noise in noisy environment. In this paper, the acoustic distance measurement method based on the interference between the transmitted wave and the reflected waves is expanded to a noise-robust method in a noisy environment. In order to measure distance in a low-signal-to-noise ratio (low-SNR) environment, we introduce a concept from synchronous addition and spectral subtraction to the proposed method. Evaluation experiments in a real environment reveal that the proposed method was valid and effective because the proposed method could measure distance in a low-SNR environment.