Speech Intelligibility in the presence of X4 Unmanned Aerial Vehicle

The main purpose of this work was to obtain background sound levels and speech intelligibility as well as to evaluate classification of speech commands in the presence of an unmanned aerial vehicle (UAV) equipped with four rotating propellers. Speech intelligibility was assessed using speech interference level (SIL) parameter according to ISO 9921. The UAV background sound levels were recorded in laboratory conditions using Norsonic140 sound analyzer in the absence of the UAV and in the presence of the UAV. The classification of speech commands/left, right, up, down, forward, backward, start, stop/recorded with Olympus LS-11 was evaluated in laboratory condition based on Mel-frequency cepstral coefficients and discriminant function analysis. The UAV was hovering at 1.5m during recordings. The A-weighted sound level obtained in the presence of the UAV was 70.5 dB(A). Speech intelligibility rating was poor in the presence of the UAV. Discriminant analysis based on Mel-frequency cepstral coefficients showed very successful classification of speech commands equal to 100%. Evaluated speech intelligibility did not exclude verbal communication with the UAV. The successful classification of speech commands in the presence of the UAV can enable the control of the UAV using voice commands and general communication with the UAV using speech.