Application of low-frequency ultrasonic communication to audio marker for augmented reality

In augmented reality (AR), image markers are widely used for rendering virtual objects. However, the performance for image markers strongly depends on the lighting environment and the distance between the image marker and a camera. Therefore, we propose an audio marker-based AR application using low frequency ultrasound (LFU) communication. The proposed method consisted of forward error correction (FEC) coding and windowed differential phase shift keying (DPSK) modulation in order to make the proposed method robust over the noisy channel. The successful transmission rate (STR) performance of the proposed system was measured according to the various distances and azimuths under noisy conditions. As a result, the proposed audio marker transceiver could operate up to around 4 m without transmission error, even at ambient noise of 70 dB.