The concept of narrow sound channel using binary time frequency masking for speech recognition of intelligent service robots

In this paper, we propose a speech recognition system with a narrow sound channel for intelligent service robots in noisy environments. The narrow sound channel is obtained by using time delay between two array microphone inputs used in the degenerate unmixing estimation technique (DUET). In the proposed system, the voice from a specific direction only passes through the sound channel, while unwanted voices from any other direction are removed. The recognition results showed that the performance of the proposed system, using a stereo microphone is higher than the normal voice recognizer, using a single ultra directional microphone, without this method.