Abstract: An anti-spoofing authentication system includes an image capture device that converts received light into a voice signal representing a captured image; a microphone that converts sound wave into a voice signal; a face detection device that detects a human face on the captured image, the face detection device including a lip detection device that detects lip features associated with the detected human face; a voice activity detection (VAD) device that detects presence of human voice in the voice signal; and an anti-spoofing device that detects a spoofing attack according to the detected lip features and the detected human voice.

Abstract: A sound source localization system includes a microphone array composed of a plurality of microphones each converting sound wave into a corresponding voice signal; a room shape estimator that determines a room shape including a location map and a corresponding template voice feature map composed of template voice features associated with a virtual sound source disposed at different locations respectively, and outputs a room reliability indicating confidence about the determined room shape; a lookup table (LUT) that pre-stores the location map and the corresponding template voice feature map; and a localizer that determines a location of a sound source according to the room reliability and similarity between a voice feature associated with the sound source and the template voice features of the template voice feature map.

Abstract: A voice activity detection (VAD) system includes a voice frame detector that detects a voice frame during which a voice signal is not silent; and a voice detector that detects presence of human speech according to the voice frame.

Abstract: An acoustic method for measuring flow velocity of fluid is provided. First, a sound wave is emitted from a transduction surface of a transducer to a fluid. The transduction surface has at least two signal transduction sections. When the sound wave is scattered into a scattered signal by the fluid, the scattered signal is received by the transduction sections. According to the scattered signal, the maximum Doppler frequencies are calculated. Then, according to these maximum Doppler frequencies, the flow velocity of fluid is calculated.