SPEECH ENHANCEMENT METHOD, DEVICE, PROGRAM, AND RECORDING MEDIUM

摘要

There is provided a sound enhancement technique that picks up sounds with a sufficiently large SN ratio, achieves a sharper directivity in a desired direction than was possible by conventional techniques while being capable of following sounds from any directions, and is capable of enhancing sounds according to distances from a microphone array. The technique uses transfer functions a i,g of sounds that comes from each of one or more positions/directions that are assumed to be sound sources arrives at each microphone to obtain a filter for a position that is a target of sound enhancement, where i denotes a direction and g denotes a distance for identifying each of the positions. Each of the transfer functions a i,g is represented by the sum of a transmission characteristic of a direct sound that directly arrives from the position determined by the direction i and the distance g and a transmission characteristic of one or more reflected sounds produced by reflection of the direct sound off an reflective object and arrive. A filter that corresponds to the position that is the target of sound enhancement is applied to frequency-domain signals transformed from M picked-up sounds picked up with M microphones to obtain a frequency-domain output signal.