HRTF
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While walking alone at night, you hear footsteps behind you... How do you realise they're coming from behind even without looking? That's because humans have the ability to perceive the direction a sound is coming from. The Homo sapiens has various ways to aquire information from the outside world. Among them, sight and hearing are often used to sense surrounding dangers. Sight is suitable to acquire precise information, however it cannot be used to sense perils other than those laying ahead. Also, it is not useful if the eyes are closed. Besides, in darkness the ability of collecting information through sight is reduced. On the other hand, hearing allows gathering information from all directions; and yet it is not affected by darkness. In addition, hearing is not merely the ability to ''listen to sound'', but it is also capable to speculate ''where the sound is coming from'' and it plays an important role in sensing danger. So how are humans capable of speculating ''where a sound is coming from''? The sound emitted by a sound source is warped by the head and the external ear before it arrives at the eardrum. According to the direction the sound comes, this ''distortion'' differs. And from that difference humans can estimate the direction from where the sound is coming from. That ''distortion'' of the sound by the head and the external ear is called Head-Related Transfer Function (HRTF). By using HRTF, it is possible to make people feel as if the sound is coming from a position where there's actually no sound source, creating a "virtual acoustic reality". In this laboratory, HTRFs are calculated through computer simulation aiming at building a virtual reality system. |