| 摘要 |
<P>PROBLEM TO BE SOLVED: To record a sound of a photographer who operates a video camera and a sound of a subject while being separated from each other. <P>SOLUTION: A microphone (a mic 1) having a rear directivity is installed behind a video camera, and a microphone (a mic 2) having a front directivity for recording a subject sound is installed in front of the video camera. All sound signals acquired by the mic 1 are considered to be originated from a noise arrived from behind the video camera. A noise cancellation circuit predicts a noise signal to be mixed into the mic 2 to generate a reverse-phase waveform of the noise signal. By superimposing the reverse-phase waveform on a sound signal waveform acquired by the mic 2, a sound waveform arrived from behind the video camera, such as a sound of a photographer and the like, is cancelled selectively. <P>COPYRIGHT: (C)2012,JPO&INPIT |
