barry14
Joined: 08 Aug 2007
Posts: 32
Helped: 2
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 09 May 2008 16:32 Re: How a sonar Camera is made ? |
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| I assume you are referring to a camera with a sonar rangefinder such as Polariod made. In this case, the method used is similar to a Navy sonar in that a pulse of sound is sent out from the camera, bounces off the potential subject, and is received at the camera. The time it takes the pulse from transmission to reception is divided by two and then multiplied by the speed of sound in air to compute the range between camera and subject. In Polaroid's case, they used frequencies of around 50 kHz and pulse widths of around 1 millisecond. One problem with this method is if there is a window between the camera and subject, the sound will reflect off the window and give an incorrect range. The other is that the camera must be pointed directly at the subject to get the correct range.
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