Why use sound in the first place? Sound wavelengths in water are about 2,000 times longer than those of visible light. Because of its longer wavelengths, sound can go around suspended particles that would otherwise block and scatter light waves. Light can’t penetrate very far in these conditions, making optical systems (like underwater cameras) ineffective. Also, optical images lack the range information found in sonar images.
The performance of an imaging sonar—from the distance at which they can detect an object, to the clarity of the image, to the number of images they can display per second—are determined by a number of specifications, most notably the operating frequency, acoustic beamwidth and processing power and time to form an image. Sound Metrics sonars use acoustic lens technology which forms beams instantaneously using zero power.
Generally speaking, a lower frequency increases the distance at which an image can be captured. A higher frequency and a smaller beamwidth used to map an object will deliver clearer images. The depth at which the sonar is deployed has no direct effect on how clearly an imaging sonar can capture a target.
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