Imaging sonar system and method

An imaging sonar system comprising:

• (a) a transmitter and receiver;
• (b) scanning transducer means coupled with said transmitter and receiver for generating sound waves and for detecting echoes therefrom, said scanning transducer means being positionable for directing the generated sound waves radially in all directions and through an arc along each radius;
• (c) analog to digital converter means coupled with said receiver for converting receiver emitted signals into digital form;
• (d) serial access memory means for accepting into storage receiver emitted signal data at a predetermined rate and for presenting for recall from storage receiver emitted signal data at a rate different than said predetermined rate;
• (e) write and read control means for respectively entering digital data into and recalling digital data from said memory means;
• and
• (f) display means coupled with said scanning transducer means and said memory means and having means synchronized with said memory read control means for displaying data recalled from said memory means as a gray code image of echoes detected by said transducer means.

A method of forming visual images of submerged scenes comprising the steps of:

• generating sound waves radially from a source onto a submerged scene and detecting echoes therefrom;
• transforming the detected sound wave echoes into an analog electrical energy signals;
• enhancing the analog electrical signal proportional to the distance the echo travels;
• digitizing the electrical signals;
• entering digital data from the digitized signals into a digital memory at a first rate;
• recalling digital data from the memory at a second rate faster than the first rate;
• displaying the recalled digital date continuously corresponding to its radial position on a display means, radially from a central position of the tube display means;
• and
• replacing the display with updated data periodically.

A method of forming a visual image of a submerged scene around a boat comprising the steps of:

• (a) generating sound waves into the water as a continuous sweep around the boat;
• (b) receiving the echoes from said sound waves;
• (c) transforming the received echoes into analog electrical energy signals;
• (d) displaying functions of the signal visually;
• (e) imparting a gain to said electrical signal proportional to the delay in the return of the echo so that the more distant appears as distinct as the closer echoes when displayed visually;
• and
• (f) periodically updating the functions of the signals as visually displayed so that a continuous display of the reflections of surfaces in the volume of water surrounding the boat is provided.

Method of forming visual images of submerged scene comprising the steps of:

• (a) generating from a source sound waves radially into water onto a submerged scene so as to contact fish in the water and the bottom surface of the water;
• (b) detecting the sound wave echoes at said source;
• (c) moving the generation and detection of the sound waves in a circular path about said source;
• (d) segregating the sound waves echoes according to their intensity;
• and
• (e) simultaneously displaying visually a representation of the said segregated sound wave echoes so that a representation of the bottom surface around the source is displayed and a representation of the fish is superposed on the display of the bottom surface and the difference in intensity of such representation of the sound wave echoes from the fish is visually brighter than the representation of the sound wave echoes from the bottom surface.

Method of forming usable digital electrical signals which are representative of a submerged scene comprising the steps of:

• generating sound waves into a body of water from a boat floating therein;
• progressively receiving, in successive sweeps around said boat, the echoes of said sound waves;
• progressively translating the received echoes into analog electrical energy signals;
• converting said analog signals into digital signals;
• storing said digital signals;
• subsequently retrieving the stored digital signals;
• progressively sensing successive angular positions from which the echoes are received;
• and
• controlling the storage of the digital signals and the subsequent retrieval thereof, in response to the sensing of such angular positions.