How Can Dolphins Recognize Fish According to Their Echoes? A Statistical Analysis of Fish Echoes

How Can Dolphins Recognize Fish According to Their Echoes? A Statistical Analysis of Fish Echoes

Echo-based object classification is a fundamental task of animals that use a biosonar system. Dolphins and porpoises should be able to rely on echoes to discriminate a predator from a prey or to select a desired prey from an undesired object. Many studies have shown that dolphins and porpoises can discriminate between objects according to their echoes. All of these studies however, used unnatur...

Doppler structure in echoes from schools of pelagic fish

The frequency distribution of energy in direct path echoes from three schools of pelagic fish is preaented. One-half-second 30-kHz CW pulses were used to study motions internal to the fish schools from distance8 up to 1200 m. The measured Doppler spread of echo enagy ranged fmm 30 Hz to 70 Hz The Doppler spread-at-side aspect is related to swimming motions by a simple algebraic model based on B...

Statistical Seabed Segmentation – from Images and Echoes to Objective Clustering

Acoustic segmentation is the provincing of a survey region based on acoustic characteristics. Geotechnical classification requires further non-acoustic information, in general. QTC systems are capable of segmentation starting with either uncalibrated echoes from a singlebeam sounder, or images from a multibeam system or a sidescan sonar. Unsupervised segmentation requires clustering, in which r...

15: Modeling Statistics of Fish Patchiness and Predicting Associated Influence on Statistics of Acoustic Echoes

Modeling Statistics of Fish Patchiness and Predicting Associated Influence on Statistics of Acoustic Echoes

To accurately describe the statistics of acoustic echoes due to the presence of fish, especially in the case of a long-range active sonar. Toward this goal, fundamental advances in the understanding of fish behavior, especially in aggregations, will be made under conditions relevant to the echo statistics problem. OBJECTIVES To develop new models of behavior of fish aggregations, including the ...