Opportunistic observations of behavioral responses by delphinids to incidental mid-frequency active (MFA) sonar were recorded in the Southern California Bight from 2004 through 2008 using visual focal follows, static hydrophones, and autonomous recorders. Sound pressure levels were calculated between 2 and 8 kHz. Surface behavioral responses were observed in 26 groups from at least three specie...

In this paper, we are interested in inferring the sources of various types of sonar features typically observed by a mobile robot. After a brief discussion of terrestrial sonar sensing, we develop a set of operators that associates arc-shaped features extracted from sonar scans with real world primitives. Our classiication scheme is probabilistic and is based on empirical data: the con-dence of...

This paper proposes the underwater terrain map building method based on the occupancy grids by using 3D point cloud from the polar sonar sensor system. Because it is expensive to use current 3D underwater sonar sensors, the low-cost 3D sensor systems are needed for the generalized purposes. So the polar-styled sonar sensor system was designed and implemented. It was constructed on the rotating ...

The paper discusses the use of dual stave forward-looking sonar to build a threedimensional underwater model for navigation in restricted waterways. The sonar normally provides separate horizontal and vertical images but when the information is synthesized into a single three-dimensional model it permits, in certain circumstances, the AUV to plan and carry out a trajectory where no path is othe...

Progress in the implementation of state-of-the-art signal processing schemes in sonar systems has been limited mainly by the moderate advancements made in sonar computing architectures and the lack of operational evaluation of the advanced processing schemes. Until recently, sonar computing architectures allowed only fast-Fourier-transform (FFT), vector-based processing schemes because of their...

The advances in robotics and imaging technologies have brought various imaging devices to the field of the unmanned exploration of new environments. Forward looking sonar is one of the newly emerging imaging methods employed in the exploration of underwater environments. While the video sequences produced by forward looking sonar systems are characterized by low signal-to-noise ratio, low resol...

Ultrasonic emissions of bats are directional and delimit the echo-acoustic space. Directionality is quantified by the aperture of the sonar beam. Recent work has shown that bats often widen their sonar beam when approaching movable prey or sharpen their sonar beam when navigating through cluttered habitats. Here we report how nose-emitting bats, Phyllostomus discolor, adjust their sonar beam to...

An experimental ultrasound scanning sonar has been developed that uses a phased ultrasonic transducer array to image objects through the air. The sonar generates arbitrary long duration broadband signals and uses pulse compression to achieve a high range resolution and a high signal to noise ratio. This paper considers using the sonar in an inverse synthetic aperture side-scan configuration, wh...

The sonar beam of an echolocating bat forms a spatial window restricting the echo information returned from the environment. Investigating the shape and orientation of the sonar beam produced by a bat as it flies and performs various behavioral tasks may yield insight into the operation of its sonar system. This paper presents recordings of vertical and horizontal cross sections of the sonar be...