Dolphin sonar research has been conducted for several decades and much has been learned about the capabilities of echolocating dolphins to detect, discriminate and recognize underwater targets. The results of these research projects suggest that dolphins possess the most sophisticated of all sonar for short ranges and shallow water where reverberation and clutter echoes are high. The critical f...

There is increasing concern about the potential effects of noise pollution on marine life in the world's oceans. For marine mammals, anthropogenic sounds may cause behavioral disruption, and this can be quantified using a risk function that relates sound exposure to a measured behavioral response. Beaked whales are a taxon of deep diving whales that may be particularly susceptible to naval sona...

The use of acoustic pulses to image materials is well-known in echography or sonar applications. We are extending this field by generating point-excited sound pulses on solid surfaces with ultrashort laser pulses and imaging the resulting surface wave propagation in real time. To see the tiny vibrations of the surface, smaller in amplitude than the dimensions of a single atom, we use another se...

Exposure to underwater sound can cause permanent hearing loss and other physiological effects in marine animals. To reduce this risk, naval sonars are sometimes gradually increased in intensity at the start of transmission ('ramp-up'). Here, we conducted experiments in which tagged humpback whales were approached with a ship to test whether a sonar operation preceded by ramp-up reduced three ri...

This paper describes the hardware and the software of a computer-based doppler-sonar system for movement detection. The design is focused on simplicity and lowcost do-it-yourself construction.

Navigation technology is one of the most important challenges in the applications of autonomous underwater vehicles (AUVs) which navigate in the complex undersea environment. The ability of localizing a robot and accurately mapping its surroundings simultaneously, namely the simultaneous localization and mapping (SLAM) problem, is a key prerequisite of truly autonomous robots. In this paper, a ...

The problem of extracting spectral lines from sonar images is treated using a complete scheme that combines an edge detector with a line tracking process. That is, the edge detection process allows lter-ing the sonar image and nding a region (zero-crossings of the second derivative of the sonar image) that includes a spectral line. The founded region is then used to initialize and to limit the ...

Obstacle avoidance is a sensor-based task designed to steer a mobile robot towards intermediate goals while avoiding unexpected local obstacles in the robot’s surroundings. Responsiveness requires that the task is computed in short time intervals, fast enough to deal with the robot inertia and dynamics limitations. Simultaneously it has to guarantee detection by gathering enough information to ...

Currently, the vast majority of autonomous mapping in robotics relies on direct measurements from costly devices such as sonar, infrared, and laser range finders. Adapting established methodologies from the structure−from−motion (SFM) subfield of computer vision to data commonly available in robotics, we have created a unique toolkit, able to render visually dense 3d maps from odometrically ann...