The sonic-waveform processing and imaging flow presented in this paper uses fullwaveform data recorded with a conventional acoustic well-logging tool, then adapts known surface-seismic processing steps and optimizes them for the borehole environment. This paper presents improvements brought to our original sonic-waveform processing and imaging flow. These improvements are better geometry assign...

Real time synthetic aperture or synthetic focus techniques for acoustic imaging have been investigated and a prototype digital imaging system has been developed. It operates by exciting, with an impulse, one element from a transducer array, digitizing the return echoes, and storing them in a Random Access Memory. When this process has been repeated for all the array elements, the focus informat...

Sound provides a natural means for exploring the ocean but current sonar systems, as used for example in swath-mapping applications, do not provide directly pictorial images of the ocean depths. Such systems are more akin to radar, which relies on travel-time information to map the environment. A new acoustic technique for providing real-time visual images of the interior of the ocean is curren...

The usage of Distributed Acoustic Sensing (DAS) in geophysics is rapidly gaining popularity due to its dense spatial sampling and low operation cost if the optical fiber is easily accessible. In the borehole environment, optical fibers for DAS are often readily available as a part of other sensing tools, such as for temperature and pressure. Although DAS provides single axial strain measurement...

We compare acoustic images obtained from actual measurements using a 49-microphone array with separable geometry. Images were obtained using four different algorithms: delay-and-sum beamforming (DAS), DAMAS2, and two regularized least-squares methods, the first using regularization, the second using total variation (TV) regularization. All algorithms were accelerated using the Kronecker array t...

duce acoustic images of the~seafloor on-line with a Sea Beam multibeam echo-sounder. This ystem uses a stand alone interface between the Sea Beam system and a grey-scale line-scan recorder. The interface is built around a Motorola 68000 microprocessor and has digitizing capabilities. I t digitizes the detected echo signals from each of the 16 preformed beams inside the Sea Beam echo process...

Proton magnetic resonance imaging (MRI) examinations were performed in six patients with seven acoustic neuromas, and the results were compared with conventional tomography of the internal auditory canals, contrast-enhanced computed tomography (CT), and air CT cisternography. All tumors were identified with MRI. The three largest tumors (greater than 1 cm diameter) looked similar to the tumors ...

Artificially structured materials with unit cells at sub-wavelength scale, known as metamaterials, have been widely used to precisely control and manipulate waves thanks to their unconventional properties which cannot be found in nature. In fact, the field of acoustic metamaterials has been much developed over the past 15 years and still keeps developing. Here, we present a topical review of me...