Workshop on Imaging of Complex Media with Acoustic and Elastic Waves

Abstract

Public rsporing burden for this collection of Information Is estimated to average 1 hour per response, Including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data need ed, and completing and reviewing the collection of information. Research SummaryThe workshop combined a tutorial approach in providing a common interdisciplinary basis with presentations and discussions of the latest research results. Contributions (13) of each of the discussions were compiled in a workshop proceedings entitled, "Imaging of Complex Media with Acoustic and Seismic Waves"

Elastic Strain Effects on Wave Scattering: Implications for Coda Wave Interferometry (CWI)

“…Imaging and monitoring techniques based on the arrival times of direct or scattered waves (using different types of waves like electromagnetic, acoustic, or elastic waves) are applied in many domains like medical imaging, nondestructive testing of materials, or seismic imaging with nominal scales ranging from mm to km (Kuperman et al, 2002;Mussett & Khan, 2000). The issue of monitoring complex media with noninvasive techniques has grown in interest in recent years and led to the development of innovative acoustic monitoring techniques (Anugonda et al, 2001;Wegler & Lühr, 2001).…”

Time-Reversal Analysis for Scatterer Characterization

“…Previous work shows that time-reversal signal processing [1,2] and analysis [3][4][5] of wave scattering data can be successfully used to achieve super-resolution in refocusing through random media [6] (i.e., better focusing than can be achieved in a homogeneous medium with the same size array) of waves onto the location of a sourceeven when the actual location of that source is unknown. This technique has obvious applications to communications in complex environments such as ocean acoustics and urban cell phone reception and transmission.…”

Reconstrução De Imagens De Ultrassom Pelo Método De Focalização Total: Técnicas Para Melhoria Da Relação Sinal Ruído

“…ou seja, a matriz K * (ω)K(ω) permite descrever qualquer processo de reversão temporal e, portanto, é denominada Operador de Reversão Temporal (ORT) [69]. Note que, nessas iterações, é sempre possível se escrever a emissão seguinte em função do vetor de entrada inicial, ou seja, o vetor transmitido depende linearmente do vetor inicial e 0 (ω).…”