نتایج جستجو برای: acoustic imaging

تعداد نتایج: 537832  

Journal: :Journal of biomedical optics 2013
Bin Huang Jun Xia Konstantin Maslov Lihong V Wang

The versatility and real-time imaging capability of commercial linear array transducers make them widely used in clinical ultrasound and photoacoustic imaging. However, they often suffer from limited detection view. For instance, acoustic waves traveling at a grazing angle to the transducer surface are difficult to detect. In this letter, we propose a simple and easy approach to ameliorate this...

2006
Q. R. YIN H. R. ZENG H. F. YU G. R. LI

Three kinds of near-field microscopy imaging mode including SEAM (Scanning electron acoustic microscopy), PFM (Piezoresponse force microscopy) and SPAM (Scanning probe acoustic microscopy) have been developed to investigate domain structures of ferroelectric ceramics, crystals and thin films in our studies. The domain imaging mechanisms are presented individually in three imaging modes. Sub-sur...

2012
Steve Norton Jon Sjogren

An analysis of a passh'e seismic method for subsur­face imaging is presenled. in which ambienl seismic noise is em­ployed as the source of iIIu,;"ination of undergro~nd scal~erers.The imaging algorithm can ,"corporate new data mto the '!'lagein a recursive fashion, which causes image background nOise todiminish over time. Under the assumption of spatially-incoherentambie...

2000
Kwon-Ha Yoon Chang Guhn Kim Seon-Kwan Juhng Jong Jin Won

The challenge presented to ultrasound imaging technology by the advent of microbubble contrast agents is to create a method that detects the echoes from bubbles in preference to the echoes from tissue. Recent progress in ultrasonography is represented by the development of harmonic and pulse inversion imaging (Fig. 1, 2). Pulse inversion imaging is a newly developed one, which uses the full ban...

2004
D. J. Wildish G. W. Pohle B. T. Hargrave L. M. Mayer

Acoustic backscatter contrast in depositional sediments under salmon farm cages in the Bay of Fundy, Canada, was correlated with localized changes in (unknown) sediment geotechnical properties, as indicated by 4 independent measures of organic enrichment. Sediment total sulfides and redox potentials, enzyme hydrolyzable amino acids, sediment profile imaging and macrofaunal samples, taken at mid...

2012
Pertti Palo Daniel Aalto Olli Aaltonen Risto-Pekka Happonen Jarmo Malinen Jani Saunavaara Martti Vainio

We present anatomic and acoustic data from a pilot study on the Finnish vowels [A, e, i, o, u, y, æ, ø]. The data were acquired simultaneously with 3D magnetic resonance imaging (MRI) and a custom built sound recording system. The data consist of a single static repetition of each vowel with constant f0. The imaging sequence was 7.6 s long and had an isotropic voxel size of 1.8 mm. We report re...

2009
M. Andrecut

Computational time reversal imaging can be used to locate the position of multiple scatterers in a known background medium. The current methods for computational time reversal imaging are based on the null subspace projection operator, obtained through the singular value decomposition of the frequency response matrix. Here, we discuss the image recovery problem from a small number of random and...

2011
Jason R. Cook Richard R. Bouchard Stanislav Y. Emelianov

In both photoacoustic (PA) and ultrasonic (US) imaging, overall image quality is influenced by the optical and acoustical properties of the medium. Consequently, with the increased use of combined PA and US (PAUS) imaging in preclinical and clinical applications, the ability to provide phantoms that are capable of mimicking desired properties of soft tissues is critical. To this end, gelatin-ba...

2002
G. S. Shekhawat H. Xie Y. Zheng R. E. Geer

The investigation of an alternate approach to nondestructive, nanoscale mechanical imaging for IC interconnect structures is reported. This approach utilizes a heterodyne interferometer based on a scanning probe microscope, also referred to as heterodyne force microscopy (HFM). This interferometer is sensitive to the relative phase difference of the two ultrasonic excitations due to spatial var...

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