A new contour-tracking algorithm is presented for ultrasound tongue image sequences, which can follow the motion of tongue contours over long durations with good robustness. To cope with missing segments caused by noise, or by the tongue midsagittal surface being parallel to the direction of ultrasound wave propagation, active contours with a contour-similarity constraint are introduced, which ...

This work investigates the potential use of direct ultrasonic vibration as an aid to penetration of granular material. Compared with non-ultrasonic penetration, required forces have been observed to reduce by an order of magnitude. Similarly, total consumed power can be reduced by up to 27%, depending on the substrate and ultrasonic amplitude used. Tests were also carried out in high-gravity co...

Ultrasound is a form of mechanical energy with its acoustic pressure wave at frequencies range from 20 to 20,000 Hz. To date, ultrasound waves are not only used in imaging medicine for diagnosis, but also are performed in physical therapy (PT) medicine for the purpose of preventing and curing disease due to its thermal and nonthermal effects, and the ultrasound frequencies used in

We study a novel method of quasi-phase-matching for third harmonic generation in a gas cell using the periodic modulation of the gas pressure and thus of the third order nonlinear coefficient in the axial direction created by an ultrasound wave. Using a comprehensive numerical model we describe the quasi-phase matched third harmonic generation of UV (at 266 nm) and VUV pulses (at 133 nm) by usi...

Micro-electric discharge machining (μ-EDM) is an important manufacturing process that is able to produce components and tools with micro-features. Improvement to this process has resulted in the use of powder mixed dielectric (PMD), which results in better surface quality and faster machining time. However, the presence of conductive powder in the dielectric fluid negatively affects the accurac...

When averaged over sources or disorder, cross correlation of diffuse fields yields the Green's function between two passive sensors. This technique is applied to elastic ultrasonic waves in an open scattering slab mimicking seismic waves in the Earth's crust. It appears that the Rayleigh wave reconstruction depends on the scattering properties of the elastic slab. Special attention is paid to t...

Ultrasound is a form of mechanical energy with its acoustic pressure wave at frequencies range from 20 to 20,000 Hz. To date, ultrasound waves are not only used in imaging medicine for diagnosis, but also are performed in physical therapy (PT) medicine for the purpose of preventing and curing disease due to its thermal and nonthermal effects, and the ultrasound frequencies used in

We present a method to determine the speed of sound in tissue using a double-ring photoacoustic sensor working in reflection mode. This method uses the cross-correlation between the laser-induced ultrasound waves detected by two concentric ring shaped sensors, while a priori information about the depth-position of the photoacoustic source is not required. We demonstrate the concept by estimatin...

A novel frequency-swept ultrasound-modulated optical tomography technique was developed to image scattering media. A frequency-swept ultrasonic wave was used to modulate the laser light passing through a scattering medium. The modulated light was received by an optical detector and was heterodyned with a reference frequency sweep. The heterodyned signal was recorded in the time domain and was t...

INTRODUCTION Automation of ultrasonic testing procedures is a kind of non-destructive testing procedures, which is involves the use of both longitudinal and transverse high-frequency sound waves for the exploration and/or mapping of both surface and sub-surface defect or irregularities. Of course the material thickness or the material loss (corrosions/ erosions) can also be observed by the conc...