Intonational structure in Japanese and English

Comparisons between Japanese and English prosodics have usually either focused on the strikingly apparent phonetic differences between the stress patterns of English and the tonal accent patterns of Japanese or concentrated upon formal similarities between the abstract arrangements of the stresses and tones. A recent investigation of tone structure in Japanese (Pierrehumbert & Beckman forthcoming), however, has convinced us that if the proper prosodic phenomena are compared, far more pervasive similarities can be discovered and of a much more concrete sort than hitherto suspected. In particular, there is now extensive evidence that Japanese tonal patterns are very sparsely specified, which suggests that they are much more similar to English intonational structures than earlier descriptions would have allowed.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S095267570000066X

Localized fluid flow measurements with an He-Ne laser spectrometer

A method for estimating structural properties of random media is described. The size, number density, and scattering strength of particles are estimated from an analysis of the radio frequency (rf) echo signal power spectrum. Simple correlation functions and the accurate scattering theory of Faran [J.J. Faran, J. Acoust. Soc. Am. 23, 405-418 (1951)], which includes the effects of shear waves, were used separately to model backscatter from spherical particles and thereby describe the structures of the medium. These methods were tested using both glass sphere-in-agar and polystyrene sphere-in-agar scattering media. With the appropriate correlation function, it was possible to measure glass sphere diameters with an accuracy of 20%. It was not possible to accurately estimate the size of polystyrene spheres with the simple spherical and Gaussian correlation models examined because of a significant shear wave contribution. Using the Faran scattering theory for spheres, however, the accuracy for estimating diameters was improved to 10% for both glass and polystyrene scattering media. It was possible to estimate the product of the average scattering particle number density and the average scattering strength per particle, but with lower accuracy than the size estimates. The dependence of the measurement accuracy on the inclusion of shear waves, the wavelength of sound, and medium attenuation are considered, and the implications for describing the structure of biological soft tissues are discussed.

/pdf/describing-small-scale-structure-in-random-media-using-pulse-707xxdgwi8.pdf

Describing small-scale structure in random media using pulse-echo ultrasound.

Three-dimensional (3D) sensing and imaging technologies have been extensively researched for many applications in the fields of entertainment, medicine, robotics, manufacturing, industrial inspection, security, surveillance, and defense due to their diverse and significant benefits. Integral imaging is a passive multiperspective imaging technique, which records multiple two-dimensional images of a scene from different perspectives. Unlike holography, it can capture a scene such as outdoor events with incoherent or ambient light. Integral imaging can display a true 3D color image with full parallax and continuous viewing angles by incoherent light; thus it does not suffer from speckle degradation. Because of its unique properties, integral imaging has been revived over the past decade or so as a promising approach for massive 3D commercialization. A series of key articles on this topic have appeared in the OSA journals, including Applied Optics. Thus, it is fitting that this Commemorative Review presents an overview of literature on physical principles and applications of integral imaging. Several data capture configurations, reconstruction, and display methods are overviewed. In addition, applications including 3D underwater imaging, 3D imaging in photon-starved environments, 3D tracking of occluded objects, 3D optical microscopy, and 3D polarimetric imaging are reviewed.

https://www.uv.es/imaging3/PDFs/2013_AO_52_0546.pdf

Advances in three-dimensional integral imaging: sensing, display, and applications [Invited]

https://iopscience.iop.org/article/10.1143/JJAP.17.1683/pdf

3-D Display System Using a Computer Generated Integral Photograph

This paper describes spectral analyses of echoes scattered by a random medium and a plane reflector by using mathematical expressions of echoes which have been proposed by us before [M. Ueda and H. Ichikawa, J. Acoust. Soc. Am. 70, 1768–1775 (1981): 75, 1012 (1984)]. It becomes possible to express the spectrum of echoes scattered by the random medium in terms of a backscattering coefficient of the random medium and a velocity potential of an ultrasonic transducer. The expressions hold for any sound field if a correlation length of the random medium is much smaller than a beamwidth and a radius of the transducer. Then the spectrum of the echo scattered by the plane reflector is expressed in terms of a directivity of the transducer. By using a ratio of the two spectrums an expression which gives the backscattering coefficient of the random medium is formulated. It works in a farfield of a flat circular transducer and at a focal plane of a concave one. It is shown that our formula contains those cases which have been proposed so far as the extreme cases of the conditions. Finally, the backscattering coefficients of sponges are measured with several transducers. The results show that our formula gives the coefficients regardless of the transducer geometry.

Spectral analysis of echoes for backscattering coefficient measurement

The solution of sound scattering of a plane wave obliquely incident on an isotropic elastic cylinder of infinite length is obtained and verified by experiment. The solution is expressed in terms of phase angles associated with partial scattered waves. It is found that, when the angle of incidence is small, supplementary resonances, which are not present in the case of normal incidence, are excited. The peaks and dips resulting from the resonances appear in the farfield form function ‖f∞‖. Experimental results for several different metals show good agreement with the calculated ones.

Sound scattering of a plane wave obliquely incident on a cylinder

An echo signal reflected from a weakly scattering volume is analyzed by using the wave equation for an inhomogeneous medium and a discrete model of the medium. The discrete model means that the medium is represented by a pile of small cubes which have uniform density and sound velocity, and the size of the cubes is assumed to be much smaller than the wavelength of ultrasonic waves. By adopting the discrete model, simple and understandable relations are obtained from the wave equation for an inhomogeneous medium. The analysis shows that the difference between echo signals scattered by density and velocity fluctuations becomes appreciable when the distance between the scatterer and a transducer is less than a radius of the transducer. The difference was detected experimentally and shows rather good agreement with the theory. Furthermore, relations are obtained which describe echo signals resulting from an arbitrary incident wave in terms of the fluctuation of specific acoustic impedance of medium. These rel...

Analysis of an echo signal reflected from a weakly scattering volume by a discrete model of the medium

This letter describes the principle and the fundamental results of experiments of a synthetic aperture sonar which enables us to resolve objects both in angle and range more sharply than the conventional ultrasonic imaging system The basic idea of this technique is to introduce pulsed waveforms to ultrasonic holography and its operations consist of collecting hologram signals with ultrasonic pulses and using a computer for storage of these signals and image calculation The elementary experiments were carried out using a single‐wire target and ultrasonic waves of 1 MHz whose pulse duration was 12 μsec The wire was set at a distance of 158 mm below the transducers and they were scanned over the hologram aperture of 50 mm across the wire The results of the computer reconstruction were coincident with the theoretically expected values

Mitsuhiro Ueda

Papers

3-D Display System Using a Computer Generated Integral Photograph

Spectral analysis of echoes for backscattering coefficient measurement

Sound scattering of a plane wave obliquely incident on a cylinder

Analysis of an echo signal reflected from a weakly scattering volume by a discrete model of the medium

Synthetic aperture sonar