The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform

S. I. Prokofjev - One of the best experts on this subject based on the ideXlab platform.

  • Estimation of Surface tension of grain boundaries in allotropes of elements
    Journal of Materials Science, 2019
    Co-Authors: S. I. Prokofjev
    Abstract:

    Recently (Prokofjev in J Mater Sci 52:4265–4277, 2017. https://doi.org/10.1007/s10853-016-0681-2 ), the empirical expressions representing the Surface tension of general-type high-angle grain boundaries in elemental solids as a function of their melting temperature and molar volume in the solid state at the melting temperature were proposed. In this paper, the application of the expressions to estimate the grain Boundary Surface tension in the allotropes of elemental solid, which do not melt but transform to the higher-temperature allotrope, is described. The parameters of the temperature dependences of grain Boundary Surface tension in allotropes of 22 elemental solids are presented.

  • Estimations of grain-Boundary Surface tension in elemental solids
    Journal of Materials Science, 2017
    Co-Authors: S. I. Prokofjev
    Abstract:

    The empiric equations estimating the temperature dependences of average Surface tension of high-angle grain boundaries in elemental solids are presented. The grain boundaries are considered as a homogeneous liquid-like layer in a solid matrix. The expressions present the grain-Boundary Surface tension as functions of the melting temperature, melting enthalpy, and molar volume of the elemental solid at the melting temperature. The empiric expressions relating grain-Boundary Surface tension with the Surface tensions of elements in the solid and liquid states at melting temperature are obtained on this basis. The relations proposed can be useful to estimate the averaged Surface tension of high-angle grain boundaries in elemental solids at high enough homologous temperature.

Lisheng Wang - One of the best experts on this subject based on the ideXlab platform.

  • Detection and Reconstruction of an Implicit Boundary Surface by Adaptively Expanding A Small Surface Patch in a 3D Image
    IEEE transactions on visualization and computer graphics, 2014
    Co-Authors: Lisheng Wang, Pai Wang, Liuhang Cheng, Yu-ping Wang
    Abstract:

    In this paper we propose a novel and easy to use 3D reconstruction method. With the method, users only need to specify a small Boundary Surface patch in a 2D section image, and then an entire continuous implicit Boundary Surface (CIBS) can be automatically reconstructed from a 3D image. In the method, a hierarchical tracing strategy is used to grow the known Boundary Surface patch gradually in the 3D image. An adaptive detection technique is applied to detect Boundary Surface patches from different local regions. The technique is based on both context dependence and adaptive contrast detection as in the human vision system. A recognition technique is used to distinguish true Boundary Surface patches from the false ones in different cubes. By integrating these different approaches, a high-resolution CIBS model can be automatically reconstructed by adaptively expanding the small Boundary Surface patch in the 3D image. The effectiveness of our method is demonstrated by its applications to a variety of real 3D images, where the CIBS with complex shapes/branches and with varying gray values/gradient magnitudes can be well reconstructed. Our method is easy to use, which provides a valuable tool for 3D image visualization and analysis as needed in many applications.

  • BMEI - Boundary Surface detection in 3D biomedical images based on local gradient thresholds
    2011 4th International Conference on Biomedical Engineering and Informatics (BMEI), 2011
    Co-Authors: Pai Wang, Liuhang Cheng, Bin Lin, Lisheng Wang
    Abstract:

    This paper proposes a method to detect the Boundary Surface with continuously changed gradient magnitudes from 3D biomedical images. Instead of selecting a constant gradient threshold, which sometimes cannot correctly separate such Boundary Surfaces from 3D images, the proposed method adaptively computes different local gradient thresholds in different local regions and uses them to detect different Boundary Surface patches. Using such scheme, the proposed method not only can well detect those Boundary Surfaces with uniformly high gradient magnitudes, but also can effectively detect the Boundary Surfaces with continuously varied gradient magnitudes from low to high. The performance of the method is illustrated by many examples from different 3D biomedical images.

  • A new strategy for Boundary Surface detection in 3D biomedical images
    2010 3rd International Conference on Biomedical Engineering and Informatics, 2010
    Co-Authors: Liuhang Cheng, Lisheng Wang, Yu Ma
    Abstract:

    Detecting Boundary Surface for the object of interest within 3D biomedical images is an important step towards understanding and quantitative analysis of the object. However, existing 3D edge detection techniques have the limitations in detecting connected edge voxels and tracing undetected edge voxels from 3D images. In this paper, we propose a new strategy to detect Boundary Surface for the object of interest in 3D biomedical image. The new strategy utilizes the connectivity of Boundary Surface in the detection and tracing of edge voxels, and is much effective in overcoming the two limitations existing in 3D edge detectors. The performance and advantages of the proposed method are illustrated by many examples from different 3D biomedical images.

  • IsoSurfaces computation for approximating Boundary Surfaces within three-dimensional images
    Journal of Electronic Imaging, 2007
    Co-Authors: Lisheng Wang, Jing Bai, Tien-tsin Wong, Pheng-ann Heng
    Abstract:

    In the visualization of three-dimensional (3D) images, specific isoSurfaces are usually extracted from 3D images and used to represent (approximate) Boundary Surfaces of certain structures within 3D images. In order to well approximate the Boundary Surfaces of these structures, it is important to determine a good isoSurface for each Boundary Surface. An isoSurface is said to be a good isoSurface of a Boundary Surface if it can approximate the Boundary Surface with the smallest error under certain error measuring criteria. The mathematical model describing the approximation problem of a Boundary Surface by isoSurfaces is constructed and studied. The method used to deduce good isoSurfaces for the Boundary Surfaces within 3D discrete images is presented. The proposed method is illustrated by examples with different real 3D biomedical images.

  • A Computational Framework for Approximating Boundary Surfaces in 3-D Biomedical Images
    IEEE Transactions on Information Technology in Biomedicine, 2007
    Co-Authors: Lisheng Wang, Pheng-ann Heng, Ping He, Xin Yang
    Abstract:

    We propose a new method for detecting and approximating the Boundary Surfaces in three-dimensional (3-D) biomedical images. Using this method, each Boundary Surface in the original 3-D image is normalized as a zero-value isoSurface of a new 3-D image transformed from the original 3-D image. A novel computational framework is proposed to perform such an image transformation. According to this framework, we first detect Boundary Surfaces from the original 3-D image and compute discrete samplings of the Boundary Surfaces. Based on these discrete samplings, a new 3-D image is constructed for each Boundary Surface such that the Boundary Surface can be well approximated by a zero-value isoSurface in the new 3-D image. In this way, the complex problem of reconstructing Boundary Surfaces in the original 3-D image is converted into a task to extract a zero-value isoSurface from the new 3-D image. The proposed technique is not only capable of adequately reconstructing complex Boundary Surfaces in 3-D biomedical images, but it also overcomes vital limitations encountered by the isoSurface-extracting method when the method is used to reconstruct Boundary Surfaces from 3-D images. The performances and advantages of the proposed computational framework are illustrated by many examples from different 3-D biomedical images.

Yue Zhao - One of the best experts on this subject based on the ideXlab platform.

  • 3D automatic segmentation method for retinal optical coherence tomography volume data using Boundary Surface enhancement
    Journal of Innovative Optical Health Sciences, 2016
    Co-Authors: Yankui Sun, Tian Zhang, Yue Zhao
    Abstract:

    With the introduction of spectral-domain optical coherence tomography (SD-OCT), much larger image datasets are routinely acquired compared to what was possible using the previous generation of time-domain OCT. Thus, there is a critical need for the development of three-dimensional (3D) segmentation methods for processing these data. We present here a novel 3D automatic segmentation method for retinal OCT volume data. Briefly, to segment a Boundary Surface, two OCT volume datasets are obtained by using a 3D smoothing filter and a 3D differential filter. Their linear combination is then calculated to generate new volume data with an enhanced Boundary Surface, where pixel intensity, Boundary position information, and intensity changes on both sides of the Boundary Surface are used simultaneously. Next, preliminary discrete Boundary points are detected from the A-Scans of the volume data. Finally, Surface smoothness constraints and a dynamic threshold are applied to obtain a smoothed Boundary Surface by corre...

  • 3D automatic segmentation method for retinal optical coherence tomography volume data using Boundary Surface enhancement
    Journal of Innovative Optical Health Sciences, 2016
    Co-Authors: Yankui Sun, Tian Zhang, Yue Zhao
    Abstract:

    With the introduction of spectral-domain optical coherence tomography (SD-OCT), much larger image datasets are routinely acquired compared to what was possible using the previous generation of time-domain OCT. Thus, there is a critical need for the development of three-dimensional (3D) segmentation methods for processing these data. We present here a novel 3D automatic segmentation method for retinal OCT volume data. Briefly, to segment a Boundary Surface, two OCT volume datasets are obtained by using a 3D smoothing filter and a 3D differential filter. Their linear combination is then calculated to generate new volume data with an enhanced Boundary Surface, where pixel intensity, Boundary position information, and intensity changes on both sides of the Boundary Surface are used simultaneously. Next, preliminary discrete Boundary points are detected from the A-Scans of the volume data. Finally, Surface smoothness constraints and a dynamic threshold are applied to obtain a smoothed Boundary Surface by correcting a small number of error points. Our method can extract retinal layer Boundary Surfaces sequentially with a decreasing search region of volume data. We performed automatic segmentation on eight human OCT volume datasets acquired from a commercial Spectralis OCT system, where each volume of datasets contains 97 OCT B-Scan images with a resolution of [Formula: see text] (each B-Scan comprising 512 A-Scans containing 496 pixels); experimental results show that this method can accurately segment seven layer Boundary Surfaces in normal as well as some abnormal eyes.

  • 3D Automatic Segmentation Method for Retinal Optical Coherence Tomography Volume Data Using Boundary Surface Enhancement
    arXiv: Computer Vision and Pattern Recognition, 2015
    Co-Authors: Yankui Sun, Tian Zhang, Yue Zhao
    Abstract:

    With the introduction of spectral-domain optical coherence tomography (SDOCT), much larger image datasets are routinely acquired compared to what was possible using the previous generation of time-domain OCT. Thus, there is a critical need for the development of 3D segmentation methods for processing these data. We present here a novel 3D automatic segmentation method for retinal OCT volume data. Briefly, to segment a Boundary Surface, two OCT volume datasets are obtained by using a 3D smoothing filter and a 3D differential filter. Their linear combination is then calculated to generate new volume data with an enhanced Boundary Surface, where pixel intensity, Boundary position information, and intensity changes on both sides of the Boundary Surface are used simultaneously. Next, preliminary discrete Boundary points are detected from the A-Scans of the volume data. Finally, Surface smoothness constraints and a dynamic threshold are applied to obtain a smoothed Boundary Surface by correcting a small number of error points. Our method can extract retinal layer Boundary Surfaces sequentially with a decreasing search region of volume data. We performed automatic segmentation on eight human OCT volume datasets acquired from a commercial Spectralis OCT system, where each volume of data consisted of 97 OCT images with a resolution of 496 512; experimental results show that this method can accurately segment seven layer Boundary Surfaces in normal as well as some abnormal eyes.

Amares Chattopadhyay - One of the best experts on this subject based on the ideXlab platform.

  • Influence of corrugated Boundary Surface and reinforcement of fibre-reinforced layer on propagation of torsional Surface wave
    Journal of Vibration and Control, 2016
    Co-Authors: Abhishek Kumar Singh, Anirban Lakshman, Amares Chattopadhyay
    Abstract:

    These days fibre-reinforced materials are frequently used in construction sector for example in dams, bridges etc. Also the earth structure and artificial structure made by human may contain irregularity or corrugation, therefore, propagation of waves and vibrations through these structures gets affected by them. Motivated by these facts the present problem aims to study the propagation of torsional Surface wave in a fibre-reinforced layer with corrugated Boundary Surface overlying an initially stressed transversely isotropic half-space. The closed form of the dispersion equation has been deduced and the notable effect of reinforcement, undulatory parameter of corrugated Boundary Surfaces of the layer, corrugation parameter of upper and lower Boundary Surfaces of the layer, initial stress acting in half-space and wave number on the phase velocity of torsional Surface wave has been exhibited. The numerical computation along with graphical illustration has been carried out for fibre-reinforced layer of carb...

Shiro Ise - One of the best experts on this subject based on the ideXlab platform.

  • Optimization of loudspeaker and microphone configurations for sound reproduction system based on Boundary Surface control principle - An optimizing approach using Gram-Schmidt orthogonalization and its evaluation -
    2010
    Co-Authors: Seigo Enomoto, Yusuke Ikeda, Shiro Ise, Satoshi Nakamura
    Abstract:

    We propose a 3-D sound reproduction system based on the Boundary Surface control principle (BoSC system) and evaluate its performance via demonstration and exhibition. The BoSC reproduction system, dome-shaped and constructed of wood, consists of 62 full-range loudspeakers and eight subwoofer loudspeakers. The BoSC recording system is designed from C80 fullerene consisting of 70 microphones of a 46-cm diameter. In the listening room, 62 full-range loudspeakers assisted by the designed inverse filters reproduce sound fields identical to the primary sound fields by reproducing sound pressure on the 70 microphones which surround the listener’s head. The BoSC system requires huge numerical calculation to reproduce authentic 3-D sound fields. Consequently, a pre-convolution calculation of the inverse filters is required to reproduce and transmit these fields. Therefore, to realize a real-time 3-D sound field reproduction system, we investigated optimization of the loudspeaker and microphone configuration using Gram-Schmidt orthogonalization. In the BoSC system, the inverse filters are determined by an inverse system of a transfer function matrix measured between each loudspeaker and microphone pair. Therefore, a transfer function matrix with a huge condition number degrades the accuracy of the reproduced sound fields. The selection of loudspeakers in the active control system that includes the BoSC system is equal to the selection of a vertical vector in the transfer function matrix. This means that for the reduction of the number of loudspeakers the vertical vector is selected up to the required numbers. By applying Gram-Schmidt orthogonalization to the selection of loudspeakers, the loudspeaker is selected in the order of linear independence from highest to lowest. In this paper, the effect of the reduction of loudspeakers and microphones is evaluated by the subjective assessment of a sound image localization test.

  • A theoretical study of the discretization of the Boundary Surface in the Boundary Surface control principle
    Acoustical Science and Technology, 2006
    Co-Authors: Takahiro Nakashima, Shiro Ise
    Abstract:

    On the basis of the Boundary Surface control (BSC) principle, it is possible to control the sound field within a volume by controlling the sound pressure and particle velocity on a Surface. It is, however, impossible to realize an active noise control (ANC) system, which controls both the sound pressure and particle velocity at all points on the Surface. Therefore, we have to control these at discrete points on the Surface. In conventional numerical studies, it is known that the discretization of the Surface decreases the effectiveness of the ANC system. To determine the amount of discretization, which is equal to the number of error sensors, we have to know the relationship between the discretization of the Surface and the effectiveness of the ANC system quantitatively. In this study, we aim to establish a method of quantifying the relationship between the discretization of the Surface and the control effectiveness in the ANC system on the basis of the BSC principle. Furthermore, we derive the arrangement of the error sensors required to obtain a desired effectiveness within a circular area using the derived equation.

  • The Boundary Surface Control Principle and Its Applications
    IEICE Transactions on Fundamentals of Electronics Communications and Computer Sciences, 2005
    Co-Authors: Shiro Ise
    Abstract:

    In order to control a sound field using multiple sources and microphones, we must choose the optimum values of parameters such as the numbers of sources and microphones, the location of the sources and the microphones and the filter tap length. Because there is a huge number of possible combinations of these conditions, the Boundary Surface control principle can be useful as a basis of a design method of such a system. In this paper, a design method of sound field reproduction and active noise control based on the BSC principle are described and several example of its application are presented.

  • A proposal of the directional speaker system based on the Boundary Surface control principle
    Electronics and Communications in Japan (Part III: Fundamental Electronic Science), 2004
    Co-Authors: Seigo Enomoto, Shiro Ise
    Abstract:

    According to the Boundary Surface control principle, it is possible to reflect the flow of acoustic energy at a Boundary if a Boundary Surface with impedance 0 can be formed by controlling the sound pressure and the particle velocity at an arbitrary position in space. If this principle is used in such a way that a Boundary Surface is formed only in the direction not intended for radiation of the sound, then a directional speaker system can be realized. In the conventional design method of the directional speaker array system, in order to achieve sharp directivity in the low frequencies, it is necessary to enlarge the array length. On the other hand, in our proposed system, it is easy to achieve sharp directivity in the low frequencies, since the Boundary Surface control principle can achieve high performance in the low frequencies. Moreover, by changing the control sound source spacing for each bandwidth, rather flat characteristics can be obtained over the entire control range. In this paper, the basic characteristics constituting guidelines for system design and the effect of control are confirmed by numerical calculations and experiments. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 88(2): 1–9, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20122

  • Active noise barrier based on the Boundary Surface control
    The Journal of the Acoustical Society of America, 1998
    Co-Authors: Shiro Ise, Hideki Tachibana
    Abstract:

    Based on the principle of the Boundary Surface control, it is possible to make a Surface which reflects acoustic energy flow by controlling the pressure and its gradient on the Surface. In order to realize this method, a system has to be made using multiple speakers and multiple microphones. The system should be adjusted so that the output signals of the multiple microphones which are located on the Surface considered to be the location of the barrier are minimized. By changing the distance between the microphones, the best effect of the active noise barrier can be obtained. For instance, in a level lower to the ground, many microphones are needed to control higher frequencies. On the other hand, in a level higher from the ground, it is not necessary to use so many microphones to control lower frequencies. The merit of this method is that the apparent height of the barrier, depending on the frequency considered, can be changed. In this paper, the active noise barrier based on the Boundary Surface control ...