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Removing fences from sweep motion videos using global 3D reconstruction and fence-aware light field rendering

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Computational Visual Media 2019年第1期5卷 21-32页

作者： Chanya Lueangwattana Shohei Mori hideo saito Department of Science and Technology Keio University Institute of Computer Graphics and Vision Graz University of Technology

Diminishing the appearance of a fence in an image is a challenging research area due to the characteristics of fences(thinness, lack of texture, etc.) and the need for occluded background restoration. In this paper, we describe a fence removal method for an image sequence captured by a user making a sweep motion, in which occluded background is potentially observed. To make use of geometric and appearance information such as consecutive images, we use two well-known approaches: structure from motion and light field rendering. Results using real image sequences show that our method can stably segment fences and preserve background details for various fence and background combinations. A new video without the fence, with frame coherence, can be successfully provided.

关键词： video fence video repair diminished reality(DR) structure from motion(SfM) light field rendering(LFR)

On-line Free-viewpoint Video:From Single to Multiple View Rendering

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International Journal of Automation and computing 2008年第3期5卷 257-267页

作者： Vincent Nozick hideo saito Graduate School of Science and Technology Keio University

In recent years, many image-based rendering techniques have advanced from static to dynamic scenes and thus become video-based rendering （VBR） methods. But actually, only a few of them can render new views on-line. We present a new VBR system that creates new views of a live dynamic scene. This system provides high quality images and does not require any background subtraction. Our method follows a plane-sweep approach and reaches real-time rendering using consumer graphic hardware, graphics processing unit （GPU）. Only one computer is used for both acquisition and rendering. The video stream acquisition is performed by at least 3 webcams. We propose an additional video stream management that extends the number of webcams to 10 or more. These considerations make our system low-cost and hence accessible for everyone. We also present an adaptation of our plane-sweep method to create simultaneously multiple views of the scene in real-time. Our system is especially designed for stereovision using autostereoscopic displays. The new views are computed from 4 webcams connected to a computer and are compressed in order to be transfered to a mobile phone. Using GPU programming, our method provides up to 16 images of the scene in real-time. The use of both GPU and CPU makes this method work on only one consumer grade computer.

关键词： Video-based rendering (VBR) free-viewpoint video view interpolation graphics processing unit (GPU) webcam stereovision autostereoscopic.

Synthesis of a stroboscopic image from a hand-held camera sequence for a sports analysis

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Computational Visual Media 2016年第3期2卷 277-289页

作者： Kunihiro Hasegawa hideo saito Keio University

This paper presents a method for synthesizing a stroboscopic image of a moving sports player from a hand-held camera sequence. This method has three steps: synthesis of background image,synthesis of stroboscopic image, and removal of player's shadow. In synthesis of background image step, all input frames masked a bounding box of the player are stitched together to generate a background image. The player is extracted by an HOG-based people *** synthesis of stroboscopic image step, the background image, the input frame, and a mask of the player synthesize a stroboscopic image. In removal of shadow step, we remove the player's shadow which negatively affects an analysis by using mean-shift. In our previous work, synthesis of background image has been timeconsuming. In this paper, by using the bounding box of the player detected by HOG and by subtracting the images for synthesizing a mask, computational speed and accuracy can be improved. These have contributed greatly to the improvement from the previous *** are main improvements and novelty points from our previous method. In experiments, we confirmed the effectiveness of the proposed method, measured the player's speed and stride length, and made a footprint image. The image sequence was captured under a simple condition that no other people were in the background and the person controlling the video camera was standing still, such like a motion parallax was not occurred. In addition, we applied the synthesis method to various scenes to confirm its versatility.

关键词： sports vision stroboscopic image stitching mask synthesis

FusionMLS:Highly dynamic 3D reconstruction with consumergrade RGB-D cameras

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Computational Visual Media 2018年第4期4卷 287-303页

作者： Siim Meerits Diego Thomas Vincent Nozick hideo saito Department of Information and Computer Science Keio University Department of Advanced Information Technology Kyushu University LIGM UMR 8049Universit'e Paris-Est Marne-la-Vall'ee Japanese–French Laboratory for Informatics CNRS

Multi-view dynamic three-dimensional reconstruction has typically required the use of custom shutter-synchronized camera rigs in order to capture scenes containing rapid movements or complex topology changes. In this paper, we demonstrate that multiple unsynchronized low-cost RGB-D cameras can be used for the same purpose. To alleviate issues caused by unsynchronized shutters, we propose a novel depth frame interpolation technique that allows synchronized data capture from highly dynamic 3 D scenes. To manage the resulting huge number of input depth images, we also introduce an efficient moving least squares-based volumetric reconstruction method that generates triangle meshes of the scene. Our approach does not store the reconstruction volume in memory,making it memory-efficient and scalable to large *** implementation is completely GPU based and works in real time. The results shown herein, obtained with real data, demonstrate the effectiveness of our proposed method and its advantages compared to stateof-the-art approaches.

关键词： 3D reconstruction RGB-D cameras motion capture GPU

PCA-based 3D Shape Reconstruction of Human Foot Using Multiple Viewpoint Cameras

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International Journal of Automation and computing 2008年第3期5卷 217-225页

作者： Edmée Amstutz Tomoaki Teshima Makoto Kimura Masaaki Mochimaru hideo saito Graduate School of Science and Technology Keio University Digital Human Research Center National Institute of Advanced Industrial Science and Technology(AIST)

This paper describes a multiple camera-based method to reconstruct the 3D shape of a human foot. From a foot database, an initial 3D model of the foot represented by a cloud of points is built. The shape parameters, which can characterize more than 92% of a foot, are defined by using the principal component analysis method. Then, using ＂active shape models＂, the initial 3D model is adapted to the real foot captured in multiple images by applying some constraints （edge points＇ distance and color variance）. We insist here on the experiment part where we demonstrate the efficiency of the proposed method on a plastic foot model, and also on real human feet with various shapes. We propose and compare different ways of texturing the foot which is needed for reconstruction. We present an experiment performed on the plastic foot model and on human feet and propose two different ways to improve the final 3D shapers accuracy according to the previous experiments＇ results. The first improvement proposed is the densification of the cloud of points used to represent the initial model and the foot database. The second improvement concerns the projected patterns used to texture the foot. We conclude by showing the obtained results for a human foot with the average computed shape error being only 1.06 mm.

关键词： Shape measurement 3D reconstruction from multiview cameras principal component analysis

Effects of Particle Size on Microstructure of the Matrix Alloy in Aluminum Matrix Composites

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Effects of Particle Size on Microstructure of the Matrix All...

Natural Convection Melting in a Rectangular Heat Storage Tank of Carbon Nanotube Dispersed Latent Heat Storage Material

International Conference on Aerospace Materials(ICAM 2006)

作者： Norio kouno hideo saito Department of Metallurgical Engineering Chiba Institute of Technology Japan Analysis Center of Materials Chiba Institute of Technology Japan

Aluminum matrix composites, reinforced by 0.15μm and 5μm Al2O3 particles with 40% volume fractions were fabricated by squeeze casting technique. The microstructure characterization near the interfaces of Al2O3p/1070Al composites was investigated by SADP and HREM techniques. Results showed that high-density dislocations were generated in the 5μm-Al2O3p/Al composite due to the thermal mismatch stress. In contrast, the matrix of the 0.15μm-Al2O3p/Al composite appeared to be nearly free dislocations and some "micro distortion areas" of 1-5nm were observed, which was attributed to the dispersion of fine sub-micron particles and uniform distribution of the stress near the interfaces.

关键词： Metal matrix composites Al2O3p/Al sub-micron Al2O3 particles Microstructure

来源： cnki会议评论

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Journal of Thermal Science 2024年第3期33卷 847-855页

作者： Shin-ichi MORITA Tomoya saito Kazunori TAKAI Yasutaka HAYAMIZU Naoto HARUKI Division of Mechanical and Electrical Engineering Kitami Institute of Technology165 Koen-choKitami-shiHokkaido090-8507Japan National Institute of Technology Yonago College4448 Hikona-cyoYonago-shiTottori683-8502Japan Okayama Prefectural University 111 KubokiSoja-shiOkayama719-1197Japan

A dispersion system fluid can convect even if the dispersoid is a solid ***,heat exchange performance can be improved while maintaining fluidity using a material with high thermal conductivity as the *** study presents the melting performance evaluation results of a latent heat storage material with a carbon nanotube(CNT)dispersion system with high thermal conductivity,which enhances the thermal conductivity of the latent heat storage material and does not limit free *** the thermal conductivity and enhancing the melting convection of the heat storage material result in increased latent heat storage *** this study,the thermal conductivity of the latent heat storage material was successfully increased by dispersing CNTs in the *** 0.1%(in mass)of multi-wall CNT(MWCNT)was dispersed in a paraffin-based latent heat storage material,the shear stress increased by 1.5 times at a shear rate of 500 s^(-1),while taking into account the potential effects of convective ***,a latent heat storage experiment was conducted in a rectangular heat storage tank using the CNT dispersion composition ratio as a parameter.A rectangular vessel with a heated vertical surface was used for the latent heat storage *** melting speed was determined by comparing the amount of latent heat stored in a CNT-dispersed latent heat storage material and a single-phase latent heat storage material *** experimental results show that the time required for the latent heat storage material to completely melt in the heat storage tank was the shortest for the single-phase latent heat storage material ***,the fastest melting progress was observed for the sample with 0.02%(in mass)MWCNT content in the melting rate range of up to approximately 40%in the *** results indicate that this phenomenon is caused by the difference in the melting rates in the upper part of the *** generated data are useful for det

关键词： latent heat storage phase change carbon nano tube free convection heat transfer

Exploiting open source omics data to advance pancreas research

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Journal of Pancreatology 2024年第1期7卷 21-27页

作者： Gayathri Swaminathan Toshie saito Sohail Z.Husain Division of Gastroenterology Hepatology and NutritionDepartment of PediatricsStanford University School of MedicineStanfordCA

The"omics"revolution has transformed the biomedical research landscape by equipping scientists with the ability to interrogate complex biological phenomenon and disease processes at an unprecedented *** volume of"big"data generated by the different omics studies such as genomics,transcriptomics,proteomics,and metabolomics has led to the concurrent development of computational tools to enable in silico analysis and aid data *** the intensive resources and high costs required to generate and analyze big data,there has been centralized,collaborative efforts to make the data and analysis tools freely available as"Open Source,"to benefit the wider research *** research studies have contributed to this"big data rush"and have additionally benefitted from utilizing the open source data as evidenced by the increasing number of new research findings and publications that stem from such *** this review,we briefly introduce the evolution of open source omics data,data types,the"FAIR"guiding principles for data management and reuse,and centralized platforms that enable free and fair data accessibility,availability,and provide tools for omics data *** illustrate,through the case study of our own experience in mining pancreatitis omics data,the power of repurposing open source data to answer translationally relevant questions in pancreas research.

关键词： Gene expression Omics Open source data Pancreatitis

Assessment of corrected time-step method for nominal ionospheric gradient calculation: A comparative analysis with spatial approaches

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Earth and Planetary Physics 2024年第4期8卷 641-649页

作者： Slamet Supriadi Prayitno Abadi Susumu saito Harry Bangkit Dwiko Unggul Prabowo Adi Purwono Ginaldi Ari Nugroho Research Center for Smart Mechatronics National Research and Innovation Agency(BRIN)BandungIndonesia Research Center for Climate and Atmosphere BRINBandungIndonesia School of Electrical Engineering Telkom UniversityKab.BandungIndonesia Electronic Navigation Research Institute National Institute of MaritimePort and Aviation TechnologyTokyoJapan Research Center for Space BRINBandungIndonesia

The effect of ionospheric delay on the ground-based augmentation system under normal conditions can be mitigated by determining the value of the nominal ionospheric gradient(σvig).The nominal ionospheric gradient is generally obtained from Continuously Operating Reference Stations data by using the spatial single-difference method(mixed-pair,station-pair,or satellite-pair)or the temporal single-difference method(time-step).The time-step method uses only a single receiver,but it still contains ionospheric temporal *** introduce a corrected time-step method using a fixed-ionospheric pierce point from the geostationary equatorial orbit satellite and test it through simulations based on the global ionospheric *** also investigate the effect of satellite paths on the corrected time-step method in the region of the equator,which tends to be in a more north–south direction and to have less coverage for the east–west ionospheric *** study also addresses the limitations of temporal variation correction coverage and recommends using only the correction from *** processes are developed under simulations because observational data are still difficult to *** findings demonstrate that the corrected time-step method yieldsσvig values consistent with other approaches.

关键词： ground-based augmentation system nominal ionospheric gradient time-step correction global ionospheric model