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Robust camera pose estimation by viewpoint classification using deep learning

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Computational Visual Media 2017年第2期3卷 189-198页

作者： Yoshik.tsu Nak.jima Hideo saito Department of Science and Technology Keio UniversityJapan

Camera pose estimation with respect to target scenes is an important technology for superimposing virtual information in augmented reality(AR). However, it is difficult to estimate the camera pose for all possible view angles because feature descriptors such as SIFT are not completely invariant from every perspective. We propose a novel method of robust camera pose estimation using multiple feature descriptor databases generated for each partitioned viewpoint, in which the feature descriptor of each k.ypoint is almost invariant. Our method estimates the viewpoint class for each input image using deep learning based on a set of training images prepared for each viewpoint class. We give two ways to prepare these images for deep learning and generating databases. In the first method, images are generated using a projection matrix to ensure robust learning in a range of environments with changing *** second method uses real images to learn a given environment around a planar pattern. Our evaluation results confirm that our approach increases the number of correct matches and the accuracy of camera pose estimation compared to the conventional method.

关键词： pose estimation augmented reality(AR) deep learning convolutional neural network

Resourceability on nuclear fuel cycle by transmutation approach

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Science China Chemistry 2012年第9期55卷 1746-1751页

作者： OZAWA Masak. saito Masak. Research Laboratory for Nuclear Reactors Tokyo Institute of Technology2-12-1-N1-1 OokayamaMeguro-kuTokyo 152-8550Japan

A resourceability on nuclear fuel cycle by transmutation of fission products in the spent fuel of nuclear reactors is discussed in this paper to investigate the feasibility of ＂creation and utilization＂ of Apr6s ORIENT from Adv.-ORIENT cycle, in which chemical ＂separation and utilization＂ of nuclear rare metals （platinum group metals, Mo, Tc, rare earth, etc.） has been proposed since FY2006. Apr6s ORIENT research program was newly initiated in FY2011 for nuclear transmutation of fission products into stable or short-lived highly-valuable elements. In the resourceability of rare earth metals from fission products, non-radioactive Nd and Dy can be created from Pr and Tb, respectively, by transmutation. Especially, the Dy creation has relatively high feasibility of about 10-20 %/y in creation rate. A proper moderation of neutrons in blank.t of fast reactors may be required to provide a high creation rate of La from Ba. In light platinum group metals, non-radioactive Ru can be created from Tc by transmutation, of which creation rate is about 4-5 %/y in blank.t of fast reactors. Pd created from Rh is almost non-radioactively depending on the isotope fraction of 107pd. Rh creation from Ru is not feasible under the neutron irradiation of typical nuclear reactors.

关键词： Apres ORIENT Advanced ORIENT cycle nuclear rare metal transmutation nuclear fuel cycle

Mapping urban building stock. for vulnerability assessment preliminary results

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International Journal of Digital Earth 2011年第S01期4卷 117-130页

作者： k.ik. saito Robin Spence Department of Architecture University of CambridgeCambridgeUK Cambridge Architectural Research Ltd CambridgeUK Willis Research Fellow Willis Research Network

This paper discusses a methodology to collect building inventory data by combining image processing techniques,field work.or tools such as Google Street View and applying statistical *** the methodology outlined in Marinescu(2002),a family of Gabor filters are first constructed,which are then applied to an optical high-resolution *** output from the processed image is segmented using Self-Organising *** paper examines the relationship between the segmented areas in the image and the building type distribution within each segmented area,by deriving the distribution from field *** relationship between the average number of buildings in these cells against the number of grid cells allocated to each segmentation cluster is also ***,using these results,the overall building inventory distribution for the whole of the case study site of Pylos is presented.

关键词： building inventory data collection remote sensing high-resolution optical satellite images Gabor filters Self-Organising Maps field data

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

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维普期刊数据库

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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 back.round restoration. In this paper, we describe a fence removal method for an image sequence captured by a user mak.ng a sweep motion, in which occluded back.round is potentially observed. To mak. use of geometric and appearance information such as consecutive images, we use two well-k.own approaches: structure from motion and light field rendering. Results using real image sequences show that our method can stably segment fences and preserve back.round details for various fence and back.round 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)

Computational Cavitation Flows at Inception and Light Stages on an Axial-Flow Pump Blade and in a Cage-Guided Control Valve

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Journal of Thermal Science 2007年第4期16卷 337-345页

作者： Sumio saito MasahiroSHIBATA HideoFUk.E Eisuk. OUTA Tok.o National College of Technology 1220-2 Kunugida-machiHachioji-shiTokyo 193-0997 Graduate student Graduate School of Science and EngineeringWaseda University Department of Mechanical Engineering Waseda UniversityOkubo 3-4-1Shinjyuku-ku Tokyo 1600072Japan

Cavitation flows induced around an axial-flow pump blade and inside a high pressure cage-type valve are simulated by a two-dimensional unsteady Navier-Stok.s analysis with the simplest treatment of bubble dynamics. The fluid is assumed as a continuum of homogeneous dispersed mixture of water and vapor nuclei. The analysis is aimed to capture transient stages with high amplitude pressure change during the birth and collapse of the bubble especially at the stage of cavitation inception. By the pump blade analysis, in which the field pressure is moderate, cavitation number of the inception and locations of developed cavitation are found to agree with experimental results in a wide flow range between high incidence and negative incidence. In the valve flow analysis, in which the water pressure of 5MPa is reduced to 2MPa, pressure change responding to the bubble collapse between the vapor pressure lower than 1 k.a and the extreme pressure of higher than 104 k.a is captured through a stable computation. Location of the inception bubble and pressure force to the valve plug is found agree well with the respective experimental features.

关键词： Cavitation unsteady CFD hydrofoil control valve homogeneous mixture inception and collapse transient pressure

Measurement of modulation induced by interaction between bubble motion and liquid-phase motion in the decaying turbulence formed by an oscillating-grid

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Particuology 2013年第2期11卷 158-169页

作者： Yasuyuk. Nagami Tak.yuk. saito Graduate School of Engineering Shizuoka University Graduate School of Science and Technology Shizuoka University

In multiphase flows, dynamical gas-liquid interactions are essential for in-depth understanding of their multi-scale phenomena and complicated structures. The purpose of the present study is to clearly extract the modulation in bubble motion and liquid motion induced by bubble-liquid interaction and to discuss the relations between bubble motion and liquid-phase motion. For this particular purpose, the decaying turbulence formed in a cylindrical acrylic pipe （diameter 149 mm, height 600 mm） by using an oscillating- grid was employed. Uniform single bubbles were launched from an in-house bubble launching device into the decaying turbulence. By comparing the bubble motion in the stagnant water with that in the oscillating-grid decaying turbulence, the transition of the 2D bubble motion （i.e., zigzagging motion） to 3D motion was enhanced in the latter. In addition, the initial conditions of the bubble motion that was not influenced by the ambient turbulence were carefully confirmed. In the area where the bubble motion started to translate from 2D motion into 3D motion, the modulation of ambient liquid-phase motion was obtained by PIV/LIF measurement. By combining these results, we quantitatively discussed the modulation of the bubble motion and ambient liquid-phase motion and considered the dominant factor for the enhancement to be the bubble-liquid interaction.

关键词： Multiphase flow Gas-liquid interaction Oscillating-grid decaying turbulence Bubble PIV/LIF LIF/HPTS

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 back.round 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 mak. 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 mak.s 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： k.nihiro Hasegawa Hideo saito k.io 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 back.round image,synthesis of stroboscopic image, and removal of player's shadow. In synthesis of back.round image step, all input frames mask.d a bounding box of the player are stitched together to generate a back.round image. The player is extracted by an HOG-based people *** synthesis of stroboscopic image step, the back.round 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 back.round 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 back.round and the person controlling the video camera was standing still, such lik. 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

APPLICATION OF THE UNIFIED STATISTICAL MATERIAL DATABASE FOR DESIGN AND LIFE/RISk.ASSESSMENT OF HIGH TEMPERATURE COMPONENTS

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Acta Metallurgica Sinica(English Letters) 2004年第4期17卷 338-344页

作者： k.Fujiyama T.Fujiwara Y.Nak.tani k.saito A.Sak.ma Y.Ak.k.ni S.Hayashi S.Matsumoto Power and Industrial Systems R&D Center Industrial and Power Systems & Services Company Toshiba Corporation Tsurumi-Ku Yokohama 230-0045 JapanThermal and Hydro Power Division Industrial and Power Systems & Services Company Toshiba Corporation Minato-Ku Tokyo 105-8001 JapanPower and Industrial Systems R&D Center Industrial and Power Systems & Services Company Toshiba Corporation Tsurumi-Ku Yokohama 230-0045 JapanKeihin Product Operations Industrial and Power Systems & Services Company Toshiba CorporationTsurumi-Ku Yokohama 230-0045 JapanKeihin Product Operations Industrial and Power Systems & Services Company Toshiba CorporationTsurumi-Ku Yokohama 230-0045 JapanThermal and Hydro Power Division Industrial and Power Systems & Services Company Toshiba Corporation Minato-Ku Tokyo 105-8001 JapanThermal and Hydro Power Division Industrial and Power Systems & Services Company Toshiba Corporation Minato-Ku Tokyo 105-8001 JapanThermal and Hydro Power Division Industrial and Power Systems & Services Company Toshiba Corporation Minato-Ku Tokyo 105-8001 Japan

Statistical manipulation of material data was conducted for probabilistic life assessment or risk.based design and maintenance for high temperature components of power plants. To obtain the statistical distribution of material properties, dominant parameters affecting material properties are introduced into normalization of statistical variables. Those parameters are hardness, chemical composition, characteristic micro structural features and so on. Creep and fatigue properties are expressed by normalized parameters and the unified statistical distributions are obtained. These probability distribution functions show good coincidence statistically with the field database of steam turbine components. It was concluded that the unified statistical baseline approach is useful for the risk.management of components in power plants.

关键词： statistical analysis material property steam turbine life assessment risk