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Radiance-based color calibration for image-based modeling with multiple cameras

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Science China(Information Sciences) 2012年第7期55卷 1509-1519页

作者： ZHAO Xu 1,2 ,ZHOU Zhong 1,2 & WU Wei 1,2 1 State Key Laboratory of Virtual Reality Technology and Systems,Beihang University,Beijing 100191,China 2 School of Computer Science and Engineering,Beihang University,Beijing 100191,China State Key Laboratory of Virtual Reality Technology and Systems Beihang University Beijing China School of Computer Science and Engineering Beihang University Beijing China

Photo-consistency estimation is an important part for many image-based modeling *** paper presents a novel radiance-based color calibration method to reduce the uncertainty of photo-consistency estimation across multiple *** idea behind our method is to convert colors into a uniform radiometric color space in which multiple image data are *** results demonstrate that our method can achieve comparable color calibration effect without adjusting camera parameters and is more robust than other existing ***,we obtain an auto-determined threshold for photo-consistency check,which will lead to a better performance than existing photo-consistency based reconstruction algorithms.

关键词： color calibration photo-consistency estimation multi-camera system image-based modeling

modeling plants with sensor data

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Science in China(Series F) 2009年第3期52卷 500-511页

作者： MA Wei XIANG Bo ZHA HongBin LIU Jia ZHANG XiaoPeng Key Laboratory of Machine Perception (Ministry of Education) Peking University Beijing 100871 China LIAMA-NLPR Institute of Automation Chinese Academy of Sciences Beijing 100080 China

Sensor data, typically images and laser data, are essential to modeling real plants. However, due to the complex geometry of the plants, the measurement data are generally limited, thereby bringing great difficulties in classifying and constructing plant organs, comprising leaves and branches. The paper presents an approach to modeling plants with the sensor data by detecting reliable sharp features, i.e. the leaf apexes of the plants with leaves and the branch tips of the plants without leaves, on volumes recovered from the raw data. The extracted features provide good estimations of correct positions of the organs. Thereafter, the leaves are reconstructed separately by simply fitting and optimizing a generic leaf model. One advantage of the method is that it involves limited manual intervention. For plants without leaves, we develop an efficient strategy for decomposition-based skeletonization by using the tip features to reconstruct the 3D models from noisy laser data. Experiments show that the sharp feature detection algorithm is effective, and the proposed plant modeling approach is competent in constructing realistic models with sensor data.

关键词： plant modeling image-based modeling laser-based modeling sharp feature detection decomposition skeletonization

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Using relief texture for interactive and tangible virtual environments

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第12期9卷 1656-1665页

作者： Junae KIM Seonhyung SHIN Gerard Jounghyun KIM Digital Contents Division Electronic and Telecommunications Research InstituteDaejon 305-700 Korea Department of Computer Science and Engineering Korea UniversitySeoul 136-713 Korea

This paper first introduces a way to improve interactivity with high polygon count virtual objects through the "mixed" use of image-based representation within one object. That is, both 3D polygonal and image-based representations are maintained for an object, and switched for rendering depending on the functional requirement of the object. Furthermore, in order to reduce the popping effect and provide smooth and gradual transition during the object representation switch, the object is subdivided with the subdivided parts possibly represented differently, i.e., using 3D models or images. As for the image-based representation, the relief texture (RT) method is used. In particular, through the use of the mixed representation, a new way called TangibleScreen is pro-posed to provide object tangibility by associating the image-based representation with a physical prop (projecting the RTs) in a selective and flexible way. Overall, the proposed method provides a way to maintain an interactive frame rate with selective perceptual details in a large-scale virtual environment, while allowing the user to interact with virtual objects in a tangible way.

关键词： Relief texture (RT) image-based modeling Tangible interaction Virtual environment

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Visual simulation of clouds

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Visual Informatics 2017年第1期1卷 1-8页

作者： Yoshinori Dobashi Kei Iwasaki Yonghao Yue Tomoyuki Nishita Hokkaido University/UEI Research Japan Wakayama University/UEI Research Japan The University of Tokyo Japan UEI Research/Hiroshima Shudo University Japan

Clouds play an important role when synthesizing realistic images of outdoor *** realistic display of clouds is therefore one of the important research topics in computer *** order to display realistic clouds,we need methods for modeling,rendering,and animating clouds *** is also important to control the shapes and appearances of clouds to create certain visual *** this paper,we explain our efforts and research results to meet such requirements,together with related researches on the visual simulation of clouds.

关键词： Clouds Procedural modeling image-based modeling Fluid simulation Feedback control Genetic algorithms