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ABSTRACT: Image-based rendering (IBR) is an promising technology for rendering photo-realistic views of scenes from a collection of
densely sampled images or videos. It provides a framework for developing revolutionary virtual reality and immersive viewing
systems. While there has been considerable progress recently in the capturing, storage and transmission of image-based representations,
most multiple camera systems are designed to be stationary and hence their ability to cope with moving objects and dynamic
environment is somewhat limited. This paper studies the design and construction of a movable image-based rendering system
based on a class of dynamic representations called plenoptic videos, its associated video processing algorithms and an application
to multiview audio-visual conferencing. It is constructed by mounting a linear array of 8 video cameras on an electrically
controllable wheel chair and its motion is controllable manually or remotely through wireless LAN by means of additional hardware
circuitry. We also developed a real-time object tracking algorithm and utilize the motion information computed to adjust continuously
the azimuth or rotation angle of the movable IBR system in order to cope with a given moving object in a large environment.
Due to imperfection in tracking and mechanical vibration encountered in movable systems, the videos may appear very shaky
and a new video stabilization technique is proposed to overcome this problem. The usefulness of the system is illustrated
by means of a multiview conferencing application using a multiview TV display. Through this pilot study, we hope to disseminate
useful experience for the design and construction of movable IBR systems with improved viewing freedom and ability to cope
with moving object in a large environment.
KeywordsImage-based rendering–Movable IBR systems–Tracking and stabilization–Multiview conferencing
Journal of Signal Processing Systems 04/2012; 67(3):305-316. · 0.67 Impact Factor
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ABSTRACT: Image-based rendering (IBR) is an emerging and promising technology for photo-realistic rendering of scenes and objects from a collection of densely sampled images and videos. This paper proposes an image-based approach to the rendering and multi-view display of ancient Chinese artifacts for cultural heritage preservation. A multiple-camera circular array was constructed to record images of the artifacts. Novel techniques for segmenting and rendering new views of the artifacts from the sampled images are developed. The multiple views so synthesized enable the ancient artifacts to be displayed in modern multi-view displays and conventional stereo systems. Several collections from the University Museum and Art Gallery at the University of Hong Kong are captured and excellent rendering results are obtained.
Circuits and Systems (ISCAS), Proceedings of 2010 IEEE International Symposium on; 07/2010
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ABSTRACT: This paper proposes an efficient algorithm for the compression, prioritized transmission and progressive rendering of circular light field (CLF) for ancient Chinese artifacts. It employs wavelet coder to achieve spatial scalability and divide the compressed data into a lower resolution base layer and an additional enhancement layer. The enhancement layer is coded as in JPEG2000 into packets where the base-layer is coded using disparity compensation prediction (DCP). The frame structure is designed to provide efficient access to the compressed data in order to support selective transmission and decoding. The depth and alpha maps are coded analogously. A prioritized transmission scheme which support interactive progressive rendering is also proposed to further reduce the latency and response time of rendering.
01/2010;
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ABSTRACT: In this paper, we propose a new method for spatial-temporal error concealment in video coding using joint motion-image inpainting. The proposed method combines motion inpainting and adaptive Markov random field (MRF) based diffusion as robust motion inpainting. Image inpainting is employed to refine the result. With robust motion inpainting, effective compromise between temporal and spatial method is achieved for each point in the missing marcroblock (MB), which provides satisfactory visual quality of the restored frame with complex motion in video
Image Processing, 2006 IEEE International Conference on; 11/2006
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ABSTRACT: Image based rendering using the plenoptic function is an efficient technique for re-rendering at different viewpoints. We study the sampling and reconstruction problem of plenoptic function as a multidimensional sampling problem. The spectral support of plenoptic function is found to be an important quantity in the efficient sampling and reconstruction of such a function. A spectral analysis for the light field, a 4D plenoptic function, is performed. Its spectrum, as a function of the depth function of the scene, is then derived. This result enables us to estimate the spectral support of the light field given some prior estimate of the depth function. Results using a piecewise constant depth model show significant improvement in rendering of the light field images. The design of the reconstruction filter is also discussed.
Image Processing, 2000. Proceedings. 2000 International Conference on; 02/2000
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ABSTRACT: A model-based control scheme for robot manipulators employing a
variable structure control law has been found to perform well, provided
that the design parameters are carefully chosen. A refinement of the
system model of this original scheme in which the actuator dynamics is
taken into consideration is studied. Practical experiments are carried
out on a commercial revolute-joint robot manipulator
Intelligent Robots and Systems '93, IROS '93. Proceedings of the 1993 IEEE/RSJ International Conference on; 08/1993
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ABSTRACT: An adaptive control scheme combining the variable structure and
model reference methods is presented. With the variable structure
technique, all known parameters of the robot system are fully used while
the unknown parameters are adaptively adjusted. The overall control
system maintains the basic structure of the computer torque controller,
but incorporates adaptive components in the system. The method removes
the requirement for persistent excitation, essential to traditional
adaptive schemes for satisfactory operation. The control algorithm
ensures the robustness of the controlled system with respect to
disturbance, since the tracking error always converges to zero
theoretically, rather than to an ill-defined residual set as in other
adaptive schemes. Using this method, the transient response can be
prescribed in advance. Thus, all the outstanding issues in adaptive
control are directly treated. Simulation analysis for a
two-degree-of-freedom robot is conducted to compare the method with the
classical model reference method and computed torque method
Robotics and Automation, 1991. Proceedings., 1991 IEEE International Conference on; 05/1991
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Intelligent Motion Control, 1990. Proceedings of the IEEE International Workshop on; 09/1990
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ABSTRACT: The effective application of the variable structure approach to model reference adaptive control using only input and output measurements is investigated. The controller, which is robust with respect to a class of bounded-input-disturbance plants with a relative degree of one, ensures convergence of the tracking error always to zero. It is not necessary to assume persistency of excitation.
Electronics Letters 08/1990; · 0.96 Impact Factor
