In this paper, we introduce a free viewpoint image generation method with an optimization method for a view dependent depth map. Image based rendering (IBR) can render photo-realistic images from natural images, and r...
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ISBN:
(纸本)9781424463794
In this paper, we introduce a free viewpoint image generation method with an optimization method for a view dependent depth map. Image based rendering (IBR) can render photo-realistic images from natural images, and ray space or light field is IBR method for 3D representation. To generate a free viewpoint image from light filed data which are captured by a camera array, a disparity map on the virtual view is required. To improve the quality of the generated image, the accurate disparity map is required;however, the computational cost of the disparity map for some optimization is usually huge. For real-time rendering, we have used a disparity optimization method called multi-pass dynamic programming (MPDP), which applies the dynamicprogramming method to the disparity map multi-directionally. In this paper, we improve the MPDP method to speed up optimization process and add occlusion detection process. The experimental results show that fast MPDP can interpolate virtual view with high quality, and the PSNR of this synthesized image to the actual image is 29.2 dB. On the contrary, a synthesized image from belief propagation, which is one of the best optimization algorism, has 29.4 dB. In addition, the MPDP computational time is almost real-time, and that time is 51.5 ms, meanwhile belief propagation takes 397.7 ms.
In volume seam carving, seam carving for three-dimensional (3D) cost volume, an optimal seam surface can be derived by graph cuts, resulting from sophisticated graph construction. However, the graph cuts algorithm is ...
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ISBN:
(纸本)9781467399616
In volume seam carving, seam carving for three-dimensional (3D) cost volume, an optimal seam surface can be derived by graph cuts, resulting from sophisticated graph construction. However, the graph cuts algorithm is not suitable for practical use because it incurs a heavy computational load. We propose a multi-pass dynamic programming (DP) based approach for volume seam carving that reduces computation time to 60 times faster and memory consumption to 10 times smaller than those of graph cuts, while maintaining a similar image quality as that of graph cuts. In our multi-pass DP, a suboptimal seam surface is created instead of a globally optimal one, but it has been experimentally confirmed by more than 198 crowd workers that such suboptimal seams are good enough for image processing.
Ray-Space is categorized by Image-Based Rendering (IBR), thus generated views have photo-realistic quality. While this method has the performance of high quality imaging, this needs a lot of images or cameras. The rea...
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ISBN:
(纸本)9780819466037
Ray-Space is categorized by Image-Based Rendering (IBR), thus generated views have photo-realistic quality. While this method has the performance of high quality imaging, this needs a lot of images or cameras. The reason why that is Ray-Space requires various direction's and position's views instead of 3D depth information. In this paper, we reduce that flood of information using view-centered ray interpolation. View-centered interpolation means estimating view dependent depth value (or disparity map) at generating view-point and interpolating that of pixel values using multi-view images and depth information. The combination of depth estimation and interpolation realizes the rendering photo-realistic images effectively. Unfortunately, however, if depth estimation is week or mistake, a lot of artifacts appear in creating images. Thus powerful depth estimation method is required. When we render the free viewpoint images video, we perform the depth estimation at every frame. Thus we want to keep a lid on computing cost. Our depth estimation method is based on dynamicprogramming (DP). This method optimizes and solves depth images at the weak matching area with high-speed performance. But scan-line noises become appeared because of the limit of DP. So, we perform the DP multi-direction pass and sum-up the result of multi-passed DPs. Our method fulfills the low computation cost and high depth estimation performance.
Efficient exact parameterized algorithms are an active research area. Such algorithms exhibit a broad interest in the theoretical community. In the last few years, implementations for computing various parameters (par...
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Efficient exact parameterized algorithms are an active research area. Such algorithms exhibit a broad interest in the theoretical community. In the last few years, implementations for computing various parameters (parameter detection) have been established in parameterized challenges, such as treewidth, treedepth, hypertree width, feedback vertex set, or vertex cover. In theory, instances, for which the considered parameter is small, can be solved fast (problem evaluation), i.e., the runtime is bounded exponential in the parameter. While such favorable theoretical guarantees exists, it is often unclear whether one can successfully implement these algorithms under practical considerations. In other words, can we design and construct implementations of parameterized algorithms such that they perform similar or even better than well-established problem solvers on instances where the parameter is small. Indeed, we can build an implementation that performs well under the theoretical assumptions. However, it could also well be that an existing solver implicitly takes advantage of a structure, which is often claimed for solvers that build on SAT-solving. In this paper, we consider finding one solution to instances of answer set programming (ASP), which is a logic-based declarative modeling and solving framework. Solutions for ASP instances are so-called answer sets. Interestingly, the problem of deciding whether an instance has an answer set is already located on the second level of the polynomial hierarchy. An ASP solver that employs treewidth as parameter and runs dynamicprogramming on tree decompositions is DynASP2. Empirical experiments show that this solver is fast on instances of small treewidth and can outperform modern ASP when one counts answer sets. It remains open, whether one can improve the solver such that it also finds one answer set fast and shows competitive behavior to modern ASP solvers on instances of low treewidth. Unfortunately, theoretical models of
The paper applies the advanced multi-pass dynamic programming (AMPDP) to solve the weekly hydrothermal generation coordination problem with direct load control (DLC) operation. The AMPDP technique can overcome the lon...
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The paper applies the advanced multi-pass dynamic programming (AMPDP) to solve the weekly hydrothermal generation coordination problem with direct load control (DLC) operation. The AMPDP technique can overcome the long calculation time and large data storage problems that the conventional dynamicprogramming (DP) method fails to resolve for large power systems and long scheduling period. The algorithm developed in this paper finds the optimal hydrothermal coordinated generation schedule of a power system that includes 48 thermal units and 8 hydro units with direct load control during a 192 hour study period. For the energy payback phenomenon of direct load control of air conditioner, the simulation of various energy payback patterns and various controllable capacities are presented in this paper.
In this paper, we introduce a novel algorithm to solve projected model counting (PMC). PMC asks to count solutions of a Boolean formula with respect to a given set of projected variables, where multiple solutions that...
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ISBN:
(纸本)9783319941448;9783319941431
In this paper, we introduce a novel algorithm to solve projected model counting (PMC). PMC asks to count solutions of a Boolean formula with respect to a given set of projected variables, where multiple solutions that are identical when restricted to the projected variables count as only one solution. Our algorithm exploits small treewidth of the primal graph of the input instance. It runs in time O(2(2k+4) n(2)) where k is the treewidth and n is the input size of the instance. In other words, we obtain that the problem PMC is fixed-parameter tractable when parameterized by treewidth. Further, we take the exponential time hypothesis (ETH) into consideration and establish lower bounds of bounded treewidth algorithms for PMC, yielding asymptotically tight runtime bounds of our algorithm.
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