An efficient I-frame R-Q model is still needed by the rate control in the latest H.264/AVC video coding standard. Some recent works introduced the gradient-based image complexity measure into the frame-layer intra rat...
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An efficient I-frame R-Q model is still needed by the rate control in the latest H.264/AVC video coding standard. Some recent works introduced the gradient-based image complexity measure into the frame-layer intra rate estimation in H.264/AVC, but the issue at the macroblock layer was not discussed. We propose a new edge-based complexity measure for this bit rate estimation problem at both the frame-layer and the macroblock-layer. The LOG operator is used in the edge extraction and an adaptive threshold selection method is proposed. The experiments show that the proposed edge-based measure has a good linear relation with the intra frame bit rate.
This paper presents a copy-paste block detection method based on characteristics of double JPEG compress. The JPEG compress will bring JPEG compression characteristics to the DCT coefficients, these characteristics ar...
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This paper presents a copy-paste block detection method based on characteristics of double JPEG compress. The JPEG compress will bring JPEG compression characteristics to the DCT coefficients, these characteristics are closely related with the quality factor. Copy-paste tamper between JPEG images will disrupt the JPEG compression characteristics of the final image. The method in this paper is designed to deal with double JPEG compression whose DCT blocks are different during the two compresses, and the experiment shows that our method can work effectively on double JPEG compression with different quality factors and is not subject to the impact of DCT blocks.
In the presence of non-gaussian noise, we propose a method for the detection of underwater ship-radiated signal. The wavelet decomposition of the underwater signal yields a natural tree structure, which is further mod...
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ISBN:
(纸本)9781424475421
In the presence of non-gaussian noise, we propose a method for the detection of underwater ship-radiated signal. The wavelet decomposition of the underwater signal yields a natural tree structure, which is further modeled by the Hidden Markov Tree (HMT). Therefore, the signal is represented as the parameter of the correspondent HMT. We analysis the likelihood defined on the parameters and form the new detection criteria. Experimental results demonstrate a reliable and robust solution of our method.
In most cases, echocardiographers examine threedimensional (3D) or four-dimensional (4D) echocardiographic images by studying several important cross sections which are defined as the optimal cross sections. It is a t...
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TV constrained reconstruction could obtain perfect results from incomplete data, and has been applied to reduce metal artifact by assuming that the projection contaminated by metal is missing. In TV constrained recons...
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TV constrained reconstruction could obtain perfect results from incomplete data, and has been applied to reduce metal artifact by assuming that the projection contaminated by metal is missing. In TV constrained reconstruction, the selection of a proper step parameter for TV minimization procedure is a key point. However, this parameter is usually selected empirically, and it is a constant for all pixels in the whole image domain, regardless of the difference of missing projection quantity at different pixels. By analyzing the relationship between the missing projections and pixels position, a Weighted Total Variation (WTV) constrained reconstruction method is proposed to reduce metal artifact in this paper. For WTV constrained method, the parameters are no longer the same, but vary over image domain as the introduced information miss rate. The simulation results show that the proposed method is more effective than current TV constraint to reduce metal artifact. Moreover, WTV constrained method is extended to other incomplete projection problems.
It is well known that Approximated Maximum Likelihood(AML) estimator has the best performance for short time sampling wideband source bearing estimation. But for a long time, the heavy computational load of maximizing...
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Detecting boundary surface for the object of interest within 3D biomedical images is an important step towards understanding and quantitative analysis of the object. However, existing 3D edge detection techniques have...
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Detecting boundary surface for the object of interest within 3D biomedical images is an important step towards understanding and quantitative analysis of the object. However, existing 3D edge detection techniques have the limitations in detecting connected edge voxels and tracing undetected edge voxels from 3D images. In this paper, we propose a new strategy to detect boundary surface for the object of interest in 3D biomedical image. The new strategy utilizes the connectivity of boundary surface in the detection and tracing of edge voxels, and is much effective in overcoming the two limitations existing in 3D edge detectors. The performance and advantages of the proposed method are illustrated by many examples from different 3D biomedical images.
Human facial shapes undergo significant variations from infancy to teenage, while they change limitedly as people age into adulthood. In this paper, facial shapes of males across ages using Euclidean distances are stu...
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Aiming at the current structured P2P system's locality of physical location and accessing resources, in the context of P4P technology, this paper takes the Pastry and P4P-Pastry algorithms as foundation, proposes ...
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Aiming at the current structured P2P system's locality of physical location and accessing resources, in the context of P4P technology, this paper takes the Pastry and P4P-Pastry algorithms as foundation, proposes a enhanced P4P routing algorithm, in which peers performed clustering to the same resources and the proximity of physical location of nodes. When routing, the node routes to the nodes which are physical adjacent to it and have the lowest cost of communication. Theory analysis and the experimental results show that the algorithm proposed in this paper has realized localization download and greatly raised the data transfer rate, reduced the load in backbone network and enhanced the network performance.
This paper introduces a new algorithm for estimating camera pose from point correspondences. Generally, the pose problem is formulated as an optimization problem whose aim is to minimize the reprojection errors. Usual...
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This paper introduces a new algorithm for estimating camera pose from point correspondences. Generally, the pose problem is formulated as an optimization problem whose aim is to minimize the reprojection errors. Usually this kind of problem is non-convex and may get trapped in local minima. For dealing with this difficulty, we combine Branch and Bound with Linear Programming to generate a global optimal solution. We first use a branch-and-bound search over rotation space to find the best rotation and the problem can then be reduced to known fixed-rotation problems for which optimal solutions can be found by Linear Programming. The proposed method can obtain the global optimal solution and is very fast. It has been tested on a real data set and the results demonstrate the accuracy and high speed of this method.
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