最新刊期
卷 15 ， 期 4 ， 2010
- 摘要：Accurate rate control is a key technology for efficient video coding and transmission. In view of the drawbacks of existing rate control algorithms, a novel idea that implements rate control by using two rate-distortion models is introduced to enhance the rate-control precision. And a new double model based rate-control algorithm is proposed by adapting the G012 framework of H.264 standard. Experiments are conducted and the results reveal that, compared with the original G012 algorithm, the proposed algorithm can efficiently enhance the rate control precision without deteriorating the reconstructed video quality关键词：rate control;rate-distortion model;prediction with two models3569|194|0更新时间：2024-05-07
- 摘要：In this paper, an encoding algorithm based on optimal SV (support vector) fitting was presented for lowbit-rate image description. The main contributions include: 1) a sample set shrinking strategy was suggested for fast simulation of the most significant AC coefficients in SVM (support vector machine) model. With almost the same accuracy as that of the traditional SVM approximation, the shrinking operation improved the regression speed and reduced the numbers of output parameter. 2) a BBB-DP(bit-by-bit differential prediction) method was suggested for DCs coding, the generation method of optimal bit stream was also proposed. Experiments demonstrated that our method saved coding time, while can acquire images of improved quality images at the same bit-rate. Unlike the previous SV coding, this rapid fitting based method is more feasible and describes the bit-stream structure in detail.关键词：low bit-rate compression;support vector regression(SVR);sample set shrinking;bit-by-bit differentiate prediction(BBB-DP);data stream description3144|188|0更新时间：2024-05-07
- 摘要：This paper depicts how to construct parametric biorthogonal wavelet family via lifting scheme, and gives the complete construction of a new class of parametric biorthogonal interpolating wavelets with one parameter. The exact parameter expressions of their associated interpolating filter banks are also derived. The free parameter provides a degree of freedom to optimize the resulting wavelets, and a previously unpublished interpolating wavelet is obtained with respect to the coding gain criteria, which has binary filter coefficients and can realize a multiplication free discrete wavelet transform（DWT）. Simulations show that the new wavelet has exhibited image compression performance superior to the most widely used 9/7 tap wavelet by Cohen et al. in the field of wavelet transform coding, yet its computational complexity has decreased by more than 17%. This indicates a better tradeoff between compression performance and computational complexity.关键词：biorthogonal wavelet;interpolating filter;discrete wavelet transforms （DWT）;lifting scheme;compression performance;computational complexity3298|211|0更新时间：2024-05-07
- 摘要：The essential matrix, which is a fundamental matrix described in the normalized image coordinate, represents the epipolar geometry relation under the condition of known camera intrinsic parameters It is well known, two non-zero singular values of the essential matrix must be equal. Therefore, according to the intrinsic property, an essential matrix-based self-calibration approach is for proposed the first time in this paper. First, the objective function is constructed by the intrinsic property of the essential matrix. Second, the particle swarm optimization is used to solve the objective function considering the drawbacks of traditional optimization algorithms. Analytical results show that the proposed method is not only highly accurate but also robust. Consequently, it is a simple but valid self-calibration method关键词：intrinsic parameters;essential matrix;fundamental matrix;PSO4500|263|0更新时间：2024-05-07
- 摘要：Due to the physical structure of a single-chip CCD image sensor, there is only a single color component at each pixel position. To recover the full color images, an image interpolation or de-mosaicking is required to reconstruct the other two color components. In this paper, a novel image interpolation algorithm in the color difference space is proposed. By using the ratio linearity property of local color and the local covariance, the optimal MMSE interpolation coefficients are obtained. These coefficients can preserve the edge details of the interpolated images.The interpolation in the color difference space takes into account the correlations between color components, so that the edge blurring and color distortion can be dramatically reduced. Compared with some of the state-of-the-art methods, experiment results demonstrate that the interpolated images using the proposed algorithm are of good quality.关键词：image sensor;color space;color filter array;covariance3208|190|0更新时间：2024-05-07
- 摘要：Nonlinear diffusion filters based on partial differential equations can well preserves the edge information while de-noise effectively, but the corners gradually become rounded and vanish while filtering. A corner preserving nonlinear diffusion filter is proposed, whose diffusion coefficient is the function of the gradient and the curvature. The new model behaves as a Gaussian filter inside the regions and smoothes less across regions； and the smoothing effect is even decreased in the corner points. These effects ensure better preservation of the corner. Visual effect with data analysis of the experiment result proves simultaneous protection of the edge and corner information.关键词：partial differential equation;nonlinear diffusion filter;corner;curvature2822|202|0更新时间：2024-05-07
- 摘要：The standards of traditional paper map symbols are inapplicable for electronic maps in new display and perception environment. Experimental studies of E-map symbols based on screen visual perception, to make new adaptive standards, are of great importance for E-map standardization, data sharing, adaptive spatial information visualization, and geo-information collaborative visualization. This paper analyzes the various screen sizes and resolutions, and points out that adopting pixel as the unit and GDI+ technique is beneficial for quantificational and artistic symbol design. Its helpful for making the goal clear and enhancing the usability of the experiment that splitting the symbols into meta-graphs from the point of their visual perception and drawing. At last, the authors find out the visual threshold of meta-graphs through the experiments based on E-Prime, and combining with the basic E-map symbol design principles, excellent topographic E-map symbols are acquired.关键词：E-map symbols;visual perception experiment;meta-graph;visual threshold;E-Prime3323|201|0更新时间：2024-05-07
- 摘要：To ensure the video QoS(quality of service) of the Web, DiffServ(differentiated service) methods are always used at the edge of network. Current label system of DiffServ is static and not so intelligent. In order to solve this problem and improve the Subject QoS, knowledge-system-based video quality guarantee model is provided and a system is built. In this system, the video adaptation is guided intelligently with the knowledge acquired at different phases of knowledge creation processes and (m,k) model is applied in label design so as to mapping to knowledge. Testing results have shown this model can satisfy the user preference and ensure video quality effectively. So it is proved that knowledge plays an important role and brings more intelligence to our system.关键词：(m;k) model;QoS guarantee;DiffServ;knowledge system3219|214|0更新时间：2024-05-07
- 摘要：In this paper, a novel method based on generalized gradient vector flow (GGVF) Snake model is proposed for segmentation of the left ventricle cardiac magnetic resonance (MR) images. Firstly, an edge-based directional generalized gradient vector flow (EDGGVF) Snake model is proposed as an improvement to GGVF, which differentiates cardiac endocardium and epicardium into positive and negative boundaries by incorporating the gradient orientation information of the images edge map. In addition, a circle-shape based energy for the Snake model is adopted considering the shape of the left ventricle. With this energy, the Snake contour can overcome the unexpected local minimum stemming from image inhomogeneity and papillary muscle. Experimental results show the method is able to segment LV endocardium and epicardium accurately and effectively.关键词：gradient vector flow;Snake model;image segmentation;left ventricle;shape constraint3722|237|0更新时间：2024-05-07
- 摘要：In recent literature of image analysis, it has been very popular to code local features into visual words. We propose a novel kernel which fuses multi-level contexts of visual words. Besides the histogram pyramid of words, our kernel also incorporates the histogram pyramid of visual phrases （the local co-occurrence patterns of words） and the context classes of those words and phrases. Then support vector machines using the kernel are trained to perform image classification. Our method performs well on a wide range of test data, such as the Corel dataset. The method is also tested in a challenging problem, the discrimination of pornographic images from bikini ones. The classification accuracy of our method is 7% higher than that of the baseline method. Experimental results demonstrate that the performance of image classification can be improved by the integration of kernel based measurements and the multi-level representation of visual words. In the future work, more compact and efficient representation of contexts should be researched.关键词：image classification;kernel;support vector machine;visual word;multi-resolution histogram3492|242|0更新时间：2024-05-07
- 摘要：Guo proposed an improved CV model （MCV model） that needs less iteration, but trapped in local optima for the influence of regions of initial contours； also some points were segmented in a wrong region or were omitted. The means gated by traditional Heviside function isnt accurate to keep the numerical stability. In this article we modify the MCV model, propose a new model using n equations of level set to structure n Regions： pre-segment the image to get the initial contours to avoid the results trapping in local optima and improve the efficiency of segmentation.Then we modify the MCV model by structuring a new symbol function to replace the Heviside function which can keep the numerical stability. Experiment results show that the new model can obtain good results efficiently.关键词：CV model;level set;image segmentation3552|287|0更新时间：2024-05-07
- 摘要：A novel method of local uncertainty based measure is proposed for line detection in the paper to tackle the problems of decrease in detection accuracy in noised images for multi-line detection of complicated work-pieces. The proposed scheme firstly partitions an object into several regions. Then a probability model of uncertainty that describes how an edge pixel belongs to a line is built within each region, and accumulated uncertainty measures for lines formed by any pair of two edge points are computed according to two point combination and the Bayesian rule. Lines are finally detected using soft voting in parameter spaces. The capability of anti-noise and fast processing speed is the key feature of the algorithm. Experimental results show that accuracy error of proposed method less than 1‰ when noise variance equals to 0.06 and detection accuracy can reach above 90%. The detection period is 1/2 of method of pure uncertainty measure and processing speed is 4~5 times faster than conventional hough transform (HT).关键词：Hough transform;uncertainty measure;multi-line detection3364|266|0更新时间：2024-05-07
- 摘要：Background subtraction is a widely used method for video object detection and its performance is dependent on the quality of background model. In this paper, an algorithm for video target detection based on adaptive learning GMM was proposed by defining an efficiency factor between pixel samples and their background models. The accumulation of efficiency factor(AEF) shows how well the models can represent the background and was used to adjust the learning-rate dynamically. At the same time, how to update the models was dependent on the changes of the background after the foreground image analysis. The performance and robustness of the algorithm has been verified experimentally.关键词：Gaussian mixture models(GMM);intelligence video surveillance;adaptive learning5334|578|0更新时间：2024-05-07
- 摘要：A new method of trademark retrieval based on average moments of feature points is proposed in the paper. First, the trademark image is divided into several concentric cells, and some special feature points are located in each sub-image according to the image's reference circle and principal orientation. The relative positions of these feature points have the invariability with respect to translation, scaling and rotation. After that, the new idea of average moments of these feature points is proposed. This feature descriptor has good robustness and is not so sensitive to noise and the delicate changes in image's edges. The experiments show that this method has good stability and can give attention to image's local features and global features at the same time. Therefore, the retrieval results match human visual percept ionk well.关键词：trademark retrieval;feature points;average moments3133|302|0更新时间：2024-05-07
- 摘要：A novel minutiae-based method using local alignment to match the deformed fingerprints is proposed in this paper. We apply texture-based and structure-based minutiae information to obtain multiple reference minutiae at first, and then globally and evenly align two sets of minutiae to obtain the common overlapping region based on these reference minutiae. Next, we use the minutiae and their closest reference minutia to establish the local correspondence. After the registration of the fingerprints according to the local correspondence, the number of matching minutiae can be counted using bounding box constraints. Experimental results confirm that the proposed algorithm which is based on local correspondence is reliable for fingerprint matching with nonlinear distortions and leads to improvement in identification performance.关键词：fingerprint matching;local alignment;minutia;multiple reference minutiae3969|279|0更新时间：2024-05-07
- 摘要：With the advance of 3D scanning, computer-aided design and scientific simulation technologies, massive meshes containing over billions of geometric primitives are becoming commonplace. It is difficult to render these meshes interactively. Out-of-core multi-resolution technique, which is one of the most efficient approaches to improve the rendering performance, has become a research hotspot in the field of computer graphics. However, the construction process for multi-resolution representation of massive meshes is often time-consuming, which is not conducive to system debugging and downstream applications. This paper proposes task scheduling based on sub-tree and dynamic construction task management mechanism, and realizes the parallel construction of multiresolution representation for massive meshes which improves the construction speed effectively.关键词：massive meshes;multiresolution representation;parallel construction3250|225|0更新时间：2024-05-07
- 摘要：The modern research in meridian has verified that the phenomenon of meridian's route is in existence. It is important to visualize the meridian's route interactively in real time. This paper analyses the geometric curve construction and proposes a method to fit transmission route of human meridian using the equation of Catmull-Rom cubic splines interpolation. The method uses 3D acupuncture points as the curve control points. The interpolation data of the whole transmission route is obtained through the Catmull-Rom interpolation algorithm. Experimental results show that this method can reconstruct transmission route of human meridian quickly and maintain the original property well.关键词：human meridian;transmission route;curve fitting3794|215|0更新时间：2024-05-07
- 摘要：This paper addresses the problem of image compression in remote sensing applications. Compared with other static images, remote-sensing images are characterized with complex textures and weak local correlation. Most of current wavelet-based algorithms of image compression have not taken this into account, in which the predictions are always performed in the horizontal or vertical directions. In order to further improve coding efficiency, an efficient remote sensing image coding algorithm based on orientation-adaptive lifting wavelet(OALW) is proposed. First, the OALW is applied to the image at the direction where the pixels have a strong correlation, rather than at the horizontal or vertical orientation. Compression is then achieved by using a subband-bit-plane encoding method. In the experiments, two satellite images are selected to test the performance of the algorithm. Experimental results illustrate that it provides higher performance than JPEG2000 in low-bits compression.关键词：remote sensing image;orientation adaptive lifting;integer wavelet;sub-band bit-plane coding;JPEG20003168|268|0更新时间：2024-05-07
- 摘要：There are plenty of structure edge features in remote sensing images besides texture features. How to capture the information contained in these features is a key point to retrieve remote sensing image effectively. Given that Contourlet transform has the function of multi-scale geometric analysis in the discrete domain, we have put forward a novel approach for image retrieval, which extracts the energy features of Contourlet subbands to obtain the edge direction information under different scales. For the ability differences in capturing different direction features, we have adopted an orthogonal compensation method to remedy them, and realized rotation invariant image retrieval through processing them with Fourier operator. Experiments on remote sensing images demonstrate this retrieval algorithm is especiauy effective for those images containing rich structural edge features.关键词：Contourlet;rotation-invariant;edge feature;remote sensing image retrieval3781|251|0更新时间：2024-05-07
- 摘要：Representing the different transportation modes with independent map layers has been widely adopted in GIS for transportation related applications. Such a data model can surely meet the requirements of visualization and data management, but the independent map layers representation makes it rather difficult to generate the inherent connectivity relationships between the transportation modes, and consequently results in the multi-criteria route planning difficult to be implemented. In this paper, a logically integrated multi-modal transportation network model is firstly presented, and a technical flow for seamless transfer among transportation modes such as private driving, bus, subway, walking etc. Then a multi-criteria route planning approach considering accurate walking guidance is proposed, in which a transparent combination of transportation modes in multi-criteria route planning is realized. It is argued that the proposed approach can provide practical, feasible and personalized travel information services.关键词：route choice;multi-modal;multi-criteria;walking guidance3615|244|0更新时间：2024-05-07
- 摘要：By the analysis of the properties of blind watermarking, a method for generating watermark information which transforms characters directly into binary code is proposed. Secondly, the mechanism of coordinate mapping and the principles of constructing mapping function for watermarking embedding and extracting are studied based on the location characteristic of vector geo-spatial data. Then, a blind watermarking algorithm for vector geo-spatial data is obtained using the proposed approaches of generating watermark information and coordinate mapping. The experiments conducted in this paper show that the algorithm is with good robust and can resist some usual attacks such as data compressing, adding, deleting, editing, clipping, translating and so on.关键词：digital watermarking;vector geo-saptial data;blind watermarking;mapping3985|277|0更新时间：2024-05-07
- Postal code：100190
- Tel：010-58887035/58887030/58887418 Email：jig@aircas.ac.cn
- Technical support is provided by Beijing Founder electronics co., LTD 京ICP备05080539号-4
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0