最新刊期
卷 13 ， 期 6 ， 2008
- 摘要：This paper is the thivteenth of the literature bibliography on computer graphics engineering in China in 2006. We collected and classified most of the important papers in computer graphics field published in Chinese, selected references from 11 important Chinese journals published in 2007 and classified these references into different categories according to their contents. Based on the overview and analysis work, we found that the number of researchers and developers engaged in computer graphics related field has been greatly increasing in the past 13 years, and many conferences are held each year, many high level achievements are made in China. In addition, computer graphics develops itself, deriving out some new research topics or directions including cross disciplines.关键词：graphics engineering;graphics processing;computer graphics;survey3343|258|0更新时间：2024-05-08
- 摘要：Volume rendering has proven to be an effective and flexible visualization method for large three dimensional data sets from scientific or medical applications perspective. Transfer functions are particularly important to the quality of volume rendered images because their role is essentially to make the data visible by assigning optical properties like color and opacity to the original values of the data set being visualized. Good transfer functions reveal the important structures in the data without obscuring them with unimportant regions. Unfortunately, specifying a good transfer function can be a difficult and tedious task due to the lack of intuitive interface and guiding information. Recent research has focused on automatic and semiautomatic techniques for creating transfer functions. A comprehensive survey of the up to date design approaches and strategies for transfer function is presented. After introducing the mathematical definition of the transfer function, different data and optical properties that can be used in the domain of transfer function are discussed. The proposed approaches of designing transfer functions can be classified into three categories;image centric, data centric and object centric methods according to the extent of automation and interaction. Their characteristics and relationship also are analyzed and reviewed in detail. Along existing methods, some potential directions for future research are predicted finally.关键词：volume rendering;transfer function;visualization;classification;user interface design4472|301|0更新时间：2024-05-08
- 摘要：Utilizing the characteristic of JPEG2000 code stream format, a joint source channel coding (JSCC) scheme was proposed in this paper. A novel irregular LDPC with weight increasing parity check (WIPC) matrix (WIPC LDPC) was first put forward, which can simply realize unequal error protection (UEP) characteristic. Then the different significant JPEG2000 code streams were coded by weight increasing parity check (WIPC) irregular LDPC with dissimilar degree bit nodes to realize UEP scheme. Simulation results show that the proposed JSCC can realize robust image transmission and outperforms other JSCC schemes proposed before.关键词：JSCC;JPEG2000;Irregular LDPC;UEP;EEP3212|235|0更新时间：2024-05-08
- 摘要：An improved EPZS(enhanced predictive zonal search) algorithm with direction based search patterns and adaptive motion estimation scheme selection based on prediction block type is presented in this paper. Utilizing high special/temporal correlation of motions in video sequences and focusing on the interactions between motion estimation and new coding tools such as multiple references and prediction block types, the algorithm can obtain almost the same PSNR as full search at very low computation cost. Compared with EPZS, it can considerably improve the speed of motion estimation, and rate distortion performance. Experiments verify the superiority of the proposed algorithm. Furthermore, the proposed algorithm is robust and capable of generating a smooth motion vector field.关键词：video coding;H.264/AVC;motion estimation;motion vector;mode decision;rate distortion optimization3058|258|0更新时间：2024-05-08
- 摘要：H.264 is the new video coding standard established by ITU and ISO，which has high coding efficiency and high compression quality. Integer DCT transform is one of the main renovation for compression efficiency improvement. For the integer DCT radix cannot be the unique within the same transform framework,finding the radix is another valuable research topic besides integer DCT theory. A generic generating algorithm for integer DCT transform radix is presented in this paper. Based on the mathematic analysis of integer DCT transform principle,four constraint conditions which shall be met by integer DCT transform matrix are given first. And then,starting from orthogonal constraint,the magnitude relation of matrix elements is formulized. The formulation,which combines the other three constraint conditions,results in a transform radix finding method by using search strategy. The simulation results show that,only through tens of seeking steps,the proposed method can find all valid radix including the one used by JVT reference model.关键词：H.264;integer DCT(discrete cosine transform);transform radix3478|224|0更新时间：2024-05-08
- 摘要：The wavelet coefficients of an image will obtain higher performance of energy concentration after its high frequency components are decreased by low pass filters. This paper makes a study of the near lossless compression scheme based on this principle. In order to make smoothing process more effective to improve compression rate of the above near lossless compression scheme, this paper presents a novel smoothing algorithm, which can achieve better smoothing performance by adaptively select appropriate filter direction for every pixel according to its horizontal and vertical gradient intensity in the process of scan. Another remarkable advantage of this algorithm is that it can smooth the image according to given maximum amplitude error, then makes the accuracy of near lossless compression adjustable. In addition, this algorithm is easy to implement for its low computation complexity. The experimental results with several standard test images demonstrate the effectiveness and adaptability of the presented algorithm in this paper.关键词：wavelet transformation;near lossless compression;adaptive smoothing algorithm;adjustable accuracy2880|276|0更新时间：2024-05-08
- 摘要：The symmetrical and asymmetrical distribution of noise correlation between digital image and digital camera are discovered in the experiment of identifing digital image origin by noise correlation. In order to improve the validity of identifi cation of digital image origin and predetermine accurately threshold of identification, a new probability density function of generalized chi square distribution is constructed within (0,1］ for asymmetrical distribution of noise correlation. A new method is proposed to apply generalized chi square distribution to describe the asymmetrical distributions of noise correlation, and using generalized Gaussian distribution to describe the symmetrical distributions of noise correlation. The experiment shows that the new method can reduce over 38% of the false rate compared with the method of generalized Gaussian distribution , consequently, it is an effective approach to reduce the false rate by diverse probability density functions to describe different distributions of noise correlation.关键词：pattern noise;wavelet filter;reference pattern;correlation;probability density function(PDF)3219|246|0更新时间：2024-05-08
- 摘要：The edge’s orientation obtained with the method of the gray gradient orientation is quite different from the real edge’s orientation. Therefore, it causes the deterioration of the high pass filtering performance, if we place the filter according to the estimated angle obtained with the gray gradient orientation. The influences of the angle of edge’s orientation and filter’s long axis on the filtering performance have been studied in this paper. Based on the analysis of the curve and combined with a coordinate transformation, an improved algorithm on the method of the gray gradient orientation is proposed. Because of the algorithm making full use of the pixels in the region for a better estimation, then the optimized estimated angle is selected, which is closer to that of the real edge’s orientation. If the orientation of the filter’s long axis is strictly consistent with that of the real edges , the filtering performance and its material experimental data are regarded as a performance criterion. The experimental result shows that using the algorithm , both the filtering performance and its material experimental data are close better to the performance criterion mentioned above.关键词：coordinate transformation;edge’s orientation estimation;anisotropic high pass filtering3204|226|0更新时间：2024-05-08
- 摘要：In this paper, we present a method called arbitrary cloning in which image matting technique and Poisson image editing are applied to accomplish the image seamless cloning. First, the object boundary is extracted through image matting technique. And Poisson equation is solved to achieve natural result for seamless cloning. Compared with state of art techniques, the algorithm shows advantages that great performance can be reached in bad conditions when there is complicated color variation in the foreground and background image. The α matte can be guided by the user input and the algorithm is not affected even when there are many holes in the foreground image. The algorithm is very flexible in application. Within current cloning technique, the algorithm guarantees better output, higher speed and diverse results.关键词：image matting;Poisson equation;gradient field;arbitrary cloning4731|296|0更新时间：2024-05-08
- 摘要：According to the characteristic of which LSB steganography can influence the image wavelet detail information, this article presents the definition of images, with wavelet detail information and the wavelet detail information energy. We calculated the wavelet detail information energy of carrier image according secrete image,and estimated LSB steganography rate using two image wavelet detail information energy. The experiment proved that this method is efficient in estimating LSB steganography when the embedding rate is not too small.关键词：wavelet detail information;steganalysis;LSB steganography3515|246|0更新时间：2024-05-08
- 摘要：Radiometric correction and geospatial correction , which are two key steps for quantitative remote sensing information, are crucial to reveal the target and background character and the actual geographical position. In this paper, a method of radiometric correction and the geospatial positioning accuracy of Landsat 5 TM data processed with precise ephemeris parameters is introduced. Test with the Landsat 5 TM data verified that the method used in China Remote Sensing Satellite Ground Station is effective to eliminate the system errors produced during the imaging process.关键词：Landsat 5;radiometric correction;geospatial positioning accuracy4646|267|0更新时间：2024-05-08
- 摘要：Aiming at the problems in the color space information, the global distribution and the local regions and edges information of an image are considered separately appearing in traditional color image segmentation, a hierarchical color image segmentation algorithm based on Fuzzy ART model is proposed. The algorithm frame mainly involves the effective utilization of the luminance distribution, the edge information and the color space information. A set of hierarchical features are extracted from the image, and making use of the ability of stable and fast incremental learning and memorizing of Fuzzy ART model, the image is partitioned into several regions hierarchically and the hierarchical representation of the image is formed. According to the hierarchical representation of the image, good segmentation results can be obtained. Compared with the FFCM algorithm, better results can also be obtained.关键词：Fuzzy ART model;color image segmentation;hierarchical segmentation3019|267|0更新时间：2024-05-08
- 摘要：There are several advantages to perform video object segmentation in a compressed domain.The primary benefit is with much high processing speed. Moreover, the video data already exiting in MPEG1 and 2 formats in many databases would have to be decompressed to employ the pixel domain techniques. In this paper, a moving objects segmentation algorithm based on gradient model in compressed domain is proposed. Firstly, DCT coefficients (AC［1］and AC［8］) are utilized to form the gradient image. Then we synthesize the edge motion message obtained from the accumulated motion vectors. Finally, desirable moving objects segmentation results are acquired.关键词：compressed domain;moving objects segmentation;gradient model;DCT coefficients;motion vectors3156|253|0更新时间：2024-05-08
- 摘要：The preprocessing of palmprint includes the palmprint segmentation and the palmprint image enhancement. According to the shortcomings of the existing preprocessing methods, in this paper, we propose a new preprocessing method of palmprint. The method uses the outside boundary of a palm as the reference line to align a palmprint. It also includes the usage of the center of the largest inscribed circle as the origin of the coordination system of palmprint and extracts the center part of the palmprint, which complete the palmprint segmentation. In addition, to enhance the contrast of palm images, this method introduces the fuzzy set theory into the unsharp masking scheme and replaces a Laplacian filter with steerable filters to extract the high frequency components. The experiment results demonstrate the method can not only extract the center part of palmprint, even under the circumstance of adducting the all of fingers, but also enhance the contrast of principle lines and wrinkles synchronously.关键词：palmprint segmentation;palmprint image enhancement;unsharp masking;fuzzy theory3279|245|0更新时间：2024-05-08
- 摘要：In order to classify the data of Hyperspectral remote sensing images automatically without prior knowledge, an unsupervised classification algorithm is presented based on the conception of convex geometry and spectral features in this paper. The endmembers are selected step by step during processing and each endmember can be identified as one class. The advantages of this algorithm are simple in theory, easy to accomplish, widely used, and without any manual assistance. The experiment shows that the classifying result of this algorithm is satisfied.关键词：hyperspectral image;unsupervised classification;endmember;conception of convex geometry3971|299|0更新时间：2024-05-08
- 摘要：A fusion algorithm of a low resolution, multi spectral image and a high resolution image based on àtrous Contourlet transform with match degree and gradient selection is proposed. First, the resource images are decomposed àtrous Contourlet transform, which the advantages of àtrous transform and Contourlet transform. Then considering that the gradient represents the details of images, and that the positive or negative coefficients are existed in the corresponding position, for the purpose that the space resolution of the fused image is as high as possible, MWGA（match degree weighted gradient algorithm）is proposed for the fusion of high frequency details. The last, the fused image is acquired the method of high frequency addition. It is proved that the fusion results especially the space detail quality of the proposed method is better comparing the traditional methods.关键词：image fusion;àtrous Contourlet transform;match degree;MWGA;high frequency addition3135|250|0更新时间：2024-05-08
- 摘要：This paper proposes a new approach for automatic extraction of roads from SAR imagery based on genetic algorithm. We first suppress the speckle by Frost filter, then detect line feature pixels to get potential road pixels. Followed that, extract primitive line segments by Radon transform on every set of connected pixels, and use genetic algorithm to group line segments to get the candidate road segments. Finally ,The snake model is used to adjust the position of the candidate road segments in order to make road segments discrimination using the road’s linear feature more effective. We show the feasibility of the approach not only by presenting reasonable results on airborne and spaceborne SAR images but also by evaluating them quantitatively based on ground truth.关键词：SAR imagery;road extraction;genetic algorithm(GA);primitive line segment extraction3774|283|0更新时间：2024-05-08
- 摘要：This paper presents a method for detecting ship wakes in SAR images based on the localization of Radon transform. Firstly, the image is normalized, and the noticeable pixel would be regarded as a constant. In localized radon space a big number will correspond to a long line segment. An appropriate threshold can decrease false alarm. By choosing appropriate structuring elements, i.e. dilation and erosion lengths, the two responses which are close enough in the vertical direction will be joined into one. The effect of erosion is that responses which are too narrow in the vertical direction will disappear entirely while responses which are wide enough will be contracted vertically.The simulation and real data processing results show that the algorithm is successful in wake features detection, wake location and computational efficiency.关键词：SAR（synthetic aperture radar）;localized radon transform;morphological image processing;wake3859|225|0更新时间：2024-05-08
- 摘要：Problems of segmentation of pulmonary nodule candidates from CT images were studied in paper, the image segmentation method proposed by Chan Vese was analysed and improved. A new level set method based on circle dependent had been deduced, and then an algorithm for segmentation of pulmonary nodule candidates in CT images had been presented, it solved the problem of detecting multi circle areas with different sizes in an image. Experiments had been done for segmentation of synthetic and clinical pulmonary images by the proposed algorithm, the experiment results show that it can detect multi circles areas correctly and efficiently, and it is robust to resist noise disturbance. This algorithm has advantages for the realization of automatic detection for lung nodules in pulmonary CT images.关键词：level sets;image segmentation;pulmonary nodule candidate;Mumford Shah model;circle dependent3376|210|0更新时间：2024-05-08
- 摘要：Measurement of the diameter and curvature of fibers plays a very important role in wool and textile industry. In this paper, an automatic measurement method based on image analysis is presented. In this method, the image processing and analysis is fully used. Firstly, this method enhances the captured images. Secondly, it uses canny operator to detect the edges of the fibers. And then, it acguires the binary images by using clustering. It does post processing operation to the binary images and extracts the skeletons of the fibers. Finally, it computes the value of diameter by Euclid distance transformation, and calculates the value of curvature. As experiments demonstrate, this method is not only more quickly than the method based on line fitting, but also generates more accurate results than the method based on line fitting because we have avoided many steps which may introduce errors.关键词：diameter;curvature;skeleton;distance transformation3734|221|0更新时间：2024-05-08
- 摘要：In the domain of 3D scene reconstruction, motion estimate and machine vision, we need to detect the corners in a image, as well as obtain more information around corners, namely we could classify the corner further. We proposed a corner classification method based on directed area. First, we applied corner detection principle of wavelet transformation, based on the eigenvectors of covariance matrices, to detect the corner on the edge of images. Secondly, we defined six types of corners based on the edge information of both sides. Finally, corners can be classified by computing three directed areas arranged in order on the edge of the corners. The experiment indicated that the method of classifying corners has higher accuracy.关键词：wavelet transforms;corner detection;directed areas;corner classification3365|228|0更新时间：2024-05-08
- 摘要：The traditional algorithms for geometric moment focus on the single rectangle windows. It has very low efficiency in the sliding window applications. This issue prompts a new fast algorithm for 2 D geometric moment. It could efficiently reuse the overlapping pixels between conjoint sliding windows, and achieves much higher computation efficiency. The average number of the multiplications and additions is O(1), regardless of the sliding windows size. Compared to the operation complexity of the traditional algorithm, known as O(N×L) in 2 D case, the new algorithm derived by this paper can improve its speed by the factor of nearly N×L. A number of computer experiments are performed to validate this conclusion. This operation speed of this new algorithm can satisfy the requirements of most real time applications.关键词：geometric moment;sliding window;fast algorithm;2 D3230|212|0更新时间：2024-05-08
- 摘要：To improve the performance of medical image registration technology, a new method based on wavelet transformation and mutual information is proposed in this paper. Decomposed wavelet sub bands of the original images are obtained using the wavelet transform. Coarse to fine multi resolution search approaches have been performed. Registration at higher levels can be performed with the result at the pervious level serving as the initial condition. Down simplex method with limited boundary is used as optimization strategy. Besides, different methods are used at different levels. Regional mutual information (RMI) which takes geometry into account is used as similarity measure at low levels and PV interpolation is applied at high level in order to prevent the optimizing process from being tapped into local maximums. The algorithm has been applied on noisy MR mono modality, PET mono modality and MR PET multimodality medical image registration. The results show that the algorithm performs fairly well. Compared with the traditional algorithms, the algorithm has some advantages such as higher precision and better anti noisy performance as well as higher computation efficiency.关键词：medical image registration;wavelet transformation;mutual information;multi resolution3590|283|0更新时间：2024-05-08
- 摘要：In order to match video sequence images efficiently and considering the effectiveness and efficiency of the SVD matching algorithm, this paper describes a more advanced SVD multi view video image matching algorithm based on a new type of invariant feature and outlier rejection strategy. The features are located at Harris corners and oriented using a blurred local gradient. This defines a rotationally invariant frame which is sampled as a feature descriptor. The color information is introduced into the distance function of SVD matching algorithm. The outliers are rejected based on motion consistency. For motion consistency a motion model was fit first between the matched points, and the threshold was set adaptively using the deviations of the motion to reject the outliers. This algorithm uses oriented patch to adapt to the effect of rotation, color features to remove the uncertainty, and motion consistency to increase the correct match ratio. The experimental results show that the algorithm can obtain lots of matching points between wide base line images, even if there is rotational transformation and different lighting conditions between two images, which proof that the algorithm has practical value.关键词：image matching;oriented patch;color weighted;motion consistency;singular value decomposition3426|259|0更新时间：2024-05-08
- 摘要：This paper proposes a multiresolution image matching framework based on graph cut theory and Hausdorff distance for aerial images with complex scene. After the establishment of Gaussian pyramid image model, we adopt graph cut segmentation in the lowest level and extract robust and integral region boundaries with full consideration of both local and global information. The output region boundaries will be used as candidate curves for further matching. After calculating the statistical information of curves as matching features, we can evaluate the coarse affine transformation parameters using simple correlation measure. The coarse affine transformation parameters estimated can be further used to search in fine levels based on the Hausdorff distance measure. The experiment shows that our method can overcome great distortion and suppress strong noise, and successfully match the images of complex scenes.关键词：graph cut;curve matching;Hausdorff distance3642|506|0更新时间：2024-05-08
- 摘要：In this paper, the problem of efficiently and precisely constructing the cylindrical panoramas view of a scene from an image sequence is considered. The proposed method firstly detects correspondences based on gray level edge feature so that the focal lens can be counted based on correspondences uniqueness. Then the focal lens will be directly used in following image matching processing with a novel adaptive mixed gray level image matching algorithm and outputs a rough panorama result. The width of it reacts to a judgment to adjust the focal lens, which induces an iterative computation to guarantee an exact focal lens. Finally an angle oriented one dimension projection template matching algorithm will be employed to modify the correspondences in narrow range and the final panorama is obtained by linear image blending. Adaptive using multiple image matching algorithms according to self relation variant after precise focal lens searching, the method redraws the accurate overlapping image horizontally and vertically. Experimental results proved that the proposed approach are given works well over most image sequence capture by handholding camera, and is fast, accurate and robust enough for real time applications.关键词：cylindrical panoramas;image mosaic;mixed gray level image matching;pattern recognition;image based rendering3914|257|0更新时间：2024-05-08
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