最新刊期
卷 8 ， 期 1 ， 2003
- 摘要：Effective multimedia authentication is an increasing important issue in a networked environment. Fragile digital watermark thus come into being. Unlike traditional digital signature which is bounded with the content, fragile watermarking works effectively for multimedia content authentication by embedding a watermark(such as identification data, serials number, text or image etc.) to multimedia documents without influencing the vision or hearing effect of multimedia. Fragile digital watermarking is of great importance in courtroom defence, reliable e-business, medical image databases, etc. When the conetent of multimedia is suspected, the extraction of fragile watermark can be used to detect and localize tampers, even present the category of tampering. To motivate the relative research in this field, we attempt to give a brief overview of fragile digital watermarking into the context of image authentication in this paper.The basic characteristics of fragile watermarking is first outlined.Then comes the discussion of current algorithms, which not only includes basic schemes--spatial domain based algorithms and transform domain based methods, but also sums up the four typical types of fragile watermarking with different applications. Possible attacks and future research topics come in the following and future direction is outlined in the end.There still need a long way for fragile digital watermarking to go into standilization and actual applications.关键词：Fragile watermarks;Image authentication2382|189|0更新时间：2024-05-08
- 摘要：Watershed transform is a classical method of image segmentation in mathematical morphology. This method, with a wide perspective, has been applied successively into some fields like remote sensing images processing of satellite and radar, biomedical and computer vision applications. Watershed transform is a relatively time consuming task, and the study of this problem has been disesteemed by researchers for its low efficiency. But also for this reason, there appear some new theories and algorithms; moreover, with the development of parallel tools, watershed transform has an increasing attention internationally. As to the resent literatures on this field, variety of formalizing model makes the definition, algorithm and implementation of watershed lack in uniform description. Pointing to this status this paper starts with a rigorous definition of watershed transform for continuous case, followed by two kinds of representative definitions for digital case. The solution of plateau problem is discussed in detail. Then some new watershed algorithms proposed in recent years are classified and analyzed, including watershed algorithms by immersion and by topographical distance. The need to distinguish between definition, algorithm specification and algorithm implementation is pointed out. Finally we present the problems and challenges of future research, including accuracy of watershed transform, problem of over-segmentation, parallelization of algorithms and so on.关键词：Watershed transform;Image segmentation;Catchment basins;Watershed line;Immersion;Topographical distance2372|152|0更新时间：2024-05-08
- 摘要：This paper analyses the characteristic of "Journal of Image and Graphics" based on the analysis on the theses, the authors, the quotations and the situation of utilization by readers that issued on "Journal of Image and Graphics" between May on 1996 and June on 2002. It is purpose that the Journal can take an active effect on strengthening interflow?activating thought?prospering research on technicality and advancing the science development by statistics. The Journal has specialist writers and steady readers though it found only a little time. This paper also reveals the present conditions of research on Image and graphics, affirms the rationality of the Journal as one of the core issues in natural science in China.关键词：Bibliometrics;Comment;Paper statistics;Journal of Image and Graphics2514|216|0更新时间：2024-05-08
- 摘要：Camera self-calibration is a fundamental problem in 3D reconstruction from un-calibrated image sequences and has been investigated by many researchers in recent years. In order to simplify the camera self-calibration process, the skew factor of the camera is usually assumed to be zero to get a group of linear equations where initial values of the camera's intrinsic parameters can be estimated, then a non-linear algorithm initialized with these values can be used to optimize the self-calibration result. However, when the camera is a complete perspective model, i.e. when the skew factor of the camera is not zero, the error of the self-calibration with the above assumption will be very large and sometimes the self-calibration algorithms will fail to get any result at all. In order to overcome the above problem, this paper addresses a self-calibration algorithm that can successfully compute the intrinsic parameters when the skew factor of the camera is not zero but known. Experiment results of synthetic data as well as real image sequences show that this algorithm can estimate the camera's intrinsic parameters precisely and make the successive 3D reconstruction more easily.关键词：camera self-calibration;3d reconstruction;Absolute quadric3479|222|0更新时间：2024-05-08
- 摘要：Semantic image retrieval is one of the key technologies to find useful multimedia information more efficiently on Internet or in multimedia database. Extraction of main regions in an image is a precondition for semantic image retrieval. In this article, an automatic approach to extract those main regions is proposed. It first partitions an image into fixed sized blocks, and an elementary segmentation is achieved by clustering the visual features of all the blocks of the image. Then the result of the original segmentation is improved by some extra processing. After that, a special method is employed to distinguish the foreground regions and background regions. Finally, the regions, which are considered not important to the image content, are eliminated, and it is done by analyzing the importance of every region. Our experiments for outdoor images containing relatively salient objects show that, the approach proposed in this paper can get rid of lots of information, which are not related to the image content, and at the same time can also reserve the main useful information for image semantics. It gives a better foundation for the further applications such as image retrieval and image understanding.关键词：Image semantics;Image segmentation;cluster analysis;Image partition;Background removal2347|236|0更新时间：2024-05-08
- 摘要：A bone maturation evaluation system based on Active Shape Models is reported in this paper. By the system the bones in a hand X-radiographic image are located and their edges are detected. According to the standard of Chinese wrist bone maturation--CHN, the bones are sorted into different grades. Having gotten all grades of the bones in the hand image, the data of bone maturation can be computed by combination of the grades with different weights. The edges of the bones in X-radiograph image are faint and the grades' definitions of CHN are very abstractive. It is difficult to detect the edges of the bones and make correct classification of them. The Active Shape Models, based on the prior knowledge of the bones' edges, is used to detect the edges of the bones and vectorize the grades' definitions in CHN. The experiments reveal that the method of Active Shape Models is valid in bones' edges detection and grades classification. Tested with a set of hand X-radiograph images, the bone maturation evaluation system has good accuracy and stability.关键词：Bone maturation evaluation;edge-detection;Active shape models2443|201|0更新时间：2024-05-08
- 摘要：Active Contour Model introduced by Kass et al is a energy-minimizing curve in essential. It is a new method of image object extraction based on top-down mechanism, which makes use of high level information to improve the speed and veracity of object extraction. It has been used more and more widely in applications of image analysis and computer vision. The original algorithm of active contour model involves four steps: setting up a variational integral on the continuous, deriving a pair of Euler equations, discretizing them, and solving the discrete equations. This algorithm suffers a number of problems. In this paper, we will firstly discuss the original algorithm and some improved algorithms of active contour model, then propose a algorithm based on the genetic algorithm and present the experiment result. The result proves that genetic algorithm settles the problem of original model that run into the local least value end enhance the success ratio of the object extraction.关键词：active contour model;genetic algorithm;Object extraction2936|209|0更新时间：2024-05-08
- 摘要：Type and shape of the car is coherent, one type of the car possess the one and only shape. Based on this fact, instead of recognition of the type of the car, recognition of the shape of the car is discussed detailed in this paper. Considering that a few methods proposed in the correlate paper are not accurate and those methods are lack of gracefulness, matrix singular value method is used in car shape recognition in this paper. As one of algebraic characters of matrix, singular value is reported to be used in image recognition, such as human face recognition, but the report about the method used in recognition of the vehicle shape has not been accessible. In order to standardize the different weight of the images in the same sites owing to different light, gray level rectified factor is put forward. At last, quantitative and qualitative analysis about the methods is proposed.关键词：Matrix singular value, Gray level rectified factor, Car shape recognition2384|199|0更新时间：2024-05-08
- 摘要：There is a kind of noise called speckle in ultrasonic images. It degrades severely the quality of image, especially edges and details. An adaptive line boundary detection technique is presented. A stick is a line segment of variable length and different orientation. Sticks are short enough that they can locally approximate the edges and certain features in the image. In particular, tissue boundaries have the appearance of straight or gently curving line segments because they are cross-sectional views of the surfaces between tissue layers. The boundaries and certain details are smooth on the scale of spacing between scan lines and generally define closed convex shapes. The algorithm works by plotting at every point the maximum local projection onto the stick. The orientation of stick is decided by hypothesis test optimizing method and the length of stick is obtained by local statistics based on region growing technique. For quantitative evaluation and comparison with adaptive speckle suppression filter (ASSF) and line edge detector(LED), two parameters as measure of the noise suppression and edge preservation are introduced. It is proved that this method can not only suppress speckle noise but also preserve even enhance issue boundary effectively by applying it to the phantom and tissue images.关键词：speckle;ultrasound;Boundary detection;Stick;region growing;Local variance to mean ratio2315|201|0更新时间：2024-05-08
- 摘要：This paper investigates a new method of reconstructing moving track from the measured value over several views when the object moves along line in 3D space. Here the camera can be one moving camera, or a set of camera being located at different position. This problem was put forward by A.Shashua first and was defined as “trajectory triangulation”. Under some restriction of the track of moving, they determined the line in 3D (moving track) from the relativity of point and line and by the aids of Grassmann-Carley algebra and Plücker coordinate. This paper brings forward a new method based on the rank restriction of the "measured matrix", that is to say if the points are on a line, the matrix formed by the coordinates of these points must have rank 3. In order to simplify the computation, the camera matrices have been transformed so that the last column of every projective matrices has only one no zero value. The algorism of the method is evaluated on both synthetic and real world images. Comparing with the method in[1], our method is simply and directly, and it can be realized in a general projective coordinate system. Moreover, it can be generalized to any situation as long as the shape of trajectory of moving object is polynomial, although only moving along line is investigated in this paper.关键词：Trajectory triangulation of lines;measurement matrix;3D reconstruct2402|184|0更新时间：2024-05-08
- 摘要：Surface model reconstruction from 3D unorganized points (points of surface or volume) is of great importance in variable fields such as computer vision, images based modeling, 3D reconstruction based on images, scientific computing visualization, etc.. Many approaches have proposed to resolve the problem, such as 3D Delaunay triangulation, CDT, Qull Hull. etc. What makes the problem very difficult is that the reconstruction surface is convex and the efficiency of algorithms is not high. In this paper we present a fast model reconstruction algorithm for 3D unorganized points based on Hugues Hoppe algorithm. First, input points are divided into small logical "cubes" whose size can be decided automatically from the unorganized points according to Marching Cubes. Then the tangible planes and normal vectors at each point are calculated and all of the normal vectors are orientated to the outside of surface based on WFS(Wide First Searching). Finally, the function of iso-surface of scalar field for Marching Cubes algorithm can be obtained. In addition, ,the algorithm improves the efficiency of Marching Cubes by looking up tables. Finally the model can be obtained by the output of Marching Cubes composed of triangular meshes. Experimental results show the high efficiency of the algorithm. And the algorithm can be applied to not only the points of the surface but also the volume data (such as 3D scanning data, MRI data).关键词：3d reconstruction;3D triangulation;Wide firt searching(WFS);Marching Cubes;Iso-surface2882|205|0更新时间：2024-05-08
- 摘要：Motion editing is the key technology to improve the re-use of motion captured data and produce complex human animation. However, few techniques are capable of editing motion at high level. In this paper, wavelet transformation is introduced into motion multi-resolution analysis and some new algorithms, namely motion feature enhancement, motion fusion and motion feature extraction and synthesis, are proposed. Motion signal is decomposed into multi-resolution levels with wavelet analysis. The coarse level represents the overall pattern of a motion signal while the fine levels describe the details. Special motion style can be highlighted through enhancing the corresponding level content. And multiple motions can be fused by multi-resolution blending to create new motions somehow like to the blended motions. Special motion style can be synthesized into other motions by texturing them with related fine levels extracted from the related motions. The experiment shows that these algorithms are well suited for motion feature editing and enable animators to edit motion effectively at high level.关键词：motion editing;wavelet transformation;Motion enhancement;Motion fusion;Motion feature extraction and synthesis2381|188|0更新时间：2024-05-08
- 摘要：This paper suggested a target segmentation scheme based on morphological processing and texture analysis. Firstly, an opening-closing filter bank performed on the gradient image for watershed segmentation is proposed. The filter bank concerns with eight structure elements, each is selected to represent the allowed neighbor patterns and used to generate a reference image for segmentation. This reference image is more suitable than the gradient one when calculating the watersheds, because its main structures are preserved while pseudo-contours are discarded. Then binary marker extraction is carried out to get initial partition. These region markers mark the relevant objects and backgrounds to act as the minima set of segmentation, the initial object boundaries are finally obtained by computing the watersheds. Secondly, a criterion with respect to the homogeneity and the contrast of textures is defined to merging regions, it weighs the contrast of two neighbor patterns and adapts itself to different sizes of neighbor patterns. Experimnts on several video sequences are presented to demonstrate that the morphological filter bank could prevent the result from over-segmentation and the criterion is also validity.关键词：Computer image processing;Image segmentation;Opening-closing filter;Watersheds;Texture homogeneity2232|226|0更新时间：2024-05-08
- 摘要：This paper gives a new learning rule about the formation of weights for two-layer max-min feedforward fuzzy associative memory (FAM) network proposed by Kosko . Based on the new rule,The feedforward FAM model is developed into a fuzzy bidirectional associative memory (BAM) model,and a fuzzy quick augmentation algorithm is also proposed,Its stability and tolerance for the BAM model are also analyzed. From the analysis, an interesting result which can store an arbitrary given multi-value patterns is obtained. When used to store binary values, The weights for BAM model take binary too, 0 or 1.So it is suitable for the VLSI and optical implementation. In order to make a comparision, binary based sample patterns have adoped. A larger number of simulation results show the advantages of a less number of weighted value,or the simple implementation, by comparing with the existing learning algorithm,such as binary based Hoperfield dummy augmentation and MBDS augmentation algorithms. On the other hand, the fuzzy quick augmentation algirithm has the merit of the simpler computation and faster convergence.关键词：Fuzzy associative memory;Augmentation learning algorithm;Connection weights2903|185|0更新时间：2024-05-08
- 摘要：After discussing the merits and demerits of the fractal theory and wavelet transformation modulus maximum in image compression, the new hybrid encoding method based on wavelet transformation modulus maximum and fractal is firstly presented in this paper. It is known that IFS is used synthesize fractal image resembling natural objects. But the maximal errors of restoration image are on the edge of image. The local maximal of wavelet transformation provides an effective technique for image edge extraction. The reconstruction of image is made from the modulus maximum of its wavelet transformation. Using the edge character of the wavelet local maximum modulus firstly performs the image encoding. Then, error image is compressed according to the self-similar of the fractal so as to obtain the good reconstructed image with the high compression rate. Later, the theory description and the detail algorithm steps are given. Finally, the experiment results show that the compression image has the properties of good vision effect,non-square effect,no edge oscillation,no image blur and high compression rate by using this kind of new hybrid encoding method.2322|185|0更新时间：2024-05-08
- 摘要：In order to achieve a high image compression ratio in fractal cloding, the ability of fractal coding to predict wavelet coefficients is anyalyzed and the traditional way of fractal coding is found to be not able to effectively predict the entire wavelet coefficients and leads to a not very good coding result. A hybrid image compression algorithm based on wavelet transforming using fractal coding and zerotree coding that can make up for this flaw effectively is presented in this paper. First, the image is discomposed into a series of subimages in different orientations and different resolutions by wavelet transform, then the subimages in the same orientations but different resolutions are formed into wavelet subtrees, just like zerotree,at last ,the wavelet subtrees are coded by the way of either fractal or zerotree coding according to the size of error when coding.. This algorithm made a effective use of the redundance within subimages as well as the self-similarities within subimages and the similarities cross scales compared with traditional fractal image coding based on wavelet transforming. The experimental with this algorithm presented in this paper also show that the proposed algorithm can obtain a good compression result in a broad compression rate scale.关键词：Wavelet subtree;fractal coding;Zerotree2390|194|0更新时间：2024-05-08
- 摘要：The wavelet-based image compression is a successful technology, and plays more and more important role in the image compression fields. But the edge fuzzy phenomenon, which occurs in the wavelet-based image compression algorithms under low bit rates, remains an open question. In order to reduce the edge fuzzy phenomenon under low bit rates to some extent, a new method of wavelet image compression based on potential fuzzy clustering quantization has been presented in this paper. The potential fuzzy clustering method is applied to quantize the detail sub band images' wavelet coefficients after the image has been decomposed by the wavelet transform. This method has two advantages. One is it considers the statistical characteristics of each detail sub band images' wavelet coefficients and the importance of detail sub band images' wavelet coefficients for saving the edge and texture information of the original image. The second advantage is it makes use of the characteristics of fuzzy set. The experimental results show that this method can get satisfying results, the edge and texture information can be saved well under low bit rates, the edge fuzzy phenomenon is reduced to some extent. And the subjective quality of the reconstructed image is improved. This paper has made some tries on fuzzy clustering quantization method in the wavelet-based image compression fields.关键词：wavelet transform;Image compression;Fuzzy cluster analysis;quantization2520|176|0更新时间：2024-05-08
- 摘要：Now, video delivery based on IP network is being used more and more. (Example: video phone and video conferences). But, since characteristics of IP network, packet loss that impairs quality of video delivery severely is inevitable. Reference Picture Selection (RPS) is a better way for error resilience. RPS does not necessarily mean extra delay in the encoder, but it need that a feedback channel can be set-up from the decoder to the encoder in order that the decoder can inform the encoder about which part of the transmitted information is corrupted by errors. RTCP (real time control protocol) is the control protocol of RTP (real-time transport protocol). RTCP provide a higher-level control information and a feedback channel. In this paper, by RPS and improved RTCP, we design and implement a mechanism that controls error in video delivery in order to reduce damage of packet loss. It has been found that this error control method can greatly improve the quality of the images transmitted on Packet network, for instance Internet.2319|163|0更新时间：2024-05-08
- 摘要：One important advantage of Geographical Information System (GIS) is its spatial analyses. According to researches and applications, the best way to implement the spatial analyses is to use the tool of model. However, many GIS systems lack spatial model base in different degrees, which in a sense constrains the spatial analysis ability of GIS. But different from common models, the spatial models must cope with and operate complex spatial data that bring many specific difficulties. So the development of spatial model is very slow compared with that of GIS applications and the related requirements. Introducing the COM technology, this paper studies the reusable spatial model base that is independent to specific applications. Then, based on the study a model base frame is advanced and its implementation is discussed. Our study shows that introduction of COM technology into GIS spatial model base, not only can enhance the reusability of GIS software, but also can help the realization of GIS spatial analyses. Because of the complexity brought by the spatial data, more issues remain to be further studied.关键词：Spatial model base;COM technology;Reusable;Geographical information system2175|187|0更新时间：2024-05-08
- 摘要：Voronoi diagram is one of the basic geometrical structures, an effective tool to solve the relatively geometrical problems. To meet the requirement of the dynamical construction and display of the relationship between spatial objects, the Voronoi-based spatial data model is put forward in this paper, which is developed on the basis of the generic object-oriental data model and can dynamically display the adjacency relations between spatial objects. In this model, voronoi polygons replace the part of the spatial relation definition in the object-oriental data model, and the frame of the Voronoi-based spatial data model is brought forward. This paper mainly focuses on the construction of the Voronoi-based spatial data model in the view of the semantic conception about spatial construction. The model is designed to make up the deficiency in the topological structure and the raster structure, and is a very effective data model to represent complicated spatial relations.关键词：Voronoi diagrams;The object-oriental data structure;Adjacency relations;The hierarchical structure2668|192|0更新时间：2024-05-08
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