最新刊期
卷 9 ， 期 12 ， 2004
- 摘要：As one of a serial of reports, this paper is a survey on multimedia researches and applications in China, 2003. Since multimedia is a cross research area, papers about multimedia technology are distributed on various journals. We checked about 3 143 papers published on 9 Chinese journals in 2003, from which we have selected 436 on multimedia technology and application. Then we made analysis on these selected papers and the statistics were compared with those from 1999 to 2002. From the results we can find that researchers in China pay more and more attention to digital watermarking, virtual reality, multimodal interface, multimedia data retrieval technology, quality of service, computer supported cooperative work, GIS and Digital Earth, which are also the international evolution trends in a quite long period. We present here an overview on the progress in multimedia technology in China, 2003. This article will provide the researchers looking up references with great convenience, and also will be helpful to editors compiling journals and for authors contributing papers.2683|211|0更新时间：2024-05-07
- 摘要：Image feature detection is a key technique in image processing, pattern recognition, content-based image retrieval, and so on. The typical image feature detectors are analyzed. From the viewpoint of information used, the literatures on image feature detection are analyzed systematically, and image feature detectors can be categorized in to two kinds, that is, gradient-based ones and phase-based ones. Characteristics of each kind are discussed. The key issues of the important image feature detector are explained extensively and comprehensively. Based on the survey, some concerned issues needed further research are presented, and the future research trends are also given.2538|196|0更新时间：2024-05-07
- 摘要：Usually, camera self-calibration is nonlinear. A linear camera calibration technique based on four point correspondences is proposed in this paper in order to obtain a linear method, and a robust Euclidean reconstruction under the random sample consensus (RANSAC) algorithms is computed from the images. The main results are: Assuming the camera undergoes two sets of translations, of which the corresponding rotation axes of camera are not parallel, then Euclidean geometry of a scene can be reconstructed linearly from four point correspondences. Experimental results on synthetic and real images have validated the proposed linear technique.2343|213|0更新时间：2024-05-07
- 摘要：Aiming at the complexity and the quality of IC cards, the location of code region and the segmentation of characters on IC card are studied. An on-line method of locating code region and segmentating characters on IC card are presented in the paper. It is based on the combination of the pre-testing location, the original position locating, the coarse region locating and the exact one. The location for different kinds of IC cards and different position of code regions on IC card are solved. The location method is discussed in detail. The multi-projection histograms are presented to segment the code. The experiment shows the result of the method is good.2664|199|0更新时间：2024-05-07
- 摘要：In this paper, we present an approach based on similarity measuring between 2D polygon sets for 3D model retrieval. The basic idea is to represent the 3D model by a series of slices composed of 2D polygon sets along certain directions. In this way, the shape-matching problem between 3D models is transformed into the similarity measuring between 2D polygon sets, in which three problems are involved: the selection of cutting directions, cutting methods and similarity measuring. To solve these problems, some strategies and rules are proposed, and their are proved by some experiments.2526|243|0更新时间：2024-05-07
- 摘要：Even multi-layer perception (MLP) classifier has been an efficient method of data classification, and the performance is often limited by the training samples space. In this paper, the MLP classifiers ensemble is used to improve the performance of image region classification in understanding of outdoor scene and a scheme for automated recognition concept classes of objects in outdoor scene images by image region classification is presented. First, the low-level visual features are extracted from the segmented image region, and then the ensemble classifiers are used to establish corresponding relationship between the visual features of image region and semantic class. Finally, the high-level semantic class of each object in an image is formed by combining the region with same label. The method has been evaluated on 150 images including five objects and recognition rate is around 87%. The experimental results show that the proposed method that has better performance compared to MLP-based method is suitable for image regions classification. Moreover, this ensemble method appears to generalize to other classification problems. (2970|216|0更新时间：2024-05-07
- 摘要：In image processing, removal of noise without blurring the image edges is a difficult problem. Typically, noise is characterized by high spatial frequencies in image. A new method for image denoising is proposed on wavelet domain, based on image multiresolution decomposition and anisotropic diffusion filtering. The original image can be regarded as high resolution wavelet sub-sampling one. A functional of preserved lower resolution information is presented. It is used to substitute for wavelet threshold denoising on image. The Euler-Lagrange equations are deduced from the variational principle by the image functional model. Image is denoised and enhanced simultaneously. The numerical schemes of the equation is based on additive operator splitting (AOS) scheme. Some experimental results demonstrate the validity of the new method for image denoising and edge preserving. And this method is also compared with other denoising methods, such as wavelets threshold filtering and anisotropic diffusion filtering. The numerical results of the application on images demonstrate the good performance of the new method.3203|190|0更新时间：2024-05-07
- 摘要：Low contrast structure can be found in many kinds of digital images, and it is a meaningful work to find out how to enhance these raw images through digital post-processing. A novel enhancement algorithm based on multi-scale edges representation of images is proposed. This algorithm is motivated by the connection between the contrast of a grayscale image and the gradient magnitude of intensity edges in the neighborhood where the contrast is measured. The undecimated dyadic wavelet transform of the original image is computed firstly by treating the columns and lines of the image separately, and then the local maxima of wavelet transform coefficients are selected out. The reconstruction of the image can be interpreted as an interpolation process, which recovers the wavelet coefficients between two consecutive modulus maxima and then calculates the inverse wavelet transform. As we know, the first derivatives of the modulus maxima are zero, and the Hermite polynomial requires the value of derivatives at the given nodes. Based on these two facts, the wavelet coefficients can be reconstructed using Hermite interpolation polynomial of degree 3 between any two adjacent maxima. By means of stretching those maxima at different levels and interpolating them with Hermite interpolation polynomials, the image can be enhanced effectively, and the different stretching factors on different levels can provide various kinds of enhancing effects, while this kind of enhancing flexibility cannot be found in other algorithms easily. This algorithm also offers abilities to control noise magnification and to enhance features of certain size within the images. Numerical experiments show that, the method can get fairly well enhancement result and the computing complexity can be low, so it is a practical fast enhancement algorithm.3249|201|0更新时间：2024-05-07
- 摘要：Level set method could efficiently solve the problem of the topologic change involved in the evolvement of the curve.Using the loop solution presented by level set method, active contour model based on global traits can segment objects efficiently.The paper uses this method to research segmentation technique in Chest Radiography Image.Taking account of the characteristic of Chest Radiography Image,a method with only once evolvement is presented here.We could get coarse lung area from original image and could get rib edge from local standard deviation image of Chest Radiography.The results verify that it is a robust way for Chest Radiography Image segmentation.2902|175|0更新时间：2024-05-07
- 摘要：A new MD (multiple description) video coding method is proposed in this paper, which is based on balanced multiwavelet image transform. First, we apply balanced multiwavelet transform to the image, and then, corresponding components of each sub-band are gathered together, so that we decompose the image into 4 MDs. By treating every frame of the video sequences like this, we can get a theme of MD video coding. A practical MD coding theme must satisfy two requirements. Firstly, each description should carry the same amount of information. Secondly, there must be dependence among each description. We find among commonly used multiwavelets, only balanced multiwavelet can satisfy the two requirements. Furthermore, based on the feature of CARDBAL2 multiwavelet and strict mathematical deduction, we find a way to estimate the lost descriptions. The experimental results presented in this paper show that even 75% data of the image is lost, we can still get a recovered image at good quality and the PSNR value is nearly 30dB.2315|193|0更新时间：2024-05-07
- 摘要：The main feature of multiple-scroll chaotic attractors is that they exhibit a rich variety of complicated chaotic dynamic phenomena and have many scroll encryption parameters that can be applied to secure communications. Based on the study of their generating mechanism, a novel scheme of multi-level digital chaos shift keying (MDCSK) via multi-scroll chaotic systems is presented. In the transmitter, the slope values of the multiple scroll chaotic attractors are modulated using multi-level digital signals, which generates MDCSK signals. In the receiver, the original multi-level digital signals are recovered according to the principle of drive-response synchronization and coherent demodulation. Compared with chaos shift keying (CSK), MDCSK has an advantage that multi-level digital signals can be encrypted, by using multi-scroll encryption parameters. Results of theoretical analysis and computer simulation are also given, which demonstrates the effectiveness of the proposed method.2815|169|0更新时间：2024-05-07
- 摘要：When users want to plan the reconstructed virtual scenes, if we obtained the information of the lighting at the time when the images were taken, we can use the rendering technologies from computer graphics to obtain new synthesized photorealistic imageries. This paper presents techniques for recovering the tilt angle of solar illuminant from a single outdoor building image, which can be integrated to most current image-base architectural rebuilding systems. Solar illumination can be treated as parallel light. Its direction can be measured by tilt and slant angle in architectural coordinate system. To calculate the tilt angle, we utilize the changes of intensities from different wall surfaces. This idea comes from SFS (Shape from Shading) technique. On the basis of the calculated tilt angle, we can easily calculate the slant angle from images by using the bulges of the wall surface and their shadows.2807|174|0更新时间：2024-05-07
- 摘要：One advantage of hyperspectral remote sensing is that it has more bands so more information could be used to recognize ground objects and estimate relative contents of materials. In this paper, pixels of hyperspectral remote sensing images of n bands are connected with points in an n-dimensional scatterplot. Pure pixels can be extracted using a method of simplex, which is a concept in convex geometry, and thus accurate hyperspectral image classification and spectral unmixing can be realized. The focus of this method is to find the simplex and to analyze it. The simplex can be found using MNF(minimum noise fraction) transform and PPI(pixel purity index) calculation, and the mapping methods used here are SAM(spectral angle mapper) classification and an unmixing method based on the simplex. All techniques here have been proved feasible by an application example. This paper also gives a procedure of the techniques. The advantages of the techniques and the procedure are that the endmenmbers for spectral mapping and unmixing can be extracted from the images themselves, and that spectral mapping and unmixing scale can be determined by users.3461|222|0更新时间：2024-05-07
- 摘要：This paper aims at the study of 3D numerical simulation of the groundwater flow field of the Changzhou-Wujin district, for revealing the main cause of the depression of the ground surface. First, the hydro-geological conditions of this area are analyzed. Based on this, a 3D numerical model of the groundwater flow field of the second confined aquifer is established. Then the numerical solution of this model is found using the 3D finite difference method. And finally, the 3D dynamic visualization of the groundwater flow field is realized using the hybrid rendering algorithm of the volume rendering combined with the techniques of computer animation. Through this study, it has been found that the main mined layer is the second confined aquifer of this district and its long term over exploitation is the main reason for giving birth to the cones of depression of the groundwater and the depression of the ground surface; the centers of the cones of depression of the groundwater are mainly distributed along the Shanghai-Nanjing railway where the industry and agriculture are flourishing and is heavily populated; the range of the depression of the ground surface and that of the cones of depression of the groundwater are basically identical, and the depression intensity and the depression rate of the ground surface are much related to the falling extent and the falling rate of the groundwater level. However, the phenomenon of the rebound of the ground surface is not prominent, when the groundwater level rises to great extent, that means the process of the depression of the ground surface is basically irreversible. Therefore, it is absolutely necessary to strictly control the mining amount of the groundwater of the second confined aquifer of this district, so as to avoid the further deterioration of the environmental geological catastrophes.2509|200|0更新时间：2024-05-07
- 摘要：Spatial relations have been comprehensively used in many applications, such as Spatial Database Query Language, Content-Based Image Retrieval and Similarity of Spatial Scenes, etc. However, because the conventional approaches of describing direction relations can not express direction information effectively when the target object is inside or intersected with minimum boundary rectangle (MBR) of the reference object, which limits the description of concepts related to spatial relations. In this paper, firstly, a detailed direction relations model (DDRM) is proposed, which can describe the information related to the interior of MBR of the reference object. The DDR includes interior, boundary and ring direction relations, and each direction relation is composed of 9 atom directions at most. The interior directions describe some concepts related to the interior of the reference object, The boundary directions deal with some terms related to boundary of the reference object, and the ring directions describe the information about the difference region between the reference object and its MBR. Secondly, after composing topological relations and DDRM, the number of discernible spatial relations about line/region, region/region and point/region increase. Unlike the current direction relations model, the DDRM is sensitive to the shape and the hole of a reference object, and is helpful to improve the ability of describing the spatial relations.2715|179|0更新时间：2024-05-07
- 摘要：ve spatial data, an algorithm of“Coordinate-consolidation Overlay”was presented. The appropriate threshold value was selected according to analysis of spatial data overlay. An extended module was developed based on this algorithm in Oracle Spatial. The correctness and validity of the solution were testified by using the spatial data in which bug happened for Oracle Spatial. In the end, an application example in overlay analyses of nationwide municipality-county map and land-use map at scale 1∶4000 000 was given by using the extended module of Oracle Spatial.2678|208|0更新时间：2024-05-07
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