最新刊期
卷 11 ， 期 10 ， 2006
- 摘要：A survey is given on interval arithmetic, affine arithmetic and their modifications such as the modified affine arithmetic in matrix or tensor form method as well as the recursive Taylor method and their applications in computer graphics and computer aided geometric design. Some future research directions and key issues are discussed.关键词：curve and surface plotting;interval arithmetic;affine arithmetic;modified affine arithmetic;recursive Taylormethod3318|210|0更新时间：2024-05-07
- 摘要：As an important part of the technology for human-machine interface,facial expression recognition(FER) have drawn much attention recently and numerous methods have been proposed.In this paper,we present the up to date development of this area in recent years.First,the three steps of the FER system are introduced: face detection,expressional feature extraction and expression classification.Second,the methods of feature extraction and expression classification are detailed in different categories.Then,we also introduce the facial expression databases which are widely used at present.Based on these databases, a comparison of the performances of several FER systems is presented.At last,we demonstrate the state of the FER technique and the possible challenges,and provide some advice about the current of FER development.关键词：facial expression recognition;expressional feature extraction;expression classification;facial expressiondatabase4238|267|0更新时间：2024-05-07
- 摘要：Facial reconstruction is a kind of scientific technology which is based on the rules of the relationship between skull and skin. It is widely applied in the fields such as criminalistics, archeology and so on. This paper introduces the whole process of computer aided 3D facial reconstruction, which including 3D reconstruction of a digital skull, reconstruction of skin from skull data, facial expression and animation etc. Various existing methods about the phases mentioned above are also reviewed. The focus of this paper is on reproducing three-dimensional facial skin based on a small quantity of landmarks and their corresponding tissue thickness, and improving of surface fitting. At last, the tendency of facial reconstruction is given.关键词：3D facial reconstruction;landmark;tissue thickness2998|267|0更新时间：2024-05-07
- 摘要：For region-growing phase unwrapping algorithm of interferometric synthetic aperture radar(InSAR),one of the key problems is to determine the seeds and the phase values of these seeds.In this paper,the optimized region-growing algorithm for 2-D phase unwrapping is discussed,involved determine the seeds and optimize the phase values of seeds.Taking the edge curves of interferogram as the seeds and analyzing the neighboring relationship of edge curves,the optimized phase values of seeds can be obtained by using the genetic algorithm.The experimental results show the computational complexity of the optimized region-growing algorithm is linearly correlative with the number of interferogram pixel.As a regional algorithm,the efficiency of the optimized region-growing algorithm can be improved by the paralleled processing.Compared with the branch-cut algorithm,the weighted least-squares algorithm and the network flow algorithm,the optimized region-growing algorithm has excellent coherence of fringe between the result image and original interferogram,as the network flow algorithm.But the computational complexity of this algorithm is far less than the network flow algorithm's.关键词：2D phase unwrapping;interferometric synthetic aperture radar;edge extract;region growing;genetic algorithm3007|226|0更新时间：2024-05-07
- 摘要：Traditional watermarking methods in the transformed domain for images can't be applied on meshes directly because meshes are generally irregular sampled data sets.This paper proposes a robust mesh watermarking algorithm using wavelet transform for semi-regular meshes obtained by remeshing.The original mesh with multiresolution representation is decomposed into a base mesh and a set of wavelet coefficient vectors by applying the wavelet transform.Based on the statistical analysis of wavelet coefficients,the watermarks are embedded by perturbing the wavelet coefficient vectors in low resolution subband,and the embedding strengths for different components of the wavelet coefficient vectors are designed differently in order to decrease the geometric distortion.Experimental results show that this algorithm satisfies imperceptibility and is robust to various attacks.关键词：mesh watermarking;multiresolution representation;wavelet transformation;mesh subdivision2689|210|0更新时间：2024-05-07
- 摘要：In the past, most image hiding techniques were applied only to gray scale images. Now, many valuable images are color images. Thus, it has become important to be able to hide color images. In this paper, an adaptive color digital image blind hiding algorithm is presented. A color scale secret image can be hidden in one color carrier image with the schemes. To increase the quantity of the embedded data, the hard c-means cluster and color quantization technology based on discriminative palettes can be used in the algorithm. In particular, in order to further enhance the security and robustness of the hidden image, the scrambling technology based on hyperchaotic mapping can be used as pre-process of color image information hiding. The coupled map lattices mapping is used to generate hyperchaotic sequences, and the secret image is encrypted by changed image pixels value and image pixels position. The initial parameters of hyperchaotic mapping can act as the private keys. The experimental results are satisfactory.关键词：color image;information hiding;hard c-means cluster;hyperchaos;color quantization2241|182|0更新时间：2024-05-07
- 摘要：With the development of network, video has been widely used in it, and the security problem of video has been brought forward. We can solve the problem with video encryption. According to the requirement of network to video encryption, this paper proposed a new scalable encryption scheme. This paper set up a video compression system based on wavelet transform, encrypt on wavelet coefficients and motion vectors shuffling, sigh flipping in the encoder, and also compared the experimental results with other schemes. Those results show this scheme can get better encryption effect, be of less key cost and higher security. At the same time, it also has small impact on compression efficiency and compression ratio. It is a high efficiency scheme of video encryption.关键词：video encryption;wavelet coefficient;motion vector2360|196|0更新时间：2024-05-07
- 摘要：In order to enhance the capacity of steganography,in this paper,an image steganographic algorithm based on Pseudo Random Number(PRN) is proposed.The same Pseudo Random Number sequence is generated by Pseudo Random Number Generator(PRNG) in the parameter certain situation.To utilize this nature of PRNG,the Integer Pseudo Random Number(IPRN) is generated and regarded as an auxiliary pixels value.First,two secret information are hided to one IPRN and one pixel value,and then the secret information which is in the IPRN is displaced to the pixel value.In this way,the two secret information bits are embedded into the pixel value.This method's characteristic is that the capacity of steganography will be enhanced in one time.The experiment proved that this method has a very good security performance and the hiding capacity.关键词：image steganograph;pseudo random number;LSB(least significant bits)2397|191|0更新时间：2024-05-07
- 摘要：To 3D scattered data,a novel algorithm for surface reconstruction is presented.Based on local flatness of surface and fundamental rule of planar triangulation,this method sorted neighbor points around reference point,R on tangent plane at R.After deleting invisible points by visibility criterion,any two adjacent points formed triangle with R.At last the planar mesh relationship returned to the space and object surface,which correctly reflects point cloud topology,is reconstructed progressively.By predefining angle thresholds,this algorithm can optimize triangles and test surface boundary and holes automatically.Several scattered data reconstructions are completed using VC++,and the results show that this algorithm is easy to implement,and can reconstruct more authentic 3D surface with a faster speed.关键词：scattered data;surface reconstruction;local flatness of surface;triangle mesh;visibility criterion2362|168|0更新时间：2024-05-07
- 摘要：This paper proposed a visibility constrain based automatic surface model reconstruction algorithm. This algorithm firstly introduced an automatic 3-dimensional Delaunay triangulated network modeling construction algorithm which is realized by insertion method, then constructed convex hulls enveloping all the known irregular points. On the base of initial Delaunay triangulated network, we proposed a new method of using the visibility information of feature points in images to calibrate the initial 3-dimensional model, and thus getting the actual surface model of object. The experiment results showed its reliability.关键词：Delaunay algorithm;mesh generation;tetrahedron;convex hull2491|216|0更新时间：2024-05-07
- 摘要：In this paper, by making use of the equivalent relation between free-space fresnel diffraction illuminated by the spherical wave and fractional fourier transform and the correlation between long distance and short distance diffraction, we proposed a new algorithm for Fresnel-diffraction based on the Wigner transform and simulated the conclusion by computer. Compared to traditional algorithm, the new one is not only more simple but also proposes a new way to study the distribution character of light space.关键词：Wigner transform;Fresnel diffraction;fractional Fourier transform2885|215|0更新时间：2024-05-07
- 摘要：In this paper,we propose a new multiple arbitrary shape regions-of-interest(ROIs) coding framework.Gray mask is incorporated to manifest the priorities of the multiple ROIs.Multiple ROIs are transformed sequentially by the ISA-DWT according to their priorities with different constraints of the target bitrate and the reconstructed regional fidelity of different priorities.Then the set partitioning in hierarchical trees(SPIHT) algorithm is modified to generate the separate compression bit streams.Experimental results show that the proposed coding framework has the following novelties:(1) it ensures the quality of the reconstructed ROIs according to their priorities;(2) it is fit for arbitrary shape ROI loss and lossless coding;(3) it achieves low complexity by reaching the target ROI PSNR.关键词：integer-to-integer SA-DWT;SPIHT;ROI;image compression2052|163|0更新时间：2024-05-07
- 摘要：Based on the relationship among the geographic events,spatial changes and the database operations,a new automatic(semi-automatic) incremental updating approach of Spatio-Temporal database(STDB) named as Event-Based Incremental Updating(E-BIU) is proposed in this paper.At first,the relationship among the events,spatial changes and the database operations is analyzed,then a total architecture of E-BIU implementation is designed,which includes an event queue,three managers and two sets of rules,and each component is presented in detail.The process of the E-BIU of the master STDB is described successively.An example of incremental updating is given to illustrate this approach at the end.The result shows that E-BIU is an efficient automatic updating approach for master STDB.关键词：incremental updating;geographic events;spatial changes;database operation;manger2685|157|0更新时间：2024-05-07
- 摘要：Spatial database construction of landuse maps plays an important role in our national land resources information management. Identifying the annotation and importing the attributes to database is a manual work in the traditional landuse database constructing, which costs a lot of time and brings low quality, In this paper, the approach of identifying the numeric annotation in scanned landuse map and importing the attributes to database automatically is discussed, and the practical software is developed. Applied in the landuse database constructing in Baotou, this methods is proved available and efficient.关键词：landuse map;numeric annotation;automatic identification;attributes importation to database2237|166|0更新时间：2024-05-07
- 摘要：Contour lines are the most important features to characterize three dimensional terrain on two dimensional map sheets. Different from a well conditioned map, aliasing and false colors in the scan of a common conditioned map are so serious that when to segment contour lines from it, many gaps due to contour lines intersecting and overlapping with other features become more intricate. In this paper an effective method for extracting contour lines from color scanned topographical maps is proposed. It focuses on reconnecting gaps of contour lines. In topographical maps segmentation, an eigenvector fitting algorithm is used for computing the color keys ofmap features( include contour lines) and the phenomena of color alias and color misalignment are greatly reduced. In contour lines reconnection, linear features extracted from the gray version of the input colormap are utilized to repair the contour lines segments extracted from the input colormap. Unlike the existing methods, it introduces corresponding solutions for different cases ofgaps in contour lines. Finally, some representative samples and national standard topographic maps with a scale of 1∶50, 000 are tested, and an evaluation scheme for the results is provided. The experiments indicate good applicability of this method in applications.关键词：topographic map;map segmentation;contour lines extraction3096|209|0更新时间：2024-05-07
- 摘要：This paper attempts to give the novel approach of gray image processing using fuzzy morphological bidirectional associative memories. This approach utilizes kernel patterns to get the correct recalls from randomly noisy gray images. How to find appropriate kernel patterns is also investigated here. The experimental results on storing and recalling gray cell images demonstrate the validity of this approach.关键词：kernel patterns;gray images;fuzzy morphology;associative memories;fuzzy neural networks2329|160|0更新时间：2024-05-07
- 摘要：A face recognition method using singular value decomposition(SVD) on human local facial area and fuzzy decision is presented in this paper to solve the problem that singular value decomposition on whole facial image can not provide enough information for face recognition.The key of this approach is that singular value decomposition is applied to different parts of human facial area instead of the whole facial region.So the rich information can be obtained for recognizing human face.The way of establishing feature vectors based on local singular value decomposition is proposed.In the recognition step,the features vector of input facial image are set up,and then the membership degrees of these features to each facial sample are computed respectively,and finally the decision can be obtained.Comparative experimental results on ORL face database show that its performance is better than that of traditional SVD-based methods.关键词：singular value decomposition;membership degree;fuzzy decision;face recognition2727|215|0更新时间：2024-05-07
- 摘要：A weighted averaging algorithm of image zooming-out based on image sub-block information is presented in this paper. This algorithm overcomes the shortcoming of some common algorithms of image zooming-out that will lead to image visible distortion. First, according to the scale-down proportion the sub-block of every pixel at zoomed-out image is obtained from original image, and then the value of every pixel can be calculated based on corresponding sub-block by the method of weighted averaging. In the process of zooming-out the whole image information is reserved to the greatest degree, and the image after zoomed-out shows good integrity. The algorithm is simple, effective and rapid. The experimental results show that the advantage is evident compared with the common algorithms especially at image integrity. But the contrast of the image is reduced. To solve this problem the paper advances an extension of gray-scale method to improve the quality of zoomed-out image in the end of the paper. The experiments have verified the effectivity of the algorithm in this paper.关键词：image zooming-out;neighborhood image block sample;image integrity;contrast;extension of gray-scale2227|183|0更新时间：2024-05-07
- 摘要：The objective of image processing is to denoise while keep the intrinsic imforrnation. A method is proposed for images denoising with double density dual-tree complex wavelet transform. It integrates the advantages of double density wavelet, dual tree wavelet and complex wavelet. It has improved directionality which increased the directions from 6 to 12. The adaptive soft threshold is applied to wavelet coefficients. It could ameliorate the ability of image denoising. The denoising and edge detection for a typical image is carried out. Simulated experiments demonstrate that the proposed approach is effective on image denoising and can keep the edge information at same time. Its mean square deviation is reduced 2.4% compared with the dual-tree complex wavelet.关键词：double density dual-tree complex wavelet transform;denoising;edge detection2556|196|0更新时间：2024-05-07
- 摘要：A robust image mosaic method is proposed to construct a panoramic view of the scene from video sequence. Firstly, block matching method based on phase correlation is employed to estimate the motion vector field of video frames. After removing the outlier motion vector caused by the image noise or moving object occlusion, the corresponding point pairs between image blocks can be determined by the dominant motion vectors, and then the parameters of projective transformation model can be iteratively estimated with the obtained correspondences to implement the video mosaicing. All the work of video mosaicing is automatically completed without manual manipulation. Experimental results using video sequence with real scene have demonstrated the availability of the method.关键词：video mosaicing;block matching;phase correlation2453|200|0更新时间：2024-05-07
- 摘要：In order to protect ancient Chu-culture of China,virtual reality technique was used to reconstruct and imitate cultural space and historic activity.According to literal recordation,ancient images and ancient relic,we reconstructed chime bell,bronze utensils,lacquers,characters,finery and architecture by 3d scanner and 3d modeling technique,and we also recovered the fading color painted on culture relic in ancient times.Motion was collected from chu-dancers by motion capture technique.Then all models were incorporated into a scene for rendering animation,and chime bell music was combined with the animation.Finally,an interactive system to exhibit culture was founded by VRML technique.The method to protect and transmit culture heritage is more acceptable and enjoyable than traditional one,which is better to attract audiences' attention,make audiences to obtain experience,increase the extent and depth of culture transmitted.关键词：cultural heritage;chime bell music and choreography;protect;reconstruction3219|169|0更新时间：2024-05-07
- 摘要：The newly risen research of artificial visual prosthesis is summarized. Based on the research on the imaging model of the visual prosthesis as well as the simulated experiment, a novel imaging model based on the selection of local prominent features is proposed, and a mean-option-score-based subjective assessment is designed to evaluate the performance of the model. The results of the experiment reveal that the imaging scheme can accentuate the areas with prominent features in the original image, so as to give observers a subjective perception of rich visual information. Thus, the model will provide a new approach for future research.关键词：visual prosthesis;pixelized vision;prominent feature;subjective assessment1915|158|0更新时间：2024-05-07
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A Minimum Translational Distance Algorithm of Convex Polyhedra Based on Nonlinear Programming Theory
摘要：The problem of minimum translational distance(MTD for short) of convex polyhedra is always an active subfield of computer graphics.The current distance algorithms are deficient in such requirements as stability,realizability,accuracy and efficiency more or less.In order to overcome these limitations,the generalized separable plane is introduced based on the definition of MTD and a new algorithm of the MTD problem using nonlinear programming is presented in the paper.This algorithm is carried out as follow.Firstly,the MTD measure is determined by defining the optimal generalized separable plane-pair.Secondly,the problem of searching the optimal plane-pair is equivalent with nonlinear programming problem under some transforms.Finally,a nonlinear optimization software is used to solve the equivalent model,and therefore MTD measure is determined by the solution.The results show that the proposed algorithm performs linearly with the size of model and over the other algorithms in most of the tests.Besides,it can provide both an accurate measure and the witness vector in a few iterations,which are gently linear with the vertex number.In addition,the implementation is simple and reliable,because only the information of vertex is required and the cycle can be avoided.So,it is a fast and efficient distance algorithm.关键词：convex polyhedral;minimum translational distance;separable plane;witness vector;nonlinear programming2533|219|0更新时间：2024-05-07
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