最新刊期
卷 12 ， 期 4 ， 2007
- 摘要：Creating realistic human animation is one of the most important research focuses,and remains problematic in the research field of computer animation.When creating realistic human animation,we need not only realistic human motion and its control techniques,but also effects of vivid body shapes and skin deformation.In this paper,a detailed survey on existing methods for human-body modeling and skin deformations is given,which can help the researchers to have a good understanding of the state of the art in this area.The existing methods are classified into three categories: surface-model based methods,volume-model based methods and hierarchical-model based methods.The advantages and disadvantages of each method are also discussed.Based on the survey of existing methods,it is pointed out that the development of 3D scanners provides a good chance for researchers.We suggest that an important research direction in human-body modeling and skin deformation is: how to combine the advantage of reality of example-based methods and the advantage of flexibility of hierarchical-based methods,in order to create very realistic human-body models and skin deformations.关键词：computer animation;human-body modeling;skin deformation;survey3406|282|0更新时间：2024-05-08
- 摘要：As an effective technique of copyright protection,digital watermarking techniques have become a new focus of interest in recent years.A useful watermark scheme should be visually imperceptible and must be robust to various attacks.In this paper,a feature-based algorithm is proposed,which embedded a binary image as watermark in DCT domain by taking into account the feature of gradient and intensity of each block.Especially we embed marker bits to locate the original block of cropped image.The proposed technique could actually survive several kinds of image processing such as image cropping,shifting,blurring,noise,sharpening and JPEG lossy compression etc.The algorithm doesn't need the original image for watermark extraction and the simulation results prove its effectiveness.关键词：digital watermarking;discrete cosine transform(DCT);feature-based;synchronize;marker bits3805|259|0更新时间：2024-05-08
- 摘要：In order to protect the copyright of the image,this paper brings forward a image non-watermarking method based on DWT,where methods of classical Cryptology is employed.A series of experiments have been cavried out and the results proved that the presented method has much better robustness comparing with another watermark method,and the method is further broaden to hide any other digital image information besides watermark.关键词：watermark;wavelet transform;robustness3895|215|0更新时间：2024-05-08
- 摘要：Long coding time is the main problem in image compression based on Fractal at present,mainly due to its heavy computation of searching the best-match domain block for each range block.In this paper,a fast K-mean clustering algorithm is proposed firstly using Partial Distortion Search to replace the time-consuming Nearest Neighbor Search process in traditional K-mean clustering algorithm.Then the K-mean clustering algorithm is used to speed up the coding: scheme the domain blocks and search the best-match block for each range block in some nearest neighbors from some nearest clusters.Furthermore,by combining other techniques such as excluding planar blocks and building domain pool from an averaged image,a fast and adjustable fractal coding scheme is obtained.Experimental results indicate that comparing to exhaustive search,the proposed method improves the coding speed and compression ratio greatly with slight quality degradation of decoded image.关键词：K-mean clustering;partial distortion search;nearest neighbor search;fractal image compression3060|235|0更新时间：2024-05-08
- 摘要：At low bit rate,images reconstructed from wavelet transform-based algorithms have blurred edges,which is called Gibbs effect.This effect hampers the recognition of objects in the image.This paper presents a new progressive image coder which employs edge detection to improve the visual appearance and possibility of recognizing the compressed images at very low bit rates.Edge information is enhanced before compression coding considering some certain weighting factors.Experimental results show that the new algorithm can yield highly recognizable images at very low bit rates.关键词：image processing;edge detection;wavelet transform;multi-scale analysis;SPIHT;zerotree3283|274|0更新时间：2024-05-08
- 摘要：How to find the optimal match block for a complex region block with high frequency signals more quickly and efficiently is a very difficult problem in fractal image compression.Considering of the parallel characteristic and the global seeking ability of genetic algorithm,combining with the characteristics of and the requests for match seeking,this paper proposes a compact genetic algorithm mutated by bit with holding the optimal individuals and applies the algorithm in the match seeking of high frequency regions.Analysis of the algorithm shows that this algorithm has much higher convergence ability,seeking speed,and global seeking ability than other random seeking algorithms.It can greatly improve the obtain ratio of the optimal match block and the seeking efficiency.Experimental results also show the superiority of its application in match seeking of fractal image compression.关键词：genetic algorithm;fractal image coding;image compression;random seeking2691|214|0更新时间：2024-05-08
- 摘要：Based on SVD(Singular value decomposition) and the energy minimum principle,an adaptive image denoising algorithm is proposed in this paper.An energy model of image denoising in matrix norm is presented for restoring noisy image.By minimizing energe on the matrix norm,the singular number of the reconstructed image is adaptively determined.Comparing with the adaptive denoising algorithm based on compression ratio and SVD,it avoids calculating the function of image compression ratio and its knee point.Furthermore,it avoids solving nonlinear partial differential equation numerically comparing with the energy minimization denoising model of bounded variation,and so it never leads to local minimum in general.Our method can denoise rapidly and effectively.It can be also implemented easily in practice.Experimental results in the paper validate our proposed method.关键词：singular value decomposition;denoising;energy minimum principle3551|287|0更新时间：2024-05-08
- 摘要：The median filters have been generally adopted to reduce impulse noise.Although many existing median approaches have been greatly improved,the results of image filtering were not satisfactory at high noise density.Thus,in this paper,a novel median algorithm is proposed.First,all pixels of the filtering window are classified.Then the median subset of the multi-elements subsets is educed.The number of the multi-elements subsets determines whether the image is filtered or whether the filtering window is extended.Finally,in simulations,the proposed algorithm is compared with several kinds of median filters in the numerical value and the vision,respectively.Experimental results show that the new filter can effectively reduce the impulse noise and preserve more details of original images.关键词：impulse noise;pixels classification;median subset;median filter2878|224|0更新时间：2024-05-08
- 摘要：Traditional camera calibration method usually need make complicated 3D calibration block or construct 3D control fields with high precision.In order to avoid this tedious work,we proposed a camera calibration method using planar control grid.First,camera's initial values of intrinsic parameters are determined base on the perfect camera model and its extrinsic parameters using a 2D direct linear transformation and collinearity equations.Image coordinates of planar grid control points are detected using an improved Hough transformation algorithm and least squares fitting.Finally,camera calibration with high accuracy is conducted using bundle adjustment with self-calibration.Good results have been obtained with real image data calibration and demonstrate the method we proposed in this paper is feasible.Calibration precision of principle point and focal length is about 0.2 and 0.3 pixels respectively,which can meet the precision requirements of close-range photogrammetry with high accuracy.关键词：direct linear transformation;collinearity equation;bundle adjustment with self-calibration;improved Hough transformation3122|211|0更新时间：2024-05-08
- 摘要：Recognizing and locating the internal corners of a planar checkerboard pattern image is very important in camera calibration.An effective approach is proposed to automatically recognize and locate the internal target corners of the planar checkerboard pattern image based on the characteristics of the local intensity and the grid line architecture.Experiments show that the approach obviously reduces the time cost for camera calibration,improves the speed of calibration process and is especially adapted for automatic calibration based on multiple images.关键词：checkerboard pattern;camera calibration;corner detecting;object recognition4173|229|0更新时间：2024-05-08
- 摘要：Fuzzy C-Means(FCM) is a popular clustering algorithm and has been widely used in fuzzy segmentation of Magnetic Resonance(MR) images.However,the segmented results using the conventional FCM when dealing with noisy MR images are not satisfying because FCM takes no spatial information of images into account.Generally an ideal MR images is assumed to be a piecewise constant.We present an improved model of conventional FCM algorithm using membership smoothing constraint.The proposed algorithm can reasonably use the spatial information of images and improve the accuracy of segmentation.The segmentation of simulated brain MR images with different noise level and real brain MR image are presented in the experiments.The results of experiments show that the proposed algorithm is more powerful than many other segmentation algorithms.关键词：image segmentation;Fuzzy C-Means(FCM) algorithm;membership smoothing constraint;spatial information of image2964|216|0更新时间：2024-05-08
- 摘要：Principal component analysis(PCA) is a well-known method in pattern recognition.But the classical PCA transforms original image matrices into same dimensional vectors which will result in very large dimension of covariance matrix and very high computational complexity when processing image matrices.Moreover,extracted feature of the images are not excellent due to the fact that thepixel's spatial relativity based on the classical PCA was neglected.This paper presents a fast-complete matrix-projection principal component analysis(FMPCA) that decreases the computational complexity and utilizes the spatial relativity between rows and columns.The experiments conducted on NUST603,Yale and ORL face database demonstrate that the proposed algorithm can not only extract image feature efficiently but also maintain more powerful and excellent performance than some other principal component analysis methods.关键词：principal component analysis(PCA);fast-complete matrix-projection PCA(FMPCA);feature extraction;block distance3527|197|0更新时间：2024-05-08
- 摘要：Current unsupervised classification methods unable to determine optimum classes and poorly suitable for large and noise-included datasets.A cluster analysis approach based on geometric probability has been put forth,which gradually generates a hierarchical classification scheme in top-down order.The step of further classification for different sub-classes at the same classification level is identical but the executive process is independent for each other.Determining class number,extracting class central position,and searching the boundaries between different classes are performed at each classification level according to the distribution structure of samples in the feature space under the theoretical support of geometric probability.The algorithm of cluster analysis based on geometric probability is contrasted to ERDAS built-in supervised and unsupervised classification algorithms via a case of classifying a TM(thematic mapper) remotely sensed image.It turns out that the one based on geometric probability can obviously improve the classification accuracy.关键词：cluster analysis;Geometric probability;classification of remotely sensed images3018|230|0更新时间：2024-05-08
- 摘要：Regular building model,characterized by rectangular outline and flat/slope/gable roof,is a general construction style,widely existing as either independent building or components of complex one.This study proposed an algorithm for building model reconstruction from airborne laser scanning data,based on feature line detection and separation of planimetric and height computations.The workflow is composed of five steps.First,ridge direction is detected in a series of horizontal plans between eaves and ridge of different heights.Second,points on the ridgeline are identified in a set of vertical sections,perpendicular to the ridgeline and within building extent.Third,planimetric parameters of feature lines are detected according to points located on them.Forth,height information is determined in vertical sections that go through each line.At last,8/10 coordinates are determined and a building model is established.关键词：airborne laser scanning/LIDAR;flat/slope/gable roof;projection;separation of planimetric and height computation;building model reconstruction2921|217|0更新时间：2024-05-08
- 摘要：There are two ways to improve the performance of land cover classification with remote sensing images.The first way is to apply new data source including GIS data and normalized difference vegetation index(NDVI) to multi-source information fusion.The second one is to use methods with higher accuracy.Support vector machines(SVM) overcome the defects of maximum-likelihood and neural networks classifiers.SVMs are suitable to process complex data of high dimension and small number of training data.In this paper,selection of SVM models including kernel functions and multi-class methods is studied in order to improve the accuracy of multi-source remote sensing images classification.Experimental results show that the SVMs have higher accuracy than other traditional classifiers for the classification of multi-source remote sensing data.The SVM with a RBF kernel function and One-against-one multi-class method is the best classifier in this study.SVM methods could greatly improve the multi-source land cover classification.关键词：support vector machines(SVM);classification;multi-source data;model selection3831|236|0更新时间：2024-05-08
- 摘要：Edge detection of intravascular ultrasound(IVUS) images is important for the diagnosis and treatment of the coronary artery disease.We adopt a spatial/temporal adaptive filtering method to reduce noise in IVUS images which contain severe blood speckle noise.An improved topologically adaptable Snakes madel(T-Snake) is proposed in the paper,based on which a method for automatically detecting the edge of IVUS image is presented.Experiments show that the edge detection method is accurate,reproducible and robust for sequential IVUS frames and also the improved T-Snake is effective and realizable and the presented method for reducing the blood speckle noise is effective as well.关键词：intravascular ultrasound;edge detection;blood speckle noise;topologically adaptable snakes3305|202|0更新时间：2024-05-08
- 摘要：In order to deal with the complexity and uncertainty in medical diagnosis,this paper proposed a new method based on fuzzy Bayesian networks,and applied it to the classification of astrocytoma malignant degrees.Introducing a fuzzy procedure with conditional Gaussian models,aiming to transform a continuous variable into a discrete one,probability model of the classification of the degree of malignancy was established,through machine learning and with expert knowledge and sample data.Two modeling experiments demonstrate the validity of this method.Thereinto,the model fusing low-level image features and high-level semantics outperforms the one with only low-level image features.Using 60 test samples,an accuracy of 81.67% is achieved.This model provides a more objective quantitative reference and novel assistant ways for doctors to predict astrocytoma malignant level.关键词：fuzzy Bayesian networks;astrocytoma;diagnosis model;machine learning2388|183|0更新时间：2024-05-08
- 摘要：According to powerful compression and expression ability for high-dimensional image of wavelet multi-scale transformation,a feature extraction and recognition technology of intersected human face based on wavelet transform and KPCA(kernel principal component analysis) is proposed in this paper.With this method,the image of human faces are firstly divided into small different pieces which then being transformed with wavelet transformation algorithm.Secondly according to the positions of intersected small images coefficients of different frequency are chosen as extracted warelet features.Thirdly with KPCA the principal components of these features and then by combining these the ultiwate discriminate features are obtained.Finally the features are classified with the classifier of SVM(support vector machine).The experimental results on ORL and Yale face database show that the proposed method is superior to traditional PCA methods and KPCA methods with wavelet transformation,and it is also fairly robust to the variety of different illumination condition,face pose and expression.关键词：wavelet transform;kernel principal component analysis(KPCA);intersected human face;features extraction;support vector machine(SVM)2630|192|0更新时间：2024-05-08
- 摘要：Ridge orientations and ridge spatial frequencies in various regions of fingerprints represent its intrinsic characteristics.In this paper,we proposed a new fast algorithm for fingerprint identification based on Haar-wavelet,which accurately extracted the fingerprint features based on the original gray scale image.The proposed algorithm requires less computational effort than conventional algorithms which are based upon minutia features extraction.The algorithm can achieve high recognition rates when tested in the standard FVC2000 fingerprint database,and complete a whole process of identification in about one second on an embedded platform based on Arm-7(Primary Frequency: 100MHz) CPU.关键词：fingerprint identification;Haar-wavelet transformation2977|283|0更新时间：2024-05-08
- 摘要：Feature point matching is a key problem of computer vision and is frequently used in object recognition,image retrieval and 3D reconstruction and so on.In this paper,an accurate feature points matching method for two-frame images was proposed.Since it was proved that the homography between two windows of corresponding feature can be geometrically approximated by an affine transformation model.The projective distortion of windows of corresponding feature was estimated and rectified by a fast iterative scheme based on the affine transformation model.At the same time,the location error of corresponding feature points produced at the feature detection stage was compensated using the estimated affine parameters.The matching results of corresponding feature points can achieve sub-pixel precision,which effectively improve the precisions of the final epipolar geometry.Experimental results of real images and the comparisons with other methods strongly demonstrate the validity and accuracy of the algorithm.关键词：feature point matching;homography;affine transformation;location error compensation;epipolar geometry4421|215|0更新时间：2024-05-08
- 摘要：In order to solve the problem of spectral distortion existed in the panchromatic and multispectral images fusion algorithm,a novel algorithm based on the biorthogonal multiwavelet transform and the method of combination of average and selection is presented.First it decomposes the intensity components which obtained by IHS transform of the registered multispectral image and biorthogonal multi-wavelet transform of the panchromatic image.Then the method of combination of average and selection and the local variance rule is separately adopted to obtain new high frequency and low frequency coefficients to enhance the edge information of fused images.Finally these images are reconstructed with composite wavelet coefficients and by performing the inverse IHS transform.The experimental results show that this algorithm can improve the spatial resolution of multispectral image while reducing spectral distortion and still maintaining its edge detail.关键词：image fusion;biorthogonal multi-wavelet;multiresolution analysis;average and selection;edge detail3293|248|0更新时间：2024-05-08
- 摘要：Combining non-separable and directional filters banks,contourlet transform can effectively capture more edges and contours in natural images than wavelets do due to its capability of representing directional information.This paper casts light on the statistical features of contourlet coefficients,according to which we set up a model using Generalized Gaussian Density Function.To test this model,we applied it in texture images selected from VisTex database.After the extraction of model parameters using moment matching method,Kullback-Leibler(K-L) Distance is used to measure the similarity between images.Experiments on 800 texture images demonstrate that the average retrieval rate using our method is about 2% to 10% higher than that of wavelet method.The method proposed improves the extraction of directional textures.关键词：Contourlet transform;texture retrieval;generalized gaussian model;K-L distance2849|204|0更新时间：2024-05-08
- 摘要：A surface matching algorithm based on genetic algorithm is proposed.By constructing the oriented depth images for each surface,a problem in 3D is transformed into a 2D problem.This algorithm calculates the matching error through image comparison,uses the genetic algorithm to optimize the matching error within the 7-dimension space,and obtains the optimal match.The algorithm is stable and efficient.关键词：surface match;genetic algorithm;oriented depth image2862|207|0更新时间：2024-05-08
- 关键词：Barnsley fern;trap technique;virtual 3D;Newton transform;generalized Mandelbrot-Julia set2836|210|0更新时间：2024-05-08
- 摘要：An algorithm was introduced to generate line-style drawings of 3D triangle meshes.In the preprocessing stage,mean curvatures of vertices were estimated.At runtime,through interaction with user,concave regions under consideration were detected and skeletons of them were extracted using a heuristic searching method.Combining skeletons with contours and adding illumination effects shapes can be illustrated with a hand-made appearance.Experimental results validate the algorithm.关键词：non-photorealistic rendering;3D model;mean curvature;concave regions;line drawing2717|193|0更新时间：2024-05-08
- 摘要：When transferring a geometric constraint equation group into an optimization model,we need a method to jump out of the local beat solution so that we can find a best global solution.Considering the speed and global capability,we adopt a composite particle group optimization algorithm.Particle swarm optimization algorithm is a kind of evolution computation technology based on group intelligence.In all evolution computations heuristic function should be included to control its own characteristic.These parameters are usually correlated with a specific problem and are defined by the users.Suitable parameter choice needs user's abundant experience and correct judgment on the information offered by the problem.More important thing is that these heuristic parameters will influence the convergence characteristic of the algorithm.Because of this even experienced users may choose an inappropriate parameter and make the problem unable to reach an effective solution.Some research on these parameters need to be carried on more and more.Here we choose the controlling parameters as an optimization solution to the particle swarm algorithm.Thus we can control the heuristic function in the PSO using the ordinal genetic algorithm and propose the composite particle swarm optimization algorithm.Finally we use this algorithm to solve the geometric constraint successfully.The experiment shows that the algorithm can find the best solution in a short time.关键词：geometric constraint solving;group intelligent algorithm;composite particle swarm optimization algorithm2823|200|0更新时间：2024-05-08
- 摘要：According to the modularized SVG Entity feature and framework,we described a relationship among SVG entity,SVG class and SVG object,and presented a software architecture for a software development based on SVG application(called SSA).In SSA,we designed a transformation algorithm to implement very large SVG entity classification;then some SVG meta-graphs were extracted from SVG entity,SVG class and SVG object and saved to RDBMS.The algorithm has solved three problems: slow execution speed in SVG application system including very large SVG entities,data reuse issue for SVG component and SVG development issue for based on RDBMS.We designed an explorer platform system of digital museum based on SSA,and compared with traditional digital museum development model based on Html/Image.Experimental results showed the effectiveness of our SSA and goods performance for SVG application development.关键词：scalable vector graphics;software architecture;meta-graph;data model2715|243|0更新时间：2024-05-08
- 关键词：reverse engineering;constraints;homotopy method;feature fitting3122|320|0更新时间：2024-05-08
- 摘要：Continuous zoning, a novel clipping thought, is put forward in this paper. The plane is divided into many different areas in different way continuously, which can abandon the lines outside the window easily and quickly, and avoid unnecessary computing the point of intersection. After secondary zoning, we implemented the series coding technique to save time and to establish connection between both codes. Then the point symmetry technique which is applied to multiple zoning is carried out in cubic zoning. The slope of the area boundary in cubic zoning is 0~, ~45~ or infinity, which is suitable for the procedure realization. Comparing to secondary coding technique, point symmetry technique can avoid redundant operation of computing the point of intersection. The procedure realization clearly expresses that the algorithm in this paper can improve the line clipping efficiency.关键词：line clipping;continuous zoning;series coding;point symmetry technique2770|173|0更新时间：2024-05-08
- 摘要：Beginning with the analysis of the ink-wash dynamic diffusion mechanism,an improved Cellular Automata(CA) model based on the characteristic factors that can reflect the effect of ink-wash diffusion more naturally is presented in this paper.The ink-accommodating and ink-adhering concept for the ink status of the fiber cell is introduced for the first time.The evolvement rules of the ink-particle movement and the water evaporating are simplified and established by the quantizing status.The simulation results show that the randomicity and motility of the ink-wash diffusion are visibly enhanced by this CA model and the simulated effect is more real than former models.At the same time,the widespread applicability for the simulated effect of ink-wash diffusion is provided by this CA method.The various 3D and styles of ink-wash brush effect will be digitally realized by 3D modeling and writing brush models.关键词：ink-wash diffusion mechanism;cellular automata;ink-wash simulation3177|210|0更新时间：2024-05-08
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