最新刊期
卷 16 ， 期 3 ， 2011
- 摘要：To simplify the computational complexity in mode selection process for H.264,a fast mode decision algorithm is proposed in this paper.According to the statistical rule of the best mode chosen by inter frame,the relationship of the temporal and spatial characteristics with the best mode is found. At each stage of inter mode selection,the temporal and spatial characteristics of macroblock(MB) are detected,once the residual homogeneous or spatial homogeneous conditions are satisfied,the mode selection process is terminated.Experimental results show that this method can make the encoding speed accelerate about 23.11% and peak signal to noise ratio(PSNR) improve about 0.058dB,with only 2.11% increase about bit rate.关键词：H.264;mode selection;residual homogeneous;spatial homogeneous;early termination3297|194|0更新时间：2024-05-07
- 摘要：In view of such problems as the limited coloration effectiveness and the illumination distribute inharmonious for the traditional enhancement algorithm, a novel Retinex algorithm of image enhancement based on Zernike moment is proposed in this paper.By the Zernike moment of the V and S components of the image, the background gray level and step height in HSV space will be calculated. These results can be used to adjust the difference of gray level in intersection pixel and improve the correlation of regional saturation, and further to enhance the illumination and restore the image coloration. Experimental results show that the algorithm can both restore the image illumination, coloration effectively and adapt to various images of different characteristics.关键词：image enhancement;Retinex algorithm;Zernike moment;HSV color space3068|310|0更新时间：2024-05-07
- 摘要：A new approach is proposed to detect JPEG image forgery through the inconsistencies of quantization table. The original quantization table is estimated iteratively by selecting qualified blocks intelligently and further used to position the approximately doctored areas. Then the doctored area is compressed by the original quantization table estimated. Using the difference between the double compressed image and the test image, doctored areas will be more precisely determined. Simulation results show that the quantization table estimation algorithm proposed is less time consuming and of higher precision. The detection algorithm can expose various kinds of JPEG image forgeries and it is more effective for small difference quality factor between the doctored area and undoctored area’s JPEG images.关键词：quantization table;JPEG compression;blind forgery detection3427|249|0更新时间：2024-05-07
- 摘要：Watermarking a 3D mode is one of the hot topics in digital watermark. The most difficulties of the watermarking model 3D models are mainly on maintaining robustness, embedding readable watermark and blind detecting watermarks. In order to enhance the robustness, this paper proposed a local geometric space based watermarking algorithm for the triangular meshes of 3D models. It is defined as a local geometric space by selected vertex and close neighboring vertices of the triangular meshes in the 3D model, Then the watermarks are embedded through adjusting the position of the selected vertex within their related spaces. The parameter of the central angle is rectified for embedding an index of a series of watermark; The distance between vertex and the central point is rectified for embedding high bit of binary numerical value. The experimental results show that the algorithm guarantees the high performance of the watermark robustness such as translation, rotation, scaling, vertex permutation, model cropping and model simplification with this approach, embedded watermarks can be detected without the original model. And the results also present an evident superiority in non sentience of embedding readable watermark.关键词：digital watermarking for 3D model;triangular mesh;local geometric space;blind detection algorithm3397|228|0更新时间：2024-05-07
- 摘要：A new switching vector median filter using ranked thresholds is proposed to remove the impulsive noise from color images. The new method utilizes thresholds related rank position of the central pixel in filtering window and the distance between the output of the classic vector median filter and the original vector to determine the noise probability. Compared with other non-switching and switching vector median filters, simulation experiments show that the new filter outperforms them in terms of both noise suppression and detail preservation.关键词：vector median filter;switching filter;impulsive noise3593|250|0更新时间：2024-05-07
- 摘要：This paper proposed a swift adaptive algorithm to restore images from impulse noise, by expanding the real signal pixels so as to smooth the noisy ones. First, the algorithm uses a critical region to distinguish signal pixels from noise and set a marked matrix. Then calculate the density of signal, which will be used to control the extent of growth adaptively. The final restored image will be obtained nearly after a simple correction on the expanded image matrix. The proposed algorithm exceeds the current ones markedly in both denoising effect and computational complexity.关键词：image denoising;impulse noise;noise suppressive;adaptive3105|206|0更新时间：2024-05-07
- 摘要：Single projector radiometric compensation technique has made it possible for a projector to display on ordinary surface with colors and textures. However, when applying these methods to multi-projectors, many issues will happen,including the inconsistence in intensity of the overlapping areas, region expansion of a single pixel, all of which will lead to failure of the compensation. This paper presents a multi-projector and camera system with the ability of geometry correction, radiometric compensation and photometric consistency and solves the problems as mentioned. We use a convenient and iterative way to obtain more precise parameter of the reflection property for the projecting surface. This only considers two or more pictures of the projecting-surface, so that it can provide much better compensation results. We also improve the blending effects of the overlapped areas of multi-projectors and thus provide a unified solution for radiometric compensation and photometric inconsistency when displaying on non-optimized surfaces with multi-projectors. Experiments indicate the improvements of the new method compared to the original algorithm.关键词：iterative compensation;intensity blending;radiometric compensation;multi-projector system3754|244|0更新时间：2024-05-07
- 摘要：To handle the large-scale optimization problem caused by regular image restoration, this paper introduces a novel image restoration method based on Bregman iterative double regularization. In this method, the designed objective function considers both the total variation regularization and the wavelet domain sparsity constraint, and solves the problem under Bregman framework with the split Bregman iterative algorithm. The algorithm converts the complex optimization problem to several iterations, each of which requires only several simple Fast Fourier Transformations and shrinkage operations. The experimental results show that the proposed method improves both the objective SNR and the subjective perceptual image quality with a faster convergence rate compared to existing approaches.关键词：image restoration;Bregman iteration;regularization;total variation;wavelet4100|284|0更新时间：2024-05-07
- 摘要：Recently, there are many practical applications of tomographic reconstruction that consist of minimizing the sum of a residual energy and image total variation (TV). In this paper, we develop an uncoupled iterative algorithm for solving the recent popular TV-regularized CT optimization problem. Using surrogate function, we split the sum minimization scheme to the minimizing weighted least square function and TV denoising with weighted norm iteratively. In order to find the stable solution of this model, we use Chambolle’s scheme to overcome the numerical difficulty due to the non differentiability of the TV norm and use Bregman scheme to accelerate the iteration process. Experimental results show that the proposed approach outperforms some existing TV tomography methods based on the gradient descent algorithms.关键词：computerized tomography reconstruction;total variation regularization;Bergman method;surrogate functions3020|220|0更新时间：2024-05-07
- 摘要：Visual cryptography scheme (VCS) is an encryption technique that utilizes human visual system in the recovering of the secret image and it does not require any complex calculation. Contrast has been a major issue of VCS schemes. Most copy machines have reversing function, in which can change a black image into a white one and vice versa. By means of the reversing operation, perfect black binary VCS with reversing can obtain ideal contrast. In this paper we conclude that we do not use existing VCS with reversing to construct an ideal contrast VCS for gray-scale images, then we show how to construct an ideal gray-scale VCS with reversing. In our scheme each participant is required to store a certain number of shares,and the number is same as that of binary VCS with reversing. Furthermore, the scheme guarantees that reconstructed image is correct since we perform certain runs operations.关键词：visual cryptography;contrast;scheme with reversing;secret sharing scheme3072|231|0更新时间：2024-05-07
- 摘要：In this paper, a novel thresholding method based on human visual perception and isoperimetric theory is presented. The proposed method first utilizes characteristics of human visual perception to find a gray level interval decided by candidate thresholds, then uses isoperimetric ratio in isoperimetric theory as a criterion to determine the optimal threshold from the candidates. Experimental results on a series of images including nondestructive testing ones show that authors’ method outperforms several existing classic thresholding methods in segmentation quality.关键词：human visual perception;isoperimetric theory;isoperimetric ratio;graph theory;threshold selection;image segmentation3889|264|0更新时间：2024-05-07
- 摘要：The classic two-dimensional Otsu image segmentation algorithm is applied widely due to its content-independent characteristic. However, it cannot be applied to real-time system for its high computation complexity. To solve this problem, we present a fast two-dimensional Otsu algorithm, in which particle swarm algorithm is adopted to reduce the computing time. Extensive experiments using real-world images show that our method evidently outperforms the classic Otsu algorithm in segmentation time, while of comparable segmentation performance with the Otsu algorithm. Thus, the improved algorithm satisfies the requirements for real-time applications.关键词：image segmentation;2D Otsu algorithm;PSO algorithm3846|314|0更新时间：2024-05-07
- 摘要：Focus contour extraction of PET images is of immense significance for the treatment of malignant tumors and cardiovascular diseases etc. However, the commonly used method based on the traditional snake model is sensitive to the position of the initial curve and it’s hard to converge to the concave boundary of the object. To address these problems, an improved GVF Snake model based on DE algorithm is proposed in this paper. The results from comparative experiments of extracting contour of human brain demonstrate that the new model is an effective method for segmenting the PET images.关键词：PET image segmentation;Snake model;GVF Snake model;DE algorithm3565|288|0更新时间：2024-05-07
- 摘要：A new affine invariants based on affine geometry for object recognition and matching is proposed in the paper. The algorithm can be divided into three following steps. Firstly, extract the centroid and extend centroid of the object region. The connecting line between them thus devides the region into two parts, and the centroids of the two parts will be recalculated. Iteratively, we can obtain the demand centroids that satisfy the requirement. Secondly, calculate the areas of the quadrangles, whose vertexes are the centroids of the regions cut by the connecting line and the centroids of the two parts. Thirdly, calculated the ratios of the areas and the affine invariant vector is acquired Besides, the parameters of the affine transform can also be computed by the coordinates of the centroids. It is proved by the experiment that the extracted affine invariants are of robustness, efficiency and high classification accuracy.关键词：affine invariants;object recognition;affine region cutting;centroid;extended centroid4110|222|0更新时间：2024-05-07
- 摘要：A scale and rotation invariant feature extraction method based on color images is proposed and been applied for the recognition of real-world scenes. Radon transform is firstly applied in the three component planes of the given color image and then the scale invariance operation is implemented in Radon transform coefficient matrixes. One-dimensional wavelet transform with the frequency B-spline wavelet is used in Radon transform coefficient matrix. The mean and variance are calculated in ridgelet coefficient matrix, and the relationship is extracted for all the frequency sub-bands under different color component plane using linear regression model. Finally rotation invariance operation is conducted for obtained features. Therefore, the proposed scale and rotation invariant features are acquired. The experimental results using the three databases show that the proposed method is reliable and efficient.关键词：ridgelet transform;frequency B-spline wavelet;scale invariance;rotation invariance;scene classification3127|320|0更新时间：2024-05-07
- 摘要：In order to overcome the effect of shadow in process of vehicles tracking under stationary camera, we present an improved codebook model detection algorithm. This method deal with vehicles sequences directly in the YUV Color Space, and the sampled background values are quantized into codebooks. Input pixel values of new frame are compared with the codebooks to identifying foreground areas. The Kalman Prediction method is used for vehicles tracking which can deal with occlusion. Experiments show that this algorithm can detect moving objects in complex traffic scenes effectively and rapidly. The proposed method can handle shadows, highlights, occlusion and the change of background all of which make this method efficient in both computation and the needs of real-time tracking.关键词：vehicles detection;codebook model;vehicles tracking;Kalman prediction3471|248|0更新时间：2024-05-07
- 摘要：In order to detect the sheet number of layered structures in print industry, a texture analysis based method is proposed. This method detects pages of print by analyzing side image of the target. The main process has four steps: At first, a Gabor filter is designed to enhance the texture in input image. Then, a serial of one-dimensional signals are extracted from the enhanced image using projection method. Third, empirical mode decomposition (EMD) is used to analyze these signals, which contain complex noise, to obtain the corresponding estimate of sheet number. Finally, the result is determined by the mode of all estimates. We designed two experiments to test stability and accuracy of the algorithm and proved its effectiveness.关键词：texture analysis;detection of the number of sheets;empirical mode decomposition (EMD);Gabor filter2924|244|0更新时间：2024-05-07
- 摘要：At present，there are intrinsic differences between machine recognition of facial expression and human perception in the facial expression recognition system, which affect the precision of facial expression recognition. In order to reduce the semantic gap between the low-level visual features of face images and high-level semantic, a novel facial expression recognition method based on semantic knowledge of analytical hierarchy process(AHP) is presented. The analytical hierarchy process method is adopted to describe the high-level semantic of face images of the training set, which further used to establish semantic features.In the stage of low-level visual features extraction, the 2nd-order principal component analysis method is proposed to extract the texture features of face images. In the recognition stage, only low-level visual features of the input face image is used, and k-nearest neighbor method combined with semantic features in the study stage is used to classify the facial expressions. The proposed method combines the low-level visual features with high-level semantic features, reducing the semantic gap between them.The experiments are conducted on Japanese Female Facial Expression (JAFFE) database and the overall recognition rate of 9392% is achieved. Theoretical analysis and experimental results both show that the proposed method has higher recognition rate.关键词：facial expression recognition;analytical hierarchy process;low-level visual feature;high-level semanteme3449|259|0更新时间：2024-05-07
- 摘要：An efficient and robust subpixel image registration method based on Local Phase Correlation (LPC) is developed in this paper. After estimating the initial translation by the traditional Phase Correlation (PC) method, the initial estimation is refined by the upsampling matrix Fourier transform of cross-correlation power spectrum. Then the translation is tuned by the refinement to achieve subpixel registration. Experiments on various image pairs show that the LPC method achieves higher registration precision, and immunes to random noise and illumination variation.关键词：matrix Fourier transform;local phase correlation;subpixel;image registration4146|287|0更新时间：2024-05-07
- 摘要：A multifocus image fusion technique based on kernel Fisher discriminant analysis and image block segmentation is proposed. Firstly, the original images are decomposed into image blocks and focus measures of each image block are computed. To achieve the parameters of the trained kernel Fisher discriminant analysis, parts of the original images are chosen as the training exemplars. Then the initial fused image is acquired with the known kernel Fisher discriminant analysis. At last, the final merged image is obtained after the original image blocks, which are located near the border between the focused and blurred areas of the original images, through processing with the redundant wavelet transform. The experimental results show that the proposed method outperforms the conventional image fusion methods. A better tradeoff can be obtained between improving the image fusion quality and reducing the computational cost with the proposed method.关键词：multifocus image;image fusion;kernel Fisher discriminant analysis;redundant wavelet transform3232|216|0更新时间：2024-05-07
- 摘要：CSHG (class specific hyper graph) model is largely influenced by the threshold of the similarity measure between two graphs. By setting a constraint to fault tolerance of clustering, the similarity measure threshold for initial optimized CSHG model is obtained using the entropy function defined on CSHG model and the initial optimized CSHG model is thus constructed. The similarity matrix of FTOG is then created and the most simplified CSHG structure is obtained. In addition, the redundant graphs in FTOG are detected and deleted using affinity propagation method and the final optimized CSHG model is acquired. Experimental results demonstrate the reliability and effectiveness.关键词：graph-clustering;class specific hyper-graph;entropy;affinity propagation3947|202|0更新时间：2024-05-07
- 摘要：A method to drive 3D facial model using single video was presented. Based on the movement characteristics, the mouth was controlled by using a mechanism model. The motion trace of the feature points was acquired by tracking video image sequence. Then we drive the grid nodes on the facial model to obtain a realistic facial animation. The results show that this method could simulate the facial movements and expressions very well.关键词：theory of mechanism;muscle model;expressing feelings;face emulation3628|210|0更新时间：2024-05-07
- 摘要：Self collision detection is the most time consuming process in deformable object simulation. In this paper, a novel algorithm is presented for performing self collision using graphics hardware. Each particle, rather than the traditional triangle, is taken as a primitive. The particle-centered local regions are bounded with a sphere, where the AABB is then enclosed. After initial culling, the AABBs of potentially colliding particles are organized in textures and sent to GPU. A linear time two-pass rendering procedure is proposed to compute the set of colliding pairs and the colliding time of each pair. Experimental results demonstrate this algorithm handles self collision at interactive rates in the context of cloth simulation.关键词：self collision detection;GPU;bounding volume hierarchy;cloth simulation3320|190|0更新时间：2024-05-07
- 摘要：A 3D simulation system of micro robotic fish was developed in windows operation system with VC++6.0 developing environment and OpenGL international graphic standard, in order to reduce the cost of obstacle avoidance research using real robotic fish and reduce the damage to the real robotic fish. A virtual robotic fish was built using polygon modeling method and the swing of fish tail was simulated. A virtual ray method which simulated infrared sensor detecting obstacles was proposed. Based on the information of multiple sensors, a composite fuzzy controller using real time fuzzy control algorithm was designed to decide the avoidance behavior of micro robotic fish. The simulation results demonstrate the composite fuzzy controller is of real-time and has high efficienly. Micro robotic fish was efficiently conducted by the composite fuzzy controller to avoid both single arbitrary shape obstacle and multiple continuous obstacles and achieved the targeting result. A reliable, realistic and convenient platform was provided for researching the autonomous obstacles avoidance capacity of micro robotic fish.关键词：micro robotic fish;composite fuzzy controller;autonomous obstacles avoidance3503|192|0更新时间：2024-05-07
- 摘要：In order to obtain a residual error map for remote sensing data after geometric correction, a GCP error propagation model was proposed. First, GCP error source was analyzed and modeled. Second, error free for geometric correction model and the uncertainty of GCP caused uncertainty of model parameter which may then be propagated to all the whole area considered were assumed. Finally, a general GCP error is defined to revise error propagation model and this alteration made the model suitable for more general condition. The proposed model is suitable for appreciate GCPs number selecting, allowable GCPs error deciding and suitable spatial arranging. This model also is very useful in remote sensing product quality control because it made it clear where residual error occurred and how much it is and we can use the final product wisely.关键词：spatial uncertainty;remote sensing;geometric correction;ground control point;error propagation3150|209|0更新时间：2024-05-07
- 摘要：A new image quality assessment approach based on quality parameter variance on image multiple resolution representation is proposed to simulate the human vision system. Firstly, a district wavelet transformation is presented to obtain multiple resolution image representation. Image quality parameter is calculated on each level resolution image. Secondly, the image quality parameter variances are calculated and the remaining error of quality parameter after linear simulation is adopted to represent the smoothness of image quality variance. Finally, the image quality assessment model based on the remaining error of different resolution image representations is proposed. Applying the traditional image quality assessment method and the new model to images of different compression ratio show that the new image quality assessment model can obtain the accordant quality assessment effect both the absolute quality parameter and subjective vision. The new model is fit for human vision.关键词：multiple resolution;simulation;image representation;vision system;quality parameter;image quality assessment3123|290|0更新时间：2024-05-07
- 摘要：Based on the metaball models, a practical method is presented for automatically reconstructing an implicit surface from given sample points on the surface of an object in R3. Firstly, a spherical representation of the model from the samples can be obtained. Secondly, the spheres are utilized as initial metaballs—this greatly improves the robustness and efficiency of the metaball-based approximation, and the initial implicit surface is constructed. Lastly, the resulting implicit surface is created by adjusting every meatball parameter in an optimizing process. The optimal spheres and local supported field functions accelerate the surface optimization strongly. Experiments demonstrate the method’s efficiency and robustness.关键词：metaball;implicit surface;sphere approximation;automatic surface reconstruction5402|211|0更新时间：2024-05-07
- 摘要：Based on the characteristics of the solar wind ion flux data fetched by Chang’E-1 (CE-1) moon-orbiting spacecraft, a new visualization analysis method for these data is developed. First, all the data fetched in a month is separated depending on whether they are obtained on the day-side or the night-side of the moon. Then the total flux intensity distributed in certain energy levels is calculated as the sole flux intensity value for each data record, and these flux intensity values are projected to an even longitude-latitude grid of the moon surface and an average intensity value is calculated for each grid which has multiple intensity values projected in. Finally after a map projection, e.g. Hammer projection to give a more conventional representation of the moon surface and a color theme is chosen to represent different intensities of ion flux, and so an intuitive visualization result of the distribution of ion flux on the day-side or the night-side of the moon in a month is obtained. By using this method it is possible to visualize and analyze the mass data of the distribution and fluctuation of solar wind ion flux in cislunar environment. The validity of this method is proven by the results of actual experiments.关键词：visualization;Chang’E-1;cislunar space environment;solar wind ion flux4307|280|0更新时间：2024-05-07
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