共查询到20条相似文献,搜索用时 31 毫秒
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In this paper, a motion-compensated de-interlacing algorithm using the Markov random field (MRF) model is proposed. The de-interlacing problem is formulated as a maximum a posteriori (MAP) MRF problem. The MAP solution is the one that minimizes an energy function, which imposes discontinuity-adaptive smoothness (DAS) spatial constraint on the de-interlaced frame. The edge direction information, which is used to formulate the DAS constraint, is implicitly indicated by weight vectors (weights for 16 digitized directions). Generally, large weights are assigned to along-edge directions and relatively small weights are assigned to across-edge directions. As a local statistical-based method, the proposed weighting method should be more robust than traditional edge-directed interpolation methods in deciding local edge directions. The proposed algorithm is implemented by an iterative optimization process, which guarantees convergence. However, a global optimal solution is not guaranteed due to computational complexity concern. Simulation results compare the proposed algorithm to other motion compensated de-interlacing algorithms. Significant improvements of de-interlaced edges are observed. 相似文献
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Selective Data Pruning-Based Compression Using High-Order Edge-Directed Interpolation 总被引:1,自引:0,他引:1
Vo D. T. Sole J. Yin P. Gomila C. Nguyen T. Q. 《IEEE transactions on image processing》2010,19(2):399-409
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New edge-directed interpolation 总被引:98,自引:0,他引:98
This paper proposes an edge-directed interpolation algorithm for natural images. The basic idea is to first estimate local covariance coefficients from a low-resolution image and then use these covariance estimates to adapt the interpolation at a higher resolution based on the geometric duality between the low-resolution covariance and the high-resolution covariance. The edge-directed property of covariance-based adaptation attributes to its capability of tuning the interpolation coefficients to match an arbitrarily oriented step edge. A hybrid approach of switching between bilinear interpolation and covariance-based adaptive interpolation is proposed to reduce the overall computational complexity. Two important applications of the new interpolation algorithm are studied: resolution enhancement of grayscale images and reconstruction of color images from CCD samples. Simulation results demonstrate that our new interpolation algorithm substantially improves the subjective quality of the interpolated images over conventional linear interpolation. 相似文献
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该文提出一种基于结构成分双向扩散的插值方法,有效地减小了插值图像的边缘扩散,从而获得更为清晰的边缘。该方法采用改进的耦合双向扩散滤波器对轮廓模板插值图像进行边缘增强。其中,为了使滤波器更精确地作用于边缘轮廓,利用形态成分分析(MCA)分离出初始插值图像中的结构分量再实行滤波;同时,改进双向扩散模型,使其能够根据边缘梯度自适应地调整边缘扩散程度,且更加柔和地控制梯度方向的像素值变化。实验结果表明,对比传统的插值方法、相关的边缘自适应插值方法以及几种应用普遍的商用软件,该方法获得的插值图像主、客观质量均有明显提升,不仅有效提高图像锐度,且边缘光滑、过渡自然,避免产生边缘锯齿和过度的人工效应。 相似文献
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Antonio Albiol Jean Serra 《Journal of Visual Communication and Image Representation》1997,8(4):367-383
This paper presents a method based in mathematical morphology to enlarge images. It does not make the low pass assumption which is common to all linear interpolation methods and which does not often hold for images. Pixels in smooth areas are properly interpolated by linear methods while those at the edges are not. The method begins with a linear interpolation and a gradient computation. The gradient serves as a measure of confidence about the linear interpolation. Then, the proposed algorithm processes the pixels in a certain order: first pixels with high confidence (smooth zones) of the image and those with a low one (edges) at the end. By doing so, it preserves both slow variations and sharp edges. The method can be applied to other image processing problems, such as edge enhancement or motion vector estimation, where there is an image and confidence information about each pixel. 相似文献
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Hou-Chun Ting Hsueh-Ming Hang 《Journal of Visual Communication and Image Representation》1997,8(4):338-355
This paper presents a novel edge preserving interpolation method for digital images. This new method reduces drastically the blurring and jaggy artifacts at the high-contrast edges, which are generally found in the interpolated images using conventional methods. This high performance is achieved by two proposed operations: a fuzzy-inference based edge preserving interpolator and a highly oblique edge compensation scheme developed based on an edge orientation detector. The former synthesizes the interpolated pixels to match the image local characteristics. Hence, edge sharpness can be retained. However, due to the small footage of the fuzzy interpolation method, it cannot avoid edge jaggedness along the highly oblique edges that have very sharp angles against one of the coordinates. Therefore, a segment matching technique is developed to identify precisely the orientation of the highly oblique edges. Combining these two techniques, we improve significantly the visual quality of the interpolated images, particularly at the high-contrast edges. Both the synthesized images (such as letters) and the natural scenes (captured by camera) have been tested and the results are very promising. 相似文献
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Edge-based image restoration. 总被引:2,自引:0,他引:2
Andrei Rare? Marcel J T Reinders Jan Biemond 《IEEE transactions on image processing》2005,14(10):1454-1468
In this paper, we propose a new image inpainting algorithm that relies on explicit edge information. The edge information is used both for the reconstruction of a skeleton image structure in the missing areas, as well as for guiding the interpolation that follows. The structure reconstruction part exploits different properties of the edges, such as the colors of the objects they separate, an estimate of how well one edge continues into another one, and the spatial order of the edges with respect to each other. In order to preserve both sharp and smooth edges, the areas delimited by the recovered structure are interpolated independently, and the process is guided by the direction of the nearby edges. The novelty of our approach lies primarily in exploiting explicitly the constraint enforced by the numerical interpretation of the sequential order of edges, as well as in the pixel filling method which takes into account the proximity and direction of edges. Extensive experiments are carried out in order to validate and compare the algorithm both quantitatively and qualitatively. They show the advantages of our algorithm and its readily application to real world cases. 相似文献
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提出了一种基于边缘判决的解码视频空域差错掩盖算法。该算法首先对丢失块邻域中的像素进行边缘检测,并对检测出的边缘判断其是否会穿过丢失块。然后使用方向选择过程提取多个候选插值方向,并通过边界像素灰度差决定最终插值方向。实验结果表明本算法有效地提高了错误图像的掩盖效果。 相似文献
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The paper sets forth an improved edge-directed image interpolation algorithm with low time complexity which is the combination
of Newton’s method and edge-directed method. It first partitions images into homogeneous areas and edge areas by setting a
preset threshold value based on the local structure characteristics, and then specified algorithms are assigned to interpolate
each classified areas, respectively. In this way, it achieves the goals of real-time interpolation and good subjective quality.
The interpolated images have higher peak signal noise ratios (PSNR) and better visual effects using proposed method than that
of using other algorithms referred to in this paper. Experimental results show that proposed method is highly performed in
image interpolation.
相似文献
Chen Zhi-FengEmail: |
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Fu Shujun Chen Jingnian 《电子科学学刊(英文版)》2006,23(1):154-156
Most image interpolation algorithms currently used suffer visually to some extent the effects of blurred edges and jagged artifacts in the image. This letter presents an adaptive feature preserving bidirectional flow process, where an inverse diffusion is performed to enhance edges along the normal directions to the isophote lines (edges), while a normal diffusion is done to remove artifacts ("jaggies") along the tangent directions. In order to preserve image features such as edges, angles and textures, the nonlinear diffusion coefficients are locally adjusted according to the first order and the second order directional derivatives of the image. Experimental results on the Lena image demonstrate that our interpolation algorithm substantially improves the subjective quality of the interpolated images over conventional interpolations. 相似文献
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传统的双三次内插方法仅在水平和垂直方向估计丢失的像素,易在边缘或纹理区域产生抖动、振铃等现象。为了克服这种现象,提出一种新的使用方向参数的双三次图像内插方法。对待内插的像素,首先在其邻域计算水平、垂直、45°和135°四个方向的梯度,以提取图像局部边缘的强度和方向。对强边缘上的像素,直接沿边缘方向采用对应方向的双三次内插模型估计像素值;否则,先分别沿梯度较大的两个方向采用相应方向的双三次内插模型估计像素,然后采用适当的权系数对所得结果加权平均。此外,为减小计算复杂度,方法中还根据图像局部方差的大小,动态使用双线性内插方法。相比于双三次内插,提出的方法能有效地保存图像边缘和细节;同时,提出的方法还能够实现任意倍数的放大。实验结果表明,与现有的边缘导向的图像内插方法相比,提出的方法具有更好的主观和客观效果,同时计算复杂度并不高。 相似文献
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基于小波的方向自适应图像插值 总被引:10,自引:0,他引:10
图像插值是图像处理的一项重要技术,经典的插值算法会产生细节模糊和边缘锯齿现象。该文提出一种基于小波的方向自适应图像插值方法,将小波变换思想和局部方向自适应插值方法结合。为了获得清晰的细节部分,对图像实施改进的方向自适应双线性插值;结合小波方法,提高插值图像的高频细节信息,并进行相关后处理,增强视觉效果。实验结果表明,该文方法插值后的图像边缘清晰光滑,有效抑制了边缘模糊和锯齿现象,相比较传统方法,插值图像的客观质量和视觉效果都得到明显增强,更加适合人眼视觉系统。 相似文献
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该文提出一种双层约束的图像插值模型,模型在原始未插值图像梯度模约束下同时基于局部和全局信息处理。使用偏微分方程处理边缘像素,锐化边缘同时平滑边缘块状效应;平滑区域像素点的插值操作使用非局部均值模型,非局部均值模型通过对原始图像全局信息加权平均得到待处理图像像素值,图像平滑。使用双层约束模型处理纹理图像可以保持纹理特征,平滑纹理部分线形特征位置的块状效应。最后理论和实验结果证明使用双层控制模型可以直接将噪声图像插值放大。 相似文献
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In this paper, we propose a nonlocal low-rank matrix completion method using edge detection and neural network to effectively exploit the nonlocal inter-pixel correlation for image interpolation and other possible applications. We first interpolate the images using some basic techniques, such as bilinear and edge-directed methods. Then, each image patch is categorized as smooth regions, edge regions, or texture regions and adaptive interpolating mechanisms are applied to each specific type of regions. Finally, for each specific type of regions, neural networks and low-rank matrix completion are employed to accurately update the results. An iteratively re-weighted minimization algorithm is used to solve the low-rank energy minimization function. Our experiments on benchmark images clearly indicate that the proposed method produces much better results than some existing algorithms using a variety of image quality metric in terms of both objective image quality assessment and subjective quality assessment. 相似文献
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Real-time artifact-free image upscaling 总被引:2,自引:0,他引:2
The problem of creating artifact-free upscaled images appearing sharp and natural to the human observer is probably more interesting and less trivial than it may appear. The solution to the problem, often referred to also as "single-image super-resolution," is related both to the statistical relationship between low-resolution and high-resolution image sampling and to the human perception of image quality. In many practical applications, simple linear or cubic interpolation algorithms are applied for this task, but the results obtained are not really satisfactory, being affected by relevant artifacts like blurring and jaggies. Several methods have been proposed to obtain better results, involving simple heuristics, edge modeling, or statistical learning. The most powerful ones, however, present a high computational complexity and are not suitable for real-time applications, while fast methods, even if edge adaptive, are not able to provide artifacts-free images. In this paper, we describe a new upscaling method (iterative curvature-based interpolation) based on a two-step grid filling and an iterative correction of the interpolated pixels obtained by minimizing an objective function depending on the second-order directional derivatives of the image intensity. We show that the constraints used to derive the function are related with those applied in another well-known interpolation method, providing good results but computationally heavy (i.e., new edge-directed interpolation (NEDI). The high quality of the images enlarged with the new method is demonstrated with objective and subjective tests, while the computation time is reduced of one to two orders of magnitude with respect to NEDI so that we were able, using a graphics processing unit implementation based on the nVidia Compute Unified Device Architecture technology, to obtain real-time performances. 相似文献