共查询到20条相似文献,搜索用时 15 毫秒
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Consistent image registration 总被引:9,自引:0,他引:9
This paper presents a new method for image registration based on jointly estimating the forward and reverse transformations between two images while constraining these transforms to be inverses of one another. This approach produces a consistent set of transformations that have less pairwise registration error, i.e., better correspondence, than traditional methods that estimate the forward and reverse transformations independently. The transformations are estimated iteratively and are restricted to preserve topology by constraining them to obey the laws of continuum mechanics. The transformations are parameterized by a Fourier series to diagonalize the covariance structure imposed by the continuum mechanics constraints and to provide a computationally efficient numerical implementation. Results using a linear elastic material constraint are presented using both magnetic resonance and X-ray computed tomography image data. The results show that the joint estimation of a consistent set of forward and reverse transformations constrained by linear-elasticity give better registration results than using either constraint alone or none at all. 相似文献
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图像配准技术性能评估及实现概况 总被引:1,自引:0,他引:1
图像配准是解决图像融合、图像镶嵌和变化检测等问题的必要前提,其应用遍及军事、遥感、医学和计算机视觉等多个领域.首先概括了图像配准技术的研究内容,然后全面论述了配准技术的性能评估及其系统实现问题,最后指出了该领域存在的主要问题,并展望了进一步的发展方向. 相似文献
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Michalis Vrigkas Christophoros Nikou Lisimachos P. Kondi 《Signal Processing: Image Communication》2013,28(5):494-508
The accuracy of image registration plays a dominant role in image super-resolution methods and in the related literature, landmark-based registration methods have gained increasing acceptance in this framework. In this work, we take advantage of a maximum a posteriori (MAP) scheme for image super-resolution in conjunction with the maximization of mutual information to improve image registration for super-resolution imaging. Local as well as global motion in the low-resolution images is considered. The overall scheme consists of two steps. At first, the low-resolution images are registered by establishing correspondences between image features. The second step is to fine-tune the registration parameters along with the high-resolution image estimation, using the maximization of mutual information criterion. Quantitative and qualitative results are reported indicating the effectiveness of the proposed scheme, which is evaluated with different image features and MAP image super-resolution computation methods. 相似文献
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SIFT算法在仿射变换、噪声、一定程度的光照条件下具有良好的匹配性能,星上宽波段相机成像尺寸都非常大,超大尺寸图像直接利用SIFT算法,在构建高斯金字塔时空间占用大,同时导致计算用时长。通过研究仿射变换矩阵,提出可以通过计算超大尺寸图像的降采样图像之间的配准系数间接获取超大尺寸图像的配准系数的方法。经过实验验证,具有一定的可行性,对于图像配准从空间上减少计算量从而节约计算时间具有一定指导意义。 相似文献
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非均匀性严重影响红外制导武器的成像质量和系统性能,有效进行非均性校正是提高红外制导武器成像质量的有效手段。高通滤波类算法对非均匀性校正的参数漂移具有很强的适应性,但易产生“鬼影”现象,影响校正结果。本文针对高通滤波类算法的缺陷,结合帧间配准技术,提出了一种基于图像配准的非均匀性校正算法。与SLTH算法和BFTH算法中利用滤波器滤波后得到的残差图像相比,本文利用图像配准和场景删除得到的残差图像能更好地消除图像中的场景信息,抑制“鬼影”效果显著。实验表明:本文算法的校正效果良好,校正结果的平均粗糙度低至3.79,优于SLTH和BFTH两种算法。而且本文算法处理速度快,达到了每秒15.83帧,是BFTH处理速度的1.63倍。 相似文献
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Thitiporn Chanwimaluang Guoliang Fan Stephen R Fransen 《IEEE transactions on information technology in biomedicine》2006,10(1):129-142
This work studies retinal image registration in the context of the National Institutes of Health (NIH) Early Treatment Diabetic Retinopathy Study (ETDRS) standard. The ETDRS imaging protocol specifies seven fields of each retina and presents three major challenges for the image registration task. First, small overlaps between adjacent fields lead to inadequate landmark points for feature-based methods. Second, the non-uniform contrast/intensity distributions due to imperfect data acquisition will deteriorate the performance of area-based techniques. Third, high-resolution images contain large homogeneous nonvascular/texureless regions that weaken the capabilities of both feature-based and area-based techniques. In this work, we propose a hybrid retinal image registration approach for ETDRS images that effectively combines both area-based and feature-based methods. Four major steps are involved. First, the vascular tree is extracted by using an efficient local entropy-based thresholding technique. Next, zeroth-order translation is estimated by maximizing mutual information based on the binary image pair (area-based). Then image quality assessment regarding the ETDRS field definition is performed based on the translation model. If the image pair is accepted, higher-order transformations will be involved. Specifically, we use two types of features, landmark points and sampling points, for affine/quadratic model estimation. Three empirical conditions are derived experimentally to control the algorithm progress, so that we can achieve the lowest registration error and the highest success rate. Simulation results on 504 pairs of ETDRS images show the effectiveness and robustness of the proposed algorithm. 相似文献
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图像配准是解决图像融合、图像镶嵌和变化检测等问题的必要前提,其应用遍及军事、遥感、医学和计算机视觉等多个领域.简要回顾了图像配准技术的发展史和研究现状,重点阐述了当前的技术热点和应用趋势,最后展望了进一步的研究方向. 相似文献
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Fast parametric elastic image registration 总被引:19,自引:0,他引:19
We present an algorithm for fast elastic multidimensional intensity-based image registration with a parametric model of the deformation. It is fully automatic in its default mode of operation. In the case of hard real-world problems, it is capable of accepting expert hints in the form of soft landmark constraints. Much fewer landmarks are needed and the results are far superior compared to pure landmark registration. Particular attention has been paid to the factors influencing the speed of this algorithm. The B-spline deformation model is shown to be computationally more efficient than other alternatives. The algorithm has been successfully used for several two-dimensional (2-D) and three-dimensional (3-D) registration tasks in the medical domain, involving MRI, SPECT, CT, and ultrasound image modalities. We also present experiments in a controlled environment, permitting an exact evaluation of the registration accuracy. Test deformations are generated automatically using a random hierarchical fractional wavelet-based generator. 相似文献
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采用PCA和PSNR的医学图像配准 总被引:1,自引:0,他引:1
医学图像配准是医学图像融合的前提,是目前医学图像处理中的热点,具有重要的临床诊断和治疗价值.利用图像矩计算医学图像的质心,根据图像坐标矩阵主分量分析(PCA)的特征矢量旋转不变性,计算参考图像和浮动图像的倾斜角,获得配准初始值;在寻找最优几何变换参数时,采用峰值信噪~(PSNR)作为参考图像和浮动图像的相似性测度.实验时,采用单纯形法作为多参数寻优方法.实验结果表明,该方法计算简单,运算量少,配准速度快,精度高,而且克服了容易陷入局部最优的问题.该方法既可用于单模态图像配准,也可以用于多模态配准. 相似文献
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针对快速鲁棒特征(SURF)算法对微观驱替图像进行配准存在的误匹配比例较高和由于提取的特征点过多导致时间偏长的问题,提出了一种改进的 SURF算法.利用了微观驱替模型的特点,提取出信息量相对比较丰富的边界,仅在边界和边界附近提取特征点.借鉴了 Hassion角点检测的方法,筛选出那些满足设定条件的稳定的特征点.实验证明,本文提出的方法在匹配正确率上得到了提高.同时,特征点匹配的耗时有所减少. 相似文献
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A bound on mutual information for image registration 总被引:11,自引:0,他引:11
An upper bound is derived for the mutual information between a fixed image and a deformable template containing a fixed number of gray-levels. The bound can be calculated by maximizing the entropy of the template under the constraint that the conditional entropy of the template, given the fixed image, be zero. This bound provides useful insight into the properties of mutual information as a similarity metric for deformable image registration. Specifically, it indicates that maximizing mutual information may not necessarily produce an optimal solution when the deformable transform is too flexible. 相似文献
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基于合成孔径雷达(SAR)图像和光学图像间的变形可用仿射变换来近似,提出了一种SAR图像和光学图像自动配准的方案.对分割后的图像进行K-L变换得到两幅图像的主分量与坐标轴之间的关系,从而得出两幅图像的角度关系,接着,利用旋转后图像的横纵象素范围的比值和前景重心偏移值得到仿射变换的缩放和平移参数,最后再利用二值图像相关对仿射变换的结果图像进行精配,从而实现较高精度的图像配准.实验结果表明,在满足精度要求的情况下,本方法可以自动完成具有明显方向性和较大前景目标图像的配准任务. 相似文献
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