结合局部能量与改进的符号距离正则项的图像目标分割算法

针对传统C-V模型对颜色不均匀图像分割失败并且对初始轮廓和位置敏感问题,以及现有符号距离正则项存在周期性振荡和局部极值问题。该文提出结合局部能量信息和改进的符号距离正则项的图像目标分割算法。首先,将全局图像信息扩展到HSV空间,并使用局部能量项信息分析每个像素及其领域内的统计特性,从而在较少的迭代次数内有效分割颜色分布不均匀图像。其次,改进现有符号距离正则项,改进后的符号距离正则项在避免水平集函数的重新初始化的同时,提高了计算效率,保证了水平集函数演化过程的稳定性。然后,定义阈值判断法的水平集函数演化的终止准则,使曲线准确演化到目标轮廓。该算法与同类模型的对比实验表明该模型具有较高的分割精度和对初始轮廓的鲁棒性。     

基于活动轮廓模型的左心室MR图像分割

本文提出一种基于局部与全局特征的活动轮廓模型左心室MR图像分割算法.该算法融合了图像局部信息和全局信息.局部信息包含了图像局部均值和方差信息,来克服图像灰度不均匀的影响.全局信息则较好地提高模型处理图像弱边界的能力,并防止模型陷入局部最优,实验结果表明,改进算法分割出较为精确的心脏左心室MR图像.     

引入判别准则的主动轮廓分割模型

基于区域信息的主动轮廓模型应用在图像分割中,难以使初始轮廓线的鲁棒性和分割强度异质图像的能力实现有效统一。针对这一缺陷,根据Fisher判别准则,在基于全局区域信息和局部区域信息的主动轮廓模型的基础上,对局部区域信息项进行了变换以及引入了判别准则,得到了一种改进的基于区域信息的主动轮廓模型。改进的模型不仅增强了初始位置的鲁棒性,而且可以有效处理强度异质图像,通过实验检验了该模型的性能。     

一种鲁棒的非均匀灰度图像分割算法

针对非均匀灰度图像分割困难及分割效率低下的问题,该文提出了一种基于活动轮廓模型的高效图像分割算法。不同于传统水平集方法中仅用单一信息定义的能量泛函,该算法结合图像的边缘信息和区域统计信息定义了一个新的能量泛函。边缘信息的利用便于演化轮廓线快速精确地定位至物体边缘;区域统计信息由局部统计信息和全局统计信息构成,一方面,局部统计信息的利用能够有效处理图像的灰度分布不均匀现象,另一方面,全局统计信息的利用避免了轮廓线陷入局部极小值。最后,在轮廓线演化过程中,通过高斯卷积核实现快速规则化,避免了传统模型计算代价高昂的重新初始化或规则化。合成图像和真实图像的实验结果表明,该文算法不仅能够快速有效分割灰度分布不均匀的弱边缘物体,而且对于多灰阶复杂结构物体也能够精确分割;同时,该算法对噪声和初始轮廓线具有较好的鲁棒性。     

图像分割中局部能量驱动的快速主动轮廓模型

为了解决图像对象灰度分布不一致性的分割难题,提高图像分割速度,提出了一个全新的快速主动轮廓模型。它由曲线周围局部的统计信息驱动曲线发生形变演化,并使用图像中的边缘信息来引导曲线的演化方向。模型中,根据区域模板与演化曲线共同定义的局部统计信息创建数据拟合项,并应用水平集方法求解曲线的演化。对合成图像和医学图像的实验结果表明,本文提出的分割模型可以同时分割多个灰度不一致的对象,分割速度快,结果稳定,对噪声具有很好的鲁棒性。     

基于C-V模型的红外图像自动分割方法研究

为解决红外图像分割中背景噪声及边界轮廓的影响,引入了基于曲线演化理论、水平集方法和M-S分割函数的C-V模型。通过将图像表达为分段常量函数来建立适当的能量函数模型,引入水平集的表示方法,在整个图像域中依据最小化分割寻找全局极小值,可令活动轮廓最终到达目标边缘。由MATLAB实现的仿真结果表明采用C-V模型对红外图像进行自动分割不受边界轮廓线连续性限制,对初始轮廓线位置不敏感,对图像噪声具有很强的鲁棒性,对均匀灰度目标分割效果良好。     

基于显著性区域的图像分割

在经典的Chan-Vese模型中结合显著性分析,提出了一种有效的目标分割方法.即首先利用频谱残差方法提取图像的显著性区域,针对阈值分割方法的缺点使用改进的自适应阈值分割方法获取目标的大致轮廓,并以此轮廓作为Chan-Vese模型中初始曲线.该方法使得活动轮廓可以从靠近目标物体的位置进行演化,去除复杂背景的干扰.这样就解决了背景复杂时无法得到较为准确的边缘的问题;同时,也减少了CV模型的迭代次数.实验结果表明无论是背景复杂的灰度图像还是医学彩色图像,该算法的分割精度和运行效率都优于CV模型.     

改进的RSF模型应用于带钢表面缺陷分割

可调拟合(Region Scalable Fitting, RSF)活动轮廓模型在分割带钢表面缺陷图像时易陷入局部最小值;此外,因引入高斯核函数导致边缘更加模糊而影响分割效果,针对这些问题,提出改进的RSF模型并应用于带钢表面缺陷分割。一方面,在RSF模型中引入局部灰度均值差异项作为新的拟合项,并且引入局部灰度方差差异代替原拟合项的参数,驱动曲线演化避免陷入局部最小值;另一方面,用双边滤波函数代替高斯核函数,避免对边缘模糊的缺陷造成二次模糊,同时更好地保护了边缘。在NEU带钢表面缺陷数据集上的仿真实验结果表明,改进的算法的分割效果和运行效率均优于其余3种模型,能够较快地准确分割出带钢表面缺陷,并且保留图像细节。     

利用局部离散度活动轮廓模型的强度非均匀图像分割

强度非均匀现象在真实图像中普遍存在,采用常规基于强度的分割算法会导致严重的误分割。针对强度非均匀图像分割,提出了基于局部离散度的活动轮廓模型分割算法。首先定义基于类内类间距离的离散度,然后利用核函数提取局部区域信息,同时加入边缘指示函数加权的轮廓线长度项能量,建立基于局部离散度的活动轮廓模型。最后引入水平集函数惩罚项,避免水平集方法在演化求解时需要不断初始化的问题。合成图像和真实图像实验结果证明本文算法性能稳定,适应于强度非均匀图像的分割。      

结合Gabor纹理特征的局域化多通道水平集分割方法

本文提出了一种局域化多通道主动轮廓模型的图像分割算法.针对纹理特征比较明显的图像,通过Gabor滤波提取纹理特征,与图像灰度信息构成多通道.考虑到演化过程中曲线内部和外部特征属性不均匀,引入局域化思想,通过计算各像素在局部区域的最小能量得到图像分割结果.最后算法结合先验形状对有遮挡目标进行分割,并能得到理想结果.大量实...     

A fuzzy energy-based active contour model with adaptive contrast constraint for local segmentation

Image segmentation is to divide an image into different parts or extract some interested objects. Active contour model and fuzzy clustering are two widely used segmentation methods, which have been integrated into an effective model in recent years. Local segmentation is often needful in medical image processing. In view of local segmentation on inhomogeneous images, a new average fuzzy energy-based active contour model is proposed in this paper, in which the total fuzzy energy integrates the approximate weighted average and arithmetic average variances of the image. And an adaptive contrast constraint condition is introduced to prevent the curve from falling into local minimum, which further improves the robustness of the segmentation model to initial contour. Experimental results on synthetic and medical images demonstrate that the proposed model has considerable improvements in terms of segmentation accuracy and robustness compared to several existing local segmentation models.     

Automatic segmentation of coronary arteries in CT imaging in the presence of kissing vessel artifacts

In this paper, we present a novel two-step algorithm for segmentation of coronary arteries in computed tomography images based on the framework of active contours. In the proposed method, both global and local intensity information is utilized in the energy calculation. The global term is defined as a normalized cumulative distribution function, which contributes to the overall active contour energy in an adaptive fashion based on image histograms, to deform the active contour away from local stationary points. Possible outliers, such as kissing vessel artifacts, are removed in the postprocessing stage by a slice-by-slice correction scheme based on multiregion competition, where both arteries and kissing vessels are identified and tracked through the slices. The efficiency and the accuracy of the proposed technique are demonstrated on both synthetic and real datasets. The results on clinical datasets show that the method is able to extract the major branches of arteries with an average distance of 0.73 voxels to the manually delineated ground truth data. In the presence of kissing vessel artifacts, the outer surface of the entire coronary tree, extracted by the proposed algorithm, is smooth and contains fewer erroneous regions, originating in kissing vessel artifacts, as compared to the initial segmentation.     

Segmentation and quantification of human vessels using a 3-D cylindrical intensity model.

We introduce a new approach for 3-D segmentation and quantification of vessels. The approach is based on a 3-D cylindrical parametric intensity model, which is directly fitted to the image intensities through an incremental process based on a Kalman filter. Segmentation results are the vessel centerline and shape, i.e., we estimate the local vessel radius, the 3-D position and 3-D orientation, the contrast, as well as the fitting error. We carried out an extensive validation using 3-D synthetic images and also compared the new approach with an approach based on a Gaussian model. In addition, the new model has been successfully applied to segment vessels from 3-D MRA and computed tomography angiography image data. In particular, we compared our approach with an approach based on the randomized Hough transform. Moreover, a validation of the segmentation results based on ground truth provided by a radiologist confirms the accuracy of the new approach. Our experiments show that the new model yields superior results in estimating the vessel radius compared to previous approaches based on a Gaussian model as well as the Hough transform.     

基于马尔可夫随机场的SAR目标切片图像分割方法

SAR目标切片图像分割是基于SAR图像目标识别的一个重要步骤。文中通过利用马尔可夫随机场模型 ,引入图像象素的局部结构信息 ,有效实现了SAR目标切片图像的高精度分割。通过对SAR目标切片图像进行统计分析 ,精确选择了分割算法的迭代初值 ,极大提高了算法的计算效率。和其它分割算法相比 ,文中算法在分割速度和精度上均有较大提高     

Adaptive model initialization and deformation for automatic segmentation of T1-weighted brain MRI data

A fully automatic, two-step, T1-weighted brain magnetic resonance imaging (MRI) segmentation method is presented. A preliminary mask of parenchyma is first estimated through adaptive image intensity analysis and mathematical morphological operations. It serves as the initial model and probability reference for a level-set algorithm in the second step, which finalizes the segmentation based on both image intensity and geometric information. The Dice coefficient and Euclidean distance between boundaries of automatic results and the corresponding references are reported for both phantom and clinical MR data. For the 28 patient scans acquired at our institution, the average Dice coefficient was 98.2% and the mean Euclidean surface distance measure was 0.074 mm. The entire segmentation for either a simulated or a clinical image volume finishes within 2 min on a modern PC system. The accuracy and speed of this technique allow us to automatically create patient-specific finite element models within the operating room on a timely basis for application in image-guided updating of preoperative scans.     

蝙蝠优化的二维Tsallis熵多阈值SAR图像分割

针对智能优化SAR图像分割算法存在计算量大、易陷入局部最优、分割精度不够等问题,融合蝙蝠算法和二维Tsallis熵多阈值,提出了一种蝙蝠优化的二维Tsallis熵多阈值SAR图像分割算法。算法利用立方映射均匀化初始蝙蝠种群,引入Levy飞行特征加强算法跳出局部最优能力,使用Powell局部搜索加快算法收敛等3方面改进蝙蝠算法;同时将二维Tsallis熵单阈值分割方法扩展到多阈值分割,建立基于多阈值的选取方法,并结合改进的蝙蝠算法,将二维Tsallis熵多阈值应用于SAR图像分割中。仿真结果表明,与其他智能优化分割算法相比,本分割算法在边缘处理和分割精度上都有明显优势。     

基于逻辑校准的多分类残差网络的肺分割算法

针对图像噪声以及血管、支气管等因素引起的肺分割困难的问题,提出了一种基于逻辑校准的多分类残差网络分割算法.该算法将图像区域划分为肺、背景及边界三类,通过扩大不同类型间的差异来提升分割准确率.算法先将图像分割为固定尺寸区域,然后利用残差网络提取纹理特征进行分类训练与测试,实现粗分割.最后对边界区域阈值处理实现细分割.利用公开数据集对该算法进行了测试,实验结果表明,此分割算法在召回率、精确率以及交并比等方面均优于当下前沿的分割网络之一的U-Net,分别达到99.79％,98.13％和97.83％,可为后续的肺部疾病临床诊断提供参考依据.     

概率图车载热成像行人检测RoIs提取方法

道路场景复杂、热成像纹理信息较少以及图像品质不稳定,RoIs提取面临挑战.阈值分割RoIs提取更多关注行人局部细节和像素间邻域关系,容易产生行人遗漏、背景粘连和行人断裂,且很难控制RoIs总量.模拟人类视觉,关注图像显著性区域及其位置和大小,提出概率图RoIs提取方法,设计凸-凹形曲线映射像素灰度值增强图像对比度;基于图像签名方法获取显著性图.融合灰度强度和显著性概率图并从中提取图像前景;设计算法搜索路面估计限定的概率图区域生成RoIs.实验表明,相对阈值分割,本文方法能够提高RoIs定位准确度、控制RoIs总量和显著减少非行人RoIs;提取等量单帧RoIs,召回率提高不低于9%.     

Infrared image segmentation algorithm based on distribution information intuitionistic fuzzy c-means clustering

Due to the sensitivity of the traditional intuitionistic fuzzy c-means (IFCM) clustering algorithm to the clustering center in image segmentation,which resulted in the low clustering precision,poor retention of details,and large time complexity,an intuitionistic fuzzy c-means clustering algorithm was proposed based on spatial distribution information suitable for infrared image segmentation of power equipment.The non-target objects with high intensity and the non-uniformity of image intensity in the infrared image had strong interference to the image segmentation,which could be effectively suppressed by the proposed algorithm.Firstly,the Gaussian model was introduced into the global spatial distribution information of power equipment to improve the IFCM algorithm.Secondly,the membership function was optimized by local spatial operator to solve the problem of edge blur and image intensity inhomogeneity.The experiments conducted on Terravic motion IR database and the data set containing 300 infrared images of power equipment show that,the relative region error rate is about 10% and is less affected by the change of fuzzy factor m.The effectiveness and applicability of the proposed algorithm are superior to other comparison algorithms.     

基于邻域空间特征的低对比度小目标分割算法

低对比度图像具有邻近像素的空间相关性高、灰度变化不明显等特点,从中分割出微小目标是非常困难的。本文提出一种新的低对比度图像提取小目标的分割算法,通过引进局部均匀度,结合局部熵获得空间分布状态,对低对比度图像进行分割,该算法充分利用了目标图像的灰度和空间属性。实验结果表明,该方法能有效地实现低对比度小目标图像的分割。相对于其他算法,分割精度更高,且抗噪性强,可以有效地降低过分分割问题。