A two-stage fuzzy multi-objective framework for segmentation of 3D MRI brain image data

Segmentation of Magnetic Resonance Imaging (MRI) brain image data has a significant impact on the computer guided medical image diagnosis and analysis. However, due to limitation of image acquisition devices and other related factors, MRI images are severely affected by the noise and inhomogeneity artefacts which lead to blurry edges in the intersection of the intra-organ soft tissue regions, making the segmentation process more difficult and challenging. This paper presents a novel two-stage fuzzy multi-objective framework (2sFMoF) for segmenting 3D MRI brain image data. In the first stage, a 3D spatial fuzzy c-means (3DSpFCM) algorithm is introduced by incorporating the 3D spatial neighbourhood information of the volume data to define a new local membership function along with the global membership function for each voxel. In particular, the membership functions actually define the underlying relationship between the voxels of a close cubic neighbourhood and image data in 3D image space. The cluster prototypes thus obtained are fed into a 3D modified fuzzy c-means (3DMFCM) algorithm, which further incorporates local voxel information to generate the final prototypes. The proposed framework addresses the shortcomings of the traditional FCM algorithm, which is highly sensitive to noise and may stuck into a local minima. The method is validated on a synthetic image volume and several simulated and in-vivo 3D MRI brain image volumes and found to be effective even in noisy data. The empirical results show the supremacy of the proposed method over the other FCM based algorithms and other related methods devised in the recent past.     

A non-local fuzzy segmentation method: Application to brain MRI

The Fuzzy C-Means (FCM) algorithm is a widely used and flexible approach to automated image segmentation, especially in the field of brain tissue segmentation from 3D MRI, where it addresses the problem of partial volume effects. In order to improve its robustness to classical image deterioration, namely noise and bias field artifacts, which arise in the MRI acquisition process, we propose to integrate into the FCM segmentation methodology concepts inspired by the non-local (NL) framework, initially defined and considered in the context of image restoration. The key algorithmic contributions of this article are the definition of an NL data term and an NL regularisation term to efficiently handle intensity inhomogeneities and noise in the data. The resulting new energy formulation is then built into an NL-FCM brain tissue segmentation algorithm. Experiments performed on both synthetic and real MRI data, leading to the classification of brain tissues into grey matter, white matter and cerebrospinal fluid, indicate a significant improvement in performance in the case of higher noise levels, when compared to a range of standard algorithms.     

Color image segmentation using histogram thresholding - Fuzzy C-means hybrid approach

This paper presents a novel histogram thresholding - fuzzy C-means hybrid (HTFCM) approach that could find different application in pattern recognition as well as in computer vision, particularly in color image segmentation. The proposed approach applies the histogram thresholding technique to obtain all possible uniform regions in the color image. Then, the Fuzzy C-means (FCM) algorithm is utilized to improve the compactness of the clusters forming these uniform regions. Experimental results have demonstrated that the low complexity of the proposed HTFCM approach could obtain better cluster quality and segmentation results than other segmentation approaches that employing ant colony algorithm.     

彩色图像分割的FCM初始化方法

针对传统模糊C-均值聚类方法所存在的过度依赖初始聚类中心、计算复杂度高等问题,提出一种新的FCM初始化方法.首先,使用维纳滤波分别对图像的R、G、B分量进行预处理,待转换为LAB色彩空间后,通过二次分水岭方法获取图像的封闭区域,并计算各区域的质心;其次,利用自适应无监督的方法对质心进行筛选和合并,将合并结果作为FCM的初始聚类中心;最后,使用FCM方法进行分割.实验结果表明,该方法不仅能够获得较准确的聚类中心,减少了迭代次数和运算时间,而且能够更好地实现图像的准确分割.     

一种自适应的模糊C均值聚类图像分割方法

针对传统的模糊C均值聚类算法(FCM)在图像分割中对噪声十分敏感这一局限性,提出一种自适应的FCM图像分割方法。该方法充分考虑图像像素的灰度信息和空间信息,根据像素的空间位置自适应地计算一个合适的相似度距离来进行聚类分割图像。实验结果表明,与传统的FCM相比,该方法能显著提高分割质量,尤其是能提高对于图像噪声的鲁棒性和分割图像区域边缘的准确性。     

Single point iterative weighted fuzzy C-means clustering algorithm for remote sensing image segmentation

In this paper, a remote sensing image segmentation procedure that utilizes a single point iterative weighted fuzzy C-means clustering algorithm is proposed based upon the prior information. This method can solve the fuzzy C-means algorithm's problem that the clustering quality is greatly affected by the data distributing and the stochastic initializing the centrals of clustering. After the probability statistics of original data, the weights of data attribute are designed to adjust original samples to the uniform distribution, and added in the process of cyclic iteration, which could be suitable for the character of fuzzy C-means algorithm so as to improve the precision. Furthermore, appropriate initial clustering centers adjacent to the actual final clustering centers can be found by the proposed single point adjustment method, which could promote the convergence speed of the overall iterative process and drastically reduce the calculation time. Otherwise, the modified algorithm is updated from multidimensional data analysis to color images clustering. Moreover, with the comparison experiments of the UCI data sets, public Berkeley segmentation dataset and the actual remote sensing data, the real validity of proposed algorithm is proved.     

Modified possibilistic fuzzy C-means algorithms for segmentation of magnetic resonance image

The brain magnetic resonance (MR) image has an embedded bias field. This field needs to be corrected to obtain the actual MR image for classification. Bias field, being a slowly varying nonlinear field, needs to be estimated. In this paper, we have proposed three schemes and in turn three algorithms to segment the given MR image while estimating the bias field. The problem is compounded when the MR image is corrupted with noise in addition to the inherent bias field. The notions of possibilistic and fuzzy membership have been combined to take care of the modeling of the bias field and noise. The weighted typicality measure together with the weighted fuzzy membership has been used to model the image. The above resulted in the proposed Bias Corrected Possibilistic Fuzzy C-Means (BCPFCM) strategy and the algorithm. Further reinforcing the neighbourhood data to the modeling aspect has resulted in the two other strategies namely Bias Corrected Possibilistic Neighborhood Fuzzy C-Means (BCPNFCM) and Bias Corrected Separately weighted Possibilistic Neighborhood Fuzzy C-Means (BCSPNFCM). The proposed algorithms have successfully been tested with synthetic data with bias field of low and high spatial frequency. Noisy brain MR images with Gaussian Noise of varying strength have been considered from the BrainWeb database. The algorithms have also been tested on real brain MR data set with axial and sagittal view and it has been found that the proposed algorithms produced segmentation results with less percentage of misclassification errors as compared to the Bias Corrected Fuzzy C-Means (BCFCM) algorithm proposed by Ahmed et al. [4]. The performance of the proposed algorithms has been compared with algorithms from other paradigm in the context of Tanimoto's index.     

非局部降噪快速模糊C-均值聚类算法

传统的模糊C-均值聚类算法未利用图像的空间信息,在分割迭加了噪声的MR图像时分割精度较差。采用了既能有效去除噪声又能较好地保持图像边缘特征的非局部降噪方法,结合基于图像灰度直方图聚类分析的快速模糊C-均值聚类算法,得到了一种具有较高分割精度的图像快速分割算法。通过对模拟图像、仿真脑部MR图像和临床脑部MR图像的分割实验,表明提出的新算法比已有的快速模糊C-均值聚类算法有更精确的图像分割能力。     

基于超像素快速模糊C均值聚类与支持向量机的柑橘病虫害区域分割

针对目前柑橘病虫害图像数据集较少,病虫害目标复杂、散漫,难以自动定位分割的问题,提出了一种基于超像素快速模糊C均值聚类(SFFCM)与支持向量机(SVM)的农业柑橘病虫害区域分割方法.该方法充分利用了SFFCM快速、鲁棒的优点,且融合了空间信息的特点,同时避免了传统SVM在图像分割上需要人工选择样本的缺点.首先,利用改...     

基于改进模糊C均值的海面目标图像分割算法

提出一种图像分割算法,解决水面无人艇在执行目标跟踪与识别任务过程中的图像快速准备分割问题。首先使用均值滤波算法对彩色的海洋背景图像进行滤波,同时利用其非参数性得到图像的聚类中心和类别数,并以此作为初始化参数进行图像的模糊C均值聚类,在此基础上进行大津法Otsu二值化处理实现目标提取。使用BSDS500标准数据集和海洋背景图像对算法的分割效果及效率进行验证,与传统的模糊C均值算法、脉冲耦合神经网络算法、自适应遗传算法以及马尔科夫随机场算法进行对比的结果显示了该算法的有效性。     

一种融入局部信息的直觉模糊C-均值聚类图像分割算法

模糊C-均值(FCM)算法对图像噪声敏感,聚类过程中只考虑图像的数值特征信息而忽略像素间空间约束关系,同时单一隶属度并不能充分描述图像的不确定性,这使得基于FCM的图像分割不够准确.融入局部信息的改进FCM算法虽然对图像噪声有一定鲁棒性,但对图像细节保持不够,难以分割微小区域.针对上述问题,提出一种基于直觉模糊集的改进模糊C-均值(IFS_FCM)图像分割算法.该方法将直觉模糊集理论融入到FCM中,充分考虑图像的不确定性,同时在目标函数中引入空间邻域信息,使得该分割算法对噪声鲁棒性增强的同时还能保持图像细节信息.实验结果表明,IFS_FCM能获得更加理想的图像分割效果.     

一种有效抑制噪音的模糊C均值图像分割算法

提出一种能够有效抑制噪音的模糊C均值聚类算法,通过构造基于灰度-中值的空间信息和塔形结构减少噪音对聚类中心的影响,塔形结构的引入缩短了运算时间,通过自适应地选取隶属度阈值避免人为设定阈值的不灵活性,在图像分割时用中值图像代替源图像消除噪声点。仿真实验表明,该方法更加适合处理受噪音污染的图像,分割结果更加精确。     

基于FCM聚类的图像分割算法

为提高现有模糊C均值聚类算法(FCM)对噪声图像分割的效果和稳定性,提出一种基于FCM的图像分割算法。利用非局部空间信息构建和图像,根据和图像的直方图,自动选择初始化聚类中心,通过求取目标函数极小值完成图像分割。理论分析和实验结果表明,该算法比现有算法更加有效和稳定,对噪声图像有更强的鲁棒性。     

改进的模糊C-均值算法在医学图像分割中的应用

针对随机选取聚类中心易使得迭代过程陷入局部最优解的缺点,提出了一种混合优化蚁群和动态模糊C-均值的图像分割方法,该方法利用蚁群算法较强处理局部极值的能力,并能动态确定聚类中心和数目.针对传统的分阶段结合遗传算法和蚁群算法的策略存在收敛速度慢,聚类精度差的问题,提出在整个优化过程综合遗传算法和蚁群算法,并在蚁群算法中引入拥挤度函数,利用遗传算法的快速性、全局收敛性提高了蚁群算法的收敛速度,同时利用蚁群算法的并行性和正反馈性提高了聚类的精确度.最后将该算法应用到医学图像分割,对比实验表明,混合算法具有很强的模糊边缘和微细边缘分割能力.     

一种快速的模糊C均值聚类彩色图像分割方法

FCM用于彩色图像分割存在聚类数目需要事先确定、计算速度慢的问题,为此,提出一种快速的模糊C均值聚类方法（FFCM）。首先,对原始彩色图像进行基于梯度图的分水岭变换,从而把原始彩色图像数据分成一些具有色彩一致性的子集;然后,利用这些子集的大小和中心点进行模糊聚类。由于FFCM聚类样本数量显著减小,因此可以大幅提高模糊C均值聚类算法的计算速度,进而可以采用聚类有效性指标确定聚类数目。实验表明,这种方法不需要事先确定聚类数目,在聚类有效性能不变的前提下,可以使模糊聚类的速度得到明显提高,实现了彩色图像的快速分割。     

Adaptive local data and membership based KL divergence incorporating C-means algorithm for fuzzy image segmentation

In this paper, a fuzzy clustering technique for image segmentation is developed by incorporating a hybrid of local spatial membership and data information into the conventional hard C-means (HCM) algorithm. This incorporation is a threefold procedure. (1) The membership function of a pixel is spatially smoothed in the pixel vicinity. (2) The Kullback-Leibler (KL) divergence between the pixel membership function and the smoothed one is added to the HCM objective function for fuzzification. (3) The resulting fuzzified HCM is regularized by adding a weighted HCM-like function where the original pixel data are replaced by locally smoothed ones. Thereby the weight is proportional to the residual of the locally smoothed membership. This residual decreases when many pixels existing in the pixel vicinity belong to the same cluster. Thus, the weighted distance decreases, allowing the pixel membership to follow the dominant membership in the pixel vicinity. The simulation results of segmenting synthetic, medical and media images have shown that the proposed algorithm provides better performance compared to several previously developed algorithms. For example, in a synthetic image, with added white Gaussian noise having a variance of 0.3, the proposed algorithm provides accuracy, sensitivity and specificity of 92%, 84% and 94.7% respectively, while the algorithm with the closest results provides 81.9% of accuracy, 62.2% of sensitivity and 86.8% of specificity. In addition, the proposed algorithm shows the capability to identify the number of clusters.     

基于空间约束的模糊C均值聚类肝脏CT图像分割

传统模糊C均值（FCM）聚类算法应用于肝脏CT图像分割时仅考虑像素本身特征,无法解决灰度不均匀造成的影响以及肝脏边界模糊造成的边界泄露的问题。为解决上述问题,提出一种结合空间约束的模糊C均值（SFCM）聚类分割算法。首先,使用二维高斯分布函数构建卷积核,利用该卷积核对源图像进行空间信息提取得到特征矩阵;然后,引入空间约束惩罚项,更新并优化目标函数得到新的迭代方程;最后,通过多次迭代,完成对肝脏CT图像的分割。实验结果表明,SFCM算法分割具有灰度不均匀和边界粘连的肝脏CT图像时得到的肝脏轮廓形状更加规则,准确率达到92.8%,比FCM和直觉模糊C均值（IFCM）算法的分割准确率分别提升了2.3和4.3个百分点,过分割率分别降低了4.9和5.3个百分点。     

基于 PSO的快速模糊 C均值图像分割算法 *

利用粒子群算法全局性和鲁棒性的特点 ,可以解决模糊 C均值算法 ( FCM)用于图像分割时对初始值敏感、容易陷入局部极小值的问题。但是设定粒子群算法的初始搜索范围依赖于人的经验 ,并且所设范围往往过大,影响算法的执行速度 ,为此提出用收敛速度快的 K均值聚类法得到的聚类中心作为粒子群算法初始搜索范围的参考 ,缩小粒子群算法的搜索范围 ,提高算法执行速度。实验表明该算法具有较高的分割速度和良好的抑制噪声的能力。