Brain MR images segmentation using statistical ratio: mapping between watershed and competitive Hopfield clustering network algorithms

Conventional watershed segmentation methods invariably produce over-segmented images due to the presence of noise or local irregularities in the source images. In this paper, a robust medical image segmentation technique is proposed, which combines watershed segmentation and the competitive Hopfield clustering network (CHCN) algorithm to minimize undesirable over-segmentation. In the proposed method, a region merging method is presented, which is based on employing the region adjacency graph (RAG) to improve the quality of watershed segmentation. The relation of inter-region similarities is then investigated using image mapping in the watershed and CHCN images to determine more appropriate region merging. The performance of the proposed technique is presented through quantitative and qualitative validation experiments on benchmark images. Significant and promising segmentation results were achieved on brain phantom simulated data.     

基于分水岭算法的MELK图像分割*

提出一种基于分水岭算法的MELK图像分割方法,以解决信息量较小的MELK图像分割问题。综合应用多种技术以避免分水岭算法的过分割问题。首先应用高斯低通滤波器对MELK图像进行增强;采用加权差分算子求取梯度图像;应用Ostu方法进行对梯度阈值化,并进行分水岭变换;最后,应用RAG区域合并方法完成MELK图像分割。实验结果表明,该分割方法能够有效地分割信息量较小的MELK图像。     

高分辨率遥感影像的多特征多核ELM分类方法

针对高分辨率遥感影像地物分布复杂多变,利用ELM的快速分类性能,提出了一种ELM的多特征多核高分辨率遥感影像分类方法。首先利用多尺度分割算法将原始影像粗分为若干地物区域;然后依据区域合并准则对粗分割图像合并得到典型地物特征的对象信息,并提取分割对象的光谱特征与空间特征;最后以多种核函数加权组合的方式构建多核ELM对影像分类,获得最终的分类结果。实验结果表明,所提方法不仅降低了对目标训练样本的要求,同时还提高了分类的准确性、及时性和完整性。     

结合分水岭机制的有监督图像背景分割算法

传统的分水岭分割算法属于无监督的图像分割算法,分割获得的子区域往往不具备现实的语义信息。在分水岭分割的基础上,利用子区域像素值的高斯统计性质,提出了一种有监督的图像背景学习方法。该算法能够通过对少量人工标注的图像样本的学习,获得刻画背景子区域规律的统计模型。在此基础上对新图片中隶属于背景的子区域进行判断和合并,从而达到区分目标与背景的目的。实验验证了算法的有效性。     

Segmentation of small objects in color images

A method for effective segmentation of small objects in color images is presented. It can be used jointly with region growing algorithms. Segmentation of small objects in color images is a difficult problem because their boundaries are close to each other. The proposed algorithm accurately determines the location of the boundary points of closely located small objects and finds the skeletons (seed regions) of those objects. The method makes use of conditions obtained by analyzing the change of color characteristics of the edge pixels along the direction that is orthogonal to the boundaries of adjacent objects. These conditions are generalized for the case of the well-known class of color images having misregistration artifacts. If high-quality seed regions are available, the final segmentation can be performed using one of the region growing methods. The segmentation algorithm based on the proposed method was tested using a large number of color images, and it proved to be very efficient.     

Segmentation and classification of brain images using firefly and hybrid kernel-based support vector machine

Abstract

Magnetic resonance imaging segmentation refers to a process of assigning labels to set of pixels or multiple regions. It plays a major role in the field of biomedical applications as it is widely used by the radiologists to segment the medical images input into meaningful regions. In recent years, various brain tumour detection techniques are presented in the literature. The entire segmentation process of our proposed work comprises three phases: threshold generation with dynamic modified region growing phase, texture feature generation phase and region merging phase. by dynamically changing two thresholds in the modified region growing approach, the first phase of the given input image can be performed as dynamic modified region growing process, in which the optimisation algorithm, firefly algorithm help to optimise the two thresholds in modified region growing. After obtaining the region growth segmented image using modified region growing, the edges can be detected with edge detection algorithm. In the second phase, the texture feature can be extracted using entropy-based operation from the input image. In region merging phase, the results obtained from the texture feature-generation phase are combined with the results of dynamic modified region growing phase and similar regions are merged using a distance comparison between regions. After identifying the abnormal tissues, the classification can be done by hybrid kernel-based SVM (Support Vector Machine). The performance analysis of the proposed method will be carried by K-cross fold validation method. The proposed method will be implemented in MATLAB with various images.     

一种基于规则的脑组织磁共振图像分割新方法

本文将小波算法、分水岭算法及基于区域的模糊C均值算法相结合,提出了一种基于规则的二次分割方法实现对脑组织磁共振图像的分割。首先,采用一种基于小波的滤波嚣去除图像中的噪声;然后采用分水岭算法实现对图像的初始分割。为克服分水岭算法的过度分割问题,本文提出了基于区域的模糊C均值（RFCM）聚类算法实现对过度分割区域的合并。尽管分水岭算法存在过度分割现象,仍有一些区域分割得并不完全,尤其是在脑脊液与灰质,或灰质与白质的过渡区域。为此,本文提出一种局部区域连续性与全局信息相结合的基于规则的多阈值分割方法,对分水岭算法初始分割不完全的区域再次分割。通过对大量模拟数据和真实数据分割的实验证明了此方法的准确性和可靠性。     

基于梯度修正和区域融合的分水岭分割算法

针对传统分水岭算法中存在的过分割现象,提出了一种基于梯度修正和层次区域融合的分水岭分割方法。该算法首先利用开闭双重建操作以及非线性变换对梯度图像进行修正;然后求取浮点活动图像并作为分水岭算法的输入;最后在区域灰度相似性准则的基础上,结合对比度和边界强度准则对分水岭变换结果进行小区域的合并,得到最终的分割结果。实验结果表明,该算法能有效地解决过分割问题,具有良好的鲁棒性和适应性。     

Automatic tongue image segmentation based on gradient vector flow and region merging

This paper presents a region merging-based automatic tongue segmentation method. First, gradient vector flow is modified as a scalar diffusion equation to diffuse the tongue image while preserving the edge structures of tongue body. Then the diffused tongue image is segmented into many small regions by using the watershed algorithm. Third, the maximal similarity-based region merging is used to extract the tongue body area under the control of tongue marker. Finally, the snake algorithm is used to refine the region merging result by setting the extracted tongue contour as the initial curve. The proposed method is qualitatively tested on 200 images by traditional Chinese medicine practitioners and quantitatively tested on 50 tongue images using the receiver operating characteristic analysis. Compared with the previous active contour model-based bi-elliptical deformable contour algorithm, the proposed method greatly enhances the segmentation performance, and it could reliably extract the tongue body from different types of tongue images.     

基于分水岭变换的多尺度遥感图像分割算法

分水岭变换是一种适用于图像分割的强有力的形态工具,能够自动生成一系列封闭分割区域。分水岭变换的不足之处在于它的过分割结果。为了克服分水岭变换固有的过度分割现象,利用非线性滤波和改进的快速区域合并算法优化分水岭变换得出的初始分割结果,并针对高分辨遥感图像所体现出来的地物的多种信息特征,结合多种特征进行了区域合并。实验结果与MeanShift算法得到的结果进行了比较,证明该算法不仅能充分利用高分辨率遥感图像中地物的信息特征获得良好的分割效果,而且大大减少了计算时间。     

结合位图切割和区域合并的彩色图像分割

就经典分水岭图像分割算法中存在的过分割问题，提出一种结合位图切割和区域合并的彩色图像分割算法。对原始彩色图像通过空域梯度算子求其梯度图像，并利用位图切割重建梯度图像；对新梯度图像进行分水岭预分割；对预分割图像基于异质性最小原则进行区域合并，并获得最终分割结果。相比于现有的同类方法，该算法引入位图切割，抑制噪声对分割结果的影响，在边缘模糊处分割准确，得到符合人类视觉的较小分割区域数目，同时在运行效率上提高。     

基于阈值约束最小生成树算法的区域合并方法

为了解决基于形态学的分水岭分割算法受噪声影响而产生的“过分割”问题,提出了基于阈值约束最小生成树算法的区域合并方法.利用图论中最小生成树算法(prim算法、kruskal算法和boruvka算法),把分割后的区域看作是图的顶点,有相邻关系的区域看作是图的边,相邻区域的特征差异看作是边的权值,通过设置合适的阈值和迭代次数进行区域合并.实验结果表明,该方法保持地物边界的同时能够快速有效地合并“过分割”区域,尤其适用于地物复杂、尺寸较大的遥感图像.     

Multiresolution-based watersheds for efficient image segmentation

This paper presents an efficient method for image segmentation based on a multiresolution application of a wavelet transform and watershed segmentation algorithm. The procedure toward complete segmentation consists of four steps: pyramid representation, image segmentation, region merging and region projection. First, pyramid representation creates multiresolution images using a wavelet transform. Second, image segmentation segments the lowest-resolution image of the pyramid using a watershed segmentation algorithm. Third, region merging merges the segmented regions using the third-order moment values of the wavelet coefficients. Finally, the segmented low-resolution image with label is projected into a full-resolution image (original image) by inverse wavelet transform. Experimental results of the presented method can be applied to the segmentation of noise or degraded images as well as reduce over-segmentation. In addition, we applied our method to human face detection with accurate and closed boundaries.     

一种改进的桥梁图像分水岭分割算法

针对传统分水岭分割方法存在的过分割问题,提出了一种改进的桥梁图像分水岭分割算法。该算法首先对桥梁裂缝图像进行高低帽形态学滤波,并运用多尺度梯度算子提取梯度图像,在分水岭变换之前使用自适应的标记提取方法对区域极小值进行标定,然后对初步分水岭分割的过分割区域使用改进fisher距离的区域合并算法进行合并,取散度作为停止度量。实验表明,该算法减少了分水岭算法的过分割现象,提高了桥梁图像分割的精确性,具有很好的鲁棒性和适应性。     

基于形态学及区域合并的分水岭图像分割算法

针对传统分水岭算法在图像分割过程中的过分割问题,提出了基于形态学标记及MSRM的分水岭改进算法。利用形态学混合开闭运算实现图像重建,采用Laplace锐化强化图像边界,其次标记目标物和背景,修正幅值图像,经分水岭变换实现图像的粗分割,然后利用MSRM区域合并法实现目标物和背景的有效分割。对比聚类分割和基于H-minima标记的分水岭算法和Otsu类间最大间距算法,改进后的算法在分割效果、算法运行时间和分割精确度和召回率上具有明显优势,与上述其他算法在平均分割时间上提升3.86 ms,2.88 ms,5.64 ms。分割交并比IOU平均值96.42%,比其他算法平均值高出12.65%,2.77%和3.07%。     

基于假设检验和区域合并的视频对象分割

提出了基于假设检验和区域合并的视频对象分割算法。初始分割采用分水岭算法，接着根据颜色相似性进行区域合并，然后利用光流场估计和全局运动估计获得全局运动的残余误差，最后以各个区域的残余误差数据进行假设检验和小区域验证来确定运动区域，通过组合所有的运动区域即可分割出具有准确边缘的完整视频对象。对MPEG-4测试序列的实验结果表明了本算法具有良好的分割性能。     

A multi-plane approach for text segmentation of complex document images

This study presents a new method, namely the multi-plane segmentation approach, for segmenting and extracting textual objects from various real-life complex document images. The proposed multi-plane segmentation approach first decomposes the document image into distinct object planes to extract and separate homogeneous objects including textual regions of interest, non-text objects such as graphics and pictures, and background textures. This process consists of two stages—localized histogram multilevel thresholding and multi-plane region matching and assembling. Then a text extraction procedure is applied on the resultant planes to detect and extract textual objects with different characteristics in the respective planes. The proposed approach processes document images regionally and adaptively according to their respective local features. Hence detailed characteristics of the extracted textual objects, particularly small characters with thin strokes, as well as gradational illuminations of characters, can be well-preserved. Moreover, this way also allows background objects with uneven, gradational, and sharp variations in contrast, illumination, and texture to be handled easily and well. Experimental results on real-life complex document images demonstrate that the proposed approach is effective in extracting textual objects with various illuminations, sizes, and font styles from various types of complex document images.     

融合mean shift和区域显著性的彩色图像分割算法

提出了一种无监督的提取图像中显著区域的彩色图像分割算法。首先,运用mean shift算法对图像进行分割,得到初始的分割结果;然后,根据给出的区域显著性的定义和区域合并策略,对初始分割结果进行合并,得到最终的分割结果。仿真结果表明,对于大多数测试图像,该算法都能获得很好的分割结果,并且具有较高的运行效率。     

一种新的基于区域和边界的图象分割方法

用分水岭方法进行图象分割时,容易造成图象的过度分割,从而使得物体的轮廓线掩埋在杂乱的分水岭线中,为了克服这种过度分割问题,提出了一种保持边界的非线性扩散方法,该方法就是先对图象进行平滑,在去噪声的同时,即减少了梯度图象中区域最小值的数目,而分水岭分割后的图象区域数目与它相同;然后,根据初始分水岭分割的结果,使用区域灰度相似性和边界强度相结合的准则,进行由底向上的层次融合,从而较好地解决了过度分割的问题。实验结果表明,该方法可提供精确且封闭的区域轮廓线。     

Rapid,man-made object morphological segmentation for aerial images using a multi-scaled,geometric image analysis

This paper describes a man-made object segmentation method for aerial images based on a modified watershed segmentation algorithm. Our segmentation procedure includes three steps: (1) a multi-scaled geometric image analysis of aerial images by the non-subsampled contourlet transform (NSCT) method, (2) watershed segmentation, and (3) region classification of man-made objects. First, background of multi-scaled geometric image analysis is introduced briefly, and NSCT is used to represent the features for the purpose of man-made object segmentation. Thanks to the properties of NSCT, it not only avoids pseudo-Gibbs phenomena around singularities in image de-noising with regard to shift invariance, but it also enriches the set of basis functions, which makes it possible to extract orientational contour of man-made objects more effectively. In the NSCT decomposition step, the best basis selection is employed for ensuring maximum information content. Second, the “texture gradient” of combined features is calculated based on the first NSCT decomposition step and the resulting best basis selection, afterward the watershed transform is applied. According to their feature values, the aerial images are divided into several homogenous regions. Third, the fractional Brownian motion (fBm) model is used to determine the man-made object regions. Last, the experimental results show that the outcome of man-made object segmentation becomes more continuous and satisfying as a result of the homogenous texture-regions extraction and the modified watershed procedure.