Shape optimization using adaptive high-order finite elements

In recent years, the state of the art in shape optimization has advanced due to new approaches proposed by various researchers. A fundamental difficulty in shape optimization is that the original finite element mesh may become invalid during large shape changes. Automatic remeshing and velocity field approaches are most commonly used for conventionalh-type finite element analysis to address this problem.In this paper, we describe a different approach to shape optimization based on the use of high-orderp-type finite elements tightly coupled to a parameterized computational geometry module. The advantages of this approach are as follows.Accurate results can be obtained with much fewer finite elements, so large shape changes are possible without remeshing.Automatic adaptive analysis may be performed so that accurate results are achieved at each step of the optimization process.Since the elements derive their geometric mapping from the underlying geometry, the fundamental equivalent of velocity field element shape updating may be readily achieved.Results are presented for sizing and shape optimization with this approach and contrasted with previous results from the literature.     

Color image segmentation using adaptive unsupervised clustering approach

This paper presents the Region Splitting and Merging-Fuzzy C-means Hybrid Algorithm (RFHA), an adaptive unsupervised clustering approach for color image segmentation, which is important in image analysis and in understanding pattern recognition and computer vision field. Histogram thresholding technique is applied in the formation of all possible cells, used to split the image into multiple homogeneous regions. The merging technique is applied to merge perceptually close homogeneous regions and obtain better initialization for the Fuzzy C-means clustering approach. Experimental results have demonstrated that the proposed scheme could obtain promising segmentation results, with 12% average improvement in clustering quality and 63% reduction in classification error compared with other existing segmentation approaches.     

Medical image segmentation using customized U-Net with adaptive activation functions

Neural Computing and Applications - Since medical imaging is a fundamental step in clinical diagnosis and treatment, medical image processing is an attractive field for researchers. Among the...     

基于自适应分割和立体视觉的快速障碍检测

首先实时提取参考路面的平均色度值,对图像进行自适应分割,初步划分出可疑障碍区域;然后选取可疑障碍区域的对角线,利用立体视觉的方法进一步检测出障碍区域.证明了两摄像机平行放置时左右图像中区域对角线的对应关系,在此基础上进行匹配计算.该方法能适应光照条件变化,提高立体视觉算法速度,实验结果表明了该方法的有效性和可靠性.     

Multilevel image segmentation with adaptive image context based thresholding

Neural network based image segmentation techniques primarily focus on the selection of appropriate thresholding points in the image feature space. Research initiatives in this direction aim at addressing this problem of effective threshold selection for activation functions. Multilevel activation functions resort to fixed and uniform thresholding mechanisms. These functions assume homogeneity of the image information content. In this paper, we propose a collection of adaptive thresholding approaches to multilevel activation functions. The proposed thresholding mechanisms incorporate the image context information in the thresholding process. Applications of these mechanisms are demonstrated on the segmentation of real life multilevel intensity images using a self-supervised multilayer self-organizing neural network (MLSONN) and a supervised pyramidal neural network (PyraNet).We also present a bi-directional self-organizing neural network (BDSONN) architecture suitable for multilevel image segmentation. The architecture uses an embedded adaptive thresholding mechanism to a characteristic multilevel activation function.The segmentation efficiencies of the thresholding mechanisms evaluated using four unsupervised measures of merit, are reported for the three neural network architectures considered.     

An adaptive image segmentation method with visual nonlinearitycharacteristics

This correspondence is concerned with a method for image segmentation on the visual principle. The inconsistency between the conventional discriminating criterion and the human vision mechanism in perceiving an object and its background is analyzed and an improved discriminating criterion with visual nonlinearity is defined. A new model and an algorithm for image segmentation calculation are proposed based on the spatially adaptive principle of human vision and the relevant hypotheses about object recognition. This is a two-stage process of image segmentation. First, initial segmentation is realized with the bottom-up segmenting algorithm, followed by the goal-driven segmenting algorithm to improve the segmentation results concerning certain regions of interest. Experimental results show that, compared with some conventional and gradient-based segmenting methods, the new method has the excellent performance of extracting small objects from the images of natural scenes with a complicated background.     

Interactive stereo image segmentation via adaptive prior selection

Multimedia Tools and Applications - Interactive stereo image segmentation (i.e., cutting out objects from stereo pairs with limited user assistance) is an important research topic in computer...     

带宽自适应MeanShift图像分割算法

MeanShift是目前为止特征空间分析的最好方法之一,但其分割结果受带宽参数的影响。图像粗糙度是与视觉感受相关的图像纹理特征,对图像纹理的描述能力很强。图像像素的平均偏移量也体现了图像像素的总体离散情况。通过对高斯核函数的创建以及图像粗糙度的描述,创新性地给出了MeanShift的窗口尺寸选择方法以及图像像素平均偏移的计算,仿真结果表明,该算法对不同类型的图像,均能得到令人满意的效果。     

Multichannel environmental sound segmentation

Applied Intelligence - This paper proposes a multichannel environmental sound segmentation method. Environmental sound segmentation is an integrated method to achieve sound source localization,...     

A scalable region-based level set method using adaptive bilateral filter for noisy image segmentation

Image segmentation plays an important role in the computer vision . However, it is extremely challenging due to low resolution, high noise and blurry boundaries. Recently, region-based models have been widely used to segment such images. The existing models often utilized Gaussian filtering to filter images, which caused the loss of edge gradient information. Accordingly, in this paper, a novel local region model based on adaptive bilateral filter is presented for segmenting noisy images. Specifically, we firstly construct a range-based adaptive bilateral filter, in which an image can well be preserved edge structures as well as resisted noise. Secondly, we present a data-driven energy model, which utilizes local information of regions centered at each pixel of image to approximate intensities inside and outside of the circular contour. The estimation approach has improved the accuracy of noisy image segmentation. Thirdly, under the premise of keeping the image original shape, a regularization function is used to accelerate the convergence speed and smoothen the segmentation contour. Experimental results of both synthetic and real images demonstrate that the proposed model is more efficient and robust to noise than the state-of-art region-based models.

     

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。     

一种基于MAS的自适应图像分割方法

复杂图像的全自动分割是极具挑战性的问题．提出了一种基于MAS的自适应图像分割方法．通过属性和行为描述Agent个体，通过合作竞争描述了Agent间的交互．MAS系统在Agent反复自适应过程中达到平衡，同时完成图像分割．通过分割复杂的医学图像证实了该方法的有效性，MAS在图像分割领域具有应用价值．     

Color image segmentation using competitive learning

Presents a color image segmentation method which divides the color space into clusters. Competitive learning is used as a tool for clustering the color space based on the least sum-of-squares criterion. We show that competitive learning converges to approximate the optimum solution based on this criterion, theoretically and experimentally. We apply this method to various color scenes and show its efficiency as a color image segmentation method. We also show the effects of using different color coordinates to be clustered, with some experimental results     

Multispectral image compression using eigenregion-based segmentation

In the study, a novel segmentation technique is proposed for multispectral satellite image compression. A segmentation decision rule composed of the principal eigenvectors of the image correlation matrix is derived to determine the similarity of image characteristics of two image blocks. Based on the decision rule, we develop an eigenregion-based segmentation technique. The proposed segmentation technique can divide the original image into some proper eigenregions according to their local terrain characteristics. To achieve better compression efficiency, each eigenregion image is then compressed by an efficient compression algorithm eigenregion-based eigensubspace transform (ER-EST). The ER-EST contains 1D eigensubspace transform (EST) and 2D-DCT to decorrelate the data in spectral and spatial domains. Before performing EST, the dimension of transformation matrix of EST is estimated by an information criterion. In this way, the eigenregion image may be approximated by a lower-dimensional components in the eigensubspace. Simulation tests performed on SPOT and Landsat TM images have demonstrated that the proposed compression scheme is suitable for multispectral satellite image.     

分水岭变换在岩屑图像分割中的应用

分水岭变换是一种基于区域和数学形态学的图像分割方法,被广泛用于灰度图像的分割之中.但传统分水岭变换过分割问题严重,图像的噪声和虚假纹理会淹没真正想得到的边缘信息.针对岩屑图像的特征,提出了一种改进的分水岭算法分割方案.先在预处理期用形态学开闭重建运算对原始图像平滑处理,在相对保留边缘不受影响的同时,降低噪声的影响.再通过非线性的阈值变换分离出目标和背景,然后在提取出目标的情况下合并过小区域,得到目标的边缘.而由于阈值变换后,区域数量已经明显减少,可以降低区域合并的运算量,提高合并速度.在求取形态学梯度时,选用了一种新的形态梯度形式,消除了形态学处理对分割结果造成的轮廓偏移现象.从实验结果看来,该算法取得了较好的分割效果.     

Topology-based image segmentation using LBP pyramids

In this paper, we present a new image segmentation algorithm which is based on local binary patterns (LBPs) and the combinatorial pyramid and which preserves structural correctness and image topology. For this purpose, we define a codification of LBPs using graph pyramids. Since the LBP code characterizes the topological category (local max, min, slope, saddle) of the gray level landscape around the center region, we use it to obtain a “minimal” image representation in terms of the topological characterization of a given 2D grayscale image. Based on this idea, we further describe our hierarchical texture aware image segmentation algorithm and compare its segmentation output and the “minimal” image representation.     

Interactive image segmentation using probabilistic hypergraphs

This paper introduces a novel interactive framework for segmenting images using probabilistic hypergraphs which model the spatial and appearance relations among image pixels. The probabilistic hypergraph provides us a means to pose image segmentation as a machine learning problem. In particular, we assume that a small set of pixels, which are referred to as seed pixels, are labeled as the object and background. The seed pixels are used to estimate the labels of the unlabeled pixels by learning on a hypergraph via minimizing a quadratic smoothness term formed by a hypergraph Laplacian matrix subject to the known label constraints. We derive a natural probabilistic interpretation of this smoothness term, and provide a detailed discussion on the relation of our method to other hypergraph and graph based learning methods. We also present a front-to-end image segmentation system based on the proposed method, which is shown to achieve promising quantitative and qualitative results on the commonly used GrabCut dataset.     

Brain image segmentation using semi-supervised clustering

The objective of brain image segmentation is to partition the brain images into different non-overlapping homogeneous regions representing the different anatomical structures. Magnetic resonance brain image segmentation has large number of applications in diagnosis of neurological disorders like Alzheimer diseases, Parkinson related syndrome etc. But automatically segmenting the MR brain image is not an easy task. To solve this problem, several unsupervised and supervised based classification techniques have been developed in the literature. But supervised classification techniques are more time consuming and cost-sensitive due to the requirement of sufficient labeled data. In contrast, unsupervised classification techniques work without using any prior information but it suffers from the local trap problems. So, to overcome the problems associated with unsupervised and supervised classification techniques, we have proposed a new semi-supervised clustering technique using the concepts of multiobjective optimization and applied this technique for automatic segmentation of MR brain images in the intensity space. Multiple centers are used to encode a cluster in the form of a string. The proposed clustering technique utilizes intensity values of the brain pixels as the features. Additionally it also assumes that the actual class label information of 10% points of a particular image data set is also known. Three cluster validity indices are utilized as the objective functions, which are simultaneously optimized using AMOSA, a modern multiobjective optimization technique based on the concepts of simulated annealing. First two cluster validity indices are symmetry distance based Sym-index and Euclidean distance based I-index, which are based on unsupervised properties. Last one is a supervised information based cluster validity index, Minkowski Index. The effectiveness of this proposed semi-supervised clustering technique is demonstrated on several simulated MR normal brain images and MR brain images having some multiple sclerosis lesions. The performance of the proposed semi-supervised clustering technique is compared with some other popular image segmentation techniques like Fuzzy C-means, Expectation Maximization and some recent image clustering techniques like multi-objective based MCMOClust technique, and Fuzzy-VGAPS clustering techniques.