基于谱聚类的多闭值图像分割方法

阈值法是图像分割的一种重要方法,在图像处理与目标识别中广为应用。因此,如何确定阈值是图像分割的关键。提出了一种新的图像阈值分割方法,即通过采用新的相似度函数的谱聚类算法(Dcut)确定图像阈值。采用基于灰度级的权值矩阵代替常用的基于图像像素级的权值矩阵描述图像像素的关系,因而算法需要的存储空间及实现的复杂性与其它基于图的图像分割方法相比大大减少。实验表明,该方法分割图像的时间少,且能够单阈值和多阈值分割图像,与现有的阈值分割方法相比,其具有更为优越的分割性能。     

基于卡方散度阈值方法的图像分割研究与实现

通过分析交叉熵阈值法的计算时间量较大的问题,提出了基于卡方散度的图像阈值化分割新准则,并从理论上分析了它与交叉熵阈值法的计算复杂性.实验结果表明,提出的图像分割准则是可行的,且计算所需时间比交叉熵阚值法有了明显减少,它对一定强度噪声干扰的图像比交叉熵法能获得更好的分割结果.     

原位分子杂交图象中银粒的分割方法研究

图象分割的图象处理的一个基本技术。运用一种改进的快速Ｏｔｓｕ阈值分割法,并结合其它处理方法原对原位分子杂效力图象中的银粒进行分割 。     

数字图像处理系统设计与实现

针对数字图像处理的需求,开发设计了基于MATLAB GUI的数字图像处理系统。系统模块中包含对文件进行编辑,包含对图像大小调整,裁剪,灰度化处理,以及显示图像的边界图,图像进行类型转换,颜色空间转换。对数字图像处理的设计主界面中一共包含以下几个实验项目,图像的变换、增强、分割、其他常用处理。图像的傅里叶变换,离散余弦变换;空间域增强、频率域增强;阈值分割、梯度分割;对图像的亮度调节,对比度调节,裁剪截取,及显示图片的底片效果。该系统主要实现了对图像的以上处理,最后通过实例来展示处理效果。测试结果表明,该系统正常实现了所需要的功能,达到了数字图像处理的目的。     

Image thresholding using type II fuzzy sets

Image thresholding is a necessary task in some image processing applications. However, due to disturbing factors, e.g. non-uniform illumination, or inherent image vagueness, the result of image thresholding is not always satisfactory. In recent years, various researchers have introduced new thresholding techniques based on fuzzy set theory to overcome this problem. Regarding images as fuzzy sets (or subsets), different fuzzy thresholding techniques have been developed to remove the grayness ambiguity/vagueness during the task of threshold selection. In this paper, a new thresholding technique is introduced which processes thresholds as type II fuzzy sets. A new measure of ultrafuzziness is also introduced and experimental results using laser cladding images are provided.     

A novel local contrast fusion-based fuzzy model for color image multilevel thresholding using grasshopper optimization

The segmentation process is considered the significant step of an image processing system due to its extreme inspiration on the subsequent image analysis. Out of various approaches, thresholding is one of the most popular schemes for image segmentation. In segmentation, image pixels are arranged in various regions based on their intensity levels. In this paper, a straightforward and efficient fusion-based fuzzy model for multilevel color image segmentation using grasshopper optimization algorithm (GOA) has been proposed. Thresholding based segmentation lacks accuracy in segmenting the ambiguous images due to their complex characteristics, uncertainties and inherent fuzziness. However, the fuzzy entropy resolves these problems, but it is unable for segmenting at higher levels and also the complexity level for selecting suitable thresholds is high. The selection of metaheuristic GOA reduces this problem by selecting optimal threshold values. Therefore, to increase the quality of the segmented image, a simple and effective multilevel thresholding method is exploited by using the concept of fusion which is based on the local contrast. Experimental outputs demonstrate that fusion-based multilevel thresholding is better than most specific segmentation methods and can be validated by comparing the different numerical parameters. Experiments on standard daily-life color and satellite images are conducted to prove the effectiveness of the proposed scheme.     

A new active contour remote sensing river image segmentation algorithm inspired from the cross entropy

The CV (Chan–Vese) model is a piecewise constant approximation of the Mumford and Shah model. It assumes that the original image can be segmented into two regions such that each region can be represented as constant grayscale value. In fact, the objective functional of the CV model actually finds a segmentation of the image such that the within-class variance is minimized. This is equivalent to the Otsu image thresholding algorithm which also aims to minimize the within-class variance. Similarly to the Otsu image thresholding algorithm, cross entropy is another widely used image thresholding algorithm and it finds a segmentation such that the cross entropy of the segmented image and the original image is minimized. Inspired from the cross entropy, a new active contour image segmentation algorithm is proposed. The region term in the new objective functional is the integral of the logarithm of the ratio between the grayscale of the original image and the mean value computed from the segmented image weighted by the grayscale of the original image. The new objective functional can be solved by the level set evolution method. A distance regularized term is added to the level set evolution equation so the level set need not be reinitialized periodically. A fast global minimization algorithm of the objective functional is also proposed which incorporates the edge term originated from the geodesic active contour model. Experimental results show that, the algorithm proposed can segment images more accurately than the CV model and the implementation speed of the fast global minimization algorithm is fast.     

A generalized multiclass histogram thresholding approach based on mixture modelling

This paper presents a new approach to multi-class thresholding-based segmentation. It considerably improves existing thresholding methods by efficiently modeling non-Gaussian and multi-modal class-conditional distributions using mixtures of generalized Gaussian distributions (MoGG). The proposed approach seamlessly: (1) extends the standard Otsu's method to arbitrary numbers of thresholds and (2) extends the Kittler and Illingworth minimum error thresholding to non-Gaussian and multi-modal class-conditional data. MoGGs enable efficient representation of heavy-tailed data and multi-modal histograms with flat or sharply shaped peaks. Experiments on synthetic data and real-world image segmentation show the performance of the proposed approach with comparison to recent state-of-the-art techniques.     

C#实现彩色图像分割

针对图像分析应用日益广泛的现状,基于阈值法对彩色图像实现分割进行论述。介绍图像分割基本概念,讲述彩色图像直方图阈值分割方法,利用二维直方图方便地寻找彩色图像阈值,最后通过C#可行的程序稳定、准确地实现彩色图像阈值分割。     

C#实现彩色图像分割

针对图像分析应用日益广泛的现状,基于阈值法对彩色图像实现分割进行论述。介绍图像分割基本概念,讲述彩色图像直方图阈值分割方法,利用二维直方图方便地寻找彩色图像阈值,最后通过C#可行的程序稳定、准确地实现彩色图像阈值分割。     

图象模糊涟缘检测的改进算法

图象在检测技术是图象处理中最重要的内容之一,且已在图象分析和识别领域中得到广泛的应用。针对图象边缘由模糊性引起的不确定性问题,提出了一种图象模糊边缘检测的改进算法,该算法是道德民确定一个阈值参数,然后根据此阈值参数来定义一个新的隶属函数,从而钭图象转化为等效的图象模糊特征平面,通过在模糊特征平面上进行增强运算,将其转换为空域图象,最后再进行边缘提取,同时还对具有多峰直方图分布图象的模糊边缘检测方法进行推广,仿真结果表明,该算法是有效的。     

A multilevel color image segmentation technique based on cuckoo search algorithm and energy curve

Amongst all the multilevel thresholding techniques, standard histogram based thresholding approaches are very impressive for bi-level thresholding. But, it is not effective to select spatial contextual information of the image for choosing optimal thresholds. In this paper, a new color image thresholding technique is presented by using an energy function to generate the energy curve of an image by considering spatial contextual information of the image. The property of this energy curve is very much similar to histogram of the image. To estimate the spatial contextual information for thresholding practice, in place of histogram, the energy curve function is used as an input. A new energy curve based color image segmentation approach using three well known objective functions named Kapur’s entropy, between-class-variance, and Tsalli’s entropy is proposed. In this paper, cuckoo search (CS) and egg lying radius-cuckoo search (ELR-CS) optimization algorithms with different parameter analysis have been used for solving the color image multilevel thresholding problem. The experimental results demonstrate that the proposed CS-Kapur’s energy curve based segmentation can powerfully and accurately search the multilevel thresholds.     

Automatic tracking and digitization of multiple radiopaque myocardial markers

An 80386 PC-based system was designed to track automatically multiple, miniature radiopaque markers implanted in the heart wall. This system eliminated the need for tedious, time-consuming manual digitization of marker coordinates. Use of a MATROX MVP-AT/NP image processing board incorporated advanced image processing and graphics features into the low-cost PC environment. Digital image enhancement and segmentation techniques (such as limiting analysis to predefined windows of interest, spatial band-pass and matched filtering, contrast stretching and clipping, linear adaptive prediction, intensity histogram analysis, adaptive binary thresholding, region growing, expanding region of analysis, and feature extraction) were incorporated into a user-friendly integrated marker processing software environment. Improved speed, accuracy, and reproducibility of the marker digitizing process were realized. These basic techniques have broad applications to other image processing needs in biomedical research.     

模糊包含度在图像分割中的应用

图像分割是图像分析、理解和机器视觉的基础。由于人眼视觉的主观性使得图像比较适合使用模糊技术进行处理。基于模糊集的包含度理论,定义了图像分割选取阈值的准则函数。实验结果表明,提出的图像阈值化分割方法是可行的,且分割性能明显优于基于模糊熵或贴近度的分割法。     

一种对光照具有鲁棒性的图像分割方法

研究了灰度图像的OTSU(最大类间方差)自动阈值分割法。OTSU方法作为一种单一阈值的分割方法,当图像受光照和反射光等的影响明显时,将会出现严重的误分割现象。考虑到OTSU方法的最大类间方差化的思想,根据灰度图像的像素点灰度的直方图分布、空间分布,提出了一个新的分割阈值方法。先根据OTSU方法的特点自设计一个函数,对图像进行变换,以便后面的处理,再对其图像以改进的OTSU方法进行分割。通过对化学实验中两种液体的拍摄图片及数字图像处理中标准图片进行试验,理论分析与实验结果表明：该方法能够对受光照及反射光影响大的图像实现正确的分割,将目标图像清晰地从背景中分割出来。     

基于模糊技术的彩色图像分割方法

由于彩色图像提供了比灰度图像更为丰富的信息,因此彩色图像处理正受到人们越来越多的关注。彩色图像分割是彩色图像处理的重要问题,目前对彩色图像的分割已提出了许多种算法,在这些算法中由于模糊技术能很好地表达和处理不确定性问题,因此在彩色图像分割领域会有更广阔的应用前景。本文主要介绍了基于模糊技术的模糊阈值分割法、模糊聚类分割法和模糊连接度分割法。     

Cross entropy based thresholding for magnetic resonance brain images using Crow Search Algorithm

Segmentation is considered the central part of an image processing system due to its high influence on the posterior image analysis. In recent years, the segmentation of magnetic resonance (MR) images has attracted the attention of the scientific community with the objective of assisting the diagnosis in different brain diseases. From several techniques, thresholding represents one of the most popular methods for image segmentation. Currently, an extensive amount of contributions has been proposed in the literature, where thresholding values are obtained by optimizing relevant criteria such as the cross entropy. However, most of such approaches are computationally expensive, since they conduct an exhaustive search strategy for obtaining the optimal thresholding values. This paper presents a general method for image segmentation. To estimate the thresholding values, the proposed approach uses the recently published evolutionary method called the Crow Search Algorithm (CSA) which is based on the behavior in flocks of crows. Different to other optimization techniques used for segmentation proposes, CSA presents a better performance, avoiding critical flaws such as the premature convergence to sub-optimal solutions and the limited exploration-exploitation balance in the search strategy. Although the proposed method can be used as a generic segmentation algorithm, its characteristics allow obtaining excellent results in the automatic segmentation of complex MR images. Under such circumstances, our approach has been evaluated using two sets of benchmark images; the first set is composed of general images commonly used in the image processing literature, while the second set corresponds to MR brain images. Experimental results, statistically validated, demonstrate that the proposed technique obtains better results in terms of quality and consistency.     

Adaptive multilevel rough entropy evolutionary thresholding

In this study, comprehensive research into rough set entropy-based thresholding image segmentation techniques has been performed producing new and robust algorithmic schemes. Segmentation is the low-level image transformation routine that partitions an input image into distinct disjoint and homogenous regions using thresholding algorithms most often applied in practical situations, especially when there is pressing need for algorithm implementation simplicity, high segmentation quality, and robustness. Combining entropy-based thresholding with rough set results in the rough entropy thresholding algorithm.The authors propose a new algorithm based on granular multilevel rough entropy evolutionary thresholding that operates on a multilevel domain. The MRET algorithm performance has been compared to the iterative RET algorithm and standard k-means clustering methods on the basis of β-index as a representative validation measure. Performance in experimental assessment suggests that granular multilevel rough entropy threshold based segmentations - MRET - present high quality, comparable with and often better than k-means clustering based segmentations. In this context, the rough entropy evolutionary thresholding MRET algorithm is suitable for specific segmentation tasks, when seeking solutions that incorporate spatial data features with particular characteristics.     

Images thresholding using ISODATA technique with gamma distribution

Image segmentation is a fundamental step in many applications of image processing. Many image segmentation techniques exist based on different methods such as classification-based methods, edge-based methods, region-based methods, and hybrid methods. The principal approach of segmentation is based on thresholding (classification) that is related to thresholds estimation problem. The ISODATA (Iterative Self-Organizing Data Analysis Technique) method is one of the classification-based methods in image segmentation. We assumed that the data in images is modeled by Gamma distribution. The objective of this paper is to explain a new method that combines Gamma distribution with the technique of ISODATA. The algorithm has two phases: splitting using Gamma distribution then merging which are done based on some predefined parameters. Experimental results showed good segmentation for artificial and real images.     

一种遗传优化和Ostu的图像模糊边缘特征提取方法

边缘检测是图像预处理的重要内容之一,在对Pal和King经典模糊边缘检测算法改进的基础上,提出了一种基于遗传算法和Otsu进行图像阈值选取,以不同阈值为基准确定出线性隶属函数,对多峰图像确定多阈值隶属函数的方法,进行模糊增强,从而提取边缘,实验结果表明该算法不仅提高了边缘提取质量,而且缩短了阈值选取时间,是一种有效性、正确性的图像处理方法。