医学图像分割技术

医学图像分割作为图像处理技术的关键步骤,为医生临床诊断、手术方案制定、病灶的定位提供重要依据。与普通图像不同,医学图像具有模糊、不均匀的特点,这使分割的难度大大增加。目前,医学图像分割技术繁多,总的来说可以分为基于区域、基于边缘、与特定理论相结合的方法。我们今后研究的重点是制定评价算法优劣的定量准则。     

关于医学图像分割的综述

医学图像分割是医学图像处理中最基本和最重要的技术,其目的是把图像空间分割成一些有意义的区域.医学图像分割技术的发展决定着医学图像处理中其它相关技术的发展.本文在大量阅读国内外近期文献的基础上,对近年来医学图像分割技术的发展进行了分类综述.     

医学图像的三维自适应迭代分割算法

医学图像分割是医学图像处理分析领域中的研究重点和难点问题,文中对医学CT图像的三维分割方法进行了深入研究,提出了一种医学CT图像的三维分割框架--三维自适应迭代分割算法(SO3DAISA).试验结果表明,本文的分割方法在很大程度上减少了人工干预、执行效率高、图像分割效果好,并且具有很好的实用性.     

医学图像分割概述

在医学研究和实践中,经常需要对人体某种组织和器官的形状、边界、截面面积以及体积进行测量,从而得出该组织病理、或功能方面的重要信息。由于偏移场的存在使核磁共振图像中局部统计特性发生变化,不同生理组织的亮度交叠分布,成为自动化分割的一个主要障碍。医学图像分割算法的研究仍是当前医学图像处理和分析的热点。本文阐述了医学图像分割的目的意义,分析医学图像分割现状,并对目前国内外医学图像分割方法进行了归纳,总结各种不同类型方法的特点。     

医学图像分割方法

随着影像医学在临床医学的成功应用,医学图像分割在临床诊疗中起着越来越重要的作用。分割算法的精准性将影响诊断结果和治疗方案,本文从医学图像分割几种常用的方法出发,结合医学图像的应用,总结了每种方法的优缺点,列举了每种方法的改进算法。最后,进一步阐述了图像分割技术的发展趋势。     

基于Kohonen神经网络算法的医学图像分割

长期以来,在医学图像处理方面,图像分割一直是该项工作中的重点,同时也是其中的难点.所谓的图像分割实质上就是遵照相关的原则对图像进行分割,使其被分为几个部分的过程.它是以图像测量、配准、融合和三维重建作为基础,所以在临床医学研究中起着举足轻重的作用.文中研究的Kohonen聚类神经网络算法是以VC++为基础,并在此基础上...     

改进的分水岭算法用于X光医学图像分割

为了提高医学图像分割质量,提出了一种基于X光医学图像的改进分水岭算法。算法在应用分水岭算法前首先对感兴趣图像进行预处理,包括对感兴趣区域进行最小阈值法,分离背景区,对前景区运用腐蚀和膨胀运算得到候选区;在分水岭变换过程中,通过像素聚类合并准则,将与主像素聚类有相同特性的次像素聚类加入到分割结果中,最终得到合并区域。试验证明,这种改进的分水岭算法使过分割现象得到减少,有效地分割和提取医学图像中的病变区域。     

改进的分水岭算法在医学图像分割中的应用

针对传统分水岭算法对噪声敏感和易于产生过分割的问题,提出了一种将同态滤波增强与控制标记符分水岭相结合的分割策略.该方法先进行同态滤波增强预处理,再采用改进控制标记符的分水岭分割算法进行分割.仿真实验表明,提出的算法很好地抑制了过分割,实现了有意义的医学图像区域分割,同时还具有较强的区域轮廓定位能力,不需要再进行后续的合并处理,算法简单,并且能够适应医学图像分类与信息提取的需求.     

图像分割技术在医学图像处理中的运用研究

医学图像处理要求比较严格,要保证做到精确清晰?随着医学图像数据量的增多,为提高图像处理质量与效率,需要进一步加深对专业处理技术的研究?其中图像分割技术作为图像处理的专业手段之一,以计算机算法为基础,对医学图像进行分割处理,对重点区域进行针对性分析,能够为疾病诊断提供更为可靠的辅助作用?本文结合医学图像处理要求,对图像分...     

图像边缘检测算法的比较分析

随着社会的快速发展,图像边缘检测的方法也逐步的多样化,为了能够全面提升其图像边缘检测的效率,需要对整体的检测方法进行全面的创新.但在实际的检测过程中,其检测环境还相对复杂,导致边缘检测的难度相对较大.所以,对检测法进行优化十分关键.本文主要针对图像边缘检测法进行比较分析.并提出了相应的优化措施.     

Image segmentation for compression of images and image sequences

Region-based image coding schemes, the so-called second generation techniques, have gained much favour in recent years. For still picture coding, they can increase the compression ratio obtained by transform coding by an order of magnitude, while maintaining adequate image representation. The success of these techniques relies on the ability to describe regions in an image succinctly by their shape and size. The algorithms presented describe methods for segmenting images. Unlike most other region based algorithms, these algorithms incorporate knowledge of the border coding process in deciding how to partition the image. The extension from single image compression to sequential image compression is also considered. A new, efficient segmentation scheme is proposed that exploits temporal redundancies between successive images, and reduces some problems associated with error accumulation in error images     

基于模糊和遗传算法的阈值分割方法

提出了一种阈值分割方法。本算法将模糊集理论和遗传算法有机地结合起来,它是一种有监督的分割方法,首先确定图像阈值的数目,然后将灰度图像模糊化,确定准则函数,采用遗传算法求得意了优解,最后经过后处理得到最终分割结果。实验表明该方法运算速度快,且对噪声不敏感,具有较高的鲁棒性。     

三维医疗影像数据自动分割算法研究

对传统的边缘提取及区域分割方法进行了一定的改进,将其扩张到了三维体数据中,并针对hessian矩阵边缘效应特别强的特点,提取其最大特征值进行图像分割,取得了一定的效果。     

Active volume models for medical image segmentation

In this paper, we propose a novel predictive model, active volume model (AVM), for object boundary extraction. It is a dynamic "object" model whose manifestation includes a deformable curve or surface representing a shape, a volumetric interior carrying appearance statistics, and an embedded classifier that separates object from background based on current feature information. The model focuses on an accurate representation of the foreground object's attributes, and does not explicitly represent the background. As we will show, however, the model is capable of reasoning about the background statistics thus can detect when is change sufficient to invoke a boundary decision. When applied to object segmentation, the model alternates between two basic operations: 1) deforming according to current region of interest (ROI), which is a binary mask representing the object region predicted by the current model, and 2) predicting ROI according to current appearance statistics of the model. To further improve robustness and accuracy when segmenting multiple objects or an object with multiple parts, we also propose multiple-surface active volume model (MSAVM), which consists of several single-surface AVM models subject to high-level geometric spatial constraints. An AVM's deformation is derived from a linear system based on finite element method (FEM). To keep the model's surface triangulation optimized, surface remeshing is derived from another linear system based on Laplacian mesh optimization (LMO). Thus efficient optimization and fast convergence of the model are achieved by solving two linear systems. Segmentation, validation and comparison results are presented from experiments on a variety of 2-D and 3-D medical images.     

基于最佳分割目标优化的医学图像分割方法

针对医学图像中组织边缘模糊、灰度不均匀、图像噪声高的问题,将改进的布谷鸟算法和信息熵结合,提出一种基于改进布谷鸟算法优化最大熵的医学图像分割方法。通过改进的布谷鸟算法优化最大熵法确定图像的最佳分割门限,在此基础上完成最佳分割点的分割。在多个实验样本上的测试结果表明,文中提出的新方法在很大程度上解决了过去几种方法的缺陷,使得分割速度与精度明显提升,另一方面,其鲁棒性也相对理想,适用于实际应用。     

空域增强算法在医学图像中的应用研究

文中以医学图像为例,对噪声大、模糊不清、对比度低的图像进行增强处理。主要工作是通过几种滤除噪声方法对比,选择中值滤波法去除噪声,然而通过直方图均衡化处理以及对图像的目标区的背景区分别做对数运算和指数运算增强对比度,突显目标区。模拟实验结果表明本文的处理方法具有良好的效果。     

Theoretical analysis of multispectral image segmentation criteria

Markov random field (MRF) image segmentation algorithms have been extensively studied, and have gained wide acceptance. However, almost all of the work on them has been experimental. This provides a good understanding of the performance of existing algorithms, but not a unified explanation of the significance of each component. To address this issue, we present a theoretical analysis of several MRF image segmentation criteria. Standard methods of signal detection and estimation are used in the theoretical analysis, which quantitatively predicts the performance at realistic noise levels. The analysis is decoupled into the problems of false alarm rate, parameter selection (Neyman-Pearson and receiver operating characteristics), detection threshold, expected a priori boundary roughness, and supervision. Only the performance inherent to a criterion, with perfect global optimization, is considered. The analysis indicates that boundary and region penalties are very useful, while distinct-mean penalties are of questionable merit. Region penalties are far more important for multispectral segmentation than for greyscale. This observation also holds for Gauss-Markov random fields, and for many separable within-class PDFs. To validate the analysis, we present optimization algorithms for several criteria. Theoretical and experimental results agree fairly well.