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。     

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.     

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。     

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,并在此基础上进行了一定的优化,为图像分割的具体应用提供基础条件,提高效果,这对医生临床诊断具有十分重要的意义。     

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.     

基于聚类神经网络算法的医学图像分割

图像分割是医学图像处理中的一个难题,它是指按照一定的原则将一幅图像或景物分成若干个部分或子集的过程.它是医学图像处理中极为重要的内容之一,是实现图像测量、配准、融合以及三维重建的基础,在临床诊断中也起着越来越重要的作用.使用VISUAL C++实现了Kohonen聚类神经网络算法,并对此算法进行了改进优化,在此基础上设计了单窗口模式的"Division"图像处理应用程序进行图像分割,达到了良好的效果,有助于医生的临床诊断.     

基于偏移场的双水平集医学图像分割算法

针对医学图像中通常伴有灰度不均、背景复杂,无法被传统水平集有效分割的特点,提出了基于偏移场的双水平集算法。为了去除医学图像中灰度不均对分割效果的影响,算法中引入偏移场拟合项,改进双水平集模型,再由改进后的双水平集算法分割医学图像中的多目标区域。实验结果表明,所提算法能有效地解决灰度不均与背景复杂的问题,将伴有灰度不均的多目标医学图像完全分割出来,获得预期的分割效果。     

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.     

基于脉冲涡流热成像的钢板缺陷检测研究

脉冲涡流热成像检测技术是一种新型的无损检测方法,研究热成像表面缺陷的数据特征,将otsu分割算法与最大熵分割算法相结合,提出基于最大熵的otsu分割算法,既能较好的分割热图像中的缺陷又能有效的识别目标缺陷的边缘。实验结果表明,相比较其他传统分割算法,具有更好的缺陷提取效果。     

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。     

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.     

Multi-path connected network for medical image segmentation

In recent years, deep learning has been successfully applied to medical image segmentation. However, as the network extends deeper, the consecutive downsampling operations will lead to more loss of spatial information. In addition, the limited data and diverse targets increase the difficulty for medical image segmentation. To address these issues, we propose a multi-path connected network (MCNet) for medical segmentation problems. It integrates multiple paths generated by pyramid pooling into the encoding phase to preserve semantic information and spatial details. We utilize multi-scale feature extractor block (MFE block) in the encoder to obtain large and multi-scale receptive fields. We evaluated MCNet on three medical datasets with different image modalities. The experimental results show that our method achieves better performance than the state-of-the-art approaches. Our model has strong feature learning ability and is robust to capture different scale targets. It can achieve satisfactory results while using only 0.98 million (M) parameters.     

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。     

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。     

DB-TASNet for disease diagnosis and lesion segmentation in medical images

Deep learning algorithms have been successfully used in the field of medical image analysis and have greatly improved application of intelligent algorithms to medical diagnosis. However, existing deep-learning-based diagnostic methods still suffer from several drawbacks: (1) In most medical image multi-tasking methods, focus segmentation and disease classification are often performed linearly, resulting in excessive reliance on the final results of focus segmentation. (2) The computational cost of the traditional attention mechanism for performing the segmentation task is very high and the convolutional architecture cannot be used to model long-distance dependencies, which in turn affects the segmentation accuracy. To address these issues, we propose a disease diagnosis and lesion segmentation model, Dual-Branch with Transformer Axial-attention Segmentation Net (DB-TASNet). DB-TASNet is built by the DenseNet-121 classification network and U-Net segmentation network improved using an axial-attention transformer model. Moreover, DB-TASNet also includes a lesion integration module to integrate segmentation results with the classification network in order to increase its attention to lesions and improve the diagnosis results. Experimental results on the Pneumothorax dataset provided by the Society for Imaging Informatics in Medicine (SIIM) show that the average AUC of the DB-TASNet classification task reaches 0.939, and the DICE coefficient of the segmentation task reaches 0.886. Such performance suggests that the proposed model may provide an efficient and effective diagnosis tool for medical personnel.