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arXiv 1703.02589cs.CV
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基于CoHOG的ALS脑图像纹理分类

Texture Classification of MR Images of the Brain in ALS using CoHOG

G M Mashrur E Elahi, Sanjay Kalra, Yee-Hong Yang

摘要:

纹理分析是计算机视觉和图像处理中的一个著名研究课题,并且具有许多应用。基于纹理特征的分类方法在分类问题中已成为一种流行的方法。我们第一次扩展了一个著名的基于梯度的方法,共现直方图的定向的连续性(CoHOG)提取纹理特征的2D磁共振图像(MRI)。与原始CoHOG方法不同,我们使用整个图像而不是子区域进行特征计算。此外,我们使用更大的邻域大小。使用Sobel、高斯导数(GD)和局部频率描述符梯度(LFDG)算子计算图像像素的梯度方向。所提取的特征向量的大小是非常大的,并且使用大量相似特征的分类不能提供最佳结果。在我们提出的方法中,据我们所知,第一次只选择了最少数量的重要特征,使用受试者操作特征(ROC)曲线(AUC)阈值下的面积<= 0.01。在本文中,我们应用所提出的方法来分类肌萎缩侧索硬化症(ALS)患者的控制。据观察,从下采样图像中选择的纹理特征在患者和对照之间是显著不同的。这些特征用于线性支持向量机(SVM)分类器中以确定分类精度。还计算了最佳灵敏度和特异性。实验中使用了三个不同的队列数据集。使用三种梯度算子和两种不同的邻域大小的方法的性能进行了分析。进行基于区域的分析,以证明患者和对照组之间的显着变化仅限于运动皮层。

英文摘要:

Texture analysis is a well-known research topic in computer vision and image processing and has many applications. Gradient-based texture methods have become popular in classification problems. For the first time we extend a well-known gradient-based method, Co-occurrence Histograms of Oriented Gradients (CoHOG) to extract texture features from 2D Magnetic Resonance Images (MRI). Unlike the original CoHOG method, we use the whole image instead of sub-regions for feature calculation. Also, we use a larger neighborhood size. Gradient orientations of the image pixels are calculated using Sobel, Gaussian Derivative (GD) and Local Frequency Descriptor Gradient (LFDG) operators. The extracted feature vector size is very large and classification using a large number of similar features does not provide the best results. In our proposed method, for the first time to our best knowledge, only a minimum number of significant features are selected using area under the receiver operator characteristic (ROC) curve (AUC) thresholds with <= 0.01. In this paper, we apply the proposed method to classify Amyotrophic Lateral Sclerosis (ALS) patients from the controls. It is observed that selected texture features from downsampled images are significantly different between patients and controls. These features are used in a linear support vector machine (SVM) classifier to determine the classification accuracy. Optimal sensitivity and specificity are also calculated. Three different cohort datasets are used in the experiments. The performance of the proposed method using three gradient operators and two different neighborhood sizes is analyzed. Region based analysis is performed to demonstrate that significant changes between patients and controls are limited to the motor cortex.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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