改进卷积神经网络的COVID-19CT影像分类方法研究

针对2019年12月在中国武汉发现的新型冠状病毒,由于RT-PCR检测具有假阴性率过高且得出结果会花费大量时间等问题,研究证明计算机断层扫描(CT)已经成为了辅助诊断和治疗新型冠状病毒肺炎的重要手段之一.由于目前公开的COVID-19 CT数据集较少,提出利用条件生成对抗网络进行数据增强以获得更多样本的CT数据集,以此...     

Automatic Detection of COVID-19 Infection Using Chest X-Ray Images Through Transfer Learning

The new coronavirus(COVID-19),declared by the World Health Organization as a pandemic,has infected more than 1 million people and killed more than 50 thousand.An infection caused by COVID-19 can develop into pneumonia,which can be detected by a chest X-ray exam and should be treated appropriately.In this work,we propose an automatic detection method for COVID-19 infection based on chest X-ray images.The datasets constructed for this study are composed of194 X-ray images of patients diagnosed with coronavirus and 194 X-ray images of healthy patients.Since few images of patients with COVID-19 are publicly available,we apply the concept of transfer learning for this task.We use different architectures of convolutional neural networks(CNNs)trained on Image Net,and adapt them to behave as feature extractors for the X-ray images.Then,the CNNs are combined with consolidated machine learning methods,such as k-Nearest Neighbor,Bayes,Random Forest,multilayer perceptron(MLP),and support vector machine(SVM).The results show that,for one of the datasets,the extractor-classifier pair with the best performance is the Mobile Net architecture with the SVM classifier using a linear kernel,which achieves an accuracy and an F1-score of 98.5%.For the other dataset,the best pair is Dense Net201 with MLP,achieving an accuracy and an F1-score of 95.6%.Thus,the proposed approach demonstrates efficiency in detecting COVID-19 in X-ray images.     

CT图像肺及肺病变区域分割方法综述

计算机断层扫描(computed tomography, CT)技术能为新冠肺炎(corona virus disease 2019,COVID-19)和肺癌等肺部疾病的诊断与治疗提供更全面的信息,但是由于肺部疾病的类型多样且复杂,使得对肺CT图像进行高质量的肺病变区域分割成为计算机辅助诊断的重难点问题。为了对肺CT图像的肺及肺病变区域分割方法的现状进行全面研究,本文综述了近年国内外发表的相关文献：对基于区域和活动轮廓的肺CT图像传统分割方法的优缺点进行比较与总结,传统的肺CT图像分割方法因其实现原理简单且分割速度快等优点,早期使用较多,但其存在分割精度不高的缺点,目前仍有不少基于传统方法的改进策略;重点分析了基于卷积神经网络(convolutional neural network, CNN)、全卷积网络(fully convolutional network, FCN)、U-Net和生成对抗网络(generative adversarial network, GAN)的肺CT图像分割网络结构改进模型的研究进展,基于深度学习的分割方法具有分割精度高、迁移学习能力强和鲁棒性高等优点,特...     

Stacked-autoencoder-based model for COVID-19 diagnosis on CT images

With the outbreak of COVID-19, medical imaging such as computed tomography (CT) based diagnosis is proved to be an effective way to fight against the rapid spread of the virus. Therefore, it is important to study computerized models for infectious detection based on CT imaging. New deep learning-based approaches are developed for CT assisted diagnosis of COVID-19. However, most of the current studies are based on a small size dataset of COVID-19 CT images as there are less publicly available datasets for patient privacy reasons. As a result, the performance of deep learning-based detection models needs to be improved based on a small size dataset. In this paper, a stacked autoencoder detector model is proposed to greatly improve the performance of the detection models such as precision rate and recall rate. Firstly, four autoencoders are constructed as the first four layers of the whole stacked autoencoder detector model being developed to extract better features of CT images. Secondly, the four autoencoders are cascaded together and connected to the dense layer and the softmax classifier to constitute the model. Finally, a new classification loss function is constructed by superimposing reconstruction loss to enhance the detection accuracy of the model. The experiment results show that our model is performed well on a small size COVID-2019 CT image dataset. Our model achieves the average accuracy, precision, recall, and F1-score rate of 94.7%, 96.54%, 94.1%, and 94.8%, respectively. The results reflect the ability of our model in discriminating COVID-19 images which might help radiologists in the diagnosis of suspected COVID-19 patients.

     

Diagnosis of COVID-19 Pneumonia via a Novel Deep Learning Architecture

COVID-19 is a contagious infection that has severe effects on the global economy and our daily life. Accurate diagnosis of COVID-19 is of importance for consultants, patients, and radiologists. In this study, we use the deep learning network AlexNet as the backbone, and enhance it with the following two aspects: 1) adding batch normalization to help accelerate the training, reducing the internal covariance shift; 2) replacing the fully connected layer in AlexNet with three classifiers: SNN, ELM, and RVFL. Therefore, we have three novel models from the deep COVID network (DC-Net) framework, which are named DC-Net-S, DC-Net-E, and DC-Net-R, respectively. After comparison, we find the proposed DC-Net-R achieves an average accuracy of 90.91% on a private dataset (available upon email request) comprising of 296 images while the specificity reaches 96.13%, and has the best performance among all three proposed classifiers. In addition, we show that our DC-Net-R also performs much better than other existing algorithms in the literature.     

Smart COVID-3D-SCNN: A Novel Method to Classify X-ray Images of COVID-19

The outbreak of the novel coronavirus has spread worldwide, and millions of people are being infected. Image or detection classification is one of the first application areas of deep learning, which has a significant contribution to medical image analysis. In classification detection, one or more images (detection) are usually used as input, and diagnostic variables (such as whether there is a disease) are used as output. The novel coronavirus has spread across the world, infecting millions of people. Early-stage detection of critical cases of COVID-19 is essential. X-ray scans are used in clinical studies to diagnose COVID-19 and Pneumonia early. For extracting the discriminative features through these modalities, deep convolutional neural networks (CNNs) are used. A siamese convolutional neural network model (COVID-3D-SCNN) is proposed in this study for the automated detection of COVID-19 by utilizing X-ray scans. To extract the useful features, we used three consecutive models working in parallel in the proposed approach. We acquired 575 COVID-19, 1200 non-COVID, and 1400 pneumonia images, which are publicly available. In our framework, augmentation is used to enlarge the dataset. The findings suggest that the proposed method outperforms the results of comparative studies in terms of accuracy 96.70%, specificity 95.55%, and sensitivity 96.62% over (COVID-19 vs. non-COVID19 vs. Pneumonia).     

面向网络社交媒体的少样本新冠谣言检测

在社交媒体上发布和传播有关新冠的谣言对民生、经济、社会等都产生了严重影响,因此通过机器学习和人工智能技术开展新冠谣言检测具有重要的研究价值和社会意义.现有谣言检测研究,一般假定进行建模和预测的事件已有充足的有标签数据,但对于新冠这类突发事件,由于可训练样本较少,所以此类模型存在局限性.该文聚焦少样本谣言检测问题,旨在使...     

结合深层密集聚合的新冠肺炎CT图像分类方法

新型冠状病毒肺炎在全球范围迅速蔓延,为快速准确地对其诊断,进而阻断疫情传播链,提出一种基于深度学习的分类网络DLDA-A-DenseNet。首先将深层密集聚合结构与DenseNet-201结合,对不同阶段的特征信息聚合,以加强对病灶的识别及定位能力;其次提出高效多尺度长程注意力以细化聚合的特征;此外针对CT图像数据集类别不均衡问题,使用均衡抽样训练策略消除偏向性。在中国胸部CT图像调查研究会提供的数据集上测试,所提方法较原始DenseNet-201在准确率、召回率、精确率、F₁分数和Kappa系数提高了2.24%、3.09%、2.09%、2.60%和3.48%;并在COVID-CISet图像数据集上测试,取得99.50%的最优准确率。结果表明,对比其他方法,提出的新冠肺炎CT图像分类方法充分提取了CT切片的病灶特征,具有更高的精度和良好的泛化性。     

Leveraging Multimodal Ensemble Fusion-Based Deep Learning for COVID-19 on Chest Radiographs

Recently, COVID-19 has posed a challenging threat to researchers, scientists, healthcare professionals, and administrations over the globe, from its diagnosis to its treatment. The researchers are making persistent efforts to derive probable solutions for managing the pandemic in their areas. One of the widespread and effective ways to detect COVID-19 is to utilize radiological images comprising X-rays and computed tomography (CT) scans. At the same time, the recent advances in machine learning (ML) and deep learning (DL) models show promising results in medical imaging. Particularly, the convolutional neural network (CNN) model can be applied to identifying abnormalities on chest radiographs. While the epidemic of COVID-19, much research is led on processing the data compared with DL techniques, particularly CNN. This study develops an improved fruit fly optimization with a deep learning-enabled fusion (IFFO-DLEF) model for COVID-19 detection and classification. The major intention of the IFFO-DLEF model is to investigate the presence or absence of COVID-19. To do so, the presented IFFO-DLEF model applies image pre-processing at the initial stage. In addition, the ensemble of three DL models such as DenseNet169, EfficientNet, and ResNet50, are used for feature extraction. Moreover, the IFFO algorithm with a multilayer perceptron (MLP) classification model is utilized to identify and classify COVID-19. The parameter optimization of the MLP approach utilizing the IFFO technique helps in accomplishing enhanced classification performance. The experimental result analysis of the IFFO-DLEF model carried out on the CXR image database portrayed the better performance of the presented IFFO-DLEF model over recent approaches.     

基于深度残差胶囊网络与注意力机制的加密流量识别方法

随着用户安全意识的提高和加密技术的发展,加密流量已经成为网络流量中的重要部分,识别加密流量成为网络流量监管的重要部分。基于传统深度学习模型的加密流量识别方法存在效果差、模型训练时间长等问题。针对上述问题,提出了一种基于深度残差胶囊网络模型（DRCN,deep residual capsule network）的加密流量识别方法。原始胶囊网络通过全连接形式堆叠导致模型耦合系数变小,无法搭建深层网络模型。针对上述问题,DRCN模型采用三维卷积算法（3DCNN）动态路由算法代替全连接动态路由算法,减少了每个胶囊层之间传递的参数,降低了运算复杂度,进而构建深层胶囊网络,提高识别的准确率和效率;引入通道注意力机制为不同的特征赋予不同的权重,减少无用特征对识别结果的影响,进一步增强模型特征提取能力;将残差网络引入胶囊网络层,搭建残差胶囊网络模块缓解了深度胶囊网络的梯度消失问题。在数据预处理方面,截取的数据包前784byte,将截取的字节转化成图像输入到DRCN模型中,该方法避免了人工特征提取,减少了加密流量识别的人工成本。在ISCXVPN2016数据集上的实验结果表明,与效果最好的BLSTM模型相比,DRCN模型的准确率提高了5.54%,模型的训练时间缩短了232s。此外,在小数据集上,DRCN模型准确率达到了94.3%。上述实验结果证明,所提出的识别方案具有较高的识别率、良好的性能和适用性。     

基于深度学习的COVID-19智能诊断系统

本研究旨在探索运用深度学习的方法辅助医生利用胸部X光片进行COVID-19诊断的可行性和准确性。首先利用公开的COVID-QU-Ex Dataset训练集训练一个UNet分割模型,实现肺部ROI区域的自动分割。其次完成对该公共数据集肺部区域的自动提取预处理。再次利用预处理后的三分类影像数据（新冠肺炎、其它肺炎、正常）采用迁移学习的方式训练了一个分类模型MBCA-COVIDNET,该模型以MobileNetV2作为骨干网络,并在其中加入坐标注意力机制（CA）。最后利用训练好的模型和Hugging Face开源软件搭建了一套方便医生使用的COVID-19智能辅助诊断系统。该模型在COVID-QU-Ex Dataset测试集上取得了高达97.98%的准确率,而该模型的参数量和MACs仅有2.23M和0.33G,易于在硬件设备上进行部署。该智能诊断系统能够很好的辅助医生进行基于胸片的COVID-19诊断,提升诊断的准确率以及诊断效率。     

COVID-19医学影像数据集及研究进展

由于影像学技术在新型冠状病毒肺炎（COVID-19）的诊断和评估中发挥了重要作用,COVID-19相关数据集陆续被公布,但目前针对相关文献中数据集以及研究进展的整理相对较少。为此,通过COVID-19相关的期刊论文、报告和相关开源数据集网站,对涉及到的新冠肺炎数据集及深度学习模型进行整理和分析,包括计算机断层扫描（CT）图像数据集和X射线（CXR）图像数据集。对这些数据集呈现的医学影像的特征进行分析;重点论述开源数据集,以及在相关数据集上表现较好的分类和分割模型。最后讨论了肺部影像学技术未来的发展趋势。     

多任务自主学习的肺癌诊断方法

针对实际任务中肺部CT图像标注数据集稀少的问题,提出一种基于自主学习的U-Net模型与C3D多任务学习网络相结合的肺癌诊断方法。对LUNA16数据集和DSB数据集进行预处理,确保切片图像体素、方向一致,利用C3D多任务学习网络模型构建肺结节检测模型,使用165张LUNA16的切片图像和161张DSB的切片图像训练改进的U-Net网络模型,并采用自主学习方式扩充标注样本,构建肿块检测模型。在此基础上,综合结节与肿块检测结果得到最终的肺癌诊断结果。实验结果表明,该方法的肺癌检测精度为85.3%±0.3%,达到了监督学习策略的检测精度。     

X-Ray Covid-19 Detection Based on Scatter Wavelet Transform and Dense Deep Neural Network

Notwithstanding the discovery of vaccines for Covid-19, the virus's rapid spread continues due to the limited availability of vaccines, especially in poor and emerging countries. Therefore, the key issues in the present COVID-19 pandemic are the early identification of COVID-19, the cautious separation of infected cases at the lowest cost and curing the disease in the early stages. For that reason, the methodology adopted for this study is imaging tools, particularly computed tomography, which have been critical in diagnosing and treating the disease. A new method for detecting Covid-19 in X-rays and CT images has been presented based on the Scatter Wavelet Transform and Dense Deep Neural Network. The Scatter Wavelet Transform has been employed as a feature extractor, while the Dense Deep Neural Network is utilized as a binary classifier. An extensive experiment was carried out to evaluate the accuracy of the proposed method over three datasets: IEEE 80200, Kaggle, and Covid-19 X-ray image data Sets. The dataset used in the experimental part consists of 14142. The numbers of training and testing images are 8290 and 2810, respectively. The analysis of the result refers that the proposed methods achieved high accuracy of 98%. The proposed model results show an excellent outcome compared to other methods in the same domain, such as (DeTraC) CNN, which achieved only 93.1%, CNN, which achieved 94%, and stacked Multi-Resolution CovXNet, which achieved 97.4%. The accuracy of CapsNet reached 97.24%.     

COVID-19肺部CT图像多尺度编解码分割

目的 新型冠状病毒肺炎(corona virus disease 2019, COVID-19)患者肺部计算机断层扫描(computed tomography, CT)图像具有明显的病变特征,快速而准确地从患者肺部CT图像中分割出病灶部位,对COVID-19患者快速诊断和监护具有重要意义。COVID-19肺炎病灶区域复杂多变,现有方法分割精度不高,且对假阴性的关注不够,导致分割结果往往具有较高的特异度,但灵敏度却很低。方法 本文提出了一个基于深度学习的多尺度编解码网络(MED-Net(multiscale encode decode network)),该网络采用资源利用率高、计算速度快的HarDNet68(harmonic densely connected network)作为主干,它主要由5个harmonic dense block(HDB)组成,首先通过5个空洞空间卷积池化金字塔(atrous spatial pyramid pooling, ASPP)对HarDNet68的第1个卷积层和第1、3、4、5个HDB提取多尺度特征。接着在并行解码器(paralleled parti...     

Real-time COVID-19 detection over chest x-ray images in edge computing

Severe Coronavirus Disease 2019 (COVID-19) has been a global pandemic which provokes massive devastation to the society, economy, and culture since January 2020. The pandemic demonstrates the inefficiency of superannuated manual detection approaches and inspires novel approaches that detect COVID-19 by classifying chest x-ray (CXR) images with deep learning technology. Although a wide range of researches about bran-new COVID-19 detection methods that classify CXR images with centralized convolutional neural network (CNN) models have been proposed, the latency, privacy, and cost of information transmission between the data resources and the centralized data center will make the detection inefficient. Hence, in this article, a COVID-19 detection scheme via CXR images classification with a lightweight CNN model called MobileNet in edge computing is proposed to alleviate the computing pressure of centralized data center and ameliorate detection efficiency. Specifically, the general framework is introduced first to manifest the overall arrangement of the computing and information services ecosystem. Then, an unsupervised model DCGAN is employed to make up for the small scale of data set. Moreover, the implementation of the MobileNet for CXR images classification is presented at great length. The specific distribution strategy of MobileNet models is followed. The extensive evaluations of the experiments demonstrate the efficiency and accuracy of the proposed scheme for detecting COVID-19 over CXR images in edge computing.     

FaNet: fast assessment network for the novel coronavirus (COVID-19) pneumonia based on 3D CT imaging and clinical symptoms

The novel coronavirus (COVID-19) pneumonia has become a serious health challenge in countries worldwide. Many radiological findings have shown that X-ray and CT imaging scans are an effective solution to assess disease severity during the early stage of COVID-19. Many artificial intelligence (AI)-assisted diagnosis works have rapidly been proposed to focus on solving this classification problem and determine whether a patient is infected with COVID-19. Most of these works have designed networks and applied a single CT image to perform classification; however, this approach ignores prior information such as the patient’s clinical symptoms. Second, making a more specific diagnosis of clinical severity, such as slight or severe, is worthy of attention and is conducive to determining better follow-up treatments. In this paper, we propose a deep learning (DL) based dual-tasks network, named FaNet, that can perform rapid both diagnosis and severity assessments for COVID-19 based on the combination of 3D CT imaging and clinical symptoms. Generally, 3D CT image sequences provide more spatial information than do single CT images. In addition, the clinical symptoms can be considered as prior information to improve the assessment accuracy; these symptoms are typically quickly and easily accessible to radiologists. Therefore, we designed a network that considers both CT image information and existing clinical symptom information and conducted experiments on 416 patient data, including 207 normal chest CT cases and 209 COVID-19 confirmed ones. The experimental results demonstrate the effectiveness of the additional symptom prior information as well as the network architecture designing. The proposed FaNet achieved an accuracy of 98.28% on diagnosis assessment and 94.83% on severity assessment for test datasets. In the future, we will collect more covid-CT patient data and seek further improvement.

     

融合多头注意力机制的新冠肺炎联合诊断与分割

目的 新冠肺炎疫情席卷全球,为快速诊断肺炎患者,确认患者肺部感染区域,大量检测网络相继提出,但现有网络大多只能处理一种任务,即诊断或分割。本文提出了一种融合多头注意力机制的联合诊断与分割网络,能同时完成X线胸片的肺炎诊断分类和新冠感染区分割。方法 整个网络由3部分组成,双路嵌入层通过两种不同的图像嵌入方式分别提取X线胸片的浅层直观特征和深层抽象特征;Transformer模块综合考虑提取到的浅层直观与深层抽象特征;分割解码器扩大特征图以输出分割区域。为响应联合训练,本文使用了一种混合损失函数以动态平衡分类与分割的训练。分类损失定义为分类对比损失与交叉熵损失的和;分割损失是二分类的交叉熵损失。结果 基于6个公开数据集的合并数据实验结果表明,所提网络取得了95.37%的精度、96.28%的召回率、95.95%的F1指标和93.88%的kappa系数,诊断分类性能超过了主流的ResNet50、VGG16(Visual Geometry Group)和Inception＿v3等网络;在新冠病灶分割表现上,相比流行的U-Net及其改进网络,取得最高的精度(95.96%),优异的敏感度(78.89...     

Prediction of Covid-19 Based on Chest X-Ray Images Using Deep Learning with CNN

The COVID-19 pandemic has caused trouble in people’s daily lives and ruined several economies around the world, killing millions of people thus far. It is essential to screen the affected patients in a timely and cost-effective manner in order to fight this disease. This paper presents the prediction of COVID-19 with Chest X-Ray images, and the implementation of an image processing system operated using deep learning and neural networks. In this paper, a Deep Learning, Machine Learning, and Convolutional Neural Network-based approach for predicting Covid-19 positive and normal patients using Chest X-Ray pictures is proposed. In this study, machine learning tools such as TensorFlow were used for building and training neural nets. Scikit-learn was used for machine learning from end to end. Various deep learning features are used, such as Conv2D, Dense Net, Dropout, Maxpooling2D for creating the model. The proposed approach had a classification accuracy of 96.43 percent and a validation accuracy of 98.33 percent after training and testing the X-Ray pictures. Finally, a web application has been developed for general users, which will detect chest x-ray images either as covid or normal. A GUI application for the Covid prediction framework was run. A chest X-ray image can be browsed and fed into the program by medical personnel or the general public.     

基于预训练-微调策略的COVID-19预测模型

COVID-19的世界性大流行对整个社会产生了严重的影响,通过数学建模对确诊病例数进行预测将有助于为公共卫生决策提供依据。在复杂多变的外部环境下,基于深度学习的传染病预测模型成为研究热点。然而,现有模型对数据量要求较高,在进行监督学习时不能很好地适应低数据量的场景,导致预测精度降低。构建结合预训练-微调策略的COVID-19预测模型P-GRU。通过在源地区数据集上采用预训练策略,使模型提前获得更多的疫情数据,从而学习到COVID-19的隐式演变规律,为模型预测提供更充分的先验知识,同时使用包含最近历史信息的固定长度序列预测后续时间点的确诊病例数,并在预测过程中考虑本地人为限制政策因素对疫情趋势的影响,实现针对目标地区数据集的精准预测。实验结果表明,预训练策略能够有效提高预测性能,相比于卷积神经网络、循环神经网络、长短期记忆网络和门控循环单元模型,P-GRU模型在平均绝对百分比误差和均方根误差评价指标上表现优异,更适合用于预测COVID-19传播趋势。