transfer learning

迁移学习
  • 文章类型: Journal Article
    技术提供了许多潜力,可用于提高基础设施的完整性和效率。裂缝是可能影响任何结构的完整性或可用性的主要问题之一。通常,使用手动检查方法会导致延误,从而使情况恶化。自动化裂缝检测对于关键基础设施的有效管理和检查已经变得非常必要。先前的裂缝检测研究采用了基于深度卷积神经网络(DCNN)的分类和定位模型。这项研究提出并比较了转移学习的DCNN作为分类模型和特征提取器来克服这一限制的裂缝检测的有效性。本文的主要目的是介绍表面裂纹检测的各种方法,并在3个不同的数据集上比较它们的性能。在这项工作中进行的实验有三个方面:最初,在三个公开可用的数据集上分析了12个转移学习的DCNN模型对裂缝检测的有效性:SDNET,CCIC和BSD。精度为53.40%,ResNet101在SDNET数据集上的性能优于其他模型。EfficientNetB0是BSD数据集上最准确(98.8%)的模型,ResNet50在CCIC数据集上表现更好,准确率为99.8%。其次,采用两种图像增强方法来增强图像,并在12个DCNN上进行学习,以提高SDNET数据集的性能。实验结果表明,增强后的图像显着提高了转移学习裂纹检测模型的准确性。此外,从DCNN的最后一个完全连接层提取的深层特征用于训练支持向量机(SVM)。深度特征与SVM的集成提高了所有DCNN数据集组合的检测精度,根据准确性分析,精度,召回,和F1得分。
    Technology offers a lot of potential that is being used to improve the integrity and efficiency of infrastructures. Crack is one of the major concerns that can affect the integrity or usability of any structure. Oftentimes, the use of manual inspection methods leads to delays which can worsen the situation. Automated crack detection has become very necessary for efficient management and inspection of critical infrastructures. Previous research in crack detection employed classification and localization-based models using Deep Convolutional Neural Networks (DCNNs). This study suggests and compares the effectiveness of transfer learned DCNNs for crack detection as a classification model and as a feature extractor to overcome this restriction. The main objective of this paper is to present various methods of crack detection on surfaces and compare their performance over 3 different datasets. Experiments conducted in this work are threefold: initially, the effectiveness of 12 transfer learned DCNN models for crack detection is analyzed on three publicly available datasets: SDNET, CCIC and BSD. With an accuracy of 53.40%, ResNet101 outperformed other models on the SDNET dataset. EfficientNetB0 was the most accurate (98.8%) model on the BSD dataset, and ResNet50 performed better with an accuracy of 99.8% on the CCIC dataset. Secondly, two image enhancement methods are employed to enhance the images and are transferred learned on the 12 DCNNs in pursuance of improving the performance of the SDNET dataset. The results from the experiments show that the enhanced images improved the accuracy of transfer-learned crack detection models significantly. Furthermore, deep features extracted from the last fully connected layer of the DCNNs are used to train the Support Vector Machine (SVM). The integration of deep features with SVM enhanced the detection accuracy across all the DCNN-dataset combinations, according to analysis in terms of accuracy, precision, recall, and F1-score.
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  • 文章类型: Journal Article
    背景:大型语言模型(LLM)具有支持健康信息学中有前途的新应用的潜力。然而,缺乏在生物医学和卫生政策背景下对LLM进行微调以执行特定任务的样本量考虑因素的实际数据。
    目的:本研究旨在评估用于微调LLM的样本量和样本选择技术,以支持针对利益冲突披露声明的自定义数据集的改进的命名实体识别(NER)。
    方法:随机抽取200份披露声明进行注释。所有“人员”和“ORG”实体均由2个评估者识别,一旦建立了适当的协议,注释者独立地注释了另外290个公开声明。从490个注释文档中,抽取了2500个不同大小范围的分层随机样本。2500个训练集子样本用于在2个模型架构(来自变压器[BERT]和生成预训练变压器[GPT]的双向编码器表示)中微调语言模型的选择,以改善NER。多元回归用于评估样本量(句子)之间的关系,实体密度(每个句子的实体[EPS]),和训练的模型性能(F1分数)。此外,单预测阈值回归模型用于评估增加样本量或实体密度导致边际收益递减的可能性。
    结果:在架构中,微调模型的顶线NER性能从F1分数=0.79到F1分数=0.96不等。双预测多元线性回归模型的多重R2在0.6057~0.7896之间有统计学意义(均P<.001)。在所有情况下,EPS和句子数是F1得分的显著预测因子(P<.001),除了GPT-2_large模型,其中每股收益不是显著的预测因子(P=0.184)。模型阈值表示由增加的训练数据集样本量(以句子的数量衡量)的边际收益递减点,点估计范围从RoBERTa_large的439个句子到GPT-2_large的527个句子。同样,阈值回归模型表明每股收益的边际收益递减,点估计在1.36和1.38之间。
    结论:相对适度的样本量可用于微调适用于生物医学文本的NER任务的LLM,和训练数据实体密度应代表性地近似生产数据中的实体密度。训练数据质量和模型架构的预期用途(文本生成与文本处理或分类)可能是,或更多,重要的是训练数据量和模型参数大小。
    BACKGROUND: Large language models (LLMs) have the potential to support promising new applications in health informatics. However, practical data on sample size considerations for fine-tuning LLMs to perform specific tasks in biomedical and health policy contexts are lacking.
    OBJECTIVE: This study aims to evaluate sample size and sample selection techniques for fine-tuning LLMs to support improved named entity recognition (NER) for a custom data set of conflicts of interest disclosure statements.
    METHODS: A random sample of 200 disclosure statements was prepared for annotation. All \"PERSON\" and \"ORG\" entities were identified by each of the 2 raters, and once appropriate agreement was established, the annotators independently annotated an additional 290 disclosure statements. From the 490 annotated documents, 2500 stratified random samples in different size ranges were drawn. The 2500 training set subsamples were used to fine-tune a selection of language models across 2 model architectures (Bidirectional Encoder Representations from Transformers [BERT] and Generative Pre-trained Transformer [GPT]) for improved NER, and multiple regression was used to assess the relationship between sample size (sentences), entity density (entities per sentence [EPS]), and trained model performance (F1-score). Additionally, single-predictor threshold regression models were used to evaluate the possibility of diminishing marginal returns from increased sample size or entity density.
    RESULTS: Fine-tuned models ranged in topline NER performance from F1-score=0.79 to F1-score=0.96 across architectures. Two-predictor multiple linear regression models were statistically significant with multiple R2 ranging from 0.6057 to 0.7896 (all P<.001). EPS and the number of sentences were significant predictors of F1-scores in all cases ( P<.001), except for the GPT-2_large model, where EPS was not a significant predictor (P=.184). Model thresholds indicate points of diminishing marginal return from increased training data set sample size measured by the number of sentences, with point estimates ranging from 439 sentences for RoBERTa_large to 527 sentences for GPT-2_large. Likewise, the threshold regression models indicate a diminishing marginal return for EPS with point estimates between 1.36 and 1.38.
    CONCLUSIONS: Relatively modest sample sizes can be used to fine-tune LLMs for NER tasks applied to biomedical text, and training data entity density should representatively approximate entity density in production data. Training data quality and a model architecture\'s intended use (text generation vs text processing or classification) may be as, or more, important as training data volume and model parameter size.
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  • 文章类型: Journal Article
    目的:深度学习可以在放射治疗中自动化描绘,减少时间和可变性。然而,它的功效因不同机构而异,扫描仪,或设置,强调在临床环境中需要适应性强的模型。我们的研究证明了迁移学习(TL)方法在增强深度学习模型在宫颈近距离放射治疗中对危险器官(OAR)进行自动分割的泛化性方面的有效性。
    方法:在3T磁共振(MR)扫描仪(RT3)上使用环形和串联涂药器进行120次扫描,开发了预训练模型。对四个OAR进行了分段和评估。分割性能通过体积骰子相似系数(vDSC)进行评估,95%Hausdorff距离(HD95),表面DSC,并添加路径长度(APL)。该模型在三个分布外的目标群体上进行了微调。前和后TL结果,以及微调扫描次数的影响,进行了比较。在观察到的和未观察到的数据分布上评估用一组训练的模型(单个)和用所有四组训练的模型(混合)。
    结果:TL提高了目标群体的分割精度,匹配预训练模型的性能。前五次微调扫描导致了最明显的改进,随着更多数据的增加,性能趋于稳定。在给定相同的训练数据的情况下,TL的性能优于从头开始训练。混合模型在RT3扫描上的表现类似于单一模型,但在看不见的数据上表现出卓越的性能。
    结论:TL可以提高MR引导的颈椎近距离放射治疗中OAR分割模型的普适性,需要较少的微调数据和减少的训练时间。这些结果为开发适应临床环境的适应性模型提供了基础。
    OBJECTIVE: Deep learning can automate delineation in radiation therapy, reducing time and variability. Yet, its efficacy varies across different institutions, scanners, or settings, emphasizing the need for adaptable and robust models in clinical environments. Our study demonstrates the effectiveness of the transfer learning (TL) approach in enhancing the generalizability of deep learning models for auto-segmentation of organs-at-risk (OARs) in cervical brachytherapy.
    METHODS: A pre-trained model was developed using 120 scans with ring and tandem applicator on a 3T magnetic resonance (MR) scanner (RT3). Four OARs were segmented and evaluated. Segmentation performance was evaluated by Volumetric Dice Similarity Coefficient (vDSC), 95 % Hausdorff Distance (HD95), surface DSC, and Added Path Length (APL). The model was fine-tuned on three out-of-distribution target groups. Pre- and post-TL outcomes, and influence of number of fine-tuning scans, were compared. A model trained with one group (Single) and a model trained with all four groups (Mixed) were evaluated on both seen and unseen data distributions.
    RESULTS: TL enhanced segmentation accuracy across target groups, matching the pre-trained model\'s performance. The first five fine-tuning scans led to the most noticeable improvements, with performance plateauing with more data. TL outperformed training-from-scratch given the same training data. The Mixed model performed similarly to the Single model on RT3 scans but demonstrated superior performance on unseen data.
    CONCLUSIONS: TL can improve a model\'s generalizability for OAR segmentation in MR-guided cervical brachytherapy, requiring less fine-tuning data and reduced training time. These results provide a foundation for developing adaptable models to accommodate clinical settings.
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  • 文章类型: Journal Article
    影子,由于没有光导致的自然现象,在农业中起着举足轻重的作用,特别是在植物光合作用等过程中。尽管有通用影子数据集,许多人遭受注释错误,并且缺乏内部可能存在人类活动的农业阴影的详细表示,不包括来自卫星或无人机视图的那些。在本文中,我们提供了一个综合生成的自上而下的阴影分割数据集的评估,其特征是逼真的渲染和精确的阴影掩模。我们的目标是确定其与现实世界数据集相比的功效,并评估注释质量和图像域等因素如何影响神经网络模型训练。要建立基线,我们训练了许多基线架构,随后使用各种免费的影子数据集探索了迁移学习。与其他阴影数据集的训练集相比,我们进一步评估了域外性能。我们的研究结果表明,AgroSegNet表现出竞争力,对迁移学习是有效的,特别是在类似于农业的领域。
    Shadow, a natural phenomenon resulting from the absence of light, plays a pivotal role in agriculture, particularly in processes such as photosynthesis in plants. Despite the availability of generic shadow datasets, many suffer from annotation errors and lack detailed representations of agricultural shadows with possible human activity inside, excluding those derived from satellite or drone views. In this paper, we present an evaluation of a synthetically generated top-down shadow segmentation dataset characterized by photorealistic rendering and accurate shadow masks. We aim to determine its efficacy compared to real-world datasets and assess how factors such as annotation quality and image domain influence neural network model training. To establish a baseline, we trained numerous baseline architectures and subsequently explored transfer learning using various freely available shadow datasets. We further evaluated the out-of-domain performance compared to the training set of other shadow datasets. Our findings suggest that AgroSegNet demonstrates competitive performance and is effective for transfer learning, particularly in domains similar to agriculture.
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  • 文章类型: Journal Article
    结直肠癌(CRC)筛查和治疗的进展导致了前所未有的组织病理学诊断病例量。虽然人工智能(AI)提出了一个潜在的解决方案,主要强调幻灯片级聚集性能,而不彻底验证每个位置的癌症,阻碍了可解释性和透明度。有效解决这些挑战对于确保AI在组织学应用中的可靠性和有效性至关重要。
    在这项研究中,我们利用内窥镜检查中息肉分割模型的迁移学习,创建了一种创新的AI算法.该算法在整个幻灯片成像(WSI)的0.25mm²网格内精确定位CRC目标。我们以这种精细粒度评估了CRC检测能力,并检查了AI对病理学家诊断行为的影响。评估使用了广泛的数据集,包括858例连续患者病例,其中1418例WSI从外部中心获得。
    我们的结果强调了网格水平的90.25%的显着灵敏度和96.60%的特异性,伴随着0.962的曲线下面积(AUC)。这意味着在幻灯片水平上有令人印象深刻的99.39%的灵敏度,再加上<0.01的负似然比,表明人工智能系统的可靠性,以排除诊断考虑。正似然比为26.54,在网格级别超过10,强调了对任何AI生成的亮点进行细致审查的必要性。因此,所有4名参与研究的病理学家在AI辅助下表现出统计学上显著的诊断改善.
    我们的迁移学习方法已经成功地产生了一种可以在整个载玻片成像中验证CRC组织学定位的算法。结果主张将AI系统集成到组织病理学诊断中,作为诊断排除应用程序或计算机辅助检测(CADe)工具。这种整合有可能减轻病理学家的工作量并最终使患者受益。
    UNASSIGNED: The progress in Colorectal cancer (CRC) screening and management has resulted in an unprecedented caseload for histopathological diagnosis. While artificial intelligence (AI) presents a potential solution, the predominant emphasis on slide-level aggregation performance without thorough verification of cancer in each location, impedes both explainability and transparency. Effectively addressing these challenges is crucial to ensuring the reliability and efficacy of AI in histology applications.
    UNASSIGNED: In this study, we created an innovative AI algorithm using transfer learning from a polyp segmentation model in endoscopy. The algorithm precisely localized CRC targets within 0.25 mm² grids from whole slide imaging (WSI). We assessed the CRC detection capabilities at this fine granularity and examined the influence of AI on the diagnostic behavior of pathologists. The evaluation utilized an extensive dataset comprising 858 consecutive patient cases with 1418 WSIs obtained from an external center.
    UNASSIGNED: Our results underscore a notable sensitivity of 90.25% and specificity of 96.60% at the grid level, accompanied by a commendable area under the curve (AUC) of 0.962. This translates to an impressive 99.39% sensitivity at the slide level, coupled with a negative likelihood ratio of <0.01, signifying the dependability of the AI system to preclude diagnostic considerations. The positive likelihood ratio of 26.54, surpassing 10 at the grid level, underscores the imperative for meticulous scrutiny of any AI-generated highlights. Consequently, all four participating pathologists demonstrated statistically significant diagnostic improvements with AI assistance.
    UNASSIGNED: Our transfer learning approach has successfully yielded an algorithm that can be validated for CRC histological localizations in whole slide imaging. The outcome advocates for the integration of the AI system into histopathological diagnosis, serving either as a diagnostic exclusion application or a computer-aided detection (CADe) tool. This integration has the potential to alleviate the workload of pathologists and ultimately benefit patients.
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  • 文章类型: Journal Article
    深度学习深刻影响了各个领域,特别是医学图像分析。该领域的传统迁移学习方法依赖于在特定领域的医学数据集上预训练的模型,这限制了它们的通用性和可访问性。在这项研究中,我们提出了一个叫做真实世界特征迁移学习的新框架,它利用最初在大规模通用数据集如ImageNet上训练的骨干模型。与从头开始训练的模型相比,我们评估了这种方法的有效性和鲁棒性,专注于对X射线图像中的肺炎进行分类的任务。我们的实验,其中包括将灰度图像转换为RGB格式,证明了真实世界的特征迁移学习在各种性能指标上始终优于传统的训练方法。这一进步有可能通过利用从通用预训练模型学习的丰富特征表示来加速医学成像中的深度学习应用。所提出的方法克服了特定领域预训练模型的局限性,从而加速医疗诊断和医疗保健领域的创新。从数学的角度来看,我们形式化现实世界的特征迁移学习的概念,并提供了一个严格的数学公式的问题。我们的实验结果提供了支持这种方法有效性的经验证据,为进一步的理论分析和探索奠定基础。这项工作有助于更广泛地理解跨域的特征可转移性,并对开发准确有效的医学图像分析模型具有重要意义。即使在资源受限的环境中。
    Deep learning has profoundly influenced various domains, particularly medical image analysis. Traditional transfer learning approaches in this field rely on models pretrained on domain-specific medical datasets, which limits their generalizability and accessibility. In this study, we propose a novel framework called real-world feature transfer learning, which utilizes backbone models initially trained on large-scale general-purpose datasets such as ImageNet. We evaluate the effectiveness and robustness of this approach compared to models trained from scratch, focusing on the task of classifying pneumonia in X-ray images. Our experiments, which included converting grayscale images to RGB format, demonstrate that real-world-feature transfer learning consistently outperforms conventional training approaches across various performance metrics. This advancement has the potential to accelerate deep learning applications in medical imaging by leveraging the rich feature representations learned from general-purpose pretrained models. The proposed methodology overcomes the limitations of domain-specific pretrained models, thereby enabling accelerated innovation in medical diagnostics and healthcare. From a mathematical perspective, we formalize the concept of real-world feature transfer learning and provide a rigorous mathematical formulation of the problem. Our experimental results provide empirical evidence supporting the effectiveness of this approach, laying the foundation for further theoretical analysis and exploration. This work contributes to the broader understanding of feature transferability across domains and has significant implications for the development of accurate and efficient models for medical image analysis, even in resource-constrained settings.
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  • 文章类型: Journal Article
    这项研究的重点是开发基于运动图像(MI)的脑机接口(BMI),使用深度学习算法来控制下肢机器人外骨骼。该研究旨在通过利用深度学习的优势来克服传统BMI方法的局限性,如自动特征提取和迁移学习。评估BMI的实验方案设计为异步,允许受试者按照自己的意愿执行心理任务。
    共有5名身体健康的受试者参加了一系列实验。来自其中两个会话的大脑信号用于通过迁移学习开发通用的深度学习模型。随后,在剩余的课程中对该模型进行了微调,并进行了评估.比较了三种不同的深度学习方法:一种没有经过微调,另一个微调了模型的所有层,第三个只微调了最后三层。评估阶段涉及参与者使用第二种深度学习方法进行解码的神经活动对外骨骼设备的专有闭环控制。
    与基于每个受试者和实验阶段训练的空间特征的方法相比,对三种深度学习方法进行了评估。展示他们的卓越表现。有趣的是,没有微调的深度学习方法实现了与基于特征的方法相当的性能,这表明,在来自不同个体和以前会话的数据上训练的通用模型可以产生类似的效果。在三种深度学习方法中,进行了比较,微调所有层权重展示了最高的性能。
    这项研究代表了迈向未来免校准方法的第一步。尽管努力通过利用其他受试者的数据来减少校准时间,完全消除被证明是不可能实现的。这项研究的发现对推进无校准方法具有显著意义,承诺将培训试验的需求降至最低。此外,本研究中采用的实验评估方案旨在复制现实生活场景,在行走或停止步态等行为的决策中,给予参与者更高的自主权。
    This research focused on the development of a motor imagery (MI) based brain-machine interface (BMI) using deep learning algorithms to control a lower-limb robotic exoskeleton. The study aimed to overcome the limitations of traditional BMI approaches by leveraging the advantages of deep learning, such as automated feature extraction and transfer learning. The experimental protocol to evaluate the BMI was designed as asynchronous, allowing subjects to perform mental tasks at their own will.
    A total of five healthy able-bodied subjects were enrolled in this study to participate in a series of experimental sessions. The brain signals from two of these sessions were used to develop a generic deep learning model through transfer learning. Subsequently, this model was fine-tuned during the remaining sessions and subjected to evaluation. Three distinct deep learning approaches were compared: one that did not undergo fine-tuning, another that fine-tuned all layers of the model, and a third one that fine-tuned only the last three layers. The evaluation phase involved the exclusive closed-loop control of the exoskeleton device by the participants\' neural activity using the second deep learning approach for the decoding.
    The three deep learning approaches were assessed in comparison to an approach based on spatial features that was trained for each subject and experimental session, demonstrating their superior performance. Interestingly, the deep learning approach without fine-tuning achieved comparable performance to the features-based approach, indicating that a generic model trained on data from different individuals and previous sessions can yield similar efficacy. Among the three deep learning approaches compared, fine-tuning all layer weights demonstrated the highest performance.
    This research represents an initial stride toward future calibration-free methods. Despite the efforts to diminish calibration time by leveraging data from other subjects, complete elimination proved unattainable. The study\'s discoveries hold notable significance for advancing calibration-free approaches, offering the promise of minimizing the need for training trials. Furthermore, the experimental evaluation protocol employed in this study aimed to replicate real-life scenarios, granting participants a higher degree of autonomy in decision-making regarding actions such as walking or stopping gait.
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  • 文章类型: Journal Article
    我们在本文中提供了各种迁移学习策略和深度学习架构的综合比较,用于成人型弥漫性神经胶质瘤的计算机辅助分类。我们评估了组织病理学图像目标域的域外ImageNet表示的泛化性,并使用自监督和多任务学习方法研究域内适应的影响,以使用组织病理学图像的中型到大型数据集对模型进行预训练。还提出了一种半监督学习方法,其中微调模型用于预测整个幻灯片图像(WSI)的未注释区域的标签。随后使用上一步中确定的地面实况标签和弱标签对模型进行重新训练,与标准的域内迁移学习相比,提供了卓越的性能,平衡的准确率为96.91%,F1分数为97.07%,和最小化病理学家的注释的努力。最后,我们提供了一个在WSI级别工作的可视化工具,它生成突出肿瘤区域的热图;因此,为病理学家提供有关WSI信息最多的部分的见解。
    We provide in this paper a comprehensive comparison of various transfer learning strategies and deep learning architectures for computer-aided classification of adult-type diffuse gliomas. We evaluate the generalizability of out-of-domain ImageNet representations for a target domain of histopathological images, and study the impact of in-domain adaptation using self-supervised and multi-task learning approaches for pretraining the models using the medium-to-large scale datasets of histopathological images. A semi-supervised learning approach is furthermore proposed, where the fine-tuned models are utilized to predict the labels of unannotated regions of the whole slide images (WSI). The models are subsequently retrained using the ground-truth labels and weak labels determined in the previous step, providing superior performance in comparison to standard in-domain transfer learning with balanced accuracy of 96.91% and F1-score 97.07%, and minimizing the pathologist\'s efforts for annotation. Finally, we provide a visualization tool working at WSI level which generates heatmaps that highlight tumor areas; thus, providing insights to pathologists concerning the most informative parts of the WSI.
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  • 文章类型: Journal Article
    X射线散射显着影响锥形束计算机断层扫描(CBCT)的图像质量。尽管卷积神经网络(CNN)在校正X射线散射方面表现出了希望,它们的有效性受到两个主要挑战的阻碍:大量数据集的必要性和模型泛化的不确定性。本研究引入了一种基于任务的范式来克服这些障碍,增强CNN在散射校正中的应用。
    使用带有U网架构的CNN,所提出的方法采用两阶段训练过程在CBCT扫描中进行散射校正。最初,CNN通过几何幻影投影对大约4000个图像对进行预训练,然后使用迁移学习(TL)对250对拟人化投影进行微调,以最少的数据实现特定任务的适应。来自投影数据的2D散射比(SR)图被认为是CNN目标,这样的地图被用来进行散射预测。特定成像任务的微调过程,比如头颈部成像,涉及模拟拟人化体模的扫描并预处理数据以进行CNN再训练。
    对于预训练阶段,观察到SR预测相当准确(SSIM≥0.9).在TL,SR预测的准确性进一步提高。与训练前的数据集相比,再训练时间相对较短(比预训练快约70倍),并且使用的样本要少得多(约小12倍)。
    开发了一种快速且低成本的方法,用于生成针对CBCT中散射校正的特定任务CNN。用所提出的方法训练的CNN模型成功地校正了拟人结构中的X射线散射,网络未知,用于模拟数据。
    UNASSIGNED: X-ray scatter significantly affects the image quality of cone beam computed tomography (CBCT). Although convolutional neural networks (CNNs) have shown promise in correcting x-ray scatter, their effectiveness is hindered by two main challenges: the necessity for extensive datasets and the uncertainty regarding model generalizability. This study introduces a task-based paradigm to overcome these obstacles, enhancing the application of CNNs in scatter correction.
    UNASSIGNED: Using a CNN with U-net architecture, the proposed methodology employs a two-stage training process for scatter correction in CBCT scans. Initially, the CNN is pre-trained on approximately 4000 image pairs from geometric phantom projections, then fine-tuned using transfer learning (TL) on 250 image pairs of anthropomorphic projections, enabling task-specific adaptations with minimal data. 2D scatter ratio (SR) maps from projection data were considered as CNN targets, and such maps were used to perform the scatter prediction. The fine-tuning process for specific imaging tasks, like head and neck imaging, involved simulating scans of an anthropomorphic phantom and pre-processing the data for CNN retraining.
    UNASSIGNED: For the pre-training stage, it was observed that SR predictions were quite accurate (SSIM≥0.9). The accuracy of SR predictions was further improved after TL, with a relatively short retraining time (≈70 times faster than pre-training) and using considerably fewer samples compared to the pre-training dataset (≈12 times smaller).
    UNASSIGNED: A fast and low-cost methodology to generate task-specific CNN for scatter correction in CBCT was developed. CNN models trained with the proposed methodology were successful to correct x-ray scatter in anthropomorphic structures, unknown to the network, for simulated data.
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  • 文章类型: Multicenter Study
    本研究旨在利用常规影像组学和迁移学习特征,建立有效的乳腺肿瘤超声图像良恶性分类模型。我们与当地医院合作,收集了一个基本数据集(DatasetA),该数据集包含1050例患者的单病灶2D超声图像,共发生良性肿瘤593例,恶性肿瘤357例。实验方法包括三个主要部分:传统的影像组学,迁移学习,和特征融合。此外,我们利用从数据集B和C获得的多中心数据评估了模型的可推广性。常规影像组学的结果表明,SVM分类器达到了0.791的最高平衡精度,而XGBoost获得了0.854的最高AUC。对于迁移学习,我们从ResNet50,Inception-v3,DenseNet121,MNASNet中提取了深层特征,和MobileNet。在这些模型中,MNASNet,具有640维的深层特征,产生了最佳性能,平衡的准确性为0.866,AUC为0.937,灵敏度为0.819,特异性为0.913。在特征融合阶段,我们训练了SVM,ExtraTrees,XGBoost,和具有早期融合功能的LightGBM,并通过加权投票对其进行评估。该方法实现了0.964的最高平衡精度和0.981的AUC。与使用个体特征进行乳腺肿瘤超声图像分类相比,将常规影像组学和迁移学习特征相结合具有明显的优势。这种自动诊断模型可以减轻患者负担,并为放射科医生提供额外的诊断支持。该模型的性能鼓励了该领域未来的前瞻性研究。
    This study aims to establish an effective benign and malignant classification model for breast tumor ultrasound images by using conventional radiomics and transfer learning features. We collaborated with a local hospital and collected a base dataset (Dataset A) consisting of 1050 cases of single lesion 2D ultrasound images from patients, with a total of 593 benign and 357 malignant tumor cases. The experimental approach comprises three main parts: conventional radiomics, transfer learning, and feature fusion. Furthermore, we assessed the model\'s generalizability by utilizing multicenter data obtained from Datasets B and C. The results from conventional radiomics indicated that the SVM classifier achieved the highest balanced accuracy of 0.791, while XGBoost obtained the highest AUC of 0.854. For transfer learning, we extracted deep features from ResNet50, Inception-v3, DenseNet121, MNASNet, and MobileNet. Among these models, MNASNet, with 640-dimensional deep features, yielded the optimal performance, with a balanced accuracy of 0.866, AUC of 0.937, sensitivity of 0.819, and specificity of 0.913. In the feature fusion phase, we trained SVM, ExtraTrees, XGBoost, and LightGBM with early fusion features and evaluated them with weighted voting. This approach achieved the highest balanced accuracy of 0.964 and AUC of 0.981. Combining conventional radiomics and transfer learning features demonstrated clear advantages over using individual features for breast tumor ultrasound image classification. This automated diagnostic model can ease patient burden and provide additional diagnostic support to radiologists. The performance of this model encourages future prospective research in this domain.
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