深度学习模型正在应用于越来越多的成功案例中,但是他们在现实世界中的表现如何?为了测试模型,组装了特定的清洁数据集。但是,当部署在现实世界中时,该模型将面临意外的分布(OOD)数据。在这项工作中,我们表明所谓的“放射科医生级” Chexnet模型未能识别所有OOD图像,并将其归类为肺部疾病。为了解决这个问题,我们提出了分发投票,这是一种对多标签分类的分布图像进行分类的新方法。使用在ID和OOD数据上训练的独立课程分布(ID)预测指标,我们平均达到99%的ID分类特异性和98%的敏感性,与胸部上以前的作品相比,端到端的性能显着提高X射线14个数据集。即使仅用ImageNet作为OOD数据训练并使用X射线OOD图像进行测试,我们的方法即使仅用Imagenet进行训练,也超过了其他基于输出的OOD检测器。
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Commonly used AI networks are very self-confident in their predictions, even when the evidence for a certain decision is dubious. The investigation of a deep learning model output is pivotal for understanding its decision processes and assessing its capabilities and limitations. By analyzing the distributions of raw network output vectors, it can be observed that each class has its own decision boundary and, thus, the same raw output value has different support for different classes. Inspired by this fact, we have developed a new method for out-of-distribution detection. The method offers an explanatory step beyond simple thresholding of the softmax output towards understanding and interpretation of the model learning process and its output. Instead of assigning the class label of the highest logit to each new sample presented to the network, it takes the distributions over all classes into consideration. A probability score interpreter (PSI) is created based on the joint logit values in relation to their respective correct vs wrong class distributions. The PSI suggests whether the sample is likely to belong to a specific class, whether the network is unsure, or whether the sample is likely an outlier or unknown type for the network. The simple PSI has the benefit of being applicable on already trained networks. The distributions for correct vs wrong class for each output node are established by simply running the training examples through the trained network. We demonstrate our OOD detection method on a challenging transmission electron microscopy virus image dataset. We simulate a real-world application in which images of virus types unknown to a trained virus classifier, yet acquired with the same procedures and instruments, constitute the OOD samples.
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我们考虑使用深度神经网络时检测到(分发外)输入数据的问题,并提出了一种简单但有效的方法来提高几种流行的ood检测方法对标签换档的鲁棒性。我们的作品是通过观察到的,即大多数现有的OOD检测算法考虑整个训练/测试数据,无论每个输入激活哪个类进入(级别差异)。通过广泛的实验,我们发现这种做法导致探测器,其性能敏感,易于标记换档。为了解决这个问题,我们提出了一种类别的阈值方案,可以适用于大多数现有的OOD检测算法,并且即使在测试分布的标签偏移存在下也可以保持相似的OOD检测性能。
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In this era of pandemic, the future of healthcare industry has never been more exciting. Artificial intelligence and machine learning (AI & ML) present opportunities to develop solutions that cater for very specific needs within the industry. Deep learning in healthcare had become incredibly powerful for supporting clinics and in transforming patient care in general. Deep learning is increasingly being applied for the detection of clinically important features in the images beyond what can be perceived by the naked human eye. Chest X-ray images are one of the most common clinical method for diagnosing a number of diseases such as pneumonia, lung cancer and many other abnormalities like lesions and fractures. Proper diagnosis of a disease from X-ray images is often challenging task for even expert radiologists and there is a growing need for computerized support systems due to the large amount of information encoded in X-Ray images. The goal of this paper is to develop a lightweight solution to detect 14 different chest conditions from an X ray image. Given an X-ray image as input, our classifier outputs a label vector indicating which of 14 disease classes does the image fall into. Along with the image features, we are also going to use non-image features available in the data such as X-ray view type, age, gender etc. The original study conducted Stanford ML Group is our base line. Original study focuses on predicting 5 diseases. Our aim is to improve upon previous work, expand prediction to 14 diseases and provide insight for future chest radiography research.
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准确地检测出具有不同语义和协变量转移相对于分布的数据(ID)数据的分布外(OOD)数据对于部署安全可靠的模型至关重要。当处理高度结果应用(例如医学成像,自动驾驶汽车等)时,情况尤其如此。目的是设计一个可以接受ID数据有意义变化的检测器,同时还拒绝了OOD制度的示例。在实践中,可以通过使用适当的评分函数(例如能量)来实现一致性来实现此双重目标,并校准检测器以拒绝一组策划的OOD数据(称为离群曝光或不久的OE)。尽管OE方法被广泛采用,但由于现实世界情景的不可预测性,组装代表性的OOD数据集既昂贵又具有挑战性,因此最新设计了无OE探测器的趋势。在本文中,我们做出了一个令人惊讶的发现,即控制对ID变化的概括和暴露于不同(合成)异常值的示例对于同时改善语义和模态转移检测至关重要。与现有方法相反,我们的方法样本在潜在空间中嵌入式体系,并通过负数据扩展构建异常示例。通过一项关于医学成像基准(MedMnist,ISIC2019和NCT)的严格实证研究,我们在语义和模态转移下的现有无OE,OOD检测方法上表现出显着的性能增长(AUROC中的15美元\%-35 \%$)。
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检测到分布输入对于在现实世界中安全部署机器学习模型至关重要。然而,已知神经网络遭受过度自信的问题,在该问题中,它们对分布和分布的输入的信心异常高。在这项工作中,我们表明,可以通过在训练中实施恒定的向量规范来通过logit归一化(logitnorm)(logitnorm)来缓解此问题。我们的方法是通过分析的激励,即logit的规范在训练过程中不断增加,从而导致过度自信的产出。因此,LogitNorm背后的关键思想是将网络优化期间输出规范的影响解散。通过LogitNorm培训,神经网络在分布数据和分布数据之间产生高度可区分的置信度得分。广泛的实验证明了LogitNorm的优势,在公共基准上,平均FPR95最高为42.30%。
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在过去的几年中,卷积神经网络(CNN)占据了计算机视野的领域,这要归功于它们提取功能及其在分类问题中出色的表现,例如在自动分析X射线中。不幸的是,这些神经网络被认为是黑盒算法,即不可能了解该算法如何实现最终结果。要将这些算法应用于不同领域并测试方法论的工作原理,我们需要使用可解释的AI技术。医学领域的大多数工作都集中在二进制或多类分类问题上。但是,在许多现实生活中,例如胸部X射线射线,可以同时出现不同疾病的放射学迹象。这引起了所谓的“多标签分类问题”。这些任务的缺点是类不平衡,即不同的标签没有相同数量的样本。本文的主要贡献是一种深度学习方法,用于不平衡的多标签胸部X射线数据集。它为当前未充分利用的Padchest数据集建立了基线,并基于热图建立了可解释的AI技术。该技术还包括概率和模型间匹配。我们系统的结果很有希望,尤其是考虑到使用的标签数量。此外,热图与预期区域相匹配,即它们标志着专家将用来做出决定的区域。
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在胸部计算机断层扫描(CT)扫描中,自动分割地面玻璃的不透明和固结可以在高资源利用时期减轻放射科医生的负担。但是,由于分布(OOD)数据默默失败,深度学习模型在临床常规中不受信任。我们提出了一种轻巧的OOD检测方法,该方法利用特征空间中的Mahalanobis距离,并无缝集成到最新的分割管道中。简单的方法甚至可以增加具有临床相关的不确定性定量的预训练模型。我们在四个胸部CT分布偏移和两个磁共振成像应用中验证我们的方法,即海马和前列腺的分割。我们的结果表明,所提出的方法在所有探索场景中有效地检测到遥远和近型样品。
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检测到分布(OOD)数据是一项任务,它正在接受计算机视觉的深度学习领域越来越多的研究注意力。但是,通常在隔离任务上评估检测方法的性能,而不是考虑串联中的潜在下游任务。在这项工作中,我们检查了存在OOD数据(SCOD)的选择性分类。也就是说,检测OOD样本的动机是拒绝它们,以便降低它们对预测质量的影响。我们在此任务规范下表明,与仅在OOD检测时进行评估时,现有的事后方法的性能大不相同。这是因为如果ID数据被错误分类,将分布分配(ID)数据与OOD数据混合在一起的问题不再是一个问题。但是,正确和不正确的预测的ID数据中的汇合变得不受欢迎。我们还提出了一种新颖的SCOD,SoftMax信息保留(SIRC)的方法,该方法通过功能不足信息来增强基于软疗法的置信度得分,以便在不牺牲正确和错误的ID预测之间的分离的情况下,可以提高其识别OOD样品的能力。在各种成像网尺度数据集和卷积神经网络体系结构上进行的实验表明,SIRC能够始终如一地匹配或胜过SCOD的基线,而现有的OOD检测方法则无法做到。
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Deep neural networks have attained remarkable performance when applied to data that comes from the same distribution as that of the training set, but can significantly degrade otherwise. Therefore, detecting whether an example is out-of-distribution (OoD) is crucial to enable a system that can reject such samples or alert users. Recent works have made significant progress on OoD benchmarks consisting of small image datasets. However, many recent methods based on neural networks rely on training or tuning with both in-distribution and out-of-distribution data. The latter is generally hard to define a-priori, and its selection can easily bias the learning. We base our work on a popular method ODIN 1 [21], proposing two strategies for freeing it from the needs of tuning with OoD data, while improving its OoD detection performance. We specifically propose to decompose confidence scoring as well as a modified input pre-processing method. We show that both of these significantly help in detection performance. Our further analysis on a larger scale image dataset shows that the two types of distribution shifts, specifically semantic shift and non-semantic shift, present a significant difference in the difficulty of the problem, providing an analysis of when ODIN-like strategies do or do not work.
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在值得信赖的机器学习中,这是一个重要的问题,可以识别与分配任务无关的输入的分布(OOD)输入。近年来,已经提出了许多分布式检测方法。本文的目的是识别共同的目标以及确定不同OOD检测方法的隐式评分函数。我们专注于在培训期间使用替代OOD数据的方法,以学习在测试时概括为新的未见外部分布的OOD检测分数。我们表明,内部和(不同)外部分布之间的二元歧视等同于OOD检测问题的几种不同的公式。当与标准分类器以共同的方式接受培训时,该二进制判别器达到了类似于离群暴露的OOD检测性能。此外,我们表明,异常暴露所使用的置信损失具有隐式评分函数,在训练和测试外部分配相同的情况下,以非平凡的方式与理论上最佳评分功能有所不同,这又是类似于训练基于能量的OOD检测器或添加背景类时使用的一种。在实践中,当以完全相同的方式培训时,所有这些方法的性能类似。
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深度神经网络已经显示出使用医学图像数据的疾病检测和分类结果。然而,他们仍然遭受处理真实世界场景的挑战,特别是可靠地检测分配(OOD)样本。我们提出了一种方法来强化皮肤和疟疾样本的ood样本,而无需在训练期间获得标记的OOD样品。具体而言,我们使用度量学习以及Logistic回归来强制深度网络学习众多丰富的类代表功能。要指导对OOD示例的学习过程,我们通过删除图像或置换图像部件中的类特定的突出区域并远离分布式样本来生成ID类似的示例。在推理时间期间,用于检测分布外样品的K +互易邻居。对于皮肤癌ood检测,我们使用两个标准基准皮肤癌症ISIC数据集AS ID,六种不同的数据集具有不同难度水平的数据集被视为出于分配。对于疟疾检测,我们使用BBBC041 Malaria DataSet作为ID和五个不同的具有挑战性的数据集,如分销。我们在先前的先前皮肤癌和疟疾OOD检测中,我们在TNR @ TPR95%中提高了最先进的结果,改善了5%和4%。
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最近的人工智能(AI)算法已在各种医学分类任务上实现了放射科医生级的性能。但是,只有少数研究涉及CXR扫描异常发现的定位,这对于向放射学家解释图像级分类至关重要。我们在本文中介绍了一个名为Vindr-CXR的可解释的深度学习系统,该系统可以将CXR扫描分类为多种胸部疾病,同时将大多数类型的关键发现本地化在图像上。 Vindr-CXR接受了51,485次CXR扫描的培训,并通过放射科医生提供的边界盒注释进行了培训。它表现出与经验丰富的放射科医生相当的表现,可以在3,000张CXR扫描的回顾性验证集上对6种常见的胸部疾病进行分类,而在接收器操作特征曲线(AUROC)下的平均面积为0.967(95%置信区间[CI]:0.958---------0.958------- 0.975)。 VINDR-CXR在独立患者队列中也得到了外部验证,并显示出其稳健性。对于具有14种类型病变的本地化任务,我们的自由响应接收器操作特征(FROC)分析表明,VINDR-CXR以每扫描确定的1.0假阳性病变的速率达到80.2%的敏感性。还进行了一项前瞻性研究,以衡量VINDR-CXR在协助六名经验丰富的放射科医生方面的临床影响。结果表明,当用作诊断工具时,提出的系统显着改善了放射科医生本身之间的一致性,平均Fleiss的Kappa的同意增加了1.5%。我们还观察到,在放射科医生咨询了Vindr-CXR的建议之后,在平均Cohen的Kappa中,它们和系统之间的一致性显着增加了3.3%。
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Pneumonia, a respiratory infection brought on by bacteria or viruses, affects a large number of people, especially in developing and impoverished countries where high levels of pollution, unclean living conditions, and overcrowding are frequently observed, along with insufficient medical infrastructure. Pleural effusion, a condition in which fluids fill the lung and complicate breathing, is brought on by pneumonia. Early detection of pneumonia is essential for ensuring curative care and boosting survival rates. The approach most usually used to diagnose pneumonia is chest X-ray imaging. The purpose of this work is to develop a method for the automatic diagnosis of bacterial and viral pneumonia in digital x-ray pictures. This article first presents the authors' technique, and then gives a comprehensive report on recent developments in the field of reliable diagnosis of pneumonia. In this study, here tuned a state-of-the-art deep convolutional neural network to classify plant diseases based on images and tested its performance. Deep learning architecture is compared empirically. VGG19, ResNet with 152v2, Resnext101, Seresnet152, Mobilenettv2, and DenseNet with 201 layers are among the architectures tested. Experiment data consists of two groups, sick and healthy X-ray pictures. To take appropriate action against plant diseases as soon as possible, rapid disease identification models are preferred. DenseNet201 has shown no overfitting or performance degradation in our experiments, and its accuracy tends to increase as the number of epochs increases. Further, DenseNet201 achieves state-of-the-art performance with a significantly a smaller number of parameters and within a reasonable computing time. This architecture outperforms the competition in terms of testing accuracy, scoring 95%. Each architecture was trained using Keras, using Theano as the backend.
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Deep Learning (DL) models tend to perform poorly when the data comes from a distribution different from the training one. In critical applications such as medical imaging, out-of-distribution (OOD) detection helps to identify such data samples, increasing the model's reliability. Recent works have developed DL-based OOD detection that achieves promising results on 2D medical images. However, scaling most of these approaches on 3D images is computationally intractable. Furthermore, the current 3D solutions struggle to achieve acceptable results in detecting even synthetic OOD samples. Such limited performance might indicate that DL often inefficiently embeds large volumetric images. We argue that using the intensity histogram of the original CT or MRI scan as embedding is descriptive enough to run OOD detection. Therefore, we propose a histogram-based method that requires no DL and achieves almost perfect results in this domain. Our proposal is supported two-fold. We evaluate the performance on the publicly available datasets, where our method scores 1.0 AUROC in most setups. And we score second in the Medical Out-of-Distribution challenge without fine-tuning and exploiting task-specific knowledge. Carefully discussing the limitations, we conclude that our method solves the sample-level OOD detection on 3D medical images in the current setting.
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Out-of-distribution (OOD) detection has attracted a large amount of attention from the machine learning research community in recent years due to its importance in deployed systems. Most of the previous studies focused on the detection of OOD samples in the multi-class classification task. However, OOD detection in the multi-label classification task remains an underexplored domain. In this research, we propose YolOOD - a method that utilizes concepts from the object detection domain to perform OOD detection in the multi-label classification task. Object detection models have an inherent ability to distinguish between objects of interest (in-distribution) and irrelevant objects (e.g., OOD objects) on images that contain multiple objects from different categories. These abilities allow us to convert a regular object detection model into an image classifier with inherent OOD detection capabilities with just minor changes. We compare our approach to state-of-the-art OOD detection methods and demonstrate YolOOD's ability to outperform these methods on a comprehensive suite of in-distribution and OOD benchmark datasets.
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由于其实际重要性,在提高神经网络安全部署方面的实际重要性,最近经济分配(OOD)检测最近受到了很大的关注。其中一个主要挑战是模型往往会对OOD数据产生高度自信的预测,这在ood检测中破坏了驾驶原理,即该模型应该仅对分布式样品充满信心。在这项工作中,我们提出了反应 - 一种简单有效的技术,用于减少对数据数据的模型过度限制。我们的方法是通过关于神经网络内部激活的新型分析,其为OOD分布显示出高度独特的签名模式。我们的方法可以有效地拓展到不同的网络架构和不同的OOD检测分数。我们经验证明,反应在全面的基准数据集套件上实现了竞争检测性能,并为我们的方法进行了理论解释。与以前的最佳方法相比,在ImageNet基准测试中,反应将假阳性率(FPR95)降低25.05%。
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机器学习模型通常会遇到与训练分布不同的样本。无法识别分布(OOD)样本,因此将该样本分配给课堂标签会显着损害模​​型的可靠性。由于其对在开放世界中的安全部署模型的重要性,该问题引起了重大关注。由于对所有可能的未知分布进行建模的棘手性,检测OOD样品是具有挑战性的。迄今为止,一些研究领域解决了检测陌生样本的问题,包括异常检测,新颖性检测,一级学习,开放式识别识别和分布外检测。尽管有相似和共同的概念,但分别分布,开放式检测和异常检测已被独立研究。因此,这些研究途径尚未交叉授粉,创造了研究障碍。尽管某些调查打算概述这些方法,但它们似乎仅关注特定领域,而无需检查不同领域之间的关系。这项调查旨在在确定其共同点的同时,对各个领域的众多著名作品进行跨域和全面的审查。研究人员可以从不同领域的研究进展概述中受益,并协同发展未来的方法。此外,据我们所知,虽然进行异常检测或单级学习进行了调查,但没有关于分布外检测的全面或最新的调查,我们的调查可广泛涵盖。最后,有了统一的跨域视角,我们讨论并阐明了未来的研究线,打算将这些领域更加紧密地融为一体。
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在医学成像中不同分布班次下概括的学习模型一直是一项长期的研究挑战。在视觉研究从业者之间有高效和强大的视觉表现学习有几个提案,特别是在敏感和临界生物医学领域。在本文中,我们提出了一种胸部X射线病理的分发通用的想法,这些胸部X射线病理学的概念使用简单的平衡批量采样技术。我们观察到,多次训练数据集之间的平衡采样可提高对培训的基线模型而不进行平衡的性能。
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为了策划高质量的数据集,识别内部和外部来源之间的数据方差是一个基本和关键的步骤。但是,尚未显着研究检测数据移位或差异的方法。对此的挑战是缺乏学习DataSet的密集代表和在医疗机构分享私人数据的困难的有效方法。为了克服这些问题,我们提出了一个统一的管道,称为MedShift以检测顶级移位样本,从而促进医疗策序。给定内部数据集A作为基础源,我们首先为每类数据集A列车以以无人监督的方式学习内部分布。其次,在不交换跨源的情况下,我们在每个类的外部数据集b上运行训练的异常检测器。具有高异常分数的数据样本被识别为移位数据。为了量化外部数据集的换档,我们将B的数据基于所获得的分数群集分组。然后,我们通过逐渐删除每个类的最大异常分数来测量B的多级分类器并测量与分类器的性能方差的班次。此外,我们还调整数据集质量指标,以帮助检查多个医疗源的分布差异。我们验证了来自肌肉骨骼射线照片(Mura)和胸部X射线数据集的MedShift的疗效,来自多个外部源。实验表明我们所提出的移位数据检测管道对医疗中心有益,以更有效地策划高质量的数据集。一个接口介绍视频,可视化我们的结果可在https://youtu.be/v3bf0p1sxqe上获得。
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