本文研究了从预先训练的模型,尤其是蒙面自动编码器中提取知识的潜力。我们的方法很简单:除了优化掩盖输入的像素重建损失外,我们还将教师模型的中间特征图与学生模型的中间特征图之间的距离最小化。此设计导致一个计算高效的知识蒸馏框架,给定1)仅使用一个少量可见的补丁子集,2)(笨拙的)教师模型仅需要部分执行,\ ie,\ ie,在前几个中,向前传播输入层,用于获得中间特征图。与直接蒸馏微型模型相比,提炼预训练的模型显着改善了下游性能。例如,通过将知识从MAE预先训练的VIT-L提炼为VIT-B,我们的方法可实现84.0%的Imagenet Top-1精度,表现优于直接将微型VIT-L蒸馏的基线,降低1.2%。更有趣的是,我们的方法即使具有极高的掩盖率也可以从教师模型中进行鲁棒性蒸馏:例如,在蒸馏过程中仅可见十个斑块,我们的VIT-B具有竞争力的前1个Imagenet精度为83.6%,在95%的掩盖率中,只有十个斑块。 ;令人惊讶的是,它仍然可以通过仅四个可见斑(98%的掩盖率)积极训练来确保82.4%的Top-1 Imagenet精度。代码和模型可在https://github.com/ucsc-vlaa/dmae上公开获得。
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视觉变形金刚最近的成功是在图像识别中挥舞着卷积神经网络(CNN)的长期优势。具体而言,就稳健性而言,最近的研究发现,无论训练设置如何,变压器本质上比CNN更强大。此外,人们认为,变形金刚的这种优越性应该在很大程度上被认为是他们的自我注意力型建筑本身。在本文中,我们通过密切研究变压器的设计来质疑这种信念。我们的发现导致了三种高效的体系结构设计,以提高鲁棒性,但很简单,可以在几行代码中实现,即a)修补输入图像,b)扩大内核大小,c)降低激活层和归一化层。将这些组件融合在一起,我们能够构建纯CNN体系结构,而没有任何类似注意力的操作,这些操作比变形金刚更强大,甚至更健壮。我们希望这项工作可以帮助社区更好地了解强大的神经体系结构的设计。该代码可在https://github.com/ucsc-vlaa/robustcnn上公开获得。
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最近,Vision-Language预训练的零拍图像分类已经表现出令人难以置信的成就,即该模型可以对任意类别进行分类而不看到该类别的其他注释图像。然而,目前尚不清楚如何在更广泛的视觉问题上进行零射识别,例如对象检测和语义分割。在本文中,我们通过在现成的预训练的视觉模型,即剪辑上建立零拍语义分割来定位零拍语义分割。很难因为语义分割和剪辑模型在不同的视觉粒度上执行,该语义分段处理在像素上时,而剪辑在图像上执行。为了解决处理粒度的差异,我们拒绝使用普遍的一级FCN基于FCN的框架,并倡导一个两级语义分割框架,其中第一阶段提取一个完全提取的掩模提案和第二阶段利用基于图像的剪辑模型在第一阶段生成的蒙版图像作物上执行零拍分类。我们的实验结果表明,这种简单的框架通过大型利润率超越了先前的最先进:+29.5 Hiou On Pascal VOC 2012 DataSet,+8.9 Hiou On Coco Stuff DataSet。凭借其简单性和强大的表现,我们希望本框架成为促进未来研究的基准。
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变压器出现为可视识别的强大工具。除了在广泛的视觉基准上展示竞争性能外,最近的作品还争辩说,变形金刚比卷曲神经网络(CNNS)更强大。令人惊讶的是,我们发现这些结论是从不公平的实验设置中得出的,其中变压器和CNN在不同的尺度上比较,并用不同的训练框架应用。在本文中,我们的目标是在变压器和CNN之间提供第一个公平和深入的比较,重点是鲁棒性评估。通过我们的统一培训设置,我们首先挑战以前的信念,使得在衡量对抗性鲁棒性时越来越多的CNN。更令人惊讶的是,如果他们合理地采用变形金刚的培训食谱,我们发现CNNS可以很容易地作为捍卫对抗性攻击的变形金刚。在关于推广样本的泛化的同时,我们显示了对(外部)大规模数据集的预训练不是对实现变压器来实现比CNN更好的性能的根本请求。此外,我们的消融表明,这种更强大的概括主要受到变压器的自我关注架构本身的影响,而不是通过其他培训设置。我们希望这项工作可以帮助社区更好地理解和基准变压器和CNN的鲁棒性。代码和模型在https://github.com/ytongbai/vits-vs-cnns上公开使用。
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我们介绍混音,一个用于对象检测的新培训范例,可以免费提高现有探测器的性能。混合通过利用不同优点的增强来增强数据增强,同时排除某些可能对培训可能有害的培训样本的强大增强。此外,它通过结合可以补偿这些错误的伪框来解决人类注释中的本地化噪声和丢失标签。通过对探测器的自动启动,可以使用这些混音功能,这可以用于预测对强大增强的训练难度,以及由于神经网络对标记错误的鲁棒性而产生可靠的伪框。发现混音是在Coco DataSet上的各种探测器上带来一致的改进。特别是,使用Reset-50 \ Cite {REN2015Faster}更快的R-CNN \ CITE {REN2015FAST}骨架的性能从41.7地图改进到44.0地图,以及CASCADE-RCNN \ CITE {CAI2018CASCADE}的准确性-small \ cite {liu2021swin}骨干从50.9地图提出到52.8地图。代码和模型将在\ url {https://github.com/mendelxu/mixtraining}上公开可用。
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批准(BN)均匀地基于一批图像的统计数据均匀地移动并缩放激活。但是,背景像素的强度分布通常主导了BN统计数据,因为背景占整个图像的很大比例。本文着重于通过前景像素的强度分布增强BN,这对于图像分割至关重要。我们提出了一种新的归一化策略,称为分类归一化(结合型),以根据分类统计数据使激活归一化。分类统计数据是通过动态调节属于前景的图像中的特定区域而获得的。结合型在从不同域获得的五个公共数据集展示了精确和稳健的分割结果,涵盖了复杂和可变的数据分布。这归因于结合体从医疗数据的多个领域(机构)捕获域不变的信息的能力。代码可从https://github.com/lambert-x/catenorm获得。
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旨在识别来自子类别的对象的细粒度视觉分类(FGVC)是一个非常具有挑战性的任务,因为固有的微妙级别差异。大多数现有工程主要通过重用骨干网络来提取检测到的歧视区域的特征来解决这个问题。然而,该策略不可避免地使管道复杂化并推动所提出的区域,其中大多数物体的大多数部分未能定位真正重要的部分。最近,视觉变压器(VIT)在传统的分类任务中表现出其强大的表现。变压器的自我关注机制将每个补丁令牌链接到分类令牌。在这项工作中,我们首先评估vit框架在细粒度识别环境中的有效性。然后,由于注意力的强度,可以直观地被认为是令牌重要性的指标,我们进一步提出了一种新颖的部分选择模块,可以应用于我们整合变压器的所有原始注意力的变压器架构进入注意地图,用于指导网络以有效,准确地选择鉴别的图像斑块并计算它们的关系。应用对比损失来扩大混淆类的特征表示之间的距离。我们将基于增强的变压器的模型Transfg命名,并通过在我们实现最先进的绩效的五个流行的细粒度基准测试中进行实验来展示它的价值。提出了更好地理解模型的定性结果。
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In this paper, we introduce a contrastive learning framework for keypoint detection (CoKe). Keypoint detection differs from other visual tasks where contrastive learning has been applied because the input is a set of images in which multiple keypoints are annotated. This requires the contrastive learning to be extended such that the keypoints are represented and detected independently, which enables the contrastive loss to make the keypoint features different from each other and from the background. Our approach has two benefits: It enables us to exploit contrastive learning for keypoint detection, and by detecting each keypoint independently the detection becomes more robust to occlusion compared to holistic methods, such as stacked hourglass networks, which attempt to detect all keypoints jointly. Our CoKe framework introduces several technical innovations. In particular, we introduce: (i) A clutter bank to represent non-keypoint features; (ii) a keypoint bank that stores prototypical representations of keypoints to approximate the contrastive loss between keypoints; and (iii) a cumulative moving average update to learn the keypoint prototypes while training the feature extractor. Our experiments on a range of diverse datasets (PASCAL3D+, MPII, ObjectNet3D) show that our approach works as well, or better than, alternative methods for keypoint detection, even for human keypoints, for which the literature is vast. Moreover, we observe that CoKe is exceptionally robust to partial occlusion and previously unseen object poses.
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Dynamic Graph Neural Networks (DGNNs) have been broadly applied in various real-life applications, such as link prediction and pandemic forecast, to capture both static structural information and temporal characteristics from dynamic graphs. Combining both time-dependent and -independent components, DGNNs manifest substantial parallel computation and data reuse potentials, but suffer from severe memory access inefficiency and data transfer overhead under the canonical one-graph-at-a-time training pattern. To tackle the challenges, we propose PiPAD, a $\underline{\textbf{Pi}}pelined$ and $\underline{\textbf{PA}}rallel$ $\underline{\textbf{D}}GNN$ training framework for the end-to-end performance optimization on GPUs. From both the algorithm and runtime level, PiPAD holistically reconstructs the overall training paradigm from the data organization to computation manner. Capable of processing multiple graph snapshots in parallel, PiPAD eliminates the unnecessary data transmission and alleviates memory access inefficiency to improve the overall performance. Our evaluation across various datasets shows PiPAD achieves $1.22\times$-$9.57\times$ speedup over the state-of-the-art DGNN frameworks on three representative models.
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We propose a novel teacher-student model for semi-supervised multi-organ segmentation. In teacher-student model, data augmentation is usually adopted on unlabeled data to regularize the consistent training between teacher and student. We start from a key perspective that fixed relative locations and variable sizes of different organs can provide distribution information where a multi-organ CT scan is drawn. Thus, we treat the prior anatomy as a strong tool to guide the data augmentation and reduce the mismatch between labeled and unlabeled images for semi-supervised learning. More specifically, we propose a data augmentation strategy based on partition-and-recovery N$^3$ cubes cross- and within- labeled and unlabeled images. Our strategy encourages unlabeled images to learn organ semantics in relative locations from the labeled images (cross-branch) and enhances the learning ability for small organs (within-branch). For within-branch, we further propose to refine the quality of pseudo labels by blending the learned representations from small cubes to incorporate local attributes. Our method is termed as MagicNet, since it treats the CT volume as a magic-cube and $N^3$-cube partition-and-recovery process matches with the rule of playing a magic-cube. Extensive experiments on two public CT multi-organ datasets demonstrate the effectiveness of MagicNet, and noticeably outperforms state-of-the-art semi-supervised medical image segmentation approaches, with +7% DSC improvement on MACT dataset with 10% labeled images.
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