Neural image classifiers are known to undergo severe performance degradation when exposed to input that exhibits covariate-shift with respect to the training distribution. Successful hand-crafted augmentation pipelines aim at either approximating the expected test domain conditions or to perturb the features that are specific to the training environment. The development of effective pipelines is typically cumbersome, and produce transformations whose impact on the classifier performance are hard to understand and control. In this paper, we show that recent Text-to-Image (T2I) generators' ability to simulate image interventions via natural-language prompts can be leveraged to train more robust models, offering a more interpretable and controllable alternative to traditional augmentation methods. We find that a variety of prompting mechanisms are effective for producing synthetic training data sufficient to achieve state-of-the-art performance in widely-adopted domain-generalization benchmarks and reduce classifiers' dependency on spurious features. Our work suggests that further progress in T2I generation and a tighter integration with other research fields may represent a significant step towards the development of more robust machine learning systems.
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Deep Neural Networks (DNNs) are vulnerable to the black-box adversarial attack that is highly transferable. This threat comes from the distribution gap between adversarial and clean samples in feature space of the target DNNs. In this paper, we use Deep Generative Networks (DGNs) with a novel training mechanism to eliminate the distribution gap. The trained DGNs align the distribution of adversarial samples with clean ones for the target DNNs by translating pixel values. Different from previous work, we propose a more effective pixel level training constraint to make this achievable, thus enhancing robustness on adversarial samples. Further, a class-aware feature-level constraint is formulated for integrated distribution alignment. Our approach is general and applicable to multiple tasks, including image classification, semantic segmentation, and object detection. We conduct extensive experiments on different datasets. Our strategy demonstrates its unique effectiveness and generality against black-box attacks.
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We introduce Patch Aligned Contrastive Learning (PACL), a modified compatibility function for CLIP's contrastive loss, intending to train an alignment between the patch tokens of the vision encoder and the CLS token of the text encoder. With such an alignment, a model can identify regions of an image corresponding to a given text input, and therefore transfer seamlessly to the task of open vocabulary semantic segmentation without requiring any segmentation annotations during training. Using pre-trained CLIP encoders with PACL, we are able to set the state-of-the-art on the task of open vocabulary zero-shot segmentation on 4 different segmentation benchmarks: Pascal VOC, Pascal Context, COCO Stuff and ADE20K. Furthermore, we show that PACL is also applicable to image-level predictions and when used with a CLIP backbone, provides a general improvement in zero-shot classification accuracy compared to CLIP, across a suite of 12 image classification datasets.
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Modern deep networks can be better generalized when trained with noisy samples and regularization techniques. Mixup and CutMix have been proven to be effective for data augmentation to help avoid overfitting. Previous Mixup-based methods linearly combine images and labels to generate additional training data. However, this is problematic if the object does not occupy the whole image as we demonstrate in Figure 1. Correctly assigning the label weights is hard even for human beings and there is no clear criterion to measure it. To tackle this problem, in this paper, we propose LUMix, which models such uncertainty by adding label perturbation during training. LUMix is simple as it can be implemented in just a few lines of code and can be universally applied to any deep networks \eg CNNs and Vision Transformers, with minimal computational cost. Extensive experiments show that our LUMix can consistently boost the performance for networks with a wide range of diversity and capacity on ImageNet, \eg $+0.7\%$ for a small model DeiT-S and $+0.6\%$ for a large variant XCiT-L. We also demonstrate that LUMix can lead to better robustness when evaluated on ImageNet-O and ImageNet-A. The source code can be found \href{https://github.com/kevin-ssy/LUMix}{here}
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Classifiers and generators have long been separated. We break down this separation and showcase that conventional neural network classifiers can generate high-quality images of a large number of categories, being comparable to the state-of-the-art generative models (e.g., DDPMs and GANs). We achieve this by computing the partial derivative of the classification loss function with respect to the input to optimize the input to produce an image. Since it is widely known that directly optimizing the inputs is similar to targeted adversarial attacks incapable of generating human-meaningful images, we propose a mask-based stochastic reconstruction module to make the gradients semantic-aware to synthesize plausible images. We further propose a progressive-resolution technique to guarantee fidelity, which produces photorealistic images. Furthermore, we introduce a distance metric loss and a non-trivial distribution loss to ensure classification neural networks can synthesize diverse and high-fidelity images. Using traditional neural network classifiers, we can generate good-quality images of 256$\times$256 resolution on ImageNet. Intriguingly, our method is also applicable to text-to-image generation by regarding image-text foundation models as generalized classifiers. Proving that classifiers have learned the data distribution and are ready for image generation has far-reaching implications, for classifiers are much easier to train than generative models like DDPMs and GANs. We don't even need to train classification models because tons of public ones are available for download. Also, this holds great potential for the interpretability and robustness of classifiers. Project page is at \url{https://classifier-as-generator.github.io/}.
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在大型数据集上,对视力任务的深度学习模型进行了培训,因为存在一个通用表示,可用于对所有样本进行预测。尽管事实证明,高复杂性模型能够学习此类表示,但对数据的特定子集进行了培训的专家,可以更有效地推断出标签。然而,使用专家的混合物会提出两个新问题,即(i)在提出新的看不见的样本时分配正确的专家。 (ii)找到培训数据的最佳分区,以使专家最依赖于共同特征。在动态路由(DR)中,提出了一个新颖的体系结构,其中每层由一组专家组成,但是在没有解决这两个挑战的情况下,我们证明该模型可以恢复使用相同的专家子集。在我们的方法中,对多元化的动态路由(DIVDR)进行了明确培训,以解决找到数据相关分区并以无监督的方法分配正确的专家的挑战。我们对MS-Coco的城市景观和对象检测以及实例分割进行了几项实验,显示了几个基线的性能的改善。
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我们研究自主代理如何学会从不同领域(例如不同环境或不同代理)中的示范中执行任务。这样的跨域模仿学习需要例如从人类专家的演示中培训人造代理。我们提出了一个可扩展的框架,该框架可以实现跨域模仿学习,而无需访问其他演示或进一步的领域知识。我们共同培训学习者的政策,并通过对抗性培训学习学习者和专家领域的映射。我们通过使用共同信息标准来找到包含与任务相关的信息的专家状态空间的嵌入,并且对域细节不变。此步骤大大简化了估计学习者和专家领域之间的映射,因此有助于端到端学习。我们证明了在相当不同的域之间成功转移了政策,而没有额外的示范,以及其他方法失败的情况。
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在图像分类中,在检测分布(OOD)数据时发生了许多发展。但是,大多数OOD检测方法是在一组标准数据集上评估的,该数据集与培训数据任意不同。没有明确的定义``好的''ood数据集。此外,最先进的OOD检测方法已经在这些标准基准上取得了几乎完美的结果。在本文中,我们定义了2类OOD数据使用与分布(ID)数据的感知/视觉和语义相似性的微妙概念。我们将附近的OOD样本定义为感知上相似但语义上与ID样本的不同,并将样本转移为视觉上不同但在语义上与ID相似的点数据。然后,我们提出了一个基于GAN的框架,用于从这两个类别中生成OOD样品,给定一个ID数据集。通过有关MNIST,CIFAR-10/100和Imagenet的广泛实验,我们表明A)在常规基准上表现出色的ART OOD检测方法对我们提出的基准测试的稳健性明显较小。 N基准测试,反之亦然,因此表明甚至可能不需要单独的OOD集来可靠地评估OOD检测中的性能。
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建模长期依赖关系对于理解计算机视觉中的任务至关重要。尽管卷积神经网络(CNN)在许多视觉任务中都表现出色,但由于它们通常由当地核层组成,因此它们仍然限制捕获长期结构化关系。但是,完全连接的图(例如变形金刚中的自我发项操作)对这种建模是有益的,但是,其计算开销非常有用。在本文中,我们提出了一个动态图形消息传递网络,与建模完全连接的图形相比,该网络大大降低了计算复杂性。这是通过在图表中自适应采样节点(以输入为条件)来实现的,以传递消息传递。基于采样节点,我们动态预测节点依赖性滤波器权重和亲和力矩阵,以在它们之间传播信息。这种公式使我们能够设计一个自我发挥的模块,更重要的是,我们将基于变压器的新骨干网络用于图像分类预处理,并用于解决各种下游任务(对象检测,实例和语义细分)。使用此模型,我们在四个不同任务上的强,最先进的基线方面显示出显着改进。我们的方法还优于完全连接的图形,同时使用较少的浮点操作和参数。代码和型号将在https://github.com/fudan-zvg/dgmn2上公开提供。
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我们为文本对图像生成引入了一种内存驱动的半参数方法,该方法基于参数和非参数技术。非参数组件是由训练集构建的图像特征的记忆库。参数组件是生成对抗网络。给定在推理时间进行新的文本描述,内存库用于选择性检索作为目标图像的基本信息提供的图像功能,从而使生成器能够产生逼真的合成结果。我们还将内容信息与语义功能一起纳入歧视器中,从而使歧视者可以做出更可靠的预测。实验结果表明,所提出的记忆驱动的半参数方法比视觉忠诚度和文本图像语义一致性都比纯粹的参数方法产生更现实的图像。
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