The recently developed discrete diffusion models perform extraordinarily well in the text-to-image task, showing significant promise for handling the multi-modality signals. In this work, we harness these traits and present a unified multimodal generation model that can conduct both the "modality translation" and "multi-modality generation" tasks using a single model, performing text-based, image-based, and even vision-language simultaneous generation. Specifically, we unify the discrete diffusion process for multimodal signals by proposing a unified transition matrix. Moreover, we design a mutual attention module with fused embedding layer and a unified objective function to emphasise the inter-modal linkages, which are vital for multi-modality generation. Extensive experiments indicate that our proposed method can perform comparably to the state-of-the-art solutions in various generation tasks.
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尽管两阶段矢量量化(VQ)生成模型允许合成高保真性和高分辨率图像,但其量化操作员将图像中的相似贴片编码为相同的索引,从而为相似的相邻区域重复使用现有的解码器体系结构的相似相似区域的重复伪像。为了解决这个问题,我们建议将空间条件的归一化结合起来,以调节量化的向量,以便将空间变体信息插入嵌入式索引图中,从而鼓励解码器生成更真实的图像。此外,我们使用多通道量化来增加离散代码的重组能力,而无需增加模型和代码簿的成本。此外,为了在第二阶段生成离散令牌,我们采用掩盖的生成图像变压器(MaskGit)来学习压缩潜在空间中的基础先验分布,该分布比常规自动回归模型快得多。两个基准数据集的实验表明,我们提出的调制VQGAN能够大大提高重建的图像质量,并提供高保真图像的产生。
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神经隐式表示在新的视图合成和来自多视图图像的高质量3D重建方面显示了其有效性。但是,大多数方法都集中在整体场景表示上,但忽略了其中的各个对象,从而限制了潜在的下游应用程序。为了学习对象组合表示形式,一些作品将2D语义图作为训练中的提示,以掌握对象之间的差异。但是他们忽略了对象几何和实例语义信息之间的牢固联系,这导致了单个实例的不准确建模。本文提出了一个新颖的框架ObjectsDF,以在3D重建和对象表示中构建具有高保真度的对象复合神经隐式表示。观察常规音量渲染管道的歧义,我们通过组合单个对象的签名距离函数(SDF)来对场景进行建模,以发挥明确的表面约束。区分不同实例的关键是重新审视单个对象的SDF和语义标签之间的牢固关联。特别是,我们将语义信息转换为对象SDF的函数,并为场景和对象开发统一而紧凑的表示形式。实验结果表明,ObjectSDF框架在表示整体对象组合场景和各个实例方面的优越性。可以在https://qianyiwu.github.io/objectsdf/上找到代码
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图像翻译和操纵随着深层生成模型的快速发展而引起了越来越多的关注。尽管现有的方法带来了令人印象深刻的结果,但它们主要在2D空间中运行。鉴于基于NERF的3D感知生成模型的最新进展,我们介绍了一项新的任务,语义到网络翻译,旨在重建由NERF模型的3D场景,该场景以一个单视语义掩码作为输入为条件。为了启动这项新颖的任务,我们提出了SEM2NERF框架。特别是,SEM2NERF通过将语义面膜编码到控制预训练的解码器的3D场景表示形式中来解决高度挑战的任务。为了进一步提高映射的准确性,我们将新的区域感知学习策略集成到编码器和解码器的设计中。我们验证了提出的SEM2NERF的功效,并证明它在两个基准数据集上的表现优于几个强基础。代码和视频可从https://donydchen.github.io/sem2nerf/获得
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桥接全球上下文交互正确对大面具的高保真图像完成非常重要。先前的方法通过深或大的接收领域(RF)卷积无法逃离附近互动的主导地位,这可能是劣等的。在本文中,我们建议将图像完成视为无缝的序列到序列预测任务,并部署变压器以直接捕获编码器中的远程依赖性。至关重要,我们使用具有小而非重叠的RF的限制性CNN,用于加权令牌表示,这允许变压器明确地模拟所有层中的相同重要性,而在使用较大的RF时,没有隐含地混淆邻居令牌。为了改善可见区域之间的外观一致性,引入了一种新的注意力层(aal)以更好地利用远方相关的高频功能。总体而言,与若干数据集上的最先进方法相比,大量实验表现出卓越的性能。
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Masked image modeling (MIM) performs strongly in pre-training large vision Transformers (ViTs). However, small models that are critical for real-world applications cannot or only marginally benefit from this pre-training approach. In this paper, we explore distillation techniques to transfer the success of large MIM-based pre-trained models to smaller ones. We systematically study different options in the distillation framework, including distilling targets, losses, input, network regularization, sequential distillation, etc, revealing that: 1) Distilling token relations is more effective than CLS token- and feature-based distillation; 2) An intermediate layer of the teacher network as target perform better than that using the last layer when the depth of the student mismatches that of the teacher; 3) Weak regularization is preferred; etc. With these findings, we achieve significant fine-tuning accuracy improvements over the scratch MIM pre-training on ImageNet-1K classification, using all the ViT-Tiny, ViT-Small, and ViT-base models, with +4.2%/+2.4%/+1.4% gains, respectively. Our TinyMIM model of base size achieves 52.2 mIoU in AE20K semantic segmentation, which is +4.1 higher than the MAE baseline. Our TinyMIM model of tiny size achieves 79.6% top-1 accuracy on ImageNet-1K image classification, which sets a new record for small vision models of the same size and computation budget. This strong performance suggests an alternative way for developing small vision Transformer models, that is, by exploring better training methods rather than introducing inductive biases into architectures as in most previous works. Code is available at https://github.com/OliverRensu/TinyMIM.
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Dataset distillation has emerged as a prominent technique to improve data efficiency when training machine learning models. It encapsulates the knowledge from a large dataset into a smaller synthetic dataset. A model trained on this smaller distilled dataset can attain comparable performance to a model trained on the original training dataset. However, the existing dataset distillation techniques mainly aim at achieving the best trade-off between resource usage efficiency and model utility. The security risks stemming from them have not been explored. This study performs the first backdoor attack against the models trained on the data distilled by dataset distillation models in the image domain. Concretely, we inject triggers into the synthetic data during the distillation procedure rather than during the model training stage, where all previous attacks are performed. We propose two types of backdoor attacks, namely NAIVEATTACK and DOORPING. NAIVEATTACK simply adds triggers to the raw data at the initial distillation phase, while DOORPING iteratively updates the triggers during the entire distillation procedure. We conduct extensive evaluations on multiple datasets, architectures, and dataset distillation techniques. Empirical evaluation shows that NAIVEATTACK achieves decent attack success rate (ASR) scores in some cases, while DOORPING reaches higher ASR scores (close to 1.0) in all cases. Furthermore, we conduct a comprehensive ablation study to analyze the factors that may affect the attack performance. Finally, we evaluate multiple defense mechanisms against our backdoor attacks and show that our attacks can practically circumvent these defense mechanisms.
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Benefiting from the intrinsic supervision information exploitation capability, contrastive learning has achieved promising performance in the field of deep graph clustering recently. However, we observe that two drawbacks of the positive and negative sample construction mechanisms limit the performance of existing algorithms from further improvement. 1) The quality of positive samples heavily depends on the carefully designed data augmentations, while inappropriate data augmentations would easily lead to the semantic drift and indiscriminative positive samples. 2) The constructed negative samples are not reliable for ignoring important clustering information. To solve these problems, we propose a Cluster-guided Contrastive deep Graph Clustering network (CCGC) by mining the intrinsic supervision information in the high-confidence clustering results. Specifically, instead of conducting complex node or edge perturbation, we construct two views of the graph by designing special Siamese encoders whose weights are not shared between the sibling sub-networks. Then, guided by the high-confidence clustering information, we carefully select and construct the positive samples from the same high-confidence cluster in two views. Moreover, to construct semantic meaningful negative sample pairs, we regard the centers of different high-confidence clusters as negative samples, thus improving the discriminative capability and reliability of the constructed sample pairs. Lastly, we design an objective function to pull close the samples from the same cluster while pushing away those from other clusters by maximizing and minimizing the cross-view cosine similarity between positive and negative samples. Extensive experimental results on six datasets demonstrate the effectiveness of CCGC compared with the existing state-of-the-art algorithms.
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As one of the prevalent methods to achieve automation systems, Imitation Learning (IL) presents a promising performance in a wide range of domains. However, despite the considerable improvement in policy performance, the corresponding research on the explainability of IL models is still limited. Inspired by the recent approaches in explainable artificial intelligence methods, we proposed a model-agnostic explaining framework for IL models called R2RISE. R2RISE aims to explain the overall policy performance with respect to the frames in demonstrations. It iteratively retrains the black-box IL model from the randomized masked demonstrations and uses the conventional evaluation outcome environment returns as the coefficient to build an importance map. We also conducted experiments to investigate three major questions concerning frames' importance equality, the effectiveness of the importance map, and connections between importance maps from different IL models. The result shows that R2RISE successfully distinguishes important frames from the demonstrations.
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Compressed videos often exhibit visually annoying artifacts, known as Perceivable Encoding Artifacts (PEAs), which dramatically degrade video visual quality. Subjective and objective measures capable of identifying and quantifying various types of PEAs are critical in improving visual quality. In this paper, we investigate the influence of four spatial PEAs (i.e. blurring, blocking, bleeding, and ringing) and two temporal PEAs (i.e. flickering and floating) on video quality. For spatial artifacts, we propose a visual saliency model with a low computational cost and higher consistency with human visual perception. In terms of temporal artifacts, self-attention based TimeSFormer is improved to detect temporal artifacts. Based on the six types of PEAs, a quality metric called Saliency-Aware Spatio-Temporal Artifacts Measurement (SSTAM) is proposed. Experimental results demonstrate that the proposed method outperforms state-of-the-art metrics. We believe that SSTAM will be beneficial for optimizing video coding techniques.
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