Recently proposed Gated Linear Networks present a tractable nonlinear network architecture, and exhibit interesting capabilities such as learning with local error signals and reduced forgetting in sequential learning. In this work, we introduce a novel gating architecture, named Globally Gated Deep Linear Networks (GGDLNs) where gating units are shared among all processing units in each layer, thereby decoupling the architectures of the nonlinear but unlearned gatings and the learned linear processing motifs. We derive exact equations for the generalization properties in these networks in the finite-width thermodynamic limit, defined by $P,N\rightarrow\infty, P/N\sim O(1)$, where P and N are the training sample size and the network width respectively. We find that the statistics of the network predictor can be expressed in terms of kernels that undergo shape renormalization through a data-dependent matrix compared to the GP kernels. Our theory accurately captures the behavior of finite width GGDLNs trained with gradient descent dynamics. We show that kernel shape renormalization gives rise to rich generalization properties w.r.t. network width, depth and L2 regularization amplitude. Interestingly, networks with sufficient gating units behave similarly to standard ReLU networks. Although gatings in the model do not participate in supervised learning, we show the utility of unsupervised learning of the gating parameters. Additionally, our theory allows the evaluation of the network's ability for learning multiple tasks by incorporating task-relevant information into the gating units. In summary, our work is the first exact theoretical solution of learning in a family of nonlinear networks with finite width. The rich and diverse behavior of the GGDLNs suggests that they are helpful analytically tractable models of learning single and multiple tasks, in finite-width nonlinear deep networks.
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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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Previous studies have explored generating accurately lip-synced talking faces for arbitrary targets given audio conditions. However, most of them deform or generate the whole facial area, leading to non-realistic results. In this work, we delve into the formulation of altering only the mouth shapes of the target person. This requires masking a large percentage of the original image and seamlessly inpainting it with the aid of audio and reference frames. To this end, we propose the Audio-Visual Context-Aware Transformer (AV-CAT) framework, which produces accurate lip-sync with photo-realistic quality by predicting the masked mouth shapes. Our key insight is to exploit desired contextual information provided in audio and visual modalities thoroughly with delicately designed Transformers. Specifically, we propose a convolution-Transformer hybrid backbone and design an attention-based fusion strategy for filling the masked parts. It uniformly attends to the textural information on the unmasked regions and the reference frame. Then the semantic audio information is involved in enhancing the self-attention computation. Additionally, a refinement network with audio injection improves both image and lip-sync quality. Extensive experiments validate that our model can generate high-fidelity lip-synced results for arbitrary subjects.
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Co-speech gesture is crucial for human-machine interaction and digital entertainment. While previous works mostly map speech audio to human skeletons (e.g., 2D keypoints), directly generating speakers' gestures in the image domain remains unsolved. In this work, we formally define and study this challenging problem of audio-driven co-speech gesture video generation, i.e., using a unified framework to generate speaker image sequence driven by speech audio. Our key insight is that the co-speech gestures can be decomposed into common motion patterns and subtle rhythmic dynamics. To this end, we propose a novel framework, Audio-driveN Gesture vIdeo gEneration (ANGIE), to effectively capture the reusable co-speech gesture patterns as well as fine-grained rhythmic movements. To achieve high-fidelity image sequence generation, we leverage an unsupervised motion representation instead of a structural human body prior (e.g., 2D skeletons). Specifically, 1) we propose a vector quantized motion extractor (VQ-Motion Extractor) to summarize common co-speech gesture patterns from implicit motion representation to codebooks. 2) Moreover, a co-speech gesture GPT with motion refinement (Co-Speech GPT) is devised to complement the subtle prosodic motion details. Extensive experiments demonstrate that our framework renders realistic and vivid co-speech gesture video. Demo video and more resources can be found in: https://alvinliu0.github.io/projects/ANGIE
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尽管已经对音频驱动的说话的面部生成取得了重大进展,但现有方法要么忽略面部情绪,要么不能应用于任意主题。在本文中,我们提出了情感感知的运动模型(EAMM),以通过涉及情感源视频来产生一次性的情感谈话面孔。具体而言,我们首先提出了一个Audio2Facial-Dynamics模块,该模块从音频驱动的无监督零和一阶密钥点运动中进行说话。然后,通过探索运动模型的属性,我们进一步提出了一个隐性的情绪位移学习者,以表示与情绪相关的面部动力学作为对先前获得的运动表示形式的线性添加位移。全面的实验表明,通过纳入两个模块的结果,我们的方法可以在具有现实情感模式的任意主题上产生令人满意的说话面部结果。
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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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半监督分割在医学成像中仍然具有挑战性,因为带注释的医学数据的量通常受到限制,并且在粘合边缘或低对比度区域附近有许多模糊的像素。为了解决这些问题,我们主张首先限制有或没有强大扰动的样品的一致性,以应用足够的平滑度正则化,并进一步鼓励班级分离以利用未标记的模棱两可的像素进行模型培训。特别是,在本文中,我们通过同时探索像素级平滑度和类间的分离,为半监督医学图像分割任务提出了SS-NET。像素级平滑度迫使模型在对抗扰动下产生不变结果。同时,阶层间的分离限制各个类特征应接近其相应的高质量原型,以使每个类别的分布紧凑和单独的不同类别。我们针对公共LA和ACDC数据集的五种最新方法评估了我们的SS-NET。在两个半监督的设置下的实验结果证明了我们提出的SS-NET的优势,在两个数据集上都实现了新的最先进(SOTA)性能。该代码可在https://github.com/ycwu1997/ss-net上找到。
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In this paper, we propose a robust 3D detector, named Cross Modal Transformer (CMT), for end-to-end 3D multi-modal detection. Without explicit view transformation, CMT takes the image and point clouds tokens as inputs and directly outputs accurate 3D bounding boxes. The spatial alignment of multi-modal tokens is performed implicitly, by encoding the 3D points into multi-modal features. The core design of CMT is quite simple while its performance is impressive. CMT obtains 73.0% NDS on nuScenes benchmark. Moreover, CMT has a strong robustness even if the LiDAR is missing. Code will be released at https://github.com/junjie18/CMT.
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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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Automatic music generation with artificial intelligence typically requires a large amount of data which is hard to obtain for many less common genres and musical instruments. To tackle this issue, we present ongoing work and preliminary findings on the possibility for deep models to transfer knowledge from language to music, by finetuning large language models pre-trained on a massive text corpus on only hundreds of MIDI files of drum performances. We show that by doing so, one of the largest, state-of-the-art models (GPT3) is capable of generating reasonable drum grooves, while models that are not pre-trained (Transformer) shows no such ability beyond naive repetition. Evaluating generated music is a challenging task, more so is evaluating drum grooves with little precedence in literature. Hence, we propose a tailored structural evaluation method and analyze drum grooves produced by GPT3 compared to those played by human professionals, exposing the strengths and weaknesses of such generation by language-to-music transfer. Our findings suggest that language-to-music transfer learning with large language models is viable and promising.
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