神经辐射场(NERF)具有密集捕获的输入图像实现光真实的视图合成。然而,鉴于稀疏的视图,NERF的几何形状极为严重,从而导致新观点合成质量的显着降解。受到自我监督的深度估计方法的启发,我们提出了structnerf,这是针对稀疏输入的室内场景的新型视图合成的解决方案。 structnerf利用自然嵌入多视图输入中的结构提示来处理NERF中无约束的几何问题。具体而言,它分别解决了纹理和非纹理区域:提出了基于贴片的多视图一致的光度损失来限制纹理区域的几何形状;对于非纹理的,我们明确地将它们限制为3D一致的平面。通过密集的自我监督深度约束,我们的方法可以改善NERF的几何形状和视图综合性能,而无需对外部数据进行任何其他培训。在几个现实世界数据集上进行的广泛实验表明,构造者超过了针对室内场景的最新方法,这些方法具有稀疏输入的定量和定性。
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通过深度传感器捕获的点云通常被噪音污染,阻碍了进一步的分析和应用。在本文中,我们强调了点分布均匀性对下游任务的重要性。我们证明了现有基于梯度的DeNoiser产生的点云尽管取得了有希望的定量结果,但仍缺乏统一性。为此,我们提出了GPCD ++,这是一种基于梯度的DeNoiser,其超轻质网络名为UNINET,以解决均匀性。与以前的最先进方法相比,我们的方法不仅会产生竞争性甚至更好地降解结果,而且还显着改善了统一性,这在很大程度上使诸如表面重建之类的应用受益。
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中心位置是否完全能够代表像素?在离散的图像表示中表示具有它们的中心的像素的错误,但是在图像超分辨率(SR)上下文中的局域脉中的信号的聚合时,它更有意义地考虑每个像素。尽管任意级图像SR领域的基于坐标的隐式表示的能力很大,但该区域的像素的性质不完全考虑。为此,我们提出了集成的位置编码(IPE),通过聚合在像素区域上聚合频率信息来扩展传统的位置编码。我们将IPE应用于最先进的任意级图像超分辨率方法:本地隐式图像功能(LIIF),呈现IPE-LIIF。我们通过定量和定性评估显示IPE-LIIF的有效性,并进一步证明了IPE泛化能力与更大的图像尺度和基于多种隐式的方法。代码将被释放。
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我们呈现NERF-SR,一种用于高分辨率(HR)新型视图合成的解决方案,主要是低分辨率(LR)输入。我们的方法是基于神经辐射场(NERF)的内置,其预测每点密度和颜色,具有多层的射击。在在任意尺度上产生图像时,NERF与超越观察图像的分辨率努力。我们的关键识别是NERF具有本地之前的,这意味着可以在附近区域传播3D点的预测,并且保持准确。我们首先通过超级采样策略来利用它,该策略在每个图像像素处射击多个光线,这在子像素级别强制了多视图约束。然后,我们表明,NERF-SR可以通过改进网络进一步提高超级采样的性能,该细化网络利用估计的深度来实现HR参考图像上的相关补丁的幻觉。实验结果表明,NERF-SR在合成和现实世界数据集的HR上为新型视图合成产生高质量结果。
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神经辐射场(NERF)使用基于坐标的神经场景表示实现了前所未有的视图合成质量。然而,NERF的视图依赖项只能处理像亮点的简单反射,而是无法处理复杂的反射,例如来自玻璃和镜子的复杂反射。在这些方案中,NERF将虚拟映像模拟为实际几何形状,这导致了不准确的深度估计,并且当违反多视图一致性时产生模糊渲染,因为只有在一些视点下只能看到反射对象。为了克服这些问题,我们介绍了nerfren,它建在nerf,以模拟思考的场景。具体地,我们建议将场景分成传输和反射的组件,并模拟具有单独的神经辐射场的两个组件。考虑到这种分解是高度限制的,我们利用几何前瞻,并仔细设计的培训策略,以实现合理的分解结果。各种自捕获场景的实验表明,我们的方法实现了高质量的新颖观看合成和物理声音深度估计结果,同时启用场景编辑应用。代码和数据将被释放。
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人类自然有效地在复杂的场景中找到突出区域。通过这种观察的动机,引入了计算机视觉中的注意力机制,目的是模仿人类视觉系统的这一方面。这种注意机制可以基于输入图像的特征被视为动态权重调整过程。注意机制在许多视觉任务中取得了巨大的成功,包括图像分类,对象检测,语义分割,视频理解,图像生成,3D视觉,多模态任务和自我监督的学习。在本调查中,我们对计算机愿景中的各种关注机制进行了全面的审查,并根据渠道注意,空间关注,暂时关注和分支注意力进行分类。相关的存储库https://github.com/menghaoguo/awesome-vision-tions致力于收集相关的工作。我们还建议了未来的注意机制研究方向。
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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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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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Blind image quality assessment (BIQA) remains challenging due to the diversity of distortion and image content variation, which complicate the distortion patterns crossing different scales and aggravate the difficulty of the regression problem for BIQA. However, existing BIQA methods often fail to consider multi-scale distortion patterns and image content, and little research has been done on learning strategies to make the regression model produce better performance. In this paper, we propose a simple yet effective Progressive Multi-Task Image Quality Assessment (PMT-IQA) model, which contains a multi-scale feature extraction module (MS) and a progressive multi-task learning module (PMT), to help the model learn complex distortion patterns and better optimize the regression issue to align with the law of human learning process from easy to hard. To verify the effectiveness of the proposed PMT-IQA model, we conduct experiments on four widely used public datasets, and the experimental results indicate that the performance of PMT-IQA is superior to the comparison approaches, and both MS and PMT modules improve the model's performance.
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