本文旨在探讨如何合成对其进行训练的现有视频脱毛模型的近距离模糊,可以很好地推广到现实世界中的模糊视频。近年来,基于深度学习的方法已在视频Deblurring任务上取得了希望的成功。但是,对现有合成数据集培训的模型仍然遭受了与现实世界中的模糊场景的概括问题。造成故障的因素仍然未知。因此,我们重新审视经典的模糊综合管道,并找出可能的原因,包括拍摄参数,模糊形成空间和图像信号处理器〜(ISP)。为了分析这些潜在因素的效果,我们首先收集一个超高帧速率(940 fps)原始视频数据集作为数据基础,以综合各种模糊。然后,我们提出了一种新颖的现实模糊合成管道,该管道通过利用模糊形成线索称为原始爆炸。通过大量实验,我们证明了在原始空间中的合成模糊并采用与现实世界测试数据相同的ISP可以有效消除合成数据的负面影响。此外,合成的模糊视频的拍摄参数,例如,曝光时间和框架速率在改善脱毛模型的性能中起着重要作用。令人印象深刻的是,与在现有合成模糊数据集中训练的训练的模型合成的模糊数据训练的模型可以获得超过5DB PSNR的增益。我们认为,新颖的现实合成管道和相应的原始视频数据集可以帮助社区轻松构建自定义的Blur数据集,以改善现实世界的视频DeBlurring性能,而不是费力地收集真实的数据对。
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由于空间和时间变化的模糊,视频脱毛是一个高度不足的问题。视频脱毛的直观方法包括两个步骤:a)检测当前框架中的模糊区域; b)利用来自相邻帧中清晰区域的信息,以使当前框架脱毛。为了实现这一过程,我们的想法是检测每个帧的像素模糊级别,并将其与视频Deblurring结合使用。为此,我们提出了一个新颖的框架,该框架利用了先验运动级(MMP)作为有效的深视频脱张的指南。具体而言,由于在曝光时间内沿其轨迹的像素运动与运动模糊水平呈正相关,因此我们首先使用高频尖锐框架的光流量的平均幅度来生成合成模糊框架及其相应的像素 - 像素 - 明智的运动幅度地图。然后,我们构建一个数据集,包括模糊框架和MMP对。然后,由紧凑的CNN通过回归来学习MMP。 MMP包括空间和时间模糊级别的信息,可以将其进一步集成到视频脱毛的有效复发性神经网络(RNN)中。我们进行密集的实验,以验证公共数据集中提出的方法的有效性。
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我们研究了从单个运动毛发图像中恢复详细运动的挑战性问题。该问题的现有解决方案估算一个单个图像序列,而无需考虑每个区域的运动歧义。因此,结果倾向于收敛到多模式可能性的平均值。在本文中,我们明确说明了这种运动歧义,使我们能够详细地生成多个合理的解决方案。关键思想是引入运动引导表示,这是对仅有四个离散运动方向的2D光流的紧凑量量化。在运动引导的条件下,模糊分解通过使用新型的两阶段分解网络导致了特定的,明确的解决方案。我们提出了一个模糊分解的统一框架,该框架支持各种界面来生成我们的运动指导,包括人类输入,来自相邻视频帧的运动信息以及从视频数据集中学习。关于合成数据集和现实世界数据的广泛实验表明,所提出的框架在定性和定量上优于以前的方法,并且还具有生产物理上合理和多样的解决方案的优点。代码可从https://github.com/zzh-tech/animation-from-blur获得。
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滚动快门(RS)失真可以解释为在RS摄像机曝光期间,随着时间的推移从瞬时全局快门(GS)框架中挑选一排像素。这意味着每个即时GS帧的信息部分,依次是嵌入到行依赖性失真中。受到这一事实的启发,我们解决了扭转这一过程的挑战性任务,即从rs失真中的图像中提取未变形的GS框架。但是,由于RS失真与其他因素相结合,例如读数设置以及场景元素与相机的相对速度,因此仅利用临时相邻图像之间的几何相关性的型号,在处理数据中,具有不同的读数设置和动态场景的数据中遭受了不良的通用性。带有相机运动和物体运动。在本文中,我们建议使用双重RS摄像机捕获的一对图像,而不是连续的框架,而RS摄像机则具有相反的RS方向,以完成这项极具挑战性的任务。基于双重反转失真的对称和互补性,我们开发了一种新型的端到端模型,即IFED,以通过卢比时间对速度场的迭代学习来生成双重光流序列。广泛的实验结果表明,IFED优于天真的级联方案,以及利用相邻RS图像的最新艺术品。最重要的是,尽管它在合成数据集上进行了训练,但显示出在从现实世界中的RS扭曲的动态场景图像中检索GS框架序列有效。代码可在https://github.com/zzh-tech/dual-versed-rs上找到。
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A recent study has shown a phenomenon called neural collapse in that the within-class means of features and the classifier weight vectors converge to the vertices of a simplex equiangular tight frame at the terminal phase of training for classification. In this paper, we explore the corresponding structures of the last-layer feature centers and classifiers in semantic segmentation. Based on our empirical and theoretical analysis, we point out that semantic segmentation naturally brings contextual correlation and imbalanced distribution among classes, which breaks the equiangular and maximally separated structure of neural collapse for both feature centers and classifiers. However, such a symmetric structure is beneficial to discrimination for the minor classes. To preserve these advantages, we introduce a regularizer on feature centers to encourage the network to learn features closer to the appealing structure in imbalanced semantic segmentation. Experimental results show that our method can bring significant improvements on both 2D and 3D semantic segmentation benchmarks. Moreover, our method ranks 1st and sets a new record (+6.8% mIoU) on the ScanNet200 test leaderboard. Code will be available at https://github.com/dvlab-research/Imbalanced-Learning.
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Although deep learning has made remarkable progress in processing various types of data such as images, text and speech, they are known to be susceptible to adversarial perturbations: perturbations specifically designed and added to the input to make the target model produce erroneous output. Most of the existing studies on generating adversarial perturbations attempt to perturb the entire input indiscriminately. In this paper, we propose ExploreADV, a general and flexible adversarial attack system that is capable of modeling regional and imperceptible attacks, allowing users to explore various kinds of adversarial examples as needed. We adapt and combine two existing boundary attack methods, DeepFool and Brendel\&Bethge Attack, and propose a mask-constrained adversarial attack system, which generates minimal adversarial perturbations under the pixel-level constraints, namely ``mask-constraints''. We study different ways of generating such mask-constraints considering the variance and importance of the input features, and show that our adversarial attack system offers users good flexibility to focus on sub-regions of inputs, explore imperceptible perturbations and understand the vulnerability of pixels/regions to adversarial attacks. We demonstrate our system to be effective based on extensive experiments and user study.
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Recently the deep learning has shown its advantage in representation learning and clustering for time series data. Despite the considerable progress, the existing deep time series clustering approaches mostly seek to train the deep neural network by some instance reconstruction based or cluster distribution based objective, which, however, lack the ability to exploit the sample-wise (or augmentation-wise) contrastive information or even the higher-level (e.g., cluster-level) contrastiveness for learning discriminative and clustering-friendly representations. In light of this, this paper presents a deep temporal contrastive clustering (DTCC) approach, which for the first time, to our knowledge, incorporates the contrastive learning paradigm into the deep time series clustering research. Specifically, with two parallel views generated from the original time series and their augmentations, we utilize two identical auto-encoders to learn the corresponding representations, and in the meantime perform the cluster distribution learning by incorporating a k-means objective. Further, two levels of contrastive learning are simultaneously enforced to capture the instance-level and cluster-level contrastive information, respectively. With the reconstruction loss of the auto-encoder, the cluster distribution loss, and the two levels of contrastive losses jointly optimized, the network architecture is trained in a self-supervised manner and the clustering result can thereby be obtained. Experiments on a variety of time series datasets demonstrate the superiority of our DTCC approach over the state-of-the-art.
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Accurate and smooth global navigation satellite system (GNSS) positioning for pedestrians in urban canyons is still a challenge due to the multipath effects and the non-light-of-sight (NLOS) receptions caused by the reflections from surrounding buildings. The recently developed factor graph optimization (FGO) based GNSS positioning method opened a new window for improving urban GNSS positioning by effectively exploiting the measurement redundancy from the historical information to resist the outlier measurements. Unfortunately, the FGO-based GNSS standalone positioning is still challenged in highly urbanized areas. As an extension of the previous FGO-based GNSS positioning method, this paper exploits the potential of the pedestrian dead reckoning (PDR) model in FGO to improve the GNSS standalone positioning performance in urban canyons. Specifically, the relative motion of the pedestrian is estimated based on the raw acceleration measurements from the onboard smartphone inertial measurement unit (IMU) via the PDR algorithm. Then the raw GNSS pseudorange, Doppler measurements, and relative motion from PDR are integrated using the FGO. Given the context of pedestrian navigation with a small acceleration most of the time, a novel soft motion model is proposed to smooth the states involved in the factor graph model. The effectiveness of the proposed method is verified step-by-step through two datasets collected in dense urban canyons of Hong Kong using smartphone-level GNSS receivers. The comparison between the conventional extended Kalman filter, several existing methods, and FGO-based integration is presented. The results reveal that the existing FGO-based GNSS standalone positioning is highly complementary to the PDR's relative motion estimation. Both improved positioning accuracy and trajectory smoothness are obtained with the help of the proposed method.
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CutMix is a vital augmentation strategy that determines the performance and generalization ability of vision transformers (ViTs). However, the inconsistency between the mixed images and the corresponding labels harms its efficacy. Existing CutMix variants tackle this problem by generating more consistent mixed images or more precise mixed labels, but inevitably introduce heavy training overhead or require extra information, undermining ease of use. To this end, we propose an efficient and effective Self-Motivated image Mixing method (SMMix), which motivates both image and label enhancement by the model under training itself. Specifically, we propose a max-min attention region mixing approach that enriches the attention-focused objects in the mixed images. Then, we introduce a fine-grained label assignment technique that co-trains the output tokens of mixed images with fine-grained supervision. Moreover, we devise a novel feature consistency constraint to align features from mixed and unmixed images. Due to the subtle designs of the self-motivated paradigm, our SMMix is significant in its smaller training overhead and better performance than other CutMix variants. In particular, SMMix improves the accuracy of DeiT-T/S, CaiT-XXS-24/36, and PVT-T/S/M/L by more than +1% on ImageNet-1k. The generalization capability of our method is also demonstrated on downstream tasks and out-of-distribution datasets. Code of this project is available at https://github.com/ChenMnZ/SMMix.
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In person re-identification (ReID) tasks, many works explore the learning of part features to improve the performance over global image features. Existing methods extract part features in an explicit manner, by either using a hand-designed image division or keypoints obtained with external visual systems. In this work, we propose to learn Discriminative implicit Parts (DiPs) which are decoupled from explicit body parts. Therefore, DiPs can learn to extract any discriminative features that can benefit in distinguishing identities, which is beyond predefined body parts (such as accessories). Moreover, we propose a novel implicit position to give a geometric interpretation for each DiP. The implicit position can also serve as a learning signal to encourage DiPs to be more position-equivariant with the identity in the image. Lastly, a set of attributes and auxiliary losses are introduced to further improve the learning of DiPs. Extensive experiments show that the proposed method achieves state-of-the-art performance on multiple person ReID benchmarks.
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