激光点云(LPC)的非均匀分布和极稀疏的性质给其高效压缩带来了重大挑战。本文提出了一个新颖的端到端,完全物质的深层框架,该框架将原始LPC编码为OCTREE结构,并分层分解OCTREE熵模型。所提出的框架利用层次的潜在变量作为侧面信息来封装兄弟姐妹和祖先依赖性,该依赖性为点云分布的建模提供了足够的上下文信息,同时启用了同一层中的Octree节点的并行编码和解码。此外,我们提出了一个用于压缩潜在变量的残留编码框架,该框架通过渐进的下采样探索了每一层的空间相关性,并用完全属于熵模型对相应的残差进行建模。此外,我们提出了剩余编码的软添加和减法,以提高网络灵活性。 LIDAR基准Semantickitti和MPEG指定数据集福特的综合实验结果表明,我们提出的框架在所有以前的LPC框架中都实现了最先进的性能。此外,我们的端到端,完全物质化的框架被实验证明是高平行和及时效率的,并且与以前的LPC压缩方法相比,与以前的最新方法相比,可以节省超过99.8%的解码时间。
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高速,高分辨率的立体视频(H2-STEREO)视频使我们能够在细粒度上感知动态3D内容。然而,对商品摄像机的收购H2-STEREO视频仍然具有挑战性。现有的空间超分辨率或时间框架插值方法分别提供了缺乏时间或空间细节的折衷解决方案。为了减轻这个问题,我们提出了一个双摄像头系统,其中一台相机捕获具有丰富空间细节的高空间分辨率低框架速率(HSR-LFR)视频,而另一个摄像头则捕获了低空间分辨率的高架框架-Rate(LSR-HFR)视频带有光滑的时间细节。然后,我们设计了一个学习的信息融合网络(LIFNET),该网络利用跨摄像机冗余,以增强两种相机视图,从而有效地重建H2-STEREO视频。即使在大型差异场景中,我们也利用一个差异网络将时空信息传输到视图上,基于该视图,我们建议使用差异引导的LSR-HFR视图基于差异引导的流量扭曲,并针对HSR-LFR视图进行互补的扭曲。提出了特征域中的多尺度融合方法,以最大程度地减少HSR-LFR视图中闭塞引起的翘曲幽灵和孔。 LIFNET使用YouTube收集的高质量立体视频数据集以端到端的方式进行训练。广泛的实验表明,对于合成数据和摄像头捕获的真实数据,我们的模型均优于现有的最新方法。消融研究探讨了各个方面,包括时空分辨率,摄像头基线,摄像头解理,长/短曝光和应用程序,以充分了解其对潜在应用的能力。
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我们提出了一种小说的无参考质量评估度量,图像转移点云质量评估(IT-PCQA),用于3D点云。对于质量评估,深度神经网络(DNN)在无参考度量设计上显示了令人信服的性能。但是,无引用PCQA最具挑战性的问题是我们缺乏大规模的主观数据库来驱动强大的网络。我们的动机是人类视觉系统(HVS)是决策者,无论质量评估的媒体类型如何。利用自然图像的丰富主观评分,我们可以通过DNN探讨人类感知的评估标准,并将预测的能力转移到3D点云。特别是,我们将自然图像视为源域和点云作为目标域,并通过无监督的对抗域适应推断云质量。为了提取有效的潜在特征并最小化域差异,我们提出了分层特征编码器和条件鉴别网络。考虑到最终目的是回归客观评分,我们在条件鉴别网络中引入了一种新的条件跨熵损失,以惩罚阻碍质量回归网络的收敛的负样本。实验结果表明,该方法可以实现比传统的无参考度量更高的性能,甚至与全引用度量的相当结果。该方法还表明,在没有昂贵和繁琐的主观评估的情况下评估特定媒体内容质量的可行性。
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Graph Neural Networks (GNNs) have shown satisfying performance on various graph learning tasks. To achieve better fitting capability, most GNNs are with a large number of parameters, which makes these GNNs computationally expensive. Therefore, it is difficult to deploy them onto edge devices with scarce computational resources, e.g., mobile phones and wearable smart devices. Knowledge Distillation (KD) is a common solution to compress GNNs, where a light-weighted model (i.e., the student model) is encouraged to mimic the behavior of a computationally expensive GNN (i.e., the teacher GNN model). Nevertheless, most existing GNN-based KD methods lack fairness consideration. As a consequence, the student model usually inherits and even exaggerates the bias from the teacher GNN. To handle such a problem, we take initial steps towards fair knowledge distillation for GNNs. Specifically, we first formulate a novel problem of fair knowledge distillation for GNN-based teacher-student frameworks. Then we propose a principled framework named RELIANT to mitigate the bias exhibited by the student model. Notably, the design of RELIANT is decoupled from any specific teacher and student model structures, and thus can be easily adapted to various GNN-based KD frameworks. We perform extensive experiments on multiple real-world datasets, which corroborates that RELIANT achieves less biased GNN knowledge distillation while maintaining high prediction utility.
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This paper presents a comprehensive survey of low-light image and video enhancement. We begin with the challenging mixed over-/under-exposed images, which are under-performed by existing methods. To this end, we propose two variants of the SICE dataset named SICE_Grad and SICE_Mix. Next, we introduce Night Wenzhou, a large-scale, high-resolution video dataset, to address the issue of the lack of a low-light video dataset that discount the use of low-light image enhancement (LLIE) to videos. The Night Wenzhou dataset is challenging since it consists of fast-moving aerial scenes and streetscapes with varying illuminations and degradation. We conduct extensive key technique analysis and experimental comparisons for representative LLIE approaches using these newly proposed datasets and the current benchmark datasets. Finally, we address unresolved issues and propose future research topics for the LLIE community.
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Online learning naturally arises in many statistical and machine learning problems. The most widely used methods in online learning are stochastic first-order algorithms. Among this family of algorithms, there is a recently developed algorithm, Recursive One-Over-T SGD (ROOT-SGD). ROOT-SGD is advantageous in that it converges at a non-asymptotically fast rate, and its estimator further converges to a normal distribution. However, this normal distribution has unknown asymptotic covariance; thus cannot be directly applied to measure the uncertainty. To fill this gap, we develop two estimators for the asymptotic covariance of ROOT-SGD. Our covariance estimators are useful for statistical inference in ROOT-SGD. Our first estimator adopts the idea of plug-in. For each unknown component in the formula of the asymptotic covariance, we substitute it with its empirical counterpart. The plug-in estimator converges at the rate $\mathcal{O}(1/\sqrt{t})$, where $t$ is the sample size. Despite its quick convergence, the plug-in estimator has the limitation that it relies on the Hessian of the loss function, which might be unavailable in some cases. Our second estimator is a Hessian-free estimator that overcomes the aforementioned limitation. The Hessian-free estimator uses the random-scaling technique, and we show that it is an asymptotically consistent estimator of the true covariance.
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In this work we propose a novel token-based training strategy that improves Transformer-Transducer (T-T) based speaker change detection (SCD) performance. The conventional T-T based SCD model loss optimizes all output tokens equally. Due to the sparsity of the speaker changes in the training data, the conventional T-T based SCD model loss leads to sub-optimal detection accuracy. To mitigate this issue, we use a customized edit-distance algorithm to estimate the token-level SCD false accept (FA) and false reject (FR) rates during training and optimize model parameters to minimize a weighted combination of the FA and FR, focusing the model on accurately predicting speaker changes. We also propose a set of evaluation metrics that align better with commercial use cases. Experiments on a group of challenging real-world datasets show that the proposed training method can significantly improve the overall performance of the SCD model with the same number of parameters.
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Computing empirical Wasserstein distance in the independence test is an optimal transport (OT) problem with a special structure. This observation inspires us to study a special type of OT problem and propose a modified Hungarian algorithm to solve it exactly. For an OT problem involving two marginals with $m$ and $n$ atoms ($m\geq n$), respectively, the computational complexity of the proposed algorithm is $O(m^2n)$. Computing the empirical Wasserstein distance in the independence test requires solving this special type of OT problem, where $m=n^2$. The associated computational complexity of the proposed algorithm is $O(n^5)$, while the order of applying the classic Hungarian algorithm is $O(n^6)$. In addition to the aforementioned special type of OT problem, it is shown that the modified Hungarian algorithm could be adopted to solve a wider range of OT problems. Broader applications of the proposed algorithm are discussed -- solving the one-to-many and the many-to-many assignment problems. Numerical experiments are conducted to validate our theoretical results. The experiment results demonstrate that the proposed modified Hungarian algorithm compares favorably with the Hungarian algorithm and the well-known Sinkhorn algorithm.
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While recent research advances in speaker diarization mostly focus on improving the quality of diarization results, there is also an increasing interest in improving the efficiency of diarization systems. In this paper, we propose a multi-stage clustering strategy, that uses different clustering algorithms for input of different lengths. Specifically, a fallback clusterer is used to handle short-form inputs; a main clusterer is used to handle medium-length inputs; and a pre-clusterer is used to compress long-form inputs before they are processed by the main clusterer. Both the main clusterer and the pre-clusterer can be configured with an upper bound of the computational complexity to adapt to devices with different constraints. This multi-stage clustering strategy is critical for streaming on-device speaker diarization systems, where the budgets of CPU, memory and battery are tight.
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人工智能(AI)系统越来越多地用于提供建议以促进人类决策。尽管大量工作探讨了如何优化AI系统以产生准确且公平的建议以及如何向人类决策者提供算法建议,但在这项工作中,我们提出了一个不同的基本问题:何时应该提供建议?由于当前不断提供算法建议的局限性的限制,我们提出了以双向方式与人类用户互动的AI系统的设计。我们的AI系统学习使用过去的人类决策为政策提供建议。然后,对于新案例,学识渊博的政策利用人类的意见来确定算法建议将是有用的案例,以及人类最好单独决定的情况。我们通过使用美国刑事司法系统的数据对审前释放决策进行大规模实验来评估我们的方法。在我们的实验中,要求参与者评估被告违反其释放条款的风险,如果释放,并受到不同建议方法的建议。结果表明,与固定的非交互式建议方法相比,我们的交互式辅助方法可以在需要时提供建议,并显着改善人类决策。我们的方法在促进人类学习,保留人类决策者的互补优势以及对建议的更积极反应方面具有额外的优势。
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