Face Anti-spoofing (FAS) is essential to secure face recognition systems from various physical attacks. However, recent research generally focuses on short-distance applications (i.e., phone unlocking) while lacking consideration of long-distance scenes (i.e., surveillance security checks). In order to promote relevant research and fill this gap in the community, we collect a large-scale Surveillance High-Fidelity Mask (SuHiFiMask) dataset captured under 40 surveillance scenes, which has 101 subjects from different age groups with 232 3D attacks (high-fidelity masks), 200 2D attacks (posters, portraits, and screens), and 2 adversarial attacks. In this scene, low image resolution and noise interference are new challenges faced in surveillance FAS. Together with the SuHiFiMask dataset, we propose a Contrastive Quality-Invariance Learning (CQIL) network to alleviate the performance degradation caused by image quality from three aspects: (1) An Image Quality Variable module (IQV) is introduced to recover image information associated with discrimination by combining the super-resolution network. (2) Using generated sample pairs to simulate quality variance distributions to help contrastive learning strategies obtain robust feature representation under quality variation. (3) A Separate Quality Network (SQN) is designed to learn discriminative features independent of image quality. Finally, a large number of experiments verify the quality of the SuHiFiMask dataset and the superiority of the proposed CQIL.
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Latent factor model estimation typically relies on either using domain knowledge to manually pick several observed covariates as factor proxies, or purely conducting multivariate analysis such as principal component analysis. However, the former approach may suffer from the bias while the latter can not incorporate additional information. We propose to bridge these two approaches while allowing the number of factor proxies to diverge, and hence make the latent factor model estimation robust, flexible, and statistically more accurate. As a bonus, the number of factors is also allowed to grow. At the heart of our method is a penalized reduced rank regression to combine information. To further deal with heavy-tailed data, a computationally attractive penalized robust reduced rank regression method is proposed. We establish faster rates of convergence compared with the benchmark. Extensive simulations and real examples are used to illustrate the advantages.
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Recently deep neural networks, which require a large amount of annotated samples, have been widely applied in nuclei instance segmentation of H\&E stained pathology images. However, it is inefficient and unnecessary to label all pixels for a dataset of nuclei images which usually contain similar and redundant patterns. Although unsupervised and semi-supervised learning methods have been studied for nuclei segmentation, very few works have delved into the selective labeling of samples to reduce the workload of annotation. Thus, in this paper, we propose a novel full nuclei segmentation framework that chooses only a few image patches to be annotated, augments the training set from the selected samples, and achieves nuclei segmentation in a semi-supervised manner. In the proposed framework, we first develop a novel consistency-based patch selection method to determine which image patches are the most beneficial to the training. Then we introduce a conditional single-image GAN with a component-wise discriminator, to synthesize more training samples. Lastly, our proposed framework trains an existing segmentation model with the above augmented samples. The experimental results show that our proposed method could obtain the same-level performance as a fully-supervised baseline by annotating less than 5% pixels on some benchmarks.
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Multilingual end-to-end models have shown great improvement over monolingual systems. With the development of pre-training methods on speech, self-supervised multilingual speech representation learning like XLSR has shown success in improving the performance of multilingual automatic speech recognition (ASR). However, similar to the supervised learning, multilingual pre-training may also suffer from language interference and further affect the application of multilingual system. In this paper, we introduce several techniques for improving self-supervised multilingual pre-training by leveraging auxiliary language information, including the language adversarial training, language embedding and language adaptive training during the pre-training stage. We conduct experiments on a multilingual ASR task consisting of 16 languages. Our experimental results demonstrate 14.3% relative gain over the standard XLSR model, and 19.8% relative gain over the no pre-training multilingual model.
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The material science literature contains up-to-date and comprehensive scientific knowledge of materials. However, their content is unstructured and diverse, resulting in a significant gap in providing sufficient information for material design and synthesis. To this end, we used natural language processing (NLP) and computer vision (CV) techniques based on convolutional neural networks (CNN) to discover valuable experimental-based information about nanomaterials and synthesis methods in energy-material-related publications. Our first system, TextMaster, extracts opinions from texts and classifies them into challenges and opportunities, achieving 94% and 92% accuracy, respectively. Our second system, GraphMaster, realizes data extraction of tables and figures from publications with 98.3\% classification accuracy and 4.3% data extraction mean square error. Our results show that these systems could assess the suitability of materials for a certain application by evaluation of synthesis insights and case analysis with detailed references. This work offers a fresh perspective on mining knowledge from scientific literature, providing a wide swatch to accelerate nanomaterial research through CNN.
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This paper proposes a hardware-efficient architecture, Linearized Convolution Network (LiCo-Net) for keyword spotting. It is optimized specifically for low-power processor units like microcontrollers. ML operators exhibit heterogeneous efficiency profiles on power-efficient hardware. Given the exact theoretical computation cost, int8 operators are more computation-effective than float operators, and linear layers are often more efficient than other layers. The proposed LiCo-Net is a dual-phase system that uses the efficient int8 linear operators at the inference phase and applies streaming convolutions at the training phase to maintain a high model capacity. The experimental results show that LiCo-Net outperforms single-value decomposition filter (SVDF) on hardware efficiency with on-par detection performance. Compared to SVDF, LiCo-Net reduces cycles by 40% on HiFi4 DSP.
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We present state advantage weighting for offline reinforcement learning (RL). In contrast to action advantage $A(s,a)$ that we commonly adopt in QSA learning, we leverage state advantage $A(s,s^\prime)$ and QSS learning for offline RL, hence decoupling the action from values. We expect the agent can get to the high-reward state and the action is determined by how the agent can get to that corresponding state. Experiments on D4RL datasets show that our proposed method can achieve remarkable performance against the common baselines. Furthermore, our method shows good generalization capability when transferring from offline to online.
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深度神经网络(DNN)已在脑病变检测和分割中广泛采用。但是,在2D MRI切片中定位小病变是具有挑战性的,需要在3D上下文聚集的粒度和计算复杂性之间取得平衡。在本文中,我们提出了一种新型的视角变压器,以增强MRI特征的提取,以进行更准确的肿瘤检测。首先,所提出的变压器在3D脑扫描中收获了不同位置之间的远程相关性。其次,变压器将一堆切片功能堆叠为多个2D视图,并增强这些特征的视图,该功能大致以有效的方式实现了3D相关计算。第三,我们将提出的变压器模块部署在变压器主链中,该模块可以有效地检测到脑损伤周围的2D区域。实验结果表明,我们提出的观看式变压器在具有挑战性的大脑MRI数据集上对大脑病变检测表现良好。
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基于图像补丁重建的自我监督学习方法在培训自动编码器方面取得了巨大的成功,其预训练的权重可以转移到微调图像理解的其他下游任务。但是,现有方法很少研究重建斑块的各种重要性和解剖结构的对称性,当它们应用于3D医学图像时。在本文中,我们提出了一种基于3D脑MRI分割任务的视觉变压器(VIT)的新颖的对称自动编码器(ASA)。我们猜想,强迫自动编码器恢复信息性图像区域可以收获更多的判别性表示,而不是恢复光滑的图像贴片。然后,我们采用基于梯度的指标来估计每个图像补丁的重要性。在预训练阶段,提议的自动编码器更多地注意根据梯度指标重建信息贴片。此外,我们求助于大脑结构的先验,并开发一种对称位置编码(SPE)方法,以更好地利用远距离但空间对称区域之间的相关性以获得有效的特征。实验结果表明,我们提出的细心对称自动编码器的表现优于三个大脑MRI分割基准的最先进的自我监督学习方法和医学图像分割模型。
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医学视觉和语言预训练(MED-VLP)由于适用于从医学图像和文本中提取通用视觉和语言表示的适用性而受到了相当大的关注。大多数现有方法主要包含三个元素:Uni-Modal编码器(即视觉编码器和语言编码器),多模式融合模块以及借口任务,很少有研究考虑医疗领域专家知识的重要性,并明确利用此类此类此类此类此类。知识以促进Med-vlp。尽管在通用域中存在具有知识增强的视觉和语言预训练(VLP)方法,但大多数人都需要现成的工具包(例如,对象检测器和场景图解析器),这些工具包在医疗领域中是不可用的。在本文中,我们提出了一种系统有效的方法,从三个角度通过结构化医学知识来增强MED-VLP。首先,考虑知识可以被视为视觉和语言之间的中间媒介,我们通过知识对齐视觉编码器和语言编码器的表示。其次,我们将知识注入多模式融合模型,以使模型能够使用知识作为补充输入图像和文本进行推理。第三,我们指导该模型通过设计知识引起的借口任务来强调图像和文本中最关键的信息。为了进行全面的评估并促进进一步的研究,我们构建了包括三个任务的医学视觉和语言基准。实验结果说明了我们方法的有效性,在所有下游任务上都实现了最先进的性能。进一步的分析探讨了我们方法的不同组成部分和预训练的各种环境的影响。
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