最先进的面部识别方法通常采用多分类管道，并采用基于SoftMax的损耗进行优化。虽然这些方法取得了巨大的成功，但基于Softmax的损失在开放式分类的角度下有其限制：训练阶段的多分类目标并没有严格匹配开放式分类测试的目标。在本文中，我们派生了一个名为全局边界Cosface的新损失（GB-Cosface）。我们的GB-COSface介绍了自适应全局边界，以确定两个面积是否属于相同的身份，使得优化目标与从开放集分类的角度与测试过程对齐。同时，由于损失配方来自于基于软MAX的损失，因此我们的GB-COSFace保留了基于软MAX的损耗的优异性能，并且证明了COSFace是拟议损失的特殊情况。我们在几何上分析并解释了所提出的GB-Cosface。多面识别基准测试的综合实验表明，所提出的GB-Cosface优于主流面部识别任务中的当前最先进的面部识别损失。与Cosface相比，我们的GB-Cosface在Tar @ Far = 1E-6，1E-5，1E-4上提高了1.58％，0.57％和0.28％的IJB-C基准。

Face recognition has made extraordinary progress owing to the advancement of deep convolutional neural networks (CNNs). The central task of face recognition, including face verification and identification, involves face feature discrimination. However, the traditional softmax loss of deep CNNs usually lacks the power of discrimination. To address this problem, recently several loss functions such as center loss, large margin softmax loss, and angular softmax loss have been proposed. All these improved losses share the same idea: maximizing inter-class variance and minimizing intra-class variance. In this paper, we propose a novel loss function, namely large margin cosine loss (LMCL), to realize this idea from a different perspective. More specifically, we reformulate the softmax loss as a cosine loss by L 2 normalizing both features and weight vectors to remove radial variations, based on which a cosine margin term is introduced to further maximize the decision margin in the angular space. As a result, minimum intra-class variance and maximum inter-class variance are achieved by virtue of normalization and cosine decision margin maximization. We refer to our model trained with LMCL as CosFace. Extensive experimental evaluations are conducted on the most popular public-domain face recognition datasets such as MegaFace Challenge, Youtube Faces (YTF) and Labeled Face in the Wild (LFW). We achieve the state-of-the-art performance on these benchmarks, which confirms the effectiveness of our proposed approach.

Recently, a popular line of research in face recognition is adopting margins in the well-established softmax loss function to maximize class separability. In this paper, we first introduce an Additive Angular Margin Loss (ArcFace), which not only has a clear geometric interpretation but also significantly enhances the discriminative power. Since ArcFace is susceptible to the massive label noise, we further propose sub-center ArcFace, in which each class contains K sub-centers and training samples only need to be close to any of the K positive sub-centers. Sub-center ArcFace encourages one dominant sub-class that contains the majority of clean faces and non-dominant sub-classes that include hard or noisy faces. Based on this self-propelled isolation, we boost the performance through automatically purifying raw web faces under massive real-world noise. Besides discriminative feature embedding, we also explore the inverse problem, mapping feature vectors to face images. Without training any additional generator or discriminator, the pre-trained ArcFace model can generate identity-preserved face images for both subjects inside and outside the training data only by using the network gradient and Batch Normalization (BN) priors. Extensive experiments demonstrate that ArcFace can enhance the discriminative feature embedding as well as strengthen the generative face synthesis.

学习歧视性面部特征在建立高性能面部识别模型方面发挥着重要作用。最近的最先进的面部识别解决方案，提出了一种在常用的分类损失函数，Softmax损失中纳入固定的惩罚率，通过最大限度地减少级别的变化来增加面部识别模型的辨别力并最大化级别的帧间变化。边缘惩罚Softmax损失，如arcFace和Cosface，假设可以使用固定的惩罚余量同样地学习不同身份之间的测地距。然而，这种学习目标对于具有不一致的间帧内变化的真实数据并不是现实的，这可能限制了面部识别模型的判别和概括性。在本文中，我们通过提出弹性罚款损失（弹性面）来放松固定的罚款边缘约束，这允许在推动阶级可分离性中灵活性。主要思想是利用从每个训练迭代中的正常分布中汲取的随机保证金值。这旨在提供决策边界机会，以提取和缩回，以允许灵活的类别可分离学习的空间。我们展示了在大量主流基准上使用相同的几何变换，展示了我们的弹性面损失和COSFace损失的优势。从更广泛的角度来看，我们的弹性面在九个主流基准中提出了最先进的面部识别性能。

基于软马克斯的损失函数及其变体（例如，界面，圆顶和弧形）可显着改善野生无约束场景中的面部识别性能。这些算法的一种常见实践是对嵌入特征和线性转换矩阵之间的乘法进行优化。但是，在大多数情况下，基于传统的设计经验给出了嵌入功能的尺寸，并且在给出固定尺寸时，使用该功能本身提高性能的研究较少。为了应对这一挑战，本文提出了一种称为subface的软关系近似方法，该方法采用了子空间功能来促进面部识别的性能。具体而言，我们在训练过程中动态选择每个批次中的非重叠子空间特征，然后使用子空间特征在基于软磁性的损失之间近似完整功能，因此，深层模型的可区分性可以显着增强，以增强面部识别。在基准数据集上进行的综合实验表明，我们的方法可以显着提高香草CNN基线的性能，这强烈证明了基于利润率的损失的子空间策略的有效性。

This paper addresses deep face recognition (FR) problem under open-set protocol, where ideal face features are expected to have smaller maximal intra-class distance than minimal inter-class distance under a suitably chosen metric space. However, few existing algorithms can effectively achieve this criterion. To this end, we propose the angular softmax (A-Softmax) loss that enables convolutional neural networks (CNNs) to learn angularly discriminative features. Geometrically, A-Softmax loss can be viewed as imposing discriminative constraints on a hypersphere manifold, which intrinsically matches the prior that faces also lie on a manifold. Moreover, the size of angular margin can be quantitatively adjusted by a parameter m. We further derive specific m to approximate the ideal feature criterion. Extensive analysis and experiments on Labeled Face in the Wild (LFW), Youtube Faces (YTF) and MegaFace Challenge show the superiority of A-Softmax loss in FR tasks. The code has also been made publicly available 1 .

This paper provides a pair similarity optimization viewpoint on deep feature learning, aiming to maximize the within-class similarity s p and minimize the between-class similarity s n . We find a majority of loss functions, including the triplet loss and the softmax cross-entropy loss, embed s n and s p into similarity pairs and seek to reduce (s n − s p ). Such an optimization manner is inflexible, because the penalty strength on every single similarity score is restricted to be equal. Our intuition is that if a similarity score deviates far from the optimum, it should be emphasized. To this end, we simply re-weight each similarity to highlight the less-optimized similarity scores. It results in a Circle loss, which is named due to its circular decision boundary. The Circle loss has a unified formula for two elemental deep feature learning paradigms, i.e., learning with class-level labels and pair-wise labels. Analytically, we show that the Circle loss offers a more flexible optimization approach towards a more definite convergence target, compared with the loss functions optimizing (s n − s p ). Experimentally, we demonstrate the superiority of the Circle loss on a variety of deep feature learning tasks. On face recognition, person re-identification, as well as several finegrained image retrieval datasets, the achieved performance is on par with the state of the art.

In this paper, we propose a conceptually simple and geometrically interpretable objective function, i.e. additive margin Softmax (AM-Softmax), for deep face verification. In general, the face verification task can be viewed as a metric learning problem, so learning large-margin face features whose intra-class variation is small and inter-class difference is large is of great importance in order to achieve good performance. Recently, Large-margin Softmax [10] and Angular Softmax [9] have been proposed to incorporate the angular margin in a multiplicative manner. In this work, we introduce a novel additive angular margin for the Softmax loss, which is intuitively appealing and more interpretable than the existing works. We also emphasize and discuss the importance of feature normalization in the paper. Most importantly, our experiments on LFW and MegaFace show that our additive margin softmax loss consistently performs better than the current state-of-the-art methods using the same network architecture and training dataset. Our code has also been made available 1 .

Recent years witnessed the breakthrough of face recognition with deep convolutional neural networks. Dozens of papers in the field of FR are published every year. Some of them were applied in the industrial community and played an important role in human life such as device unlock, mobile payment, and so on. This paper provides an introduction to face recognition, including its history, pipeline, algorithms based on conventional manually designed features or deep learning, mainstream training, evaluation datasets, and related applications. We have analyzed and compared state-of-the-art works as many as possible, and also carefully designed a set of experiments to find the effect of backbone size and data distribution. This survey is a material of the tutorial named The Practical Face Recognition Technology in the Industrial World in the FG2023.

视觉世界中新对象的不断出现对现实世界部署中当前的深度学习方法构成了巨大的挑战。由于稀有性或成本，新任务学习的挑战通常会加剧新类别的数据。在这里，我们探讨了几乎没有类别学习的重要任务（FSCIL）及其极端数据稀缺条件。理想的FSCIL模型都需要在所有类别上表现良好，无论其显示顺序或数据的匮乏。开放式现实世界条件也需要健壮，并可以轻松地适应始终在现场出现的新任务。在本文中，我们首先重新评估当前的任务设置，并为FSCIL任务提出更全面和实用的设置。然后，受到FSCIL和现代面部识别系统目标的相似性的启发，我们提出了我们的方法 - 增强角损失渐进分类或爱丽丝。在爱丽丝（Alice）中，我们建议使用角度损失损失来获得良好的特征。由于所获得的功能不仅需要紧凑，而且还需要足够多样化以维持未来的增量类别的概括，我们进一步讨论了类增强，数据增强和数据平衡如何影响分类性能。在包括CIFAR100，Miniimagenet和Cub200在内的基准数据集上的实验证明了爱丽丝在最新的FSCIL方法上的性能提高。

基于深度学习的分类中特征表示的主要挑战之一是设计表现出强大歧视力的适当损失功能。经典的SoftMax损失并不能明确鼓励对特征的歧视性学习。研究的一个流行方向是将边缘纳入良好的损失中，以实施额外的课内紧凑性和阶层间的可分离性，但是，这是通过启发式手段而不是严格的数学原则来开发的。在这项工作中，我们试图通过将原则优化目标提出为最大的利润率来解决这一限制。具体而言，我们首先将类别的边缘定义为级别间的可分离性的度量，而样品边缘是级别的紧凑性的度量。因此，为了鼓励特征的歧视性表示，损失函数应促进类和样品的最大可能边缘。此外，我们得出了广义的保证金软损失，以得出现有基于边缘的损失的一般结论。这个原则性的框架不仅提供了新的观点来理解和解释现有的基于保证金的损失，而且还提供了新的见解，可以指导新工具的设计，包括样本保证金正则化和最大的平衡案例的最大保证金损失，和零中心的正则化案例。实验结果证明了我们的策略对各种任务的有效性，包括视觉分类，分类不平衡，重新识别和面部验证。

Although significant progress has been made in face recognition, demographic bias still exists in face recognition systems. For instance, it usually happens that the face recognition performance for a certain demographic group is lower than the others. In this paper, we propose MixFairFace framework to improve the fairness in face recognition models. First of all, we argue that the commonly used attribute-based fairness metric is not appropriate for face recognition. A face recognition system can only be considered fair while every person has a close performance. Hence, we propose a new evaluation protocol to fairly evaluate the fairness performance of different approaches. Different from previous approaches that require sensitive attribute labels such as race and gender for reducing the demographic bias, we aim at addressing the identity bias in face representation, i.e., the performance inconsistency between different identities, without the need for sensitive attribute labels. To this end, we propose MixFair Adapter to determine and reduce the identity bias of training samples. Our extensive experiments demonstrate that our MixFairFace approach achieves state-of-the-art fairness performance on all benchmark datasets.

面部图像的质量显着影响底层识别算法的性能。面部图像质量评估（FIQA）估计捕获的图像的效用在实现可靠和准确的识别性能方面。在这项工作中，我们提出了一种新的学习范式，可以在培训过程中学习内部网络观察。基于此，我们所提出的CR-FiQA使用该范例来通过预测其相对分类性来估计样品的面部图像质量。基于关于其类中心和最近的负类中心的角度空间中的训练样本特征表示来测量该分类性。我们通过实验说明了面部图像质量与样本相对分类性之间的相关性。由于此类属性仅为培训数据集可观察到，因此我们建议从培训数据集中学习此属性，并利用它来预测看不见样品的质量措施。该培训同时执行，同时通过用于面部识别模型训练的角度裕度罚款的软墨损失来优化类中心。通过对八个基准和四个面部识别模型的广泛评估实验，我们展示了我们提出的CR-FiQA在最先进（SOTA）FIQ算法上的优越性。

目前最先进的基于深度学习的面部识别（FR）模型需要大量的核心训练身份。然而，由于隐私意识不断增长，禁止访问用户设备上的面部图像以不断改进面部识别模型。联合学习（FL）是一种解决隐私问题的技术，可以在不共享客户端之间的数据的情况下协作优化模型。在这项工作中，我们提出了一个基于FLIS的框架，称为FEDFR，以通过隐私感知方式改进通用面部表示。此外，该框架通过所提出的解耦特征定制模块共同优化相应客户端的个性化模型。客户特定的个性化模型可以服务于本地设备的注册标识所需的优化面部识别体验。据我们所知，我们是第一个探索FL Setup中的个性化脸部识别的人。拟议的框架被验证，优于以前的几种通用和个性化的面部识别基准与多种情景的识别基准。源代码和我们提出的个性化FR基准下的FL Setup可用于https://github.com/jackie840129/fedfr。

在本文中，我们试图在抽象嵌入空间中绘制额叶和轮廓面图像之间的连接。我们使用耦合编码器网络利用此连接将额叶/配置文件的面部图像投影到一个常见的潜在嵌入空间中。提出的模型通过最大化面部两种视图之间的相互信息来迫使嵌入空间中表示的相似性。拟议的耦合编码器从三个贡献中受益于与极端姿势差异的匹配面。首先，我们利用我们的姿势意识到的对比学习来最大程度地提高身份额叶和概况表示之间的相互信息。其次，由在过去的迭代中积累的潜在表示组成的内存缓冲区已集成到模型中，因此它可以比小批量大小相对较多的实例。第三，一种新颖的姿势感知的对抗结构域适应方法迫使模型学习从轮廓到额叶表示的不对称映射。在我们的框架中，耦合编码器学会了扩大真实面孔和冒名顶替面部分布之间的边距，这导致了相同身份的不同观点之间的高度相互信息。通过对四个基准数据集的广泛实验，评估和消融研究来研究拟议模型的有效性，并与引人入胜的最新算法进行比较。

数据清洁，体系结构和损失功能设计是导致高性能面部识别的重要因素。以前，研究社区试图提高每个单个方面的性能，但未能在共同搜索所有三个方面的最佳设计时提出统一的解决方案。在本文中，我们首次确定这些方面彼此紧密结合。实际上，优化各个方面的设计实际上极大地限制了性能并偏向算法设计。具体而言，我们发现最佳模型体系结构或损耗函数与数据清洁紧密相结合。为了消除单一研究研究的偏见并提供对面部识别模型设计的总体理解，我们首先仔细设计了每个方面的搜索空间，然后引入了全面的搜索方法，以共同搜索最佳数据清洁，架构和损失功能设计。在我们的框架中，我们通过使用基于创新的增强学习方法来使拟议的全面搜索尽可能灵活。对百万级面部识别基准的广泛实验证明了我们新设计的搜索空间在每个方面和全面搜索的有效性。我们的表现要优于为每个研究轨道开发的专家算法。更重要的是，我们分析了我们搜索的最佳设计与单个因素的独立设计之间的差异。我们指出，强大的模型倾向于通过更困难的培训数据集和损失功能进行优化。我们的实证研究可以为未来的研究提供指导，以实现更健壮的面部识别系统。

3D可线模型（3DMMS）是面部形状和外观的生成模型。然而，传统3DMMS的形状参数满足多变量高斯分布，而嵌入式嵌入满足过边距分布，并且这种冲突使得面部重建模型同时保持忠诚度和形状一致性的挑战。为了解决这个问题，我们提出了一种用于单眼脸部重建的新型3DMM的球体面部模型（SFM），这可以保持既有忠诚度和身份一致性。我们的SFM的核心是可以用于重建3D面形状的基矩阵，并且通过采用在第一和第二阶段中使用3D和2D训练数据的两级训练方法来学习基本矩阵。为了解决分发不匹配，我们设计一种新的损失，使形状参数具有超球的潜在空间。广泛的实验表明，SFM具有高表示能力和形状参数空间的聚类性能。此外，它产生富翼面形状，并且形状在单眼性重建中的挑战条件下是一致的。

面部识别系统必须处理可能导致匹配决策不正确的大型变量（例如不同的姿势，照明和表达）。这些可变性可以根据面部图像质量来测量，这在样本的效用上定义了用于识别的实用性。以前的识别作品不使用这种有价值的信息或利用非本质上的质量估算。在这项工作中，我们提出了一种简单且有效的面部识别解决方案（Qmagface），其将质量感知的比较分数与基于大小感知角裕度损耗的识别模型相结合。所提出的方法包括比较过程中特定于模型的面部图像质量，以增强在无约束情况下的识别性能。利用利用损失诱导的质量与其比较评分之间的线性，我们的质量意识比较功能简单且高度普遍。在几个面部识别数据库和基准上进行的实验表明，引入的质量意识导致识别性能一致的改进。此外，所提出的Qmagface方法在挑战性环境下特别好，例如交叉姿势，跨年或跨品。因此，它导致最先进的性能在几个面部识别基准上，例如在XQLFQ上的98.50％，83.97％，CFP-FP上的98.74％。 QMagface的代码是公开可用的。

Holistic methods using CNNs and margin-based losses have dominated research on face recognition. In this work, we depart from this setting in two ways: (a) we employ the Vision Transformer as an architecture for training a very strong baseline for face recognition, simply called fViT, which already surpasses most state-of-the-art face recognition methods. (b) Secondly, we capitalize on the Transformer's inherent property to process information (visual tokens) extracted from irregular grids to devise a pipeline for face recognition which is reminiscent of part-based face recognition methods. Our pipeline, called part fViT, simply comprises a lightweight network to predict the coordinates of facial landmarks followed by the Vision Transformer operating on patches extracted from the predicted landmarks, and it is trained end-to-end with no landmark supervision. By learning to extract discriminative patches, our part-based Transformer further boosts the accuracy of our Vision Transformer baseline achieving state-of-the-art accuracy on several face recognition benchmarks.

很少有射击学习（FSL）由于其在模型训练中的能力而无需过多的数据而引起了计算机视觉的越来越多的关注。 FSL具有挑战性，因为培训和测试类别（基础与新颖集）可能会在很大程度上多样化。传统的基于转移的解决方案旨在将从大型培训集中学到的知识转移到目标测试集中是有限的，因为任务分配转移的关键不利影响没有充分解决。在本文中，我们通过结合度量学习和通道注意的概念扩展了基于转移方法的解决方案。为了更好地利用特征主链提取的特征表示，我们提出了特定于类的通道注意（CSCA）模块，该模块通过分配每个类别的CSCA权重向量来学会突出显示每个类中的判别通道。与旨在学习全球班级功能的一般注意力模块不同，CSCA模块旨在通过非常有效的计算来学习本地和特定的特定功能。我们评估了CSCA模块在标准基准测试中的性能，包括Miniimagenet，Cifar-imagenet，Cifar-FS和Cub-200-200-2011。实验在电感和/跨域设置中进行。我们取得了新的最新结果。