When considering person re-identification (re-ID) as a retrieval process, re-ranking is a critical step to improve its accuracy. Yet in the re-ID community, limited effort has been devoted to re-ranking, especially those fully automatic, unsupervised solutions. In this paper, we propose a -reciprocal encoding method to re-rank the re-ID results. Our hypothesis is that if a gallery image is similar to the probe in the -reciprocal nearest neighbors, it is more likely to be a true match. Specifically, given an image, areciprocal feature is calculated by encoding its -reciprocal nearest neighbors into a single vector, which is used for reranking under the Jaccard distance. The final distance is computed as the combination of the original distance and the Jaccard distance. Our re-ranking method does not require any human interaction or any labeled data, so it is applicable to large-scale datasets. Experiments on the largescale Market-1501, CUHK03, MARS, and PRW datasets confirm the effectiveness of our method 1 .

This paper contributes a new high quality dataset for person re-identification, named "Market-1501". Generally, current datasets: 1) are limited in scale; 2) consist of hand-drawn bboxes, which are unavailable under realistic settings; 3) have only one ground truth and one query image for each identity (close environment). To tackle these problems, the proposed Market-1501 dataset is featured in three aspects. First, it contains over 32,000 annotated bboxes, plus a distractor set of over 500K images, making it the largest person re-id dataset to date. Second, images in Market-1501 dataset are produced using the Deformable Part Model (DPM) as pedestrian detector. Third, our dataset is collected in an open system, where each identity has multiple images under each camera.As a minor contribution, inspired by recent advances in large-scale image search, this paper proposes an unsupervised Bag-of-Words descriptor. We view person reidentification as a special task of image search. In experiment, we show that the proposed descriptor yields competitive accuracy on VIPeR, CUHK03, and Market-1501 datasets, and is scalable on the large-scale 500k dataset.

Most existing person re-identification methods compute the matching relations between person images across camera views based on the ranking of the pairwise similarities. This matching strategy with the lack of the global viewpoint and the context's consideration inevitably leads to ambiguous matching results and sub-optimal performance. Based on a natural assumption that images belonging to the same person identity should not match with images belonging to multiple different person identities across views, called the unicity of person matching on the identity level, we propose an end-to-end person unicity matching architecture for learning and refining the person matching relations. First, we adopt the image samples' contextual information in feature space to generate the initial soft matching results by using graph neural networks. Secondly, we utilize the samples' global context relationship to refine the soft matching results and reach the matching unicity through bipartite graph matching. Given full consideration to real-world person re-identification applications, we achieve the unicity matching in both one-shot and multi-shot settings of person re-identification and further develop a fast version of the unicity matching without losing the performance. The proposed method is evaluated on five public benchmarks, including four multi-shot datasets MSMT17, DukeMTMC, Market1501, CUHK03, and a one-shot dataset VIPeR. Experimental results show the superiority of the proposed method on performance and efficiency.

Person re-identification (Re-ID) aims at retrieving a person of interest across multiple non-overlapping cameras. With the advancement of deep neural networks and increasing demand of intelligent video surveillance, it has gained significantly increased interest in the computer vision community. By dissecting the involved components in developing a person Re-ID system, we categorize it into the closed-world and open-world settings. The widely studied closed-world setting is usually applied under various research-oriented assumptions, and has achieved inspiring success using deep learning techniques on a number of datasets. We first conduct a comprehensive overview with in-depth analysis for closed-world person Re-ID from three different perspectives, including deep feature representation learning, deep metric learning and ranking optimization. With the performance saturation under closed-world setting, the research focus for person Re-ID has recently shifted to the open-world setting, facing more challenging issues. This setting is closer to practical applications under specific scenarios. We summarize the open-world Re-ID in terms of five different aspects. By analyzing the advantages of existing methods, we design a powerful AGW baseline, achieving state-of-the-art or at least comparable performance on twelve datasets for FOUR different Re-ID tasks. Meanwhile, we introduce a new evaluation metric (mINP) for person Re-ID, indicating the cost for finding all the correct matches, which provides an additional criteria to evaluate the Re-ID system for real applications. Finally, some important yet under-investigated open issues are discussed.

在本文中，我们在爱尔兰都柏林都柏林的大型和繁忙机场中介绍了一个基于图像的人重新识别数据集。与所有可公开的基于图像的数据集不同，我们的数据集除帧号和相机和人员ID之外还包含时间戳信息。我们的数据集也完全是匿名的，以遵守现代数据隐私法规。我们将最先进的人重新识别模型应用于我们的数据集，并显示通过利用可用的时间戳信息，我们能够在地图中实现37.43％的显着增益，并且在Rank1精度中的增益为30.22％。我们还提出了一个贝叶斯颞次重新排名的后处理步骤，该步骤进一步增加了10.03％的地图增益和Rank1精度度量的9.95％。在其他基于图像的人重新识别数据集中不可能结合视觉和时间信息的工作。我们认为，拟议的新数据集将能够进一步开发人员重新识别研究，以挑战现实世界应用。 Daa DataSet可以从HTTPS://bit.ly/3Atxtd6下载

Heterogeneous face re-identification, namely matching heterogeneous faces across disjoint visible light (VIS) and near-infrared (NIR) cameras, has become an important problem in video surveillance application. However, the large domain discrepancy between heterogeneous NIR-VIS faces makes the performance of face re-identification degraded dramatically. To solve this problem, a multimodal fusion ranking optimization algorithm for heterogeneous face re-identification is proposed in this paper. Firstly, we design a heterogeneous face translation network to obtain multimodal face pairs, including NIR-VIS/NIR-NIR/VIS-VIS face pairs, through mutual transformation between NIR-VIS faces. Secondly, we propose linear and non-linear fusion strategies to aggregate initial ranking lists of multimodal face pairs and acquire the optimized re-ranked list based on modal complementarity. The experimental results show that the proposed multimodal fusion ranking optimization algorithm can effectively utilize the complementarity and outperforms some relative methods on the SCface dataset.

近年来，随着对公共安全的需求越来越多，智能监测网络的快速发展，人员重新识别（RE-ID）已成为计算机视野领域的热门研究主题之一。人员RE-ID的主要研究目标是从不同的摄像机中检索具有相同身份的人。但是，传统的人重新ID方法需要手动标记人的目标，这消耗了大量的劳动力成本。随着深度神经网络的广泛应用，出现了许多基于深入的基于学习的人物的方法。因此，本文促进研究人员了解最新的研究成果和该领域的未来趋势。首先，我们总结了对几个最近公布的人的研究重新ID调查，并补充了系统地分类基于深度学习的人的重新ID方法的最新研究方法。其次，我们提出了一种多维分类，根据度量标准和表示学习，将基于深度学习的人的重新ID方法分为四类，包括深度度量学习，本地特征学习，生成的对抗学习和序列特征学习的方法。此外，我们根据其方法和动机来细分以上四类，讨论部分子类别的优缺点。最后，我们讨论了一些挑战和可能的研究方向的人重新ID。

Although the performance of person Re-Identification (ReID) has been significantly boosted, many challenging issues in real scenarios have not been fully investigated, e.g., the complex scenes and lighting variations, viewpoint and pose changes, and the large number of identities in a camera network. To facilitate the research towards conquering those issues, this paper contributes a new dataset called MSMT17 with many important features, e.g., 1) the raw videos are taken by an 15-camera network deployed in both indoor and outdoor scenes, 2) the videos cover a long period of time and present complex lighting variations, and 3) it contains currently the largest number of annotated identities, i.e., 4,101 identities and 126,441 bounding boxes. We also observe that, domain gap commonly exists between datasets, which essentially causes severe performance drop when training and testing on different datasets. This results in that available training data cannot be effectively leveraged for new testing domains. To relieve the expensive costs of annotating new training samples, we propose a Person Transfer Generative Adversarial Network (PTGAN) to bridge the domain gap. Comprehensive experiments show that the domain gap could be substantially narrowed-down by the PTGAN.

人员搜索是一个有关的任务，旨在共同解决人员检测和人员重新识别（RE-ID）。虽然最先前的方法侧重于学习稳健的个人功能，但由于照明，大构成方差和遮挡，仍然很难区分令人困惑的人。上下文信息实际上是人们搜索任务，这些任务在减少混淆方面搜索。为此，我们提出了一个名为注意上下文感知嵌入（ACAE）的新颖的上下文特征头，这增强了上下文信息。 Acae反复审查图像内部和图像内的该人员，以查找类似的行人模式，允许它隐含地学会找到可能的共同旅行者和有效地模范上下文相关的实例的关系。此外，我们提出了图像记忆库来提高培训效率。实验上，ACAE在基于不同的一步法时显示出广泛的促销。我们的整体方法实现了最先进的结果与先前的一步法。

The main contribution of this paper is a simple semisupervised pipeline that only uses the original training set without collecting extra data. It is challenging in 1) how to obtain more training data only from the training set and 2) how to use the newly generated data. In this work, the generative adversarial network (GAN) is used to generate unlabeled samples. We propose the label smoothing regularization for outliers (LSRO). This method assigns a uniform label distribution to the unlabeled images, which regularizes the supervised model and improves the baseline.We verify the proposed method on a practical problem: person re-identification (re-ID). This task aims to retrieve a query person from other cameras. We adopt the deep convolutional generative adversarial network (DCGAN) for sample generation, and a baseline convolutional neural network (CNN) for representation learning. Experiments show that adding the GAN-generated data effectively improves the discriminative ability of learned CNN embeddings. On three large-scale datasets, Market-1501, CUHK03 and DukeMTMC-reID, we obtain +4.37%, +1.6% and +2.46% improvement in rank-1 precision over the baseline CNN, respectively. We additionally apply the proposed method to fine-grained bird recognition and achieve a +0.6% improvement over a strong baseline. The code is available at https://github.com/layumi/Person-reID_GAN .

从图像中学习代表，健壮和歧视性信息对于有效的人重新识别（RE-ID）至关重要。在本文中，我们提出了一种基于身体和手部图像的人重新ID的端到端判别深度学习的复合方法。我们仔细设计了本地感知的全球注意力网络（Laga-Net），这是一个多分支深度网络架构，由一个用于空间注意力的分支组成，一个用于渠道注意。注意分支集中在图像的相关特征上，同时抑制了无关紧要的背景。为了克服注意力机制的弱点，与像素改组一样，我们将相对位置编码整合到空间注意模块中以捕获像素的空间位置。全球分支机构打算保留全球环境或结构信息。对于打算捕获细粒度信息的本地分支，我们进行统一的分区以水平在Conv-Layer上生成条纹。我们通过执行软分区来检索零件，而无需明确分区图像或需要外部线索，例如姿势估计。一组消融研究表明，每个组件都会有助于提高拉加网络的性能。对四个受欢迎的人体重新ID基准和两个公开可用的手数据集的广泛评估表明，我们的建议方法始终优于现有的最新方法。

Recently, Person Re-Identification (Re-ID) has received a lot of attention. Large datasets containing labeled images of various individuals have been released, allowing researchers to develop and test many successful approaches. However, when such Re-ID models are deployed in new cities or environments, the task of searching for people within a network of security cameras is likely to face an important domain shift, thus resulting in decreased performance. Indeed, while most public datasets were collected in a limited geographic area, images from a new city present different features (e.g., people's ethnicity and clothing style, weather, architecture, etc.). In addition, the whole frames of the video streams must be converted into cropped images of people using pedestrian detection models, which behave differently from the human annotators who created the dataset used for training. To better understand the extent of this issue, this paper introduces a complete methodology to evaluate Re-ID approaches and training datasets with respect to their suitability for unsupervised deployment for live operations. This method is used to benchmark four Re-ID approaches on three datasets, providing insight and guidelines that can help to design better Re-ID pipelines in the future.

人员搜索是人重新识别（RE-ID）的扩展任务。但是，大多数现有的一步人搜索工作尚未研究如何使用现有的高级RE-ID模型来提高由于人员检测和重新ID的集成而促进了一步人搜索性能。为了解决这个问题，我们提出了更快，更强大的一步人搜索框架，教师导师的解解网络（TDN），使单步搜索享受现有的重新ID研究的优点。所提出的TDN可以通过将高级人的RE-ID知识转移到人员搜索模型来显着提高人员搜索性能。在提议的TDN中，为了从重新ID教师模型到单步搜索模型的更好的知识转移，我们通过部分解除两个子任务来设计一个强大的一步人搜索基础框架。此外，我们提出了一种知识转移桥模块，以弥合在重新ID模型和一步人搜索模型之间不同的输入格式引起的比例差距。在测试期间，我们进一步提出了与上下文人员战略的排名来利用全景图像中的上下文信息以便更好地检索。两个公共人员搜索数据集的实验证明了该方法的有利性能。

媒体中的人员搜索已经看到互联网应用程序的潜力，例如视频剪辑和字符集。这项任务很常见，但忽略了以前的人员搜索工作，专注于监视场景。媒体情景从监视场景中有一些不同的挑战。例如，一个人可能经常改变衣服。为了减轻这个问题，本文提出了一个统一的探测器和图形网络（UDGNET），用于媒体中的人员搜索。 UDGNET是第一个检测和重新识别人体和头部的第一个人搜索框架。具体地，它首先基于统一网络构建两个分支以检测人体和头部，然后检测到的主体和头部用于重新识别。这种双重任务方法可以显着增强歧视性学习。为了解决布料不断变化的问题，UDGNET构建了两个图形，以探索布换器样本中的可靠链接，并利用图形网络来学习更好的嵌入。这种设计有效地增强了人们搜索的鲁棒性，以改变布什挑战。此外，我们证明了UDGNET可以通过基于锚和无锚的人搜索框架来实现，并进一步实现性能改进。本文还为媒体（PSM）中的人员搜索提供了大规模数据集，其提供身体和头部注释。它是迄今为止媒体搜索的最大数据集。实验表明，UDGNET在MAP中通过12.1％提高了Anipor的模型。同时，它在监控和长期情景中显示出良好的概括。数据集和代码将可用：https://github.com/shuxjweb/psm.git。

The combination of global and partial features has been an essential solution to improve discriminative performances in person re-identification (Re-ID) tasks. Previous part-based methods mainly focus on locating regions with specific pre-defined semantics to learn local representations, which increases learning difficulty but not efficient or robust to scenarios with large variances. In this paper, we propose an end-to-end feature learning strategy integrating discriminative information with various granularities. We carefully design the Multiple Granularity Network (MGN), a multi-branch deep network architecture consisting of one branch for global feature representations and two branches for local feature representations. Instead of learning on semantic regions, we uniformly partition the images into several stripes, and vary the number of parts in different local branches to obtain local feature representations with multiple granularities. Comprehensive experiments implemented on the mainstream evaluation datasets including Market-1501, DukeMTMC-reid and CUHK03 indicate that our method robustly achieves state-of-the-art performances and outperforms any existing approaches by a large margin. For example, on Market-1501 dataset in single query mode, we obtain a top result of Rank-1/mAP=96.6%/94.2% with this method after re-ranking.

最近的研究表明，明确的深度特征匹配以及大规模和多样化的训练数据都可以显着提高人员重新识别的泛化。然而，在大规模数据上学习深度匹配者的效率尚未得到充分研究。虽然使用分类参数或课程内存是一种流行的方式，但它会引发大的内存和计算成本。相比之下，迷你批量内的成对深度度量学习将是一个更好的选择。然而，最受欢迎的随机采样方法，众所周知的PK采样器，对深度度量学习不是信息性和有效的。虽然在线硬示例挖掘在一定程度上提高了学习效率，但随机采样后迷你批次仍然有限。这激发了我们在数据采样阶段之前探讨了先前使用硬示例挖掘。为此，在本文中，我们提出了一种有效的跨批量采样方法，称为图形采样（GS），用于大规模深度度量学习。基本思想是为每个时代开始的所有类构建最近的邻居关系图。然后，每个迷你批处理由随机选择的类和其最近的邻类组成，以便为学习提供信息和具有挑战性的例子。与适应的竞争性基线一起，我们在更广泛的人中改善了先前的最先进状态，在MAP中最明显重新鉴定，高达24％和13.8％。此外，所提出的方法还优于竞争性基线在地图中排名-1和5.3％的竞争性基线。同时，培训时间明显减少了多达五次，例如五次。在具有8,000个身份的大型数据集中培训12.2小时至2.3小时。代码可在https://github.com/shengcailiao/qaconv获得。

查询扩展（QE）是一种改进图像搜索应用中检索度量的熟悉方法。使用QE时，在新的查询向量上进行搜索，在来自数据库的查询和图像上使用聚合函数构造的新查询向量。最近的作品产生了学习聚合功能的QE技术，而以前的技术是基于手工制作的聚合函数，例如，采用查询的最近邻居的平均值。但是，大多数QE方法都集中在直接在查询和直接最近邻居上工作的聚合函数。在这项工作中，呈现了一个分层模型，图表查询扩展（GQE），其以监督方式学习并在查询的扩展邻域上执行聚合，从而增加在计算查询扩展时从数据库中使用的信息，并使用最近邻居图的结构。该技术实现了最先进的结果，从而获得了已知的基准。

人类识别是事件检测，人跟踪和公共安全的重要课题。有许多方法提出了人类识别，例如面部识别，人重新识别和步态识别。通常，现有方法主要将查询图像分类为图像库集合（I2i）中的特定标识。这对场景非常有限，其中仅在广泛的视频监控应用程序（A2i或I2a）中提供了查询或属性库集合的文本描述。然而，非常少量的努力已经致力于无模式识别，即，以可扩展的方式识别在库中设置的查询。在这项工作中，我们采取初步尝试，并以可扩展的方式制定这样一种新的无模式人类识别（命名为MFHI）任务作为通用零射击学习模型。同时，它能够通过学习每个身份的鉴别性原型来弥合视觉和语义模态。此外，在视觉模型上强制执行语义引导的空间注意，以获得具有高全局类别级和本地属性级别辨别的表示。最后，我们在两个共同挑战的识别任务中设计和开展广泛的实验，包括面部识别和人员重新识别，证明我们的方法优于一种在无模式人体识别方面的各种最先进的方法。

人员搜索旨在共同本地化和识别来自自然的查询人员，不可用的图像，这在过去几年中在计算机视觉社区中积极研究了这一图像。在本文中，我们将在全球和本地围绕目标人群的丰富的上下文信息中阐述，我们分别指的是场景和组上下文。与以前的作品单独处理这两种类型的作品，我们将它们利用统一的全球本地上下文网络（GLCNet），其具有直观的功能增强。具体地，以多级方式同时增强重新ID嵌入和上下文特征，最终导致人员搜索增强，辨别特征。我们对两个人搜索基准（即Cuhk-Sysu和PRW）进行实验，并将我们的方法扩展到更具有挑战性的环境（即，在MovieIenet上的字符搜索）。广泛的实验结果表明，在三个数据集上的最先进方法中提出的GLCNET的一致性改进。我们的源代码，预先训练的型号，以及字符搜索的新设置可以：https://github.com/zhengpeng7/llcnet。

In this paper, we are interested in learning a generalizable person re-identification (re-ID) representation from unlabeled videos. Compared with 1) the popular unsupervised re-ID setting where the training and test sets are typically under the same domain, and 2) the popular domain generalization (DG) re-ID setting where the training samples are labeled, our novel scenario combines their key challenges: the training samples are unlabeled, and collected form various domains which do no align with the test domain. In other words, we aim to learn a representation in an unsupervised manner and directly use the learned representation for re-ID in novel domains. To fulfill this goal, we make two main contributions: First, we propose Cycle Association (CycAs), a scalable self-supervised learning method for re-ID with low training complexity; and second, we construct a large-scale unlabeled re-ID dataset named LMP-video, tailored for the proposed method. Specifically, CycAs learns re-ID features by enforcing cycle consistency of instance association between temporally successive video frame pairs, and the training cost is merely linear to the data size, making large-scale training possible. On the other hand, the LMP-video dataset is extremely large, containing 50 million unlabeled person images cropped from over 10K Youtube videos, therefore is sufficient to serve as fertile soil for self-supervised learning. Trained on LMP-video, we show that CycAs learns good generalization towards novel domains. The achieved results sometimes even outperform supervised domain generalizable models. Remarkably, CycAs achieves 82.2% Rank-1 on Market-1501 and 49.0% Rank-1 on MSMT17 with zero human annotation, surpassing state-of-the-art supervised DG re-ID methods. Moreover, we also demonstrate the superiority of CycAs under the canonical unsupervised re-ID and the pretrain-and-finetune scenarios.