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 .

最近，无监督的人重新识别（RE-ID）引起了人们的关注，因为其开放世界情景设置有限，可用的带注释的数据有限。现有的监督方法通常无法很好地概括在看不见的域上，而无监督的方法（大多数缺乏多范围的信息），并且容易患有确认偏见。在本文中，我们旨在从两个方面从看不见的目标域上找到更好的特征表示形式，1）在标记的源域上进行无监督的域适应性和2）2）在未标记的目标域上挖掘潜在的相似性。此外，提出了一种协作伪标记策略，以减轻确认偏见的影响。首先，使用生成对抗网络将图像从源域转移到目标域。此外，引入了人身份和身份映射损失，以提高生成图像的质量。其次，我们提出了一个新颖的协作多元特征聚类框架（CMFC），以学习目标域的内部数据结构，包括全局特征和部分特征分支。全球特征分支（GB）在人体图像的全球特征上采用了无监督的聚类，而部分特征分支（PB）矿山在不同人体区域内的相似性。最后，在两个基准数据集上进行的广泛实验表明，在无监督的人重新设置下，我们的方法的竞争性能。

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.

Person re-identification (re-ID) models trained on one domain often fail to generalize well to another. In our attempt, we present a "learning via translation" framework. In the baseline, we translate the labeled images from source to target domain in an unsupervised manner. We then train re-ID models with the translated images by supervised methods. Yet, being an essential part of this framework, unsupervised image-image translation suffers from the information loss of source-domain labels during translation.Our motivation is two-fold. First, for each image, the discriminative cues contained in its ID label should be maintained after translation. Second, given the fact that two domains have entirely different persons, a translated image should be dissimilar to any of the target IDs. To this end, we propose to preserve two types of unsupervised similarities, 1) self-similarity of an image before and after translation, and 2) domain-dissimilarity of a translated source image and a target image. Both constraints are implemented in the similarity preserving generative adversarial network (SPGAN) which consists of an Siamese network and a Cy-cleGAN. Through domain adaptation experiment, we show that images generated by SPGAN are more suitable for domain adaptation and yield consistent and competitive re-ID accuracy on two large-scale datasets.

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.

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。

Employing part-level features for pedestrian image description offers fine-grained information and has been verified as beneficial for person retrieval in very recent literature. A prerequisite of part discovery is that each part should be well located. Instead of using external cues, e.g., pose estimation, to directly locate parts, this paper lays emphasis on the content consistency within each part.Specifically, we target at learning discriminative partinformed features for person retrieval and make two contributions. (i) A network named Part-based Convolutional Baseline (PCB). Given an image input, it outputs a convolutional descriptor consisting of several part-level features. With a uniform partition strategy, PCB achieves competitive results with the state-of-the-art methods, proving itself as a strong convolutional baseline for person retrieval. (ii) A refined part pooling (RPP) method. Uniform partition inevitably incurs outliers in each part, which are in fact more similar to other parts. RPP re-assigns these outliers to the parts they are closest to, resulting in refined parts with enhanced within-part consistency. Experiment confirms that RPP allows PCB to gain another round of performance boost. For instance, on the Market-1501 dataset, we achieve (77.4+4.2)% mAP and (92.3+1.5)% rank-1 accuracy, surpassing the state of the art by a large margin.

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.

In this paper, we introduce Random Erasing, a new data augmentation method for training the convolutional neural network (CNN). In training, Random Erasing randomly selects a rectangle region in an image and erases its pixels with random values. In this process, training images with various levels of occlusion are generated, which reduces the risk of over-fitting and makes the model robust to occlusion. Random Erasing is parameter learning free, easy to implement, and can be integrated with most of the CNN-based recognition models. Albeit simple, Random Erasing is complementary to commonly used data augmentation techniques such as random cropping and flipping, and yields consistent improvement over strong baselines in image classification, object detection and person reidentification. Code is available at: https://github. com/zhunzhong07/Random-Erasing.

由于其在智能城市和城市监测中的潜在应用，车辆重新ID最近引起了热烈的关注。然而，它遭受了通过观察变化和照明变化引起的大型阶级变化，以及阶级相似性，特别是对于具有类似外观的不同标识。为了处理这些问题，在本文中，我们提出了一种新颖的深度网络架构，其由有意义的属性引导，包括相机视图，车辆类型和用于车辆RE-ID的颜色。特别是，我们的网络是端到端训练的，并包含由相应属性嵌入的深度特征的三个子网（即，相机视图，车辆类型和车辆颜色）。此外，为了克服不同视图的有限载体图像的缺点，我们设计了一个视图指定的生成的对抗性网络来生成多视图车辆图像。对于网络培训，我们在Veri-776数据集上注释了视图标签。请注意，只能使用ID信息直接在其他数据集上直接在其他数据集上采用预先训练的视图（以及类型和颜色）子网，这展示了我们模型的泛化。基准数据集Veri-776和车辆的广泛实验表明，拟议的方法实现了有希望的性能，并对车辆重新ID的新型最先进的性能。

Person re-identification plays a significant role in realistic scenarios due to its various applications in public security and video surveillance. Recently, leveraging the supervised or semi-unsupervised learning paradigms, which benefits from the large-scale datasets and strong computing performance, has achieved a competitive performance on a specific target domain. However, when Re-ID models are directly deployed in a new domain without target samples, they always suffer from considerable performance degradation and poor domain generalization. To address this challenge, we propose a Deep Multimodal Fusion network to elaborate rich semantic knowledge for assisting in representation learning during the pre-training. Importantly, a multimodal fusion strategy is introduced to translate the features of different modalities into the common space, which can significantly boost generalization capability of Re-ID model. As for the fine-tuning stage, a realistic dataset is adopted to fine-tune the pre-trained model for better distribution alignment with real-world data. Comprehensive experiments on benchmarks demonstrate that our method can significantly outperform previous domain generalization or meta-learning methods with a clear margin. Our source code will also be publicly available at https://github.com/JeremyXSC/DMF.

Pretraining is a dominant paradigm in computer vision. Generally, supervised ImageNet pretraining is commonly used to initialize the backbones of person re-identification (Re-ID) models. However, recent works show a surprising result that CNN-based pretraining on ImageNet has limited impacts on Re-ID system due to the large domain gap between ImageNet and person Re-ID data. To seek an alternative to traditional pretraining, here we investigate semantic-based pretraining as another method to utilize additional textual data against ImageNet pretraining. Specifically, we manually construct a diversified FineGPR-C caption dataset for the first time on person Re-ID events. Based on it, a pure semantic-based pretraining approach named VTBR is proposed to adopt dense captions to learn visual representations with fewer images. We train convolutional neural networks from scratch on the captions of FineGPR-C dataset, and then transfer them to downstream Re-ID tasks. Comprehensive experiments conducted on benchmark datasets show that our VTBR can achieve competitive performance compared with ImageNet pretraining - despite using up to 1.4x fewer images, revealing its potential in Re-ID pretraining.

监督人员重新识别（RE-ID）方法需要大量的成对手动标记数据，这些数据不适用于重新ID部署的大多数真实情景。另一方面，无监督的RE-ID方法依赖于未标记的数据来培训模型，但与监督的重新ID方法相比，执行差劲。在这项工作中，我们的目标是将无监督的重新识别学习与少数人的注释相结合，以实现竞争性能。为此目标，我们提出了一个无人监督的聚类主动学习（UCAL）重新ID深度学习方法。它能够逐步地发现代表性的质心对并要求人类注释它们。这些标记的代表成对数据可以通过其他大量未标记的数据来改善无监督的表示学习模型。更重要的是，由于选择了代表性质心对注释，UCAL可以使用非常低成本的人力努力工作。广泛的实验表明，在三个重新ID基准数据集上展示了拟议的模型的优越性。

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 .

人重新识别（RE-ID）在公共安全和视频监控等应用中起着重要作用。最近，从合成数据引擎的普及中获益的合成数据学习，从公众眼中引起了极大的关注。但是，现有数据集数量，多样性和变性有限，并且不能有效地用于重新ID问题。为了解决这一挑战，我们手动构造一个名为FineGPR的大型人数据集，具有细粒度的属性注释。此外，旨在充分利用FineGPR的潜力，并推广从数百万综合数据的高效培训，我们提出了一个名为AOST的属性分析流水线，它动态地学习了真实域中的属性分布，然后消除了合成和现实世界之间的差距因此，自由地部署到新场景。在基准上进行的实验表明，FineGPR具有AOST胜过（或与）现有的实际和合成数据集，这表明其对重新ID任务的可行性，并证明了众所周知的较少的原则。我们的Synthetic FineGPR数据集可公开可用于\ URL {https://github.com/jeremyxsc/finegpr}。

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.

Jitendra Malik once said, "Supervision is the opium of the AI researcher". Most deep learning techniques heavily rely on extreme amounts of human labels to work effectively. In today's world, the rate of data creation greatly surpasses the rate of data annotation. Full reliance on human annotations is just a temporary means to solve current closed problems in AI. In reality, only a tiny fraction of data is annotated. Annotation Efficient Learning (AEL) is a study of algorithms to train models effectively with fewer annotations. To thrive in AEL environments, we need deep learning techniques that rely less on manual annotations (e.g., image, bounding-box, and per-pixel labels), but learn useful information from unlabeled data. In this thesis, we explore five different techniques for handling AEL.

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。

Suffering from the extreme training data imbalance between seen and unseen classes, most of existing state-of-theart approaches fail to achieve satisfactory results for the challenging generalized zero-shot learning task. To circumvent the need for labeled examples of unseen classes, we propose a novel generative adversarial network (GAN) that synthesizes CNN features conditioned on class-level semantic information, offering a shortcut directly from a semantic descriptor of a class to a class-conditional feature distribution. Our proposed approach, pairing a Wasserstein GAN with a classification loss, is able to generate sufficiently discriminative CNN features to train softmax classifiers or any multimodal embedding method. Our experimental resultsdemonstrate a significant boost in accuracy over the state of the art on five challenging datasets -CUB, FLO, SUN, AWA and ImageNet -in both the zero-shot learning and generalized zero-shot learning settings.

组织病理学分析是对癌前病变诊断的本金标准。从数字图像自动组织病理学分类的目标需要监督培训，这需要大量的专家注释，这可能是昂贵且耗时的收集。同时，精确分类从全幻灯片裁剪的图像斑块对于基于标准滑动窗口的组织病理学幻灯片分类方法是必不可少的。为了减轻这些问题，我们提出了一个精心设计的条件GaN模型，即hostogan，用于在类标签上合成现实组织病理学图像补丁。我们还研究了一种新颖的合成增强框架，可选择地添加由我们提出的HADOGAN生成的新的合成图像补丁，而不是直接扩展与合成图像的训练集。通过基于其指定标签的置信度和实际标记图像的特征相似性选择合成图像，我们的框架为合成增强提供了质量保证。我们的模型在两个数据集上进行评估：具有有限注释的宫颈组织病理学图像数据集，以及具有转移性癌症的淋巴结组织病理学图像的另一个数据集。在这里，我们表明利用具有选择性增强的组织产生的图像导致对宫颈组织病理学和转移性癌症数据集分别的分类性能（分别为6.7％和2.8％）的显着和一致性。