Pedestrian detection in the wild remains a challenging problem especially for scenes containing serious occlusion. In this paper, we propose a novel feature learning method in the deep learning framework, referred to as Feature Calibration Network (FC-Net), to adaptively detect pedestrians under various occlusions. FC-Net is based on the observation that the visible parts of pedestrians are selective and decisive for detection, and is implemented as a self-paced feature learning framework with a self-activation (SA) module and a feature calibration (FC) module. In a new self-activated manner, FC-Net learns features which highlight the visible parts and suppress the occluded parts of pedestrians. The SA module estimates pedestrian activation maps by reusing classifier weights, without any additional parameter involved, therefore resulting in an extremely parsimony model to reinforce the semantics of features, while the FC module calibrates the convolutional features for adaptive pedestrian representation in both pixel-wise and region-based ways. Experiments on CityPersons and Caltech datasets demonstrate that FC-Net improves detection performance on occluded pedestrians up to 10% while maintaining excellent performance on non-occluded instances.

Pedestrian detection in the wild remains a challenging problem especially when the scene contains significant occlusion and/or low resolution of the pedestrians to be detected. Existing methods are unable to adapt to these difficult cases while maintaining acceptable performance. In this paper we propose a novel feature learning model, referred to as CircleNet, to achieve feature adaptation by mimicking the process humans looking at low resolution and occluded objects: focusing on it again, at a finer scale, if the object can not be identified clearly for the first time. CircleNet is implemented as a set of feature pyramids and uses weight sharing path augmentation for better feature fusion. It targets at reciprocating feature adaptation and iterative object detection using multiple top-down and bottom-up pathways. To take full advantage of the feature adaptation capability in CircleNet, we design an instance decomposition training strategy to focus on detecting pedestrian instances of various resolutions and different occlusion levels in each cycle. Specifically, CircleNet implements feature ensemble with the idea of hard negative boosting in an end-to-end manner. Experiments on two pedestrian detection datasets, Caltech and CityPersons, show that CircleNet improves the performance of occluded and low-resolution pedestrians with significant margins while maintaining good performance on normal instances.

Due to object detection's close relationship with video analysis and image understanding, it has attracted much research attention in recent years. Traditional object detection methods are built on handcrafted features and shallow trainable architectures. Their performance easily stagnates by constructing complex ensembles which combine multiple low-level image features with high-level context from object detectors and scene classifiers. With the rapid development in deep learning, more powerful tools, which are able to learn semantic, high-level, deeper features, are introduced to address the problems existing in traditional architectures. These models behave differently in network architecture, training strategy and optimization function, etc. In this paper, we provide a review on deep learning based object detection frameworks. Our review begins with a brief introduction on the history of deep learning and its representative tool, namely Convolutional Neural Network (CNN). Then we focus on typical generic object detection architectures along with some modifications and useful tricks to improve detection performance further. As distinct specific detection tasks exhibit different characteristics, we also briefly survey several specific tasks, including salient object detection, face detection and pedestrian detection. Experimental analyses are also provided to compare various methods and draw some meaningful conclusions. Finally, several promising directions and tasks are provided to serve as guidelines for future work in both object detection and relevant neural network based learning systems.

行人检测的典型方法侧重于在拥挤的行人之间进行处理，或处理各种行人的各种鳞片。用大量外观多样性检测不同的行人剪影，不同观点或不同的敷料等行人仍然是一个至关重要的挑战。除了大多数现有方法，我们建议使用与学习特征空间中不同外观之间的行人之间的语义距离的方式进行对比学习以引导特征学习，以引导对比学习以引导特征学习。外观多样性，而行人和背景之间的距离最大化。为了促进对比学习的效率和有效性，我们构建具有代表性行人外观的示例性词典作为先验知识，以构建有效的对比训练对并因此引导对比学习。此外，通过测量提议与示例性词典之间的语义距离，进一步利用构建的示例性词典以评估推理期间的行人提案的质量。对白天和夜间行人检测的广泛实验验证了该方法的有效性。

行人检测是自主驱动系统中最关键的模块。虽然相机通常用于此目的，但其质量严重降低了低光夜间驾驶场景。另一方面，热摄像机图像的质量在类似条件下保持不受影响。本文采用RGB和热图像提出了一种用于行人检测的端到端多峰融合模型。其新颖的时空深度网络架构能够有效利用多模式输入。它由两个不同的可变形ResNext-50编码器组成，用于来自两个方式的特征提取。这两个编码特征的融合发生在由几个图形关注网络和特征融合单元组成的多模式特征嵌入模块（MUFEM）内部。随后将MUFEM的最后一个特征融合单元的输出传递给两个CRF的空间细化。通过在四个不同方向横穿四个RNN的帮助下，通过应用渠道明智的关注和提取上下文信息来实现特征的进一步提高。最后，单级解码器使用这些特征映射来生成每个行人和分数图的边界框。我们在三个公开可用的多模式行人检测基准数据集，即Kaist，CVC-14和Utokyo上进行了广泛的框架实验。每个每个结果都改善了各种最先进的性能。在https://youtu.be/fdjdsifuucs，可以看到一个简短的视频以及其定性结果的概述。我们的源代码将在发布论文时发布。

物体检测通常需要在现代深度学习方法中基于传统或锚盒的滑动窗口分类器。但是，这些方法中的任何一个都需要框中的繁琐配置。在本文中，我们提供了一种新的透视图，其中检测对象被激励为高电平语义特征检测任务。与边缘，角落，斑点和其他特征探测器一样，所提出的探测器扫描到全部图像的特征点，卷积自然适合该特征点。但是，与这些传统的低级功能不同，所提出的探测器用于更高级别的抽象，即我们正在寻找有物体的中心点，而现代深层模型已经能够具有如此高级别的语义抽象。除了Blob检测之外，我们还预测了中心点的尺度，这也是直接的卷积。因此，在本文中，通过卷积简化了行人和面部检测作为直接的中心和规模预测任务。这样，所提出的方法享有一个无盒设置。虽然结构简单，但它对几个具有挑战性的基准呈现竞争准确性，包括行人检测和面部检测。此外，执行交叉数据集评估，证明所提出的方法的卓越泛化能力。可以访问代码和模型（https://github.com/liuwei16/csp和https://github.com/hasanirtiza/pedestron）。

随着深度卷积神经网络的兴起，对象检测在过去几年中取得了突出的进步。但是，这种繁荣无法掩盖小物体检测（SOD）的不令人满意的情况，这是计算机视觉中臭名昭著的挑战性任务之一，这是由于视觉外观不佳和由小目标的内在结构引起的嘈杂表示。此外，用于基准小对象检测方法基准测试的大规模数据集仍然是瓶颈。在本文中，我们首先对小物体检测进行了详尽的审查。然后，为了催化SOD的发展，我们分别构建了两个大规模的小物体检测数据集（SODA），SODA-D和SODA-A，分别集中在驾驶和空中场景上。 SODA-D包括24704个高质量的交通图像和277596个9个类别的实例。对于苏打水，我们收集2510个高分辨率航空图像，并在9个类别上注释800203实例。众所周知，拟议的数据集是有史以来首次尝试使用针对多类SOD量身定制的大量注释实例进行大规模基准测试。最后，我们评估主流方法在苏打水上的性能。我们预计发布的基准可以促进SOD的发展，并产生该领域的更多突破。数据集和代码将很快在：\ url {https://shaunyuan22.github.io/soda}上。

对象检测是计算机视觉领域中最基本而具有挑战性的研究主题之一。最近，在航拍图像中的这一主题的研究取得了巨大的进步。然而，复杂的背景和更糟糕的成像质量是空中物体检测中的明显问题。大多数最先进的方法倾向于开发具有艰巨计算复杂性的时空特征校准的精心关注机制，同时令人惊讶地忽略了通道中特征校准的重要性。在这项工作中，我们提出了一种简单而有效的校准引导（CG）方案，以增强特征变压器时尚中的信道通信，其可以基于全局特征亲和力相关性自适应地确定每个信道的校准权重。具体地，对于给定的一组特征映射，CG首先将每个信道和剩余信道之间的特征相似性计算为中间校准引导。然后，通过通过引导操作聚合加权加权的所有信道来重新表示每个信道。我们的CG是一般模块，可以插入任何深度神经网络，该网络被命名为CG-Net。为了展示其有效性和效率，在航空图像中的定向对象检测任务和水平物体检测任务中进行了广泛的实验。两个具有挑战性的基准（DotA和HRSC2016）的实验结果表明，我们的CG-Net可以通过公平计算开销的准确性实现新的最先进的性能。源代码已在https://github.com/weizongqi/cg-net中开放源

两阶段探测器在物体检测和行人检测中是最新的。但是，当前的两个阶段探测器效率低下，因为它们在多个步骤中进行边界回归，即在区域提案网络和边界框头中进行回归。此外，基于锚的区域提案网络在计算上的训练价格很高。我们提出了F2DNET，这是一种新型的两阶段检测体系结构，通过使用我们的焦点检测网络和边界框以我们的快速抑制头替换区域建议网络，从而消除了当前两阶段检测器的冗余。我们在顶级行人检测数据集上进行基准F2DNET，将其与现有的最新检测器进行彻底比较，并进行交叉数据集评估，以测试我们模型对未见数据的普遍性。我们的F2DNET在城市人员，加州理工学院行人和欧元城市人数据集中分别获得8.7 \％，2.2 \％和6.1 \％MR-2，分别在单个数据集上进行培训并达到20.4 \％\％\％和26.2 \％MR-2。使用渐进式微调时，加州理工学院行人和城市人员数据集的重型闭塞设置。此外，与当前的最新时间相比，F2DNET的推理时间明显较小。代码和训练有素的模型将在https://github.com/abdulhannankhan/f2dnet上找到。

最近，融合了激光雷达点云和相机图像，提高了3D对象检测的性能和稳健性，因为这两种方式自然具有强烈的互补性。在本文中，我们通过引入新型级联双向融合〜（CB融合）模块和多模态一致性〜（MC）损耗来提出用于多模态3D对象检测的EPNet ++。更具体地说，所提出的CB融合模块提高点特征的丰富语义信息，以级联双向交互融合方式具有图像特征，导致更全面且辨别的特征表示。 MC损失明确保证预测分数之间的一致性，以获得更全面且可靠的置信度分数。基蒂，JRDB和Sun-RGBD数据集的实验结果展示了通过最先进的方法的EPNet ++的优越性。此外，我们强调一个关键但很容易被忽视的问题，这是探讨稀疏场景中的3D探测器的性能和鲁棒性。广泛的实验存在，EPNet ++优于现有的SOTA方法，在高稀疏点云壳中具有显着的边距，这可能是降低LIDAR传感器的昂贵成本的可用方向。代码将来会发布。

Single-frame InfraRed Small Target (SIRST) detection has been a challenging task due to a lack of inherent characteristics, imprecise bounding box regression, a scarcity of real-world datasets, and sensitive localization evaluation. In this paper, we propose a comprehensive solution to these challenges. First, we find that the existing anchor-free label assignment method is prone to mislabeling small targets as background, leading to their omission by detectors. To overcome this issue, we propose an all-scale pseudo-box-based label assignment scheme that relaxes the constraints on scale and decouples the spatial assignment from the size of the ground-truth target. Second, motivated by the structured prior of feature pyramids, we introduce the one-stage cascade refinement network (OSCAR), which uses the high-level head as soft proposals for the low-level refinement head. This allows OSCAR to process the same target in a cascade coarse-to-fine manner. Finally, we present a new research benchmark for infrared small target detection, consisting of the SIRST-V2 dataset of real-world, high-resolution single-frame targets, the normalized contrast evaluation metric, and the DeepInfrared toolkit for detection. We conduct extensive ablation studies to evaluate the components of OSCAR and compare its performance to state-of-the-art model-driven and data-driven methods on the SIRST-V2 benchmark. Our results demonstrate that a top-down cascade refinement framework can improve the accuracy of infrared small target detection without sacrificing efficiency. The DeepInfrared toolkit, dataset, and trained models are available at https://github.com/YimianDai/open-deepinfrared to advance further research in this field.

人的大脑可以毫不费力地识别和定位对象，而基于激光雷达点云的当前3D对象检测方法仍然报告了较低的性能，以检测闭塞和远处的对象：点云的外观由于遮挡而变化很大，并且在沿线的固有差异沿点固有差异变化。传感器的距离。因此，设计功能表示对此类点云至关重要。受到人类联想识别的启发，我们提出了一个新颖的3D检测框架，该框架通过域的适应来使对象完整特征。我们弥合感知域之间的差距，其中特征是从具有亚最佳表示的真实场景中得出的，以及概念域，其中功能是从由不批准对象组成的增强场景中提取的，并具有丰富的详细信息。研究了一种可行的方法，可以在没有外部数据集的情况下构建概念场景。我们进一步介绍了一个基于注意力的重新加权模块，该模块可适应地增强更翔实区域的特征。该网络的功能增强能力将被利用，而无需在推理过程中引入额外的成本，这是各种3D检测框架中的插件。我们以准确性和速度都在Kitti 3D检测基准上实现了新的最先进性能。关于Nuscenes和Waymo数据集的实验也验证了我们方法的多功能性。

大多数最先进的实例级人类解析模型都采用了两阶段的基于锚的探测器，因此无法避免启发式锚盒设计和像素级别缺乏分析。为了解决这两个问题，我们设计了一个实例级人类解析网络，该网络在像素级别上无锚固且可解决。它由两个简单的子网络组成：一个用于边界框预测的无锚检测头和一个用于人体分割的边缘引导解析头。无锚探测器的头继承了像素样的优点，并有效地避免了对象检测应用中证明的超参数的敏感性。通过引入部分感知的边界线索，边缘引导的解析头能够将相邻的人类部分与彼此区分开，最多可在一个人类实例中，甚至重叠的实例。同时，利用了精炼的头部整合盒子级别的分数和部分分析质量，以提高解析结果的质量。在两个多个人类解析数据集（即CIHP和LV-MHP-V2.0）和一个视频实例级人类解析数据集（即VIP）上进行实验，表明我们的方法实现了超过全球级别和实例级别的性能最新的一阶段自上而下的替代方案。

3D object detection from LiDAR point cloud is a challenging problem in 3D scene understanding and has many practical applications. In this paper, we extend our preliminary work PointRCNN to a novel and strong point-cloud-based 3D object detection framework, the part-aware and aggregation neural network (Part-A 2 net). The whole framework consists of the part-aware stage and the part-aggregation stage. Firstly, the part-aware stage for the first time fully utilizes free-of-charge part supervisions derived from 3D ground-truth boxes to simultaneously predict high quality 3D proposals and accurate intra-object part locations. The predicted intra-object part locations within the same proposal are grouped by our new-designed RoI-aware point cloud pooling module, which results in an effective representation to encode the geometry-specific features of each 3D proposal. Then the part-aggregation stage learns to re-score the box and refine the box location by exploring the spatial relationship of the pooled intra-object part locations. Extensive experiments are conducted to demonstrate the performance improvements from each component of our proposed framework. Our Part-A 2 net outperforms all existing 3D detection methods and achieves new state-of-the-art on KITTI 3D object detection dataset by utilizing only the LiDAR point cloud data. Code is available at https://github.com/sshaoshuai/PointCloudDet3D.

In object detection, the intersection over union (IoU) threshold is frequently used to define positives/negatives. The threshold used to train a detector defines its quality. While the commonly used threshold of 0.5 leads to noisy (low-quality) detections, detection performance frequently degrades for larger thresholds. This paradox of high-quality detection has two causes: 1) overfitting, due to vanishing positive samples for large thresholds, and 2) inference-time quality mismatch between detector and test hypotheses. A multi-stage object detection architecture, the Cascade R-CNN, composed of a sequence of detectors trained with increasing IoU thresholds, is proposed to address these problems. The detectors are trained sequentially, using the output of a detector as training set for the next. This resampling progressively improves hypotheses quality, guaranteeing a positive training set of equivalent size for all detectors and minimizing overfitting. The same cascade is applied at inference, to eliminate quality mismatches between hypotheses and detectors. An implementation of the Cascade R-CNN without bells or whistles achieves state-of-the-art performance on the COCO dataset, and significantly improves high-quality detection on generic and specific object detection datasets, including VOC, KITTI, CityPerson, and WiderFace. Finally, the Cascade R-CNN is generalized to instance segmentation, with nontrivial improvements over the Mask R-CNN. To facilitate future research, two implementations are made available at https://github.com/zhaoweicai/cascade-rcnn (Caffe) and https://github.com/zhaoweicai/Detectron-Cascade-RCNN (Detectron).

遮挡对人重新识别（Reid）构成了重大挑战。现有方法通常依赖于外部工具来推断可见的身体部位，这在计算效率和Reid精度方面可能是次优。特别是，在面对复杂的闭塞时，它们可能会失败，例如行人之间的遮挡。因此，在本文中，我们提出了一种名为M质量感知部分模型（QPM）的新方法，用于遮挡鲁棒Reid。首先，我们建议共同学习零件特征和预测部分质量分数。由于没有提供质量注释，我们介绍了一种自动将低分分配给闭塞体部位的策略，从而削弱了遮挡体零落在Reid结果上的影响。其次，基于预测部分质量分数，我们提出了一种新颖的身份感知空间关注（ISA）模块。在该模块中，利用粗略标识感知功能来突出目标行人的像素，以便处理行人之间的遮挡。第三，我们设计了一种自适应和有效的方法，用于了解来自每个图像对的共同非遮挡区域的全局特征。这种设计至关重要，但经常被现有方法忽略。 QPM有三个关键优势：1）它不依赖于培训或推理阶段的任何外部工具; 2）它处理由物体和其他行人引起的闭塞; 3）它是高度计算效率。对闭塞Reid的四个流行数据库的实验结果证明QPM始终如一地以显着的利润方式优于最先进的方法。 QPM代码将被释放。

面部检测是为了在图像中搜索面部的所有可能区域，并且如果有任何情况，则定位面部。包括面部识别，面部表情识别，面部跟踪和头部姿势估计的许多应用假设面部的位置和尺寸在图像中是已知的。近几十年来，研究人员从Viola-Jones脸上检测器创造了许多典型和有效的面部探测器到当前的基于CNN的CNN。然而，随着图像和视频的巨大增加，具有面部刻度的变化，外观，表达，遮挡和姿势，传统的面部探测器被挑战来检测野外面孔的各种“脸部。深度学习技术的出现带来了非凡的检测突破，以及计算的价格相当大的价格。本文介绍了代表性的深度学习的方法，并在准确性和效率方面提出了深度和全面的分析。我们进一步比较并讨论了流行的并挑战数据集及其评估指标。进行了几种成功的基于深度学习的面部探测器的全面比较，以使用两个度量来揭示其效率：拖鞋和延迟。本文可以指导为不同应用选择合适的面部探测器，也可以开发更高效和准确的探测器。

LiDAR-based 3D Object detectors have achieved impressive performances in many benchmarks, however, multisensors fusion-based techniques are promising to further improve the results. PointPainting, as a recently proposed framework, can add the semantic information from the 2D image into the 3D LiDAR point by the painting operation to boost the detection performance. However, due to the limited resolution of 2D feature maps, severe boundary-blurring effect happens during re-projection of 2D semantic segmentation into the 3D point clouds. To well handle this limitation, a general multimodal fusion framework MSF has been proposed to fuse the semantic information from both the 2D image and 3D points scene parsing results. Specifically, MSF includes three main modules. First, SOTA off-the-shelf 2D/3D semantic segmentation approaches are employed to generate the parsing results for 2D images and 3D point clouds. The 2D semantic information is further re-projected into the 3D point clouds with calibrated parameters. To handle the misalignment between the 2D and 3D parsing results, an AAF module is proposed to fuse them by learning an adaptive fusion score. Then the point cloud with the fused semantic label is sent to the following 3D object detectors. Furthermore, we propose a DFF module to aggregate deep features in different levels to boost the final detection performance. The effectiveness of the framework has been verified on two public large-scale 3D object detection benchmarks by comparing with different baselines. The experimental results show that the proposed fusion strategies can significantly improve the detection performance compared to the methods using only point clouds and the methods using only 2D semantic information. Most importantly, the proposed approach significantly outperforms other approaches and sets new SOTA results on the nuScenes testing benchmark.

近年来，自主驾驶LIDAR数据的3D对象检测一直在迈出卓越的进展。在最先进的方法中，已经证明了将点云进行编码为鸟瞰图（BEV）是有效且有效的。与透视图不同，BEV在物体之间保留丰富的空间和距离信息;虽然在BEV中相同类型的更远物体不会较小，但它们包含稀疏点云特征。这一事实使用共享卷积神经网络削弱了BEV特征提取。为了解决这一挑战，我们提出了范围感知注意网络（RAANET），提取更强大的BEV功能并产生卓越的3D对象检测。范围感知的注意力（RAA）卷曲显着改善了近距离的特征提取。此外，我们提出了一种新的辅助损耗，用于密度估计，以进一步增强覆盖物体的Raanet的检测精度。值得注意的是，我们提出的RAA卷积轻量级，并兼容，以集成到用于BEV检测的任何CNN架构中。 Nuscenes DataSet上的广泛实验表明，我们的提出方法优于基于LIDAR的3D对象检测的最先进的方法，具有16 Hz的实时推断速度，为LITE版本为22 Hz。该代码在匿名GitHub存储库HTTPS://github.com/Anonymous0522 / ange上公开提供。

车辆重新识别（RE-ID）旨在通过不同的摄像机检索具有相同车辆ID的图像。当前的零件级特征学习方法通​​常通过统一的部门，外部工具或注意力建模来检测车辆零件。但是，此部分功能通常需要昂贵的额外注释，并在不可靠的零件遮罩预测的情况下导致次优性能。在本文中，我们提出了一个针对车辆重新ID的弱监督零件注意网络（Panet）和零件式网络（PMNET）。首先，Panet通过与零件相关的通道重新校准和基于群集的掩模生成无需车辆零件监管信息来定位车辆零件。其次，PMNET利用教师指导的学习来从锅et中提取特定于车辆的特定功能，并进行多尺度的全球零件特征提取。在推断过程中，PMNET可以自适应提取歧视零件特征，而无需围绕锅et定位，从而防止了不稳定的零件掩模预测。我们将重新ID问题作为一个多任务问题，并采用同质的不确定性来学习最佳的ID损失权衡。实验是在两个公共基准上进行的，这表明我们的方法优于最近的方法，这不需要额外的注释，即CMC@5的平均增加3.0％，而Veri776的MAP中不需要超过1.4％。此外，我们的方法可以扩展到遮挡的车辆重新ID任务，并具有良好的概括能力。