Monocular 3D object detection is a key problem for autonomous vehicles, as it provides a solution with simple configuration compared to typical multi-sensor systems. The main challenge in monocular 3D detection lies in accurately predicting object depth, which must be inferred from object and scene cues due to the lack of direct range measurement. Many methods attempt to directly estimate depth to assist in 3D detection, but show limited performance as a result of depth inaccuracy. Our proposed solution, Categorical Depth Distribution Network (CaDDN), uses a predicted categorical depth distribution for each pixel to project rich contextual feature information to the appropriate depth interval in 3D space. We then use the computationally efficient bird's-eye-view projection and single-stage detector to produce the final output detections. We design CaDDN as a fully differentiable end-to-end approach for joint depth estimation and object detection. We validate our approach on the KITTI 3D object detection benchmark, where we rank 1 st among published monocular methods. We also provide the first monocular 3D detection results on the newly released Waymo Open Dataset. We provide a code release for CaDDN which is made available here.

Compared to typical multi-sensor systems, monocular 3D object detection has attracted much attention due to its simple configuration. However, there is still a significant gap between LiDAR-based and monocular-based methods. In this paper, we find that the ill-posed nature of monocular imagery can lead to depth ambiguity. Specifically, objects with different depths can appear with the same bounding boxes and similar visual features in the 2D image. Unfortunately, the network cannot accurately distinguish different depths from such non-discriminative visual features, resulting in unstable depth training. To facilitate depth learning, we propose a simple yet effective plug-and-play module, One Bounding Box Multiple Objects (OBMO). Concretely, we add a set of suitable pseudo labels by shifting the 3D bounding box along the viewing frustum. To constrain the pseudo-3D labels to be reasonable, we carefully design two label scoring strategies to represent their quality. In contrast to the original hard depth labels, such soft pseudo labels with quality scores allow the network to learn a reasonable depth range, boosting training stability and thus improving final performance. Extensive experiments on KITTI and Waymo benchmarks show that our method significantly improves state-of-the-art monocular 3D detectors by a significant margin (The improvements under the moderate setting on KITTI validation set are $\mathbf{1.82\sim 10.91\%}$ mAP in BEV and $\mathbf{1.18\sim 9.36\%}$ mAP in 3D}. Codes have been released at https://github.com/mrsempress/OBMO.

单眼3D对象检测是低成本自主剂感知其周围环境的常见解决方案。单眼检测已分为两类：（1）直接从正面视图图像推断3D边界框的直接方法； （2）3D中间表示方法将图像映射到3D空间以进行后续3D检测。第二类不仅脱颖而出，不仅是因为3D检测锻造的伪装在更有意义和代表性的特征的怜悯下，而且还因为新兴的SOTA端到端的预测和计划范式需要从感知中获得鸟类视图的特征图管道。但是，在转换为3D表示形式时，这些方法不能保证对象在潜在空间中的隐式方向和位置与在欧几里得空间中明确观察到的物体一致，这会损害模型性能。因此，我们认为，隐式和显式特征的一致性很重要，并提出了一种新颖的单眼检测方法，名为CIEF，并具有第一个方向感知的图像主链，以消除随后的3D表示中隐式和显式特征的差异。作为第二个贡献，我们引入了射线注意机制。与以前的方法相反，该方法沿着投影射线重复特征或依靠另一个Intermedia froustum Point云，我们将图像特征直接转换为具有稳定特征的Voxel表示。我们还提出了一个手工制作的高斯位置编码函数，该函数的表现优于正弦的编码函数，但保持连续的好处。 CIEF在提交时间的3D和BEV检测基准的所有报告的方法中排名第一。

In this paper we propose to exploit multiple related tasks for accurate multi-sensor 3D object detection. Towards this goal we present an end-to-end learnable architecture that reasons about 2D and 3D object detection as well as ground estimation and depth completion. Our experiments show that all these tasks are complementary and help the network learn better representations by fusing information at various levels. Importantly, our approach leads the KITTI benchmark on 2D, 3D and bird's eye view object detection, while being real-time. * Equal contribution.† Work done as part of Uber AI Residency program.

In this paper, we propose a novel 3D object detector that can exploit both LIDAR as well as cameras to perform very accurate localization. Towards this goal, we design an end-to-end learnable architecture that exploits continuous convolutions to fuse image and LIDAR feature maps at different levels of resolution. Our proposed continuous fusion layer encode both discrete-state image features as well as continuous geometric information. This enables us to design a novel, reliable and efficient end-to-end learnable 3D object detector based on multiple sensors. Our experimental evaluation on both KITTI as well as a large scale 3D object detection benchmark shows significant improvements over the state of the art.

对于许多应用程序，包括自动驾驶，机器人抓握和增强现实，单眼3D对象检测是一项基本但非常重要的任务。现有的领先方法倾向于首先估算输入图像的深度，并基于点云检测3D对象。该例程遭受了深度估计和对象检测之间固有的差距。此外，预测误差积累也会影响性能。在本文中，提出了一种名为MonopCN的新方法。引入单频道的洞察力是，我们建议在训练期间模拟基于点云的探测器的特征学习行为。因此，在推理期间，学习的特征和预测将与基于点云的检测器相似。为了实现这一目标，我们建议一个场景级仿真模块，一个ROI级别的仿真模块和一个响应级仿真模块，这些模块逐渐用于检测器的完整特征学习和预测管道。我们将我们的方法应用于著名的M3D-RPN检测器和CADDN检测器，并在Kitti和Waymo Open数据集上进行了广泛的实验。结果表明，我们的方法始终提高不同边缘的不同单眼探测器的性能，而无需更改网络体系结构。我们的方法最终达到了最先进的性能。

鉴于其经济性与多传感器设置相比，从单眼输入中感知的3D对象对于机器人系统至关重要。它非常困难，因为单个图像无法提供预测绝对深度值的任何线索。通过双眼方法进行3D对象检测，我们利用了相机自我运动提供的强几何结构来进行准确的对象深度估计和检测。我们首先对此一般的两视案例进行了理论分析，并注意两个挑战：1）来自多个估计的累积错误，这些估计使直接预测棘手； 2）由静态摄像机和歧义匹配引起的固有难题。因此，我们建立了具有几何感知成本量的立体声对应关系，作为深度估计的替代方案，并以单眼理解进一步补偿了它，以解决第二个问题。我们的框架（DFM）命名为深度（DFM），然后使用已建立的几何形状将2D图像特征提升到3D空间并检测到其3D对象。我们还提出了一个无姿势的DFM，以使其在摄像头不可用时可用。我们的框架在Kitti基准测试上的优于最先进的方法。详细的定量和定性分析也验证了我们的理论结论。该代码将在https://github.com/tai-wang/depth-from-motion上发布。

由于LIDAR传感器捕获的精确深度信息缺乏准确的深度信息，单眼3D对象检测是一个关键而挑战的自主驾驶任务。在本文中，我们提出了一种立体引导的单目3D对象检测网络，称为SGM3D，其利用立体图像提取的鲁棒3D特征来增强从单眼图像中学到的特征。我们创新地研究了多粒度域适配模块（MG-DA）以利用网络的能力，以便仅基于单手套提示产生立体模拟功能。利用粗均衡特征级以及精细锚级域适配，以引导单眼分支。我们介绍了一个基于IOO匹配的对齐模块（iou-ma），用于立体声和单眼域之间的对象级域适应，以减轻先前阶段中的不匹配。我们对最具挑战性的基蒂和Lyft数据集进行了广泛的实验，并实现了新的最先进的性能。此外，我们的方法可以集成到许多其他单眼的方法中以提高性能而不引入任何额外的计算成本。

基于摄像头的3D对象探测器由于其更广泛的部署而欢迎其比LIDAR传感器较低。我们首先重新访问先前的立体声检测器DSGN，以表示代表3D几何和语义的立体音量构建方式。我们抛光立体声建模，并提出高级版本DSGN ++，旨在在三个主要方面增强整个2d到3D管道的有效信息流。首先，为了有效地将2D信息提高到立体声音量，我们提出了深度扫地（DPS），以允许较密集的连接并提取深度引导的特征。其次，为了掌握不同间距的功能，我们提出了一个新颖的立体声音量 - 双视立体声卷（DSV），该卷（DSV）集成了前视图和顶部视图功能，并重建了相机frustum中的子素深度。第三，随着前景区域在3D空间中的占主导地位，我们提出了一种多模式数据编辑策略-Stereo-lidar拷贝性 - 可确保跨模式对齐并提高数据效率。没有铃铛和哨子，在流行的Kitti基准测试中的各种模式设置中进行了广泛的实验表明，我们的方法始终优于所有类别的基于相机的3D检测器。代码可从https://github.com/chenyilun95/dsgn2获得。

3D object detection is an essential task in autonomous driving. Recent techniques excel with highly accurate detection rates, provided the 3D input data is obtained from precise but expensive LiDAR technology. Approaches based on cheaper monocular or stereo imagery data have, until now, resulted in drastically lower accuracies -a gap that is commonly attributed to poor image-based depth estimation. However, in this paper we argue that it is not the quality of the data but its representation that accounts for the majority of the difference. Taking the inner workings of convolutional neural networks into consideration, we propose to convert image-based depth maps to pseudo-LiDAR representations -essentially mimicking the LiDAR signal. With this representation we can apply different existing LiDAR-based detection algorithms. On the popular KITTI benchmark, our approach achieves impressive improvements over the existing state-of-the-art in image-based performance -raising the detection accuracy of objects within the 30m range from the previous state-of-the-art of 22% to an unprecedented 74%. At the time of submission our algorithm holds the highest entry on the KITTI 3D object detection leaderboard for stereo-image-based approaches. Our code is publicly available at https: //github.com/mileyan/pseudo_lidar.

We address the problem of real-time 3D object detection from point clouds in the context of autonomous driving. Computation speed is critical as detection is a necessary component for safety. Existing approaches are, however, expensive in computation due to high dimensionality of point clouds. We utilize the 3D data more efficiently by representing the scene from the Bird's Eye View (BEV), and propose PIXOR, a proposal-free, single-stage detector that outputs oriented 3D object estimates decoded from pixelwise neural network predictions. The input representation, network architecture, and model optimization are especially designed to balance high accuracy and real-time efficiency. We validate PIXOR on two datasets: the KITTI BEV object detection benchmark, and a large-scale 3D vehicle detection benchmark. In both datasets we show that the proposed detector surpasses other state-of-the-art methods notably in terms of Average Precision (AP), while still runs at > 28 FPS.

以视觉为中心的BEV感知由于其固有的优点，最近受到行业和学术界的关注，包括展示世界自然代表和融合友好。随着深度学习的快速发展，已经提出了许多方法来解决以视觉为中心的BEV感知。但是，最近没有针对这个小说和不断发展的研究领域的调查。为了刺激其未来的研究，本文对以视觉为中心的BEV感知及其扩展进行了全面调查。它收集并组织了最近的知识，并对常用算法进行了系统的综述和摘要。它还为几项BEV感知任务提供了深入的分析和比较结果，从而促进了未来作品的比较并激发了未来的研究方向。此外，还讨论了经验实现细节并证明有利于相关算法的开发。

已经尝试通过融合立体声摄像机图像和激光镜传感器数据或使用LIDAR进行预训练，而仅用于测试的单眼图像来检测3D对象，但是由于精确度较低而仅尝试使用单眼图像序列的尝试较少。另外，当仅使用单眼图像的深度预测时，只能预测尺度不一致的深度，这就是研究人员不愿单独使用单眼图像的原因。因此，我们提出了一种通过仅使用单眼图像序列来预测绝对深度和检测3D对象的方法，通过启用检测网络和深度预测网络的端到端学习。结果，所提出的方法超过了Kitti 3D数据集中性能的其他现有方法。即使在训练期间一起使用单眼图像和3D激光雷达以提高性能，与使用相同输入的其他方法相比，我们的展览也是最佳性能。此外，端到端学习不仅可以改善深度预测性能，而且还可以实现绝对深度预测，因为我们的网络利用了这样一个事实，即3D对象（例如汽车）的大小由大约大小确定。

由于其低成本和设置简单性，单眼3D检测引起了社区的广泛关注。它以RGB图像为输入，并预测3D空间中的3D框。最具挑战性的子任务在于实例深度估计。以前的工作通常使用直接估计方法。但是，在本文中，我们指出RGB图像的实例深度是非直觉的。它是由视觉深度线索和实例属性线索结合在一起的，因此很难在网络中直接学习。因此，我们建议将实例深度重新调整为实例视觉表面深度（视觉深度）和实例属性深度（属性深度）的组合。视觉深度与对象的外观和图像上的位置有关。相比之下，属性深度依赖于对象的固有属性，这些属性与图像上的对象仿射转换不变。相应地，我们将3D位置的不确定性分解为视觉深度不确定性和属性深度不确定性。通过结合不同类型的深度和相关的不确定性，我们可以获得最终的实例深度。此外，单眼3D检测中的数据增强通常由于身体性质而受到限制，从而阻碍了性能的提高。根据提出的实例深度分解策略，我们可以缓解此问题。对Kitti进行了评估，我们的方法实现了新的最新结果，并且广泛的消融研究验证了我们方法中每个组件的有效性。这些代码在https://github.com/spengliang/did-m3d上发布。

它得到了很好的认识到，从深度感知的LIDAR点云和语义富有的立体图像中融合互补信息将有利于3D对象检测。然而，探索稀疏3D点和密集2D像素之间固有的不自然相互作用并不重要。为了简化这种困难，最近的建议通常将3D点投影到2D图像平面上以对图像数据进行采样，然后聚合点处的数据。然而，这种方法往往遭受点云和RGB图像的分辨率之间的不匹配，导致次优性能。具体地，作为多模态数据聚合位置的稀疏点导致高分辨率图像的严重信息丢失，这反过来破坏了多传感器融合的有效性。在本文中，我们呈现VPFNET - 一种新的架构，可以在“虚拟”点处巧妙地对齐和聚合点云和图像数据。特别地，它们的密度位于3D点和2D像素的密度之间，虚拟点可以很好地桥接两个传感器之间的分辨率间隙，从而保持更多信息以进行处理。此外，我们还研究了可以应用于点云和RGB图像的数据增强技术，因为数据增强对迄今为止对3D对象探测器的贡献不可忽略。我们对Kitti DataSet进行了广泛的实验，与最先进的方法相比，观察到了良好的性能。值得注意的是，我们的VPFNET在KITTI测试集上实现了83.21 \％中等3D AP和91.86 \％适度的BEV AP，自2021年5月21日起排名第一。网络设计也考虑了计算效率 - 我们可以实现FPS 15对单个NVIDIA RTX 2080TI GPU。该代码将用于复制和进一步调查。

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.

配备摄像机的无人机可以显着增强人类在3D空间中具有显着的可操作性，从而使人类感知世界的能力。具有讽刺意味的是，无人机的对象检测始终是在2D图像空间中进行的，这从根本上限制了其理解3D场景的能力。此外，由于缺乏变形模型，无法直接应用于为自动驾驶开发的现有3D对象检测方法，这对于具有敏感变形和小物体的遥远空中透视至关重要。为了填补空白，这项工作提出了一个名为DVDET的双视检测系统，以在2D图像空间和3D物理空间中实现空中单眼对象检测。为了解决严重的视图变形问题，我们提出了一个可训练的可训练的可训练的转换模块，该模块可以从无人机的角度正确地扭曲信息到BEV。与汽车的单眼方法相比，我们的转换包括一个可学习的可变形网络，可显式修改严重的偏差。为了应对数据集挑战，我们提出了一个名为AM3D-SIM的新的大规模模拟数据集，该数据集由AirSim和Carla的共模制成，以及一个名为AM3D-REAL的新的现实世界空中数据集，由DJI Matrice 300 RTK收集，在两个数据集中，都提供了3D对象检测的高质量注释。广泛的实验表明，i）空中单眼3D对象检测是可行的； ii）在仿真数据集中预先训练的模型受益于现实世界的性能，iii）DVDET也有益于汽车的单眼3D对象检测。为了鼓励更多的研究人员调查该领域，我们将在https://sjtu-magic.github.io/dataset/am3d/中发布数据集和相关代码。

在鸟眼中学习强大的表现（BEV），以进行感知任务，这是趋势和吸引行业和学术界的广泛关注。大多数自动驾驶算法的常规方法在正面或透视视图中执行检测，细分，跟踪等。随着传感器配置变得越来越复杂，从不同的传感器中集成了多源信息，并在统一视图中代表功能至关重要。 BEV感知继承了几个优势，因为代表BEV中的周围场景是直观和融合友好的。对于BEV中的代表对象，对于随后的模块，如计划和/或控制是最可取的。 BEV感知的核心问题在于（a）如何通过从透视视图到BEV来通过视图转换来重建丢失的3D信息； （b）如何在BEV网格中获取地面真理注释； （c）如何制定管道以合并来自不同来源和视图的特征； （d）如何适应和概括算法作为传感器配置在不同情况下各不相同。在这项调查中，我们回顾了有关BEV感知的最新工作，并对不同解决方案进行了深入的分析。此外，还描述了该行业的BEV方法的几种系统设计。此外，我们推出了一套完整的实用指南，以提高BEV感知任务的性能，包括相机，激光雷达和融合输入。最后，我们指出了该领域的未来研究指示。我们希望该报告能阐明社区，并鼓励对BEV感知的更多研究。我们保留一个活跃的存储库来收集最新的工作，并在https://github.com/openperceptionx/bevperception-survey-recipe上提供一包技巧的工具箱。

Object detection in point clouds is an important aspect of many robotics applications such as autonomous driving. In this paper we consider the problem of encoding a point cloud into a format appropriate for a downstream detection pipeline. Recent literature suggests two types of encoders; fixed encoders tend to be fast but sacrifice accuracy, while encoders that are learned from data are more accurate, but slower. In this work we propose PointPillars, a novel encoder which utilizes PointNets to learn a representation of point clouds organized in vertical columns (pillars). While the encoded features can be used with any standard 2D convolutional detection architecture, we further propose a lean downstream network. Extensive experimentation shows that PointPillars outperforms previous encoders with respect to both speed and accuracy by a large margin. Despite only using lidar, our full detection pipeline significantly outperforms the state of the art, even among fusion methods, with respect to both the 3D and bird's eye view KITTI benchmarks. This detection performance is achieved while running at 62 Hz: a 2 -4 fold runtime improvement. A faster version of our method matches the state of the art at 105 Hz. These benchmarks suggest that PointPillars is an appropriate encoding for object detection in point clouds.

In this work, we study 3D object detection from RGB-D data in both indoor and outdoor scenes. While previous methods focus on images or 3D voxels, often obscuring natural 3D patterns and invariances of 3D data, we directly operate on raw point clouds by popping up RGB-D scans. However, a key challenge of this approach is how to efficiently localize objects in point clouds of large-scale scenes (region proposal). Instead of solely relying on 3D proposals, our method leverages both mature 2D object detectors and advanced 3D deep learning for object localization, achieving efficiency as well as high recall for even small objects. Benefited from learning directly in raw point clouds, our method is also able to precisely estimate 3D bounding boxes even under strong occlusion or with very sparse points. Evaluated on KITTI and SUN RGB-D 3D detection benchmarks, our method outperforms the state of the art by remarkable margins while having real-time capability. * Majority of the work done as an intern at Nuro, Inc. depth to point cloud 2D region (from CNN) to 3D frustum 3D box (from PointNet)