6D object pose estimation problem has been extensively studied in the field of Computer Vision and Robotics. It has wide range of applications such as robot manipulation, augmented reality, and 3D scene understanding. With the advent of Deep Learning, many breakthroughs have been made; however, approaches continue to struggle when they encounter unseen instances, new categories, or real-world challenges such as cluttered backgrounds and occlusions. In this study, we will explore the available methods based on input modality, problem formulation, and whether it is a category-level or instance-level approach. As a part of our discussion, we will focus on how 6D object pose estimation can be used for understanding 3D scenes.

This paper addresses the challenge of 6DoF pose estimation from a single RGB image under severe occlusion or truncation. Many recent works have shown that a two-stage approach, which first detects keypoints and then solves a Perspective-n-Point (PnP) problem for pose estimation, achieves remarkable performance. However, most of these methods only localize a set of sparse keypoints by regressing their image coordinates or heatmaps, which are sensitive to occlusion and truncation. Instead, we introduce a Pixel-wise Voting Network (PVNet) to regress pixel-wise unit vectors pointing to the keypoints and use these vectors to vote for keypoint locations using RANSAC. This creates a flexible representation for localizing occluded or truncated keypoints. Another important feature of this representation is that it provides uncertainties of keypoint locations that can be further leveraged by the PnP solver. Experiments show that the proposed approach outperforms the state of the art on the LINEMOD, Occlusion LINEMOD and YCB-Video datasets by a large margin, while being efficient for real-time pose estimation. We further create a Truncation LINEMOD dataset to validate the robustness of our approach against truncation. The code will be avaliable at https://zju-3dv.github.io/pvnet/.

The goal of this paper is to estimate the 6D pose and dimensions of unseen object instances in an RGB-D image. Contrary to "instance-level" 6D pose estimation tasks, our problem assumes that no exact object CAD models are available during either training or testing time. To handle different and unseen object instances in a given category, we introduce Normalized Object Coordinate Space (NOCS)-a shared canonical representation for all possible object instances within a category. Our region-based neural network is then trained to directly infer the correspondence from observed pixels to this shared object representation (NOCS) along with other object information such as class label and instance mask. These predictions can be combined with the depth map to jointly estimate the metric 6D pose and dimensions of multiple objects in a cluttered scene. To train our network, we present a new contextaware technique to generate large amounts of fully annotated mixed reality data. To further improve our model and evaluate its performance on real data, we also provide a fully annotated real-world dataset with large environment and instance variation. Extensive experiments demonstrate that the proposed method is able to robustly estimate the pose and size of unseen object instances in real environments while also achieving state-of-the-art performance on standard 6D pose estimation benchmarks.

We present a method for 3D object detection and pose estimation from a single image. In contrast to current techniques that only regress the 3D orientation of an object, our method first regresses relatively stable 3D object properties using a deep convolutional neural network and then combines these estimates with geometric constraints provided by a 2D object bounding box to produce a complete 3D bounding box. The first network output estimates the 3D object orientation using a novel hybrid discrete-continuous loss, which significantly outperforms the L2 loss. The second output regresses the 3D object dimensions, which have relatively little variance compared to alternatives and can often be predicted for many object types. These estimates, combined with the geometric constraints on translation imposed by the 2D bounding box, enable us to recover a stable and accurate 3D object pose. We evaluate our method on the challenging KITTI object detection benchmark [2] both on the official metric of 3D orientation estimation and also on the accuracy of the obtained 3D bounding boxes. Although conceptually simple, our method outperforms more complex and computationally expensive approaches that leverage semantic segmentation, instance level segmentation and flat ground priors [4] and sub-category detection [23][24]. Our discrete-continuous loss also produces state of the art results for 3D viewpoint estimation on the Pascal 3D+ dataset[26].

我们提出了一种称为DPODV2（密集姿势对象检测器）的三个阶段6 DOF对象检测方法，该方法依赖于致密的对应关系。我们将2D对象检测器与密集的对应关系网络和多视图姿势细化方法相结合，以估计完整的6 DOF姿势。与通常仅限于单眼RGB图像的其他深度学习方法不同，我们提出了一个统一的深度学习网络，允许使用不同的成像方式（RGB或DEPTH）。此外，我们提出了一种基于可区分渲染的新型姿势改进方法。主要概念是在多个视图中比较预测并渲染对应关系，以获得与所有视图中预测的对应关系一致的姿势。我们提出的方法对受控设置中的不同数据方式和培训数据类型进行了严格的评估。主要结论是，RGB在对应性估计中表现出色，而如果有良好的3D-3D对应关系，则深度有助于姿势精度。自然，他们的组合可以实现总体最佳性能。我们进行广泛的评估和消融研究，以分析和验证几个具有挑战性的数据集的结果。 DPODV2在所有这些方面都取得了出色的成果，同时仍然保持快速和可扩展性，独立于使用的数据模式和培训数据的类型

Estimating 6D poses of objects from images is an important problem in various applications such as robot manipulation and virtual reality. While direct regression of images to object poses has limited accuracy, matching rendered images of an object against the input image can produce accurate results. In this work, we propose a novel deep neural network for 6D pose matching named DeepIM. Given an initial pose estimation, our network is able to iteratively refine the pose by matching the rendered image against the observed image. The network is trained to predict a relative pose transformation using a disentangled representation of 3D location and 3D orientation and an iterative training process. Experiments on two commonly used benchmarks for 6D pose estimation demonstrate that DeepIM achieves large improvements over stateof-the-art methods. We furthermore show that DeepIM is able to match previously unseen objects.

深度学习识别的进步导致使用2D图像准确的对象检测。然而，这些2D感知方法对于完整的3D世界信息不足。同时，高级3D形状估计接近形状本身的焦点，而不考虑公制量表。这些方法无法确定对象的准确位置和方向。为了解决这个问题，我们提出了一个框架，该框架共同估计了从单个RGB图像的度量标度形状和姿势。我们的框架有两个分支：公制刻度对象形状分支（MSO）和归一化对象坐标空间分支（NOC）。 MSOS分支估计在相机坐标中观察到的度量标准形状。 NOCS分支预测归一化对象坐标空间（NOCS）映射，并从预测的度量刻度网格与渲染的深度图执行相似性转换，以获得6D姿势和大小。此外，我们介绍了归一化对象中心估计（NOCE），以估计从相机到物体中心的几何对齐距离。我们在合成和实际数据集中验证了我们的方法，以评估类别级对象姿势和形状。

Estimating the 6D pose of known objects is important for robots to interact with the real world. The problem is challenging due to the variety of objects as well as the complexity of a scene caused by clutter and occlusions between objects. In this work, we introduce PoseCNN, a new Convolutional Neural Network for 6D object pose estimation. PoseCNN estimates the 3D translation of an object by localizing its center in the image and predicting its distance from the camera. The 3D rotation of the object is estimated by regressing to a quaternion representation. We also introduce a novel loss function that enables PoseCNN to handle symmetric objects. In addition, we contribute a large scale video dataset for 6D object pose estimation named the YCB-Video dataset. Our dataset provides accurate 6D poses of 21 objects from the YCB dataset observed in 92 videos with 133,827 frames. We conduct extensive experiments on our YCB-Video dataset and the OccludedLINEMOD dataset to show that PoseCNN is highly robust to occlusions, can handle symmetric objects, and provide accurate pose estimation using only color images as input. When using depth data to further refine the poses, our approach achieves state-of-the-art results on the challenging OccludedLINEMOD dataset. Our code and dataset are available at https://rse-lab.cs.washington.edu/projects/posecnn/.

像素级别的2D对象语义理解是计算机视觉中的一个重要主题，可以帮助在日常生活中深入了解对象（例如功能和可折扣）。然而，最先前的方法直接在2D图像中的对应关系上培训，这是端到端，但在3D空间中失去了大量信息。在本文中，我们提出了一种关于在3D域中预测图像对应语义的新方法，然后将它们突出回2D图像以实现像素级别的理解。为了获得当前图像数据集中不存在的可靠的3D语义标签，我们构建一个名为KeyPointNet的大型关键点知识引擎，其中包含103,450个关键点和来自16个对象类别的8,234个3D模型。我们的方法利用3D视觉中的优势，并可以明确地理由对物体自动阻塞和可见性。我们表明我们的方法在标准语义基准上给出了比较甚至卓越的结果。

我们介绍了日常桌面对象的998 3D型号的数据集及其847,000个现实世界RGB和深度图像。每个图像的相机姿势和对象姿势的准确注释都以半自动化方式执行，以促进将数据集用于多种3D应用程序，例如形状重建，对象姿势估计，形状检索等。3D重建由于缺乏适当的现实世界基准来完成该任务，并证明我们的数据集可以填补该空白。整个注释数据集以及注释工具和评估基线的源代码可在http://www.ocrtoc.org/3d-reconstruction.html上获得。

A key technical challenge in performing 6D object pose estimation from RGB-D image is to fully leverage the two complementary data sources. Prior works either extract information from the RGB image and depth separately or use costly post-processing steps, limiting their performances in highly cluttered scenes and real-time applications. In this work, we present DenseFusion, a generic framework for estimating 6D pose of a set of known objects from RGB-D images. DenseFusion is a heterogeneous architecture that processes the two data sources individually and uses a novel dense fusion network to extract pixel-wise dense feature embedding, from which the pose is estimated. Furthermore, we integrate an end-to-end iterative pose refinement procedure that further improves the pose estimation while achieving near real-time inference. Our experiments show that our method outperforms state-of-the-art approaches in two datasets, YCB-Video and LineMOD. We also deploy our proposed method to a real robot to grasp and manipulate objects based on the estimated pose. Our code and video are available at https://sites.google.com/view/densefusion/.

我们呈现ROCA，一种新的端到端方法，可以从形状数据库到单个输入图像中检索并对齐3D CAD模型。这使得从2D RGB观察开始观察到的场景的3D感知，其特征在于轻质，紧凑，清洁的CAD表示。我们的方法的核心是我们基于密集的2D-3D对象对应关系和促使对齐的可差的对准优化。因此，罗卡可以提供强大的CAD对准，同时通过利用2D-3D对应关系来学习几何上类似CAD模型来同时通知CAD检索。SCANNET的真实世界图像实验表明，Roca显着提高了现有技术，从检索感知CAD准确度为9.5％至17.6％。

We introduce MegaPose, a method to estimate the 6D pose of novel objects, that is, objects unseen during training. At inference time, the method only assumes knowledge of (i) a region of interest displaying the object in the image and (ii) a CAD model of the observed object. The contributions of this work are threefold. First, we present a 6D pose refiner based on a render&compare strategy which can be applied to novel objects. The shape and coordinate system of the novel object are provided as inputs to the network by rendering multiple synthetic views of the object's CAD model. Second, we introduce a novel approach for coarse pose estimation which leverages a network trained to classify whether the pose error between a synthetic rendering and an observed image of the same object can be corrected by the refiner. Third, we introduce a large-scale synthetic dataset of photorealistic images of thousands of objects with diverse visual and shape properties and show that this diversity is crucial to obtain good generalization performance on novel objects. We train our approach on this large synthetic dataset and apply it without retraining to hundreds of novel objects in real images from several pose estimation benchmarks. Our approach achieves state-of-the-art performance on the ModelNet and YCB-Video datasets. An extensive evaluation on the 7 core datasets of the BOP challenge demonstrates that our approach achieves performance competitive with existing approaches that require access to the target objects during training. Code, dataset and trained models are available on the project page: https://megapose6d.github.io/.

实时机器人掌握，支持随后的精确反对操作任务，是高级高级自治系统的优先目标。然而，尚未找到这样一种可以用时间效率进行充分准确的掌握的算法。本文提出了一种新的方法，其具有2阶段方法，它使用深神经网络结合快速的2D对象识别，以及基于点对特征框架的随后的精确和快速的6D姿态估计来形成实时3D对象识别和抓握解决方案能够多对象类场景。所提出的解决方案有可能在实时应用上稳健地进行，需要效率和准确性。为了验证我们的方法，我们进行了广泛且彻底的实验，涉及我们自己的数据集的费力准备。实验结果表明，该方法在5CM5DEG度量标准中的精度97.37％，平均距离度量分数99.37％。实验结果显示了通过使用该方法的总体62％的相对改善（5cm5deg度量）和52.48％（平均距离度量）。此外，姿势估计执行也显示出运行时间的平均改善47.6％。最后，为了说明系统在实时操作中的整体效率，进行了一个拾取和放置的机器人实验，并显示了90％的准确度的令人信服的成功率。此实验视频可在https://sites.google.com/view/dl-ppf6dpose/上获得。

我们考虑了单个RGB图像的类别级别6D姿势估计的问题。我们的方法代表对象类别作为Cuboid网格，并了解每个网格顶点的神经特征激活的生成模型，以通过可区分的渲染执行姿势估计。基于渲染的方法的一个常见问题是，它们依靠边界框建议，这些建议不会传达有关对象3D旋转的信息，并且当对象被部分遮挡时不可靠。取而代之的是，我们引入了一种粗到1的优化策略，该策略利用渲染过程来估算一组稀疏的6D对象建议集，随后通过基于梯度的优化进行了完善。实现我们方法融合的关键是一种神经特征表示，训练了使用对比度学习的尺度和旋转不变的训练。我们的实验表明，与先前的工作相比，尤其是在强烈的部分遮挡下，类别级别的6D姿势估计性能增强。

RGB图像的刚性对象的可伸缩6D构成估计旨在处理多个对象并推广到新物体。我们建立在一个著名的自动编码框架的基础上，以应对对象对称性和缺乏标记的训练数据，我们通过将自动编码器的潜在表示形状分解为形状并构成子空间来实现可伸缩性。潜在形状空间通过对比度度量学习模型不同对象的相似性，并将潜在姿势代码与旋转检索的规范旋转进行比较。由于不同的对象对称会诱导不一致的潜在姿势空间，因此我们用规范旋转重新输入形状表示，以生成形状依赖的姿势代码簿以进行旋转检索。我们在两个基准上显示了最新的性能，其中包含无类别和每日对象的无纹理CAD对象，并通过扩展到跨类别的每日对象的更具挑战性的设置，进一步证明了可扩展性。

我们提出了一种方法，用于估计具有单个RGB图像的可用3D模型的刚性对象的6DOF姿势。与基于经典对应的方法不同，该方法可以预测输入图像的像素的3D对象坐标，该建议的方法可以预测3D对象坐标在相机frustum中采样的3D查询点。从像素到3D点的移动，这是受到3D重建方法的最新PIFU式方法的启发，可以对整个对象（包括（自我）遮挡部分）进行推理。对于与与像素对齐的图像功能相关的3D查询点，我们训练完全连接的神经网络来预测：（i）相应的3D对象坐标，以及（ii）签名到对象表面的签名距离，首先定义仅适用于地表附近的查询点。我们将该网络实现的映射称为神经通信字段。然后，通过Kabsch-Ransac算法从预测的3D-3D对应关系中稳健地估计对象姿势。所提出的方法在三个BOP数据集上实现了最先进的结果，并且在咬合挑战性案例中表现出了优越。项目网站在：linhuang17.github.io/ncf。

We introduce an approach for recovering the 6D pose of multiple known objects in a scene captured by a set of input images with unknown camera viewpoints. First, we present a single-view single-object 6D pose estimation method, which we use to generate 6D object pose hypotheses. Second, we develop a robust method for matching individual 6D object pose hypotheses across different input images in order to jointly estimate camera viewpoints and 6D poses of all objects in a single consistent scene. Our approach explicitly handles object symmetries, does not require depth measurements, is robust to missing or incorrect object hypotheses, and automatically recovers the number of objects in the scene. Third, we develop a method for global scene refinement given multiple object hypotheses and their correspondences across views. This is achieved by solving an object-level bundle adjustment problem that refines the poses of cameras and objects to minimize the reprojection error in all views. We demonstrate that the proposed method, dubbed Cosy-Pose, outperforms current state-of-the-art results for single-view and multi-view 6D object pose estimation by a large margin on two challenging benchmarks: the YCB-Video and T-LESS datasets. Code and pre-trained models are available on the project webpage. 5

我们提出了一种对类别级别的6D对象姿势和大小估计的新方法。为了解决类内的形状变化，我们学习规范形状空间（CASS），统一表示，用于某个对象类别的各种情况。特别地，CASS被建模为具有标准化姿势的规范3D形状深度生成模型的潜在空间。我们训练变形式自动编码器（VAE），用于从RGBD图像中的规范空间中生成3D点云。 VAE培训以跨类方式培训，利用公开的大型3D形状存储库。由于3D点云在归一化姿势（具有实际尺寸）中生成，因此VAE的编码器学习视图分解RGBD嵌入。它将RGBD图像映射到任意视图中以独立于姿势的3D形状表示。然后通过将对象姿势与用单独的深神经网络提取的输入RGBD的姿势相关的特征进行对比姿势估计。我们将CASS和姿势和大小估计的学习集成到最终的培训网络中，实现了最先进的性能。

本文介绍了一种新型的多视图6 DOF对象姿势细化方法，重点是改进对合成数据训练的方法。它基于DPOD检测器，该检测器会在每个帧中产生密集的2D-3D对应关系。我们选择使用多个具有已知相机转换的帧，因为它允许通过可解释的ICP样损耗函数引入几何约束。损耗函数是通过可区分的渲染器实现的，并经过迭代进行了优化。我们还证明，仅根据合成数据训练的完整检测和完善管道可用于自动标记的真实数据。我们对linemod，caslusion，自制和YCB-V数据集执行定量评估，并与对合成和真实数据训练的最新方法相比，报告出色的性能。我们从经验上证明，我们的方法仅需要几个帧，并且可以在外部摄像机校准中关闭相机位置和噪音，从而使其实际用法更加容易且无处不在。