We propose an approach for semantic imitation, which uses demonstrations from a source domain, e.g. human videos, to accelerate reinforcement learning (RL) in a different target domain, e.g. a robotic manipulator in a simulated kitchen. Instead of imitating low-level actions like joint velocities, our approach imitates the sequence of demonstrated semantic skills like "opening the microwave" or "turning on the stove". This allows us to transfer demonstrations across environments (e.g. real-world to simulated kitchen) and agent embodiments (e.g. bimanual human demonstration to robotic arm). We evaluate on three challenging cross-domain learning problems and match the performance of demonstration-accelerated RL approaches that require in-domain demonstrations. In a simulated kitchen environment, our approach learns long-horizon robot manipulation tasks, using less than 3 minutes of human video demonstrations from a real-world kitchen. This enables scaling robot learning via the reuse of demonstrations, e.g. collected as human videos, for learning in any number of target domains.

Semantic navigation is necessary to deploy mobile robots in uncontrolled environments like our homes, schools, and hospitals. Many learning-based approaches have been proposed in response to the lack of semantic understanding of the classical pipeline for spatial navigation, which builds a geometric map using depth sensors and plans to reach point goals. Broadly, end-to-end learning approaches reactively map sensor inputs to actions with deep neural networks, while modular learning approaches enrich the classical pipeline with learning-based semantic sensing and exploration. But learned visual navigation policies have predominantly been evaluated in simulation. How well do different classes of methods work on a robot? We present a large-scale empirical study of semantic visual navigation methods comparing representative methods from classical, modular, and end-to-end learning approaches across six homes with no prior experience, maps, or instrumentation. We find that modular learning works well in the real world, attaining a 90% success rate. In contrast, end-to-end learning does not, dropping from 77% simulation to 23% real-world success rate due to a large image domain gap between simulation and reality. For practitioners, we show that modular learning is a reliable approach to navigate to objects: modularity and abstraction in policy design enable Sim-to-Real transfer. For researchers, we identify two key issues that prevent today's simulators from being reliable evaluation benchmarks - (A) a large Sim-to-Real gap in images and (B) a disconnect between simulation and real-world error modes - and propose concrete steps forward.

We consider the problem of embodied visual navigation given an image-goal (ImageNav) where an agent is initialized in an unfamiliar environment and tasked with navigating to a location 'described' by an image. Unlike related navigation tasks, ImageNav does not have a standardized task definition which makes comparison across methods difficult. Further, existing formulations have two problematic properties; (1) image-goals are sampled from random locations which can lead to ambiguity (e.g., looking at walls), and (2) image-goals match the camera specification and embodiment of the agent; this rigidity is limiting when considering user-driven downstream applications. We present the Instance-specific ImageNav task (InstanceImageNav) to address these limitations. Specifically, the goal image is 'focused' on some particular object instance in the scene and is taken with camera parameters independent of the agent. We instantiate InstanceImageNav in the Habitat Simulator using scenes from the Habitat-Matterport3D dataset (HM3D) and release a standardized benchmark to measure community progress.

We present a retrospective on the state of Embodied AI research. Our analysis focuses on 13 challenges presented at the Embodied AI Workshop at CVPR. These challenges are grouped into three themes: (1) visual navigation, (2) rearrangement, and (3) embodied vision-and-language. We discuss the dominant datasets within each theme, evaluation metrics for the challenges, and the performance of state-of-the-art models. We highlight commonalities between top approaches to the challenges and identify potential future directions for Embodied AI research.

We present the Habitat-Matterport 3D Semantics (HM3DSEM) dataset. HM3DSEM is the largest dataset of 3D real-world spaces with densely annotated semantics that is currently available to the academic community. It consists of 142,646 object instance annotations across 216 3D spaces and 3,100 rooms within those spaces. The scale, quality, and diversity of object annotations far exceed those of prior datasets. A key difference setting apart HM3DSEM from other datasets is the use of texture information to annotate pixel-accurate object boundaries. We demonstrate the effectiveness of HM3DSEM dataset for the Object Goal Navigation task using different methods. Policies trained using HM3DSEM perform outperform those trained on prior datasets. Introduction of HM3DSEM in the Habitat ObjectNav Challenge lead to an increase in participation from 400 submissions in 2021 to 1022 submissions in 2022.

如果我们想在将它们部署在现实中之前在模拟中训练机器人，那么假定减少SIM2REAL差距的人似乎很自然，并且几乎是不言而喻的，涉及创建富裕性的模拟器（因为现实就是事实）。我们挑战了这一假设并提出了相反的假设-SIM2REAL转移机器人可以通过较低（不是更高）的保真度模拟来改善。我们使用3种不同的机器人（A1，Aliengo，Spot）对这一假设进行了系统的大规模评估 - 在现实世界中以及2个不同的模拟器（栖息地和Igibson）。我们的结果表明，与期望相反，增加忠诚无助于学习。由于模拟速度缓慢（防止大规模学习）和对模拟物理学不准确的过度拟合，因此性能较差。取而代之的是，使用现实世界数据构建机器人运动的简单模型可以改善学习和概括。

我们提出了一种可扩展的方法，用于学习开放世界对象目标导航（ObjectNAV） - 要求虚拟机器人（代理）在未探索的环境中找到对象的任何实例（例如，“查找接收器”）。我们的方法完全是零拍的 - 即，它不需要任何形式的objectNav奖励或演示。取而代之的是，我们训练图像目标导航（ImagenAv）任务，在该任务中，代理在其中找到了捕获图片（即目标图像）的位置。具体而言，我们将目标图像编码为多模式的语义嵌入空间，以在未注释的3D环境（例如HM3D）中以大规模训练语义目标导航（Senanticnav）代理。训练后，可以指示Semanticnav代理查找以自由形式的自然语言描述的对象（例如，“接收器”，“浴室水槽”等），通过将语言目标投射到相同的多模式，语义嵌入空间中。结果，我们的方法启用了开放世界的ObjectNAV。我们在三个ObjectNAV数据集（Gibson，HM3D和MP3D）上广泛评估了我们的代理商，并观察到成功的4.2％-20.0％的绝对改进。作为参考，这些收益与2020年至2021年Objectnav挑战赛竞争对手之间成功的5％改善相似或更好。在开放世界的环境中，我们发现我们的代理商可以概括为明确提到的房间（例如，“找到厨房水槽”）的复合说明，并且何时可以推断目标室（例如，”找到水槽和炉子”）。

我们介绍了Soundspaces 2.0，这是一个用于3D环境的基于几何的音频渲染的平台。考虑到现实世界环境的3D网格，Soundspaces可以为从任意麦克风位置捕获的任意声音生成高度逼真的声音。它与现有的3D视觉资产一起支持一系列视听研究任务，例如视听导航，映射，源定位和分离以及声学匹配。与现有资源相比，Soundspaces 2.0具有允许连续的空间采样，对新型环境的概括以及可配置的麦克风和材料属性的优点。据我们所知，这是第一个基于几何的声学模拟，它提供了高忠诚和现实主义，同时也足够快地用于体现学习。我们展示了模拟器的属性，并根据现实世界的音频测量进行了基准性能。此外，通过涵盖具体导航和远场自动语音识别的两个下游任务，突出了后者的SIM2REAL性能。 Soundspaces 2.0可公开使用，以促进对感知系统的更广泛研究，这些系统既可以看到和听到。

自主代理可以在新环境中导航而不构建明确的地图吗？对于PointGoal Navigation的任务（“转到$ \ delta x $，$ \ delta y $'），在理想化的设置（否RGB -D和驱动噪声，完美的GPS+Compass）下，答案是一个明确的“是” - 由任务无形组件（CNNS和RNN）组成的无地图神经模型接受了大规模增强学习训练，在标准数据集（Gibson）上取得了100％的成功。但是，对于PointNav在现实环境中（RGB-D和致动噪声，没有GPS+Compass），这是一个悬而未决的问题。我们在本文中解决了一个。该任务的最强成绩是成功的71.7％。首先，我们确定了性能下降的主要原因：GPS+指南针的缺失。带有RGB-D传感和致动噪声的完美GPS+指南针的代理商取得了99.8％的成功（Gibson-V2 Val）。这表明（解释模因）强大的视觉探子仪是我们对逼真的PointNav所需的全部。如果我们能够实现这一目标，我们可以忽略感应和致动噪声。作为我们的操作假设，我们扩展了数据集和模型大小，并开发了无人批准的数据启发技术来训练模型以进行视觉探测。我们在栖息地现实的PointNAV挑战方面的最新状态从71％降低到94％的成功（+23，31％相对）和53％至74％的SPL（+21，40％相对）。虽然我们的方法不饱和或“解决”该数据集，但这种强大的改进与有希望的零射击SIM2REAL转移（到Locobot）相结合提供了与假设一致的证据，即即使在现实环境中，显式映射也不是必需的。 。

We study the problem of synthesizing immersive 3D indoor scenes from one or more images. Our aim is to generate high-resolution images and videos from novel viewpoints, including viewpoints that extrapolate far beyond the input images while maintaining 3D consistency. Existing approaches are highly complex, with many separately trained stages and components. We propose a simple alternative: an image-to-image GAN that maps directly from reprojections of incomplete point clouds to full high-resolution RGB-D images. On the Matterport3D and RealEstate10K datasets, our approach significantly outperforms prior work when evaluated by humans, as well as on FID scores. Further, we show that our model is useful for generative data augmentation. A vision-and-language navigation (VLN) agent trained with trajectories spatially-perturbed by our model improves success rate by up to 1.5% over a state of the art baseline on the R2R benchmark. Our code will be made available to facilitate generative data augmentation and applications to downstream robotics and embodied AI tasks.