Navigation

Vision-language navigation (VLN) requires an agent to navigate through an 3D environment based on visual observations and natural language instructions. It is clear that the pivotal factor for successful navigation lies in the comprehensive scene understanding. Previous VLN agents employ monocular frameworks to extract 2D features of perspective views directly. Though straightforward they struggle for capturing 3D geometry and semantics leading to a partial and incomplete environment representation. To achieve a comprehensive 3D representation with fine-grained details we introduce a Volumetric Environment Representation (VER) which voxelizes the physical world into structured 3D cells. For each cell VER aggregates multi-view 2D features into such a unified 3D space via 2D-3D sampling. Through coarse-to-fine feature extraction and multi-task learning for VER our agent predicts 3D occupancy 3D room layout and 3D bounding boxes jointly. Based on online collected VERs our agent performs volume state estimation and builds episodic memory for predicting the next step. Experimental results show our environment representations from multi-task learning lead to evident performance gains on VLN. Our model achieves state-of-the-art performance across VLN benchmarks (R2R REVERIE and R4R).

In the pursuit of robust and generalizable environment perception and language understanding the ubiquitous challenge of dataset bias continues to plague vision-and-language navigation (VLN) agents hindering their performance in unseen environments. This paper introduces the generalized cross-modal causal transformer (GOAT) a pioneering solution rooted in the paradigm of causal inference. By delving into both observable and unobservable confounders within vision language and history we propose the back-door and front-door adjustment causal learning (BACL and FACL) modules to promote unbiased learning by comprehensively mitigating potential spurious correlations. Additionally to capture global confounder features we propose a cross-modal feature pooling (CFP) module supervised by contrastive learning which is also shown to be effective in improving cross-modal representations during pre-training. Extensive experiments across multiple VLN datasets (R2R REVERIE RxR and SOON) underscore the superiority of our proposed method over previous state-of-the-art approaches. Code is available at https://github.com/CrystalSixone/VLN-GOAT.

Route planning for navigation under partial observability plays a crucial role in modern robotics and autonomous driving. Existing route planning approaches can be categorized into two main classes: traditional autoregressive and diffusion-based methods. The former often fails due to its myopic nature while the latter either assumes full observability or struggles to adapt to unfamiliar scenarios due to strong couplings with behavior cloning from experts. To address these deficiencies we propose a versatile diffusion-based approach for both 2D and 3D route planning under partial observability. Specifically our value-guided diffusion policy first generates plans to predict actions across various timesteps providing ample foresight to the planning. It then employs a differentiable planner with state estimations to derive a value function directing the agent's exploration and goal-seeking behaviors without seeking experts while explicitly addressing partial observability. During inference our policy is further enhanced by a best-plan-selection strategy substantially boosting the planning success rate. Moreover we propose projecting point clouds derived from RGB-D inputs onto 2D grid-based bird-eye-view maps via semantic segmentation generalizing to 3D environments. This simple yet effective adaption enables zero-shot transfer from 2D-trained policy to 3D cutting across the laborious training for 3D policy and thus certifying our versatility. Experimental results demonstrate our superior performance particularly in navigating situations beyond expert demonstrations surpassing state-of-the-art autoregressive and diffusion-based baselines for both 2D and 3D scenarios.

Building a generalist agent that can interact with the world is an ultimate goal for humans thus spurring the research for embodied navigation where an agent is required to navigate according to instructions or respond to queries. Despite the major progress attained previous works primarily focus on task-specific agents and lack generalizability to unseen scenarios. Recently LLMs have presented remarkable capabilities across various fields and provided a promising opportunity for embodied navigation. Drawing on this we propose the first generalist model for embodied navigation NaviLLM. It adapts LLMs to embodied navigation by introducing schema-based instruction. The schema-based instruction flexibly casts various tasks into generation problems thereby unifying a wide range of tasks. This approach allows us to integrate diverse data sources from various datasets into the training equipping NaviLLM with a wide range of capabilities required by embodied navigation. We conduct extensive experiments to evaluate the performance and generalizability of our model. The experimental results demonstrate that our unified model achieves state-of-the-art performance on CVDN SOON and ScanQA. Specifically it surpasses the previous stats-of-the-art method by a significant margin of 29% in goal progress on CVDN. Moreover our model also demonstrates strong generalizability and presents impressive results on unseen tasks e.g. embodied question answering and 3D captioning.

Accuracy and computational efficiency are the most important metrics to Visual Inertial Navigation System (VINS). The existing VINS algorithms with either high accuracy or low computational complexity are difficult to provide the high precision localization in resource-constrained devices. To this end we propose a novel filter-based VINS framework named SchurVINS (SV) which could guarantee both high accuracy by building a complete residual model and low computational complexity with Schur complement. Technically we first formulate the full residual model where Gradient Hessian and observation covariance are explicitly modeled. Then Schur complement is employed to decompose the full model into ego-motion residual model and landmark residual model. Finally Extended Kalman Filter (EKF) update is implemented in these two models with high efficiency. Experiments on EuRoC and TUM-VI datasets show that our method notably outperforms state-of-the-art (SOTA) methods in both accuracy and computational complexity. The experimental code of SchurVINS is available at https://github.com/bytedance/SchurVINS.

While there has been remarkable progress recently in the fields of manipulation and locomotion mobile manipulation remains a long-standing challenge. Compared to locomotion or static manipulation a mobile system must make a diverse range of long-horizon tasks feasible in unstructured and dynamic environments. While the applications are broad and interesting there are a plethora of challenges in developing these systems such as coordination between the base and arm reliance on onboard perception for perceiving and interacting with the environment and most importantly simultaneously integrating all these parts together. Prior works approach the problem using disentangled modular skills for mobility and manipulation that are trivially tied together. This causes several limitations such as compounding errors delays in decision-making and no whole-body coordination. In this work we present a reactive mobile manipulation framework that uses an active visual system to consciously perceive and react to its environment. Similar to how humans leverage whole-body and hand-eye coordination we develop a mobile manipulator that exploits its ability to move and see more specifically -- to move in order to see and to see in order to move. This allows it to not only move around and interact with its environment but also choose "when" to perceive "what" using an active visual system. We observe that such an agent learns to navigate around complex cluttered scenarios while displaying agile whole-body coordination using only ego-vision without needing to create environment maps. Videos are available at https://spin-robot.github.io

We leverage Large Language Models (LLM) for zeroshot Semantic Audio Visual Navigation (SAVN). Existing methods utilize extensive training demonstrations for reinforcement learning yet achieve relatively low success rates and lack generalizability. The intermittent nature of auditory signals further poses additional obstacles to inferring the goal information. To address this challenge we present the Reflective and Imaginative Language Agent (RILA). By employing multi-modal models to process sensory data we instruct an LLM-based planner to actively explore the environment. During the exploration our agent adaptively evaluates and dismisses inaccurate perceptual descriptions. Additionally we introduce an auxiliary LLMbased assistant to enhance global environmental comprehension by mapping room layouts and providing strategic insights. Through comprehensive experiments and analysis we show that our method outperforms relevant baselines without training demonstrations from the environment and complementary semantic information.

Neural implicit scene representations have recently shown encouraging results in dense visual SLAM. However existing methods produce low-quality scene reconstruction and low-accuracy localization performance when scaling up to large indoor scenes and long sequences. These limitations are mainly due to their single global radiance field with finite capacity which does not adapt to large scenarios. Their end-to-end pose networks are also not robust enough with the growth of cumulative errors in large scenes. To this end we introduce PLGSLAM a neural visual SLAM system capable of high-fidelity surface reconstruction and robust camera tracking in real-time. To handle large-scale indoor scenes PLGSLAM proposes a progressive scene representation method which dynamically allocates new local scene representation trained with frames within a local sliding window. This allows us to scale up to larger indoor scenes and improves robustness (even under pose drifts). In local scene representation PLGSLAM utilizes tri-planes for local high-frequency features with multi-layer perceptron (MLP) networks for the low-frequency feature achieving smoothness and scene completion in unobserved areas. Moreover we propose local-to-global bundle adjustment method with a global keyframe database to address the increased pose drifts on long sequences. Experimental results demonstrate that PLGSLAM achieves state-of-the-art scene reconstruction results and tracking performance across various datasets and scenarios (both in small and large-scale indoor environments).

Image-goal navigation is a challenging task that requires an agent to navigate to a goal indicated by an image in unfamiliar environments. Existing methods utilizing diverse scene memories suffer from inefficient exploration since they use all historical observations for decision-making without considering the goal-relevant fraction. To address this limitation we present MemoNav a novel memory model for image-goal navigation which utilizes a working memory-inspired pipeline to improve navigation performance. Specifically we employ three types of navigation memory. The node features on a map are stored in the short-term memory (STM) as these features are dynamically updated. A forgetting module then retains the informative STM fraction to increase efficiency. We also introduce long-term memory (LTM) to learn global scene representations by progressively aggregating STM features. Subsequently a graph attention module encodes the retained STM and the LTM to generate working memory (WM) which contains the scene features essential for efficient navigation. The synergy among these three memory types boosts navigation performance by enabling the agent to learn and leverage goal-relevant scene features within a topological map. Our evaluation on multi-goal tasks demonstrates that MemoNav significantly outperforms previous methods across all difficulty levels in both Gibson and Matterport3D scenes. Qualitative results further illustrate that MemoNav plans more efficient routes.

Vision-and-language navigation (VLN) enables the agent to navigate to a remote location following the natural language instruction in 3D environments. At each navigation step the agent selects from possible candidate locations and then makes the move. For better navigation planning the lookahead exploration strategy aims to effectively evaluate the agent's next action by accurately anticipating the future environment of candidate locations. To this end some existing works predict RGB images for future environments while this strategy suffers from image distortion and high computational cost. To address these issues we propose the pre-trained hierarchical neural radiance representation model (HNR) to produce multi-level semantic features for future environments which are more robust and efficient than pixel-wise RGB reconstruction. Furthermore with the predicted future environmental representations our lookahead VLN model is able to construct the navigable future path tree and select the optimal path via efficient parallel evaluation. Extensive experiments on the VLN-CE datasets confirm the effectiveness of our method.

As a new embodied vision task Instance ImageGoal Navigation (IIN) aims to navigate to a specified object depicted by a goal image in an unexplored environment. The main challenge of this task lies in identifying the target object from different viewpoints while rejecting similar distractors. Existing ImageGoal Navigation methods usually adopt the simple Exploration-Exploitation framework and ignore the identification of specific instance during navigation. In this work we propose to imitate the human behaviour of "getting closer to confirm" when distinguishing objects from a distance. Specifically we design a new modular navigation framework named Instance-aware Exploration-Verification-Exploitation (IEVE) for instancelevel image goal navigation. Our method allows for active switching among the exploration verification and exploitation actions thereby facilitating the agent in making reasonable decisions under different situations. On the challenging HabitatMatterport 3D semantic (HM3DSEM) dataset our method surpasses previous state-of-theart work with a classical segmentation model (0.684 vs. 0.561 success) or a robust model (0.702 vs. 0.561 success). Our code will be made publicly available at https://github.com/XiaohanLei/IEVE.

Implicit neural SLAM has achieved remarkable progress recently. Nevertheless existing methods face significant challenges in non-ideal scenarios such as motion blur or lighting variation which often leads to issues like convergence failures localization drifts and distorted mapping. To address these challenges we propose EN-SLAM the first event-RGBD implicit neural SLAM framework which effectively leverages the high rate and high dynamic range advantages of event data for tracking and mapping. Specifically EN-SLAM proposes a differentiable CRF (Camera Response Function) rendering technique to generate distinct RGB and event camera data via a shared radiance field which is optimized by learning a unified implicit representation with the captured event and RGBD supervision. Moreover based on the temporal difference property of events we propose a temporal aggregating optimization strategy for the event joint tracking and global bundle adjustment capitalizing on the consecutive difference constraints of events significantly enhancing tracking accuracy and robustness. Finally we construct the simulated dataset DEV-Indoors and real captured dataset DEV-Reals containing 6 scenes 17 sequences with practical motion blur and lighting changes for evaluations. Experimental results show that our method outperforms the SOTA methods in both tracking ATE and mapping ACC with a real-time 17 FPS in various challenging environments. Project page: https://delinqu.github.io/EN-SLAM.

We contribute the Habitat Synthetic Scene Dataset a dataset of 211 high-quality 3D scenes and use it to test navigation agent generalization to realistic 3D environments. Our dataset represents real interiors and contains a diverse set of 18656 models of real-world objects. We investigate the impact of synthetic 3D scene dataset scale and realism on the task of training embodied agents to find and navigate to objects (ObjectGoal navigation). By comparing to synthetic 3D scene datasets from prior work we find that scale helps in generalization but the benefits quickly saturate making visual fidelity and correlation to real-world scenes more important. Our experiments show that agents trained on our smaller-scale dataset can match or outperform agents trained on much larger datasets. Surprisingly we observe that agents trained on just 122 scenes from our dataset outperform agents trained on 10000 scenes from the ProcTHOR-10K dataset in terms of zero-shot generalization in real-world scanned environments.

We present the first application of 3D Gaussian Splatting in monocular SLAM the most fundamental but the hardest setup for Visual SLAM. Our method which runs live at 3fps utilises Gaussians as the only 3D representation unifying the required representation for accurate efficient tracking mapping and high-quality rendering. Designed for challenging monocular settings our approach is seamlessly extendable to RGB-D SLAM when an external depth sensor is available. Several innovations are required to continuously reconstruct 3D scenes with high fidelity from a live camera. First to move beyond the original 3DGS algorithm which requires accurate poses from an offline Structure from Motion (SfM) system we formulate camera tracking for 3DGS using direct optimisation against the 3D Gaussians and show that this enables fast and robust tracking with a wide basin of convergence. Second by utilising the explicit nature of the Gaussians we introduce geometric verification and regularisation to handle the ambiguities occurring in incremental 3D dense reconstruction. Finally we introduce a full SLAM system which not only achieves state-of-the-art results in novel view synthesis and trajectory estimation but also reconstruction of tiny and even transparent objects.

In this paper we introduce GS-SLAM that first utilizes 3D Gaussian representation in the Simultaneous Localization and Mapping (SLAM) system. It facilitates a better balance between efficiency and accuracy. Compared to recent SLAM methods employing neural implicit representations our method utilizes a real-time differentiable splatting rendering pipeline that offers significant speedup to map optimization and RGB-D rendering. Specifically we propose an adaptive expansion strategy that adds new or deletes noisy 3D Gaussians in order to efficiently reconstruct new observed scene geometry and improve the mapping of previously observed areas. This strategy is essential to extend 3D Gaussian representation to reconstruct the whole scene rather than synthesize a static object in existing methods. Moreover in the pose tracking process an effective coarse-to-fine technique is designed to select reliable 3D Gaussian representations to optimize camera pose resulting in runtime reduction and robust estimation. Our method achieves competitive performance compared with existing state-of-the-art real-time methods on the Replica TUM-RGBD datasets. Project page: \href https://gs-slam.github.io/ https://gs-slam.github.io/ .

The Embodied AI community has recently made significant strides in visual navigation tasks exploring targets from 3D coordinates objects language description and images. However these navigation models often handle only a single input modality as the target. With the progress achieved so far it is time to move towards universal navigation models capable of handling various goal types enabling more effective user interaction with robots. To facilitate this goal we propose GOAT-Bench a benchmark for the universal navigation task referred to as GO to AnyThing (GOAT). In this task the agent is directed to navigate to a sequence of targets specified by the category name language description or instance image in an open-vocabulary fashion. We benchmark monolithic RL and modular methods on the GOAT task analyzing their performance across modalities the role of explicit and implicit scene memories their robustness to noise in goal specifications and the impact of memory in lifelong scenarios.

Automatic web navigation aims to build a web agent that can follow language instructions to execute complex and diverse tasks on real-world websites. Existing work primarily takes HTML documents as input which define the contents and action spaces (i.e. actionable elements and operations) of webpages. Nevertheless HTML documents may not provide a clear task-related context for each element making it hard to select the right (sequence of) actions. In this paper we propose to contextualize HTML elements through their "dual views" in webpage screenshots: each HTML element has its corresponding bounding box and visual content in the screenshot. We build upon the insight---web developers tend to arrange task-related elements nearby on webpages to enhance user experiences---and propose to contextualize each element with its neighbor elements using both textual and visual features. The resulting representations of HTML elements are more informative for the agent to take action. We validate our method on the recently released Mind2Web dataset which features diverse navigation domains and tasks on real-world websites. Our method consistently outperforms the baseline in all the scenarios including cross-task cross-website and cross-domain ones.

Visual navigation is to let the agent reach the target according to the continuous visual input. In most previous works visual navigation is usually assumed to be done in a static and ideal environment: the target is always reachable with no need to alter the environment. However the "messy" environments are more general and practical in our daily lives where the agent may get blocked by obstacles. Thus Interactive Navigation (InterNav) is introduced to navigate to the objects in more realistic "messy" environments according to the object interaction. Prior work on InterNav learns short-term interaction through extensive trials with reinforcement learning. However interaction does not guarantee efficient navigation that is planning obstacle interactions that make shorter paths and consume less effort is also crucial. In this paper we introduce an effect-oriented affordance map to enable long-term interactive navigation extending the existing map-based navigation framework to the domain of dynamic environment. We train a set of affordance functions predicting available interactions and the time cost of removing obstacles which informatively support an interactive modular system to address interaction and long-term planning. Experiments on the ProcTHOR simulator demonstrate the capability of our affordance-driven system in long-term navigation in complex dynamic environments.