Clio: Real-time Task-Driven Open-Set 3D Scene Graph Construction

Core Concepts

Clio constructs a hierarchical 3D scene graph of the environment in real-time, where the representation only retains task-relevant objects and regions.

Abstract

The paper proposes Clio, a novel approach for building task-driven 3D scene graphs in real-time with embedded open-set semantics.
The key insights are:

Progress in vision-language models allows specifying tasks as a list of natural language instructions.
Modern foundation models for task-agnostic segmentation provide a way to over-segment an image into a potentially large number of segments, which can be reprojected to 3D.

The authors formulate task-aware 3D scene understanding as the problem of compressing the task-agnostic primitives into a cluster of task-relevant concepts, which are maximally informative about the given tasks. This is naturally expressed using the Information Bottleneck (IB) principle.
The authors develop an Agglomerative IB algorithm to cluster the 3D primitives into task-relevant objects and regions. They integrate this algorithm into a real-time system, Clio, that constructs a hierarchical 3D scene graph of the environment as the robot explores it.
Clio is evaluated on several datasets, showing that it can construct more parsimonious and useful map representations compared to baselines, while running in real-time. The authors also demonstrate Clio's use on a real robot (Boston Dynamics Spot) for mobile manipulation tasks.

Stats

"Modern tools for class-agnostic image segmentation (e.g., SegmentAnything) and open-set semantic understanding (e.g., CLIP) provide unprecedented opportunities for robot perception and mapping."
"Recent works, including [3–7], build metric-semantic 3D maps by detecting objects and regions corresponding to a closed set of semantic labels."
"Clio not only allows real-time open-set 3D scene graph construction, but also improves the accuracy of task execution by limiting the map to relevant objects and regions."

Quotes

"While traditional closed-set metric-semantic maps were restricted to tens or hundreds of semantic classes, we can now build maps with a plethora of objects and countless semantic variations."
"Humans not only take into account the task when (consciously or unconsciously) deciding which objects to represent and how, but are also able to consequently ignore parts of a scene that are irrelevant to the task [12]."
"Clio takes a list of tasks specified in natural language at the beginning of operation: for instance, these can be the tasks the robot is envisioned to perform during its lifetime or during its current deployment."

Key Insights Distilled From

Clio: Real-time Task-Driven Open-Set 3D Scene Graphs

by Dominic Magg... at arxiv.org 04-23-2024

https://arxiv.org/pdf/2404.13696.pdf

Deeper Inquiries

How can Clio's task-driven clustering be extended to handle more complex, multi-step tasks

To extend Clio's task-driven clustering to handle more complex, multi-step tasks, several enhancements can be implemented:

Hierarchical Task Representation: Introduce a hierarchical task representation where complex tasks are broken down into a series of simpler sub-tasks. Each sub-task can then be associated with specific clusters of objects or regions in the scene graph. By hierarchically organizing tasks, Clio can effectively handle multi-step tasks.

Temporal Reasoning: Incorporate temporal reasoning capabilities to track the state of the environment over time and link actions to their consequences. This would enable Clio to understand the sequential nature of multi-step tasks and adjust the scene graph accordingly.

Memory Mechanisms: Implement memory mechanisms to store past task executions and their outcomes. By leveraging memory, Clio can learn from previous experiences and adapt its clustering strategy for future multi-step tasks.

Dynamic Task Adaptation: Develop algorithms that allow Clio to dynamically adapt its clustering based on the current task context. This adaptability ensures that the scene graph representation remains relevant and optimized for the specific multi-step task at hand.

Interactive Learning: Enable interactive learning where users can provide feedback on the clustering results for multi-step tasks. This feedback loop helps Clio refine its clustering approach over time and improve its performance on complex tasks.

By incorporating these enhancements, Clio can effectively handle more complex, multi-step tasks by dynamically adjusting its scene graph representation to suit the task requirements.

How robust is Clio's performance to variations in the foundation models (e.g., different CLIP models) used for computing the task-relevance of primitives

Clio's performance is robust to variations in the foundation models used for computing the task-relevance of primitives, such as different CLIP models. Here are some factors that contribute to this robustness:

Model Agnostic Approach: Clio's task-driven clustering framework is designed to be model-agnostic, allowing it to work with various foundation models seamlessly. This flexibility ensures that Clio can adapt to different models without significant changes to its core algorithm.

Parameter Tuning: Clio's task-driven clustering algorithm allows for parameter tuning to optimize performance with different foundation models. By adjusting parameters related to task relevance and similarity metrics, Clio can accommodate variations in model characteristics.

Feature Fusion: Clio can incorporate features from multiple foundation models to enhance task-relevance computations. By fusing information from different models, Clio can leverage the strengths of each model and mitigate any weaknesses.

Transfer Learning: Clio can benefit from transfer learning techniques to leverage knowledge gained from one model to improve performance with another. By transferring task-relevance insights across models, Clio can maintain robust performance across variations.

Overall, Clio's design considerations, parameter flexibility, feature fusion capabilities, and potential for transfer learning contribute to its robustness in handling variations in foundation models for computing task-relevance.

Can Clio's approach be generalized to other types of task representations beyond natural language, such as demonstrations or reward functions

Clio's approach can be generalized to other types of task representations beyond natural language, such as demonstrations or reward functions, by incorporating the following adaptations:

Demonstration-Based Clustering: For task representations based on demonstrations, Clio can utilize imitation learning techniques to cluster objects or regions based on observed actions. By learning from demonstrations, Clio can infer task-relevant clusters and optimize the scene graph accordingly.

Reward-Driven Optimization: When tasks are defined by reward functions, Clio can employ reinforcement learning methods to optimize the scene graph based on maximizing cumulative rewards. By associating rewards with different clusters, Clio can learn to prioritize task-relevant representations.

Multi-Modal Task Inputs: Clio can be extended to handle multi-modal task representations by integrating information from diverse sources, such as natural language, demonstrations, and reward signals. By fusing multi-modal inputs, Clio can create a comprehensive understanding of task requirements and tailor the scene graph accordingly.

Task Abstraction Layers: Introduce abstraction layers in Clio's clustering algorithm to handle different types of task representations. By abstracting task information into a common format, Clio can process diverse task inputs uniformly and generate task-driven scene graphs effectively.

By incorporating these adaptations, Clio can generalize its approach to accommodate various types of task representations beyond natural language, enabling versatile applications in robotics and spatial perception tasks.