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# Computer Science# Computer Vision and Pattern Recognition

Next-Active Object Anticipation in VR and AR

A new model predicts interactions in virtual environments by focusing on objects.

― 7 min read


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Table of Contents

In recent years, technologies like virtual reality (VR) and augmented reality (AR) have become popular. These technologies allow users to interact with their surroundings in a way that feels very real. One important aspect of these experiences is understanding how people interact with objects around them. This understanding is key to making VR and AR experiences more engaging.

When we watch someone interacting with objects, we can often predict what they will do next. For example, if a person is holding a glass, we can guess they might fill it with water or wash it. By predicting these actions and the objects involved, we can enhance the overall experience in virtual settings.

However, predicting these interactions is not easy. It requires knowledge of what objects are present and how they will be used. Our goal is to develop a method that uses the current knowledge of objects to predict future actions and the timing of these actions. This method focuses on a specific task known as Short-Term Object interaction anticipation (STA).

The Importance of Objects in Interactions

Objects play a critical role in understanding how people act. By recognizing which objects are relevant in a scene, we can anticipate what actions might follow. For example, if a person picks up a fork, we can expect that they might use it to eat or cut food.

In our approach, we emphasize the importance of the Next-Active Object (NAO). This concept refers to the object that is likely to be used next by a person. If we can accurately determine which object will be engaged with at a future moment, we can make better predictions about the associated actions.

The Challenge of Anticipating Object Interactions

Anticipating object interactions is complex. It requires knowing not just what the object is but also predicting when the action will start. This timing is often referred to as the Time to Contact (TTC). The challenge lies in accurately identifying both the object and the timing of its use.

Current methods often focus on general actions without considering specific objects. As a result, they may miss important details about the interactions taking place. A more nuanced approach that includes both object dynamics and scene context can lead to better predictions.

Introducing NAOGAT

To address the challenges mentioned, we propose a new model called NAOGAT (Next-Active-Object Guided Anticipation Transformer). This model is designed to focus specifically on predicting the next-active object and the corresponding actions. It uses data from both video frames and object detections to make its predictions.

The NAOGAT model operates using a multi-modal architecture that is capable of processing information from different sources. By examining the relationships between objects and the overall scene, this model aims to predict not just which object will be used next, but also when and how it will be used.

How NAOGAT Works

The NAOGAT model consists of several components that work together to achieve its goals. Below, we outline the main steps involved in its operation.

Feature Extraction

First, we gather features from the video frames and detect objects within these frames. The video frames are processed through a backbone network that enables the extraction of valuable features. In parallel, we use an object detector to identify relevant objects within each frame, capturing their positions and characteristics.

Understanding Context

Once we have extracted the features, we combine them to create a comprehensive representation of the scene. This representation includes information about motion and object placements. By analyzing this combined data, the model can begin to understand the context in which actions take place.

Predicting the Next-Active Object

With a clear understanding of the scene, the model predicts the NAO based on the last observed frame. It uses the details gathered about object positions and relationships to make accurate predictions about which object will be interacted with next.

Motion Dynamics

The model doesn’t just focus on the object itself but also considers the motion of the objects in the scene. By understanding how objects move over time, the model can better estimate when a person will reach for or use an object. This knowledge enhances the prediction of future actions and the time it would take to contact the object.

Final Predictions

The NAOGAT model combines all the gathered information to make final predictions regarding the object class, location, future action, and time to contact. It evaluates all relevant data to ensure that its predictions are not only accurate but also relevant to the observed scene.

Importance of Context-Aware Predictions

By integrating various data points and focusing on Next-Active Objects, the NAOGAT model offers context-aware predictions. This is crucial in applications where the actions may change based on subtle changes in the environment or object interactions.

The ability to predict not only what will happen but also the timing involved can lead to more immersive VR and AR experiences. For instance, if a user is about to perform an action, the system can preemptively adapt the environment, enhancing user engagement.

Experimental Analyses

We evaluated the performance of the NAOGAT model using two large datasets: Ego4D and EpicKitchen-100. These datasets contain numerous examples of people interacting with objects in various settings, making them ideal for testing the model.

Ego4D Dataset

The Ego4D dataset is one of the largest collections of first-person videos available. It contains diverse scenes where people engage with various objects. We specifically focused on the short-term anticipation tasks, which allowed us to assess how well the NAOGAT model could predict next-active objects and associated actions.

EpicKitchen-100 Dataset

EpicKitchen-100 consists of recordings of daily activities in kitchen environments. This dataset provides a rich source of data for action anticipation tasks. Similar to the Ego4D dataset, we leveraged this collection to evaluate the effectiveness of our model.

Results

The results of our experiments demonstrated the strength of the NAOGAT model. The findings revealed significant improvements in predicting next-active objects and their associated actions compared to existing methods.

Performance Metrics

We measured the model's performance across several metrics, including average precision for various prediction types. Our model outperformed baseline methods on key indicators, showcasing its ability to accurately identify objects, predict future actions, and estimate time to contact.

Insights from Analyses

Detailed analysis of the results highlighted the importance of next-active object identification in anticipating actions. The NAOGAT model excelled at considering object dynamics, which directly contributed to improved performance in time to contact predictions.

Practical Applications

The capabilities of the NAOGAT model have several practical implications. In virtual reality and augmented reality, the ability to predict actions can significantly enhance user experiences. By anticipating what a user might do next, systems can adapt fluidly and create a more engaging environment.

In robotics, understanding object interactions can inform how machines learn to interact naturally with their surroundings. This could lead to advancements in how robots assist humans in daily tasks, ultimately improving efficiency and user satisfaction.

Future Directions

While the performance of the NAOGAT model is promising, there are areas for further exploration. Future research could explore the integration of additional cues, such as human gestures and gaze direction, to refine predictions even more.

Additionally, improving object detection accuracy and handling more complex scenes with multiple objects could enhance overall performance. Investigating how action recognition impacts next-active object identification is also a potential avenue for growth.

Conclusion

Effective anticipation of human-object interactions is crucial for creating immersive experiences in virtual environments. The NAOGAT model represents a significant step forward in understanding and predicting these interactions by focusing on the next-active object and its context.

By leveraging motion dynamics and integrating various data sources, the model offers enhanced accuracy in predicting actions. The practical applications of this work extend beyond virtual reality and can significantly impact fields such as robotics and automation.

In summary, the NAOGAT model holds great potential for improving our understanding of how people interact with objects, paving the way for more engaging and effective virtual experiences in the future.

Original Source

Title: Leveraging Next-Active Objects for Context-Aware Anticipation in Egocentric Videos

Abstract: Objects are crucial for understanding human-object interactions. By identifying the relevant objects, one can also predict potential future interactions or actions that may occur with these objects. In this paper, we study the problem of Short-Term Object interaction anticipation (STA) and propose NAOGAT (Next-Active-Object Guided Anticipation Transformer), a multi-modal end-to-end transformer network, that attends to objects in observed frames in order to anticipate the next-active-object (NAO) and, eventually, to guide the model to predict context-aware future actions. The task is challenging since it requires anticipating future action along with the object with which the action occurs and the time after which the interaction will begin, a.k.a. the time to contact (TTC). Compared to existing video modeling architectures for action anticipation, NAOGAT captures the relationship between objects and the global scene context in order to predict detections for the next active object and anticipate relevant future actions given these detections, leveraging the objects' dynamics to improve accuracy. One of the key strengths of our approach, in fact, is its ability to exploit the motion dynamics of objects within a given clip, which is often ignored by other models, and separately decoding the object-centric and motion-centric information. Through our experiments, we show that our model outperforms existing methods on two separate datasets, Ego4D and EpicKitchens-100 ("Unseen Set"), as measured by several additional metrics, such as time to contact, and next-active-object localization. The code will be available upon acceptance.

Authors: Sanket Thakur, Cigdem Beyan, Pietro Morerio, Vittorio Murino, Alessio Del Bue

Last Update: 2023-10-05 00:00:00

Language: English

Source URL: https://arxiv.org/abs/2308.08303

Source PDF: https://arxiv.org/pdf/2308.08303

Licence: https://creativecommons.org/licenses/by/4.0/

Changes: This summary was created with assistance from AI and may have inaccuracies. For accurate information, please refer to the original source documents linked here.

Thank you to arxiv for use of its open access interoperability.

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