A basic experiment in probability theory is drawing without replacement from an urn filled with multiple balls of different colours. Clearly, it is physically impossible to overdraw, that is, to draw more balls from t...
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A basic experiment in probability theory is drawing without replacement from an urn filled with multiple balls of different colours. Clearly, it is physically impossible to overdraw, that is, to draw more balls from the urn than it contains. This paper demonstrates that overdrawing does make sense mathematically, once we allow signed distributions with negative probabilities. A new (conservative) extension of the familiar hypergeometric ('draw-and-delete') distribution is introduced that allows draws of arbitrary sizes, including overdraws. The underlying theory makes use of the dual basis functions of the Bernstein polynomials, which play a prominent role in computer graphics. Negative probabilities are treated systematically in the framework of categorical probability and the central role of datastructures such as multisets and monads is emphasised.
Given a real scene and a virtual scene, the indoor scene transformation problem is defined as transforming the layout of the input virtual scene. The transformed layout preserves as much as possible the relationship b...
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ISBN:
(纸本)9798350348392
Given a real scene and a virtual scene, the indoor scene transformation problem is defined as transforming the layout of the input virtual scene. The transformed layout preserves as much as possible the relationship between the furniture in the input virtual scene, and the input real scene provides the user with as much passive haptic as possible when exploring the virtual scene. We propose a real-scene constrained deep scene transformer to solve this problem. First, we introduce the deep scene matching network to predict the matching relationship between real furniture and virtual furniture. Then we introduce a layout refinement algorithm based on the refinement parameter network to arrange the matched virtual furniture into the new virtual scene. At last, we introduce a deep scene generating network to arrange the unmatched virtual furniture into the new virtual scene.
Neural Radiance Fields (NeRF) are a rapidly growing area of research with wide-ranging applications in computer vision, graphics, robotics, and more. In order to streamline the development and deployment of NeRF resea...
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ISBN:
(纸本)9798400701597
Neural Radiance Fields (NeRF) are a rapidly growing area of research with wide-ranging applications in computer vision, graphics, robotics, and more. In order to streamline the development and deployment of NeRF research, we propose a modular PyTorch framework, Nerfstudio. Our framework includes plug-and-play components for implementing NeRF-based methods, which make it easy for researchers and practitioners to incorporate NeRF into their projects. Additionally, the modular design enables support for extensive real-time visualization tools, streamlined pipelines for importing captured in-the-wild data, and tools for exporting to video, point cloud and mesh representations. The modularity of Nerfstudio enables the development of Nerfacto, our method that combines components from recent papers to achieve a balance between speed and quality, while also remaining flexible to future modifications. To promote community-driven development, all associated code and data are made publicly available with open-source licensing.
The use of self-avatars is gaining popularity thanks to affordable VR headsets. Unfortunately, mainstream VR devices often use a small number of trackers and provide low-accuracy animations. Previous studies have show...
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ISBN:
(纸本)9798350348156
The use of self-avatars is gaining popularity thanks to affordable VR headsets. Unfortunately, mainstream VR devices often use a small number of trackers and provide low-accuracy animations. Previous studies have shown that the Sense of Embodiment, and in particular the Sense of Agency, depends on the extent to which the avatar's movements mimic the user's movements. However, few works study such effect for tasks requiring a precise interaction with the environment, i.e., tasks that require accurate manipulation, precise foot stepping, or correct body poses. In these cases, users are likely to notice inconsistencies between their self-avatars and their actual pose. In this paper, we study the impact of the animation fidelity of the user avatar on a variety of tasks that focus on arm movement, leg movement and body posture. We compare three different animation techniques: two of them using Inverse Kinematics to reconstruct the pose from sparse input (6 trackers), and a third one using a professional motion capture system with 17 inertial sensors. We evaluate these animation techniques both quantitatively (completion time, unintentional collisions, pose accuracy) and qualitatively (Sense of Embodiment). Our results show that the animation quality affects the Sense of Embodiment. Inertial-based MoCap performs significantly better in mimicking body poses. Surprisingly, IK-based solutions using fewer sensors outperformed MoCap in tasks requiring accurate positioning, which we attribute to the higher latency and the positional drift that causes errors at the end-effectors, which are more noticeable in contact areas such as the feet.
In our lives, we encounter various stressors that may cause negative mental and bodily reactions to make us feel frustrated, angry, or irritated. Effective methods to manage or reduce stress and anxiety are essential ...
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ISBN:
(纸本)9798350328387
In our lives, we encounter various stressors that may cause negative mental and bodily reactions to make us feel frustrated, angry, or irritated. Effective methods to manage or reduce stress and anxiety are essential for a healthy life, and several stress-management approaches are found to be useful for stress relief, such as meditation, taking a rest, walking around nature, or even breaking things in a smash room. Previous research has revealed that certain experiences in virtual reality (VR) are effective for reducing stress as traditional real-world methods. However, it is still unclear how the stress relief effects are associated with other factors like individual user profile in terms of different treatment activities. In this paper, we report our findings from a formal user study that investigates the effects of two virtual activities: (1) VR Meditation and (2) VR Smash Room experience, compared with a traditional Sitting-in-Silence method. Our results show that VR Meditation has a better stress relief effect compared to VR Smash Room and Sitting-in-Silence, and the effects of the treatments are correlated with the participants' personalities. We discuss the findings and implications addressing potential benefits/impacts of different stress-relief activities in VR.
Three-dimensional curve drawing in Augmented Reality (AR) enables users to create 3D curves that fit within the real-world scene. It has applications in 3D design, sculpting, and animation. However, the task complexit...
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ISBN:
(纸本)9798350348156
Three-dimensional curve drawing in Augmented Reality (AR) enables users to create 3D curves that fit within the real-world scene. It has applications in 3D design, sculpting, and animation. However, the task complexity increases when the desirable path for the curve is obstructed by the physical environment or by what the camera can see. For example, it is difficult to draw a curve that wraps around an object or scales to out-of-reach places. We propose WARPY, an environment-aware 3D curve drawing tool for mobile AR. Our system enables users to draw freeform curves from a distance in AR by combining 2D-to-3D sketch inference with geometric proxies. Geometric Proxies can be obtained via 3D scanning or from a list of pre-defined primitives. WARPY also provides a multi-view mode to enable users to sketch a curve from multiple viewpoints, which is useful if the target curve cannot fit within the camera's field of view. We conducted two user studies and found that WARPY can be a viable tool to help users create complex and large curves in AR.
An important application of augmented reality (AR) is the design of interfaces that reveal parts of the real world to which the user does not have line of sight. The design space for such interfaces is vast, with many...
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ISBN:
(纸本)9798350348156
An important application of augmented reality (AR) is the design of interfaces that reveal parts of the real world to which the user does not have line of sight. The design space for such interfaces is vast, with many options for integrating the visualization of the occluded parts of the scene into the user's main view. This paper compares four AR interfaces for disocclusion: X-ray, Cutaway, Picture-inpicture, and Multiperspective. The interfaces are compared in a within-subjects study (N = 33) over four tasks: counting dynamic spheres, pointing to the direction of an occluded person, finding the closest object to a given object, and finding pairs of matching numbers. The results show that Cutaway leads to poor performance in tasks where the user needs to see both the occluder and the occludee;that Picture-in-picture and Multiperspective have a visualization comprehensiveness advantage over Cutaway and X-ray, but a disadvantage in terms of directional guidance;that X-ray has a task completion time disadvantage due to the visualization complexity;and that participants gave Cutaway and Picture-in-picture high, and Multiperspective and X-ray low usability scores.
The realistic interaction with physical phenomena is a crucial aspect of human-computer interaction (HCI) in virtual reality (VR). However, the real-time performance of physical simulation, interactive computation, an...
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ISBN:
(纸本)9798350328387
The realistic interaction with physical phenomena is a crucial aspect of human-computer interaction (HCI) in virtual reality (VR). However, the real-time performance of physical simulation, interactive computation, and rendering is the bottleneck of physics-based VR HCI. To address these challenges, we propose a novel physics-oriented framework for multi-material objects and free-hand interaction, termed PhyVR. This framework enables users to interact with diverse virtual phenomena dynamically. At the algorithm level, we develop a unified particle system to describe both the virtual multi-materials and the user's avatar for the efficiency issue, optimize collision detection, and accelerate the HCI algorithms with a variable fine-coarse particle sampling scheme. At the rendering level, we introduce a hybrid particle-grid anisotropic algorithm for surface reconstruction, enabling real-time and visually convincing fluid rendering. Comprehensive experiments and user studies demonstrate that our framework effectively captures various physical interaction phenomena, providing an enhanced user experience and paving the way for expanding VR-related HCI applications.
Educational virtual reality (VR) applications are the most recent addition to the learning management tools in this modern age. Due to health concerns, financial concerns, and convenience, people are looking for alter...
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ISBN:
(纸本)9798350328387
Educational virtual reality (VR) applications are the most recent addition to the learning management tools in this modern age. Due to health concerns, financial concerns, and convenience, people are looking for alternate ways to teach and learn. An efficient VR-based teaching interface could enhance student engagement, learning outcomes, and overall educational experience. Typically, teachers in a VR classroom do not have a way to know what students are doing since students are not visible. An efficient teaching interface should include some mechanism for a teacher to monitor students and alert the teacher if a student is trying to catch the attention of the teacher. An ideal interface would be one, which helps a teacher effectively monitor students while teaching without increasing the cognitive load of the teacher. In this paper, we present a comparative study of two such student monitoring interfaces. In the first interface, the student activity related information is shown using icons near the student avatar (representing a student in the VR environment). While in the second interface, a set of centrally-arranged emoticon-like visual indicators are present in addition to the student avatar, and the student activity related information is shown near the student emoticon. We present a detailed user experiment comparing the two interfaces in terms of teaching management, student monitoring capability, cognitive load, and user preference. Participants preferred and performed better with Indicator-located interface over avatar-located interface.
Marker-based optical motion capture (MoCap) aims to estimate 3L) human motions from a sequence of input raw markers. In this paper, we propose a divide-and -conquer strategy based MoCap solving network that accurately...
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ISBN:
(纸本)9798350348392
Marker-based optical motion capture (MoCap) aims to estimate 3L) human motions from a sequence of input raw markers. In this paper, we propose a divide-and -conquer strategy based MoCap solving network that accurately retrieves 31) human skeleton motions from raw marker sequences in real-time. Our core idea is to decompose the task of direct estimation of global human motion from all markers into first solving sub-motions of local. parts and then aggregating submotions into a global one to achieve accurate motion estimation.
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