arXiv subjects

Parastoo Abtahi

Publications and source records attributed to Parastoo Abtahi.

9 recordsLinked to original sources

arXiv2026

Uncertain Pointer: Situated Feedforward Visualizations for Ambiguity-Aware AR Target Selection

Target disambiguation is crucial in resolving input ambiguity in augmented reality (AR), especially for queries over distant objects or cluttered scenes on the go. Yet, visual feedforward techniques that support this process remain underexplored. We present Uncertain Pointer, a systematic exploration of feedforward visualizations that annotate multiple candidate targets before user confirmation, either by adding distinct visual identities (e.g., colors) to support disambiguation or by modulating visual intensity (e.g., opacity) to convey system uncertainty. First, we construct a pointer space of 25 pointers by analyzing existing placement strategies and visual signifiers used in target visualizations across 30 years of relevant literature. We then evaluate them through two online experiments (n = 60 and 40), measuring user preference, confidence, mental ease, target visibility, and identifiability across varying object distances and sparsities. Finally, from the results, we derive design recommendations in choosing different Uncertain Pointers based on AR context and disambiguation techniques.

cs.HC↗

arXiv2026

Gesturing Toward Abstraction: Multimodal Convention Formation in Collaborative Physical Tasks

A quintessential feature of human intelligence is the ability to create ad hoc conventions over time to achieve shared goals efficiently. We investigate how communication strategies evolve through repeated collaboration as people coordinate on shared procedural abstractions. To this end, we conducted an online unimodal study (n = 98) using natural language to probe abstraction hierarchies. In a follow-up lab study (n = 40), we examined how multimodal communication (speech and gestures) changed during physical collaboration. Pairs used augmented reality to isolate their partner's hand and voice; one participant viewed a 3D virtual tower and sent instructions to the other, who built the physical tower. Participants became faster and more accurate by establishing linguistic and gestural abstractions and using cross-modal redundancy to emphasize key changes from previous interactions. Based on these findings, we extend probabilistic models of convention formation to multimodal settings, capturing shifts in modality preferences. Our findings and model provide building blocks for designing convention-aware intelligent agents situated in the physical world.

cs.HC↗

arXiv2026

Explainable OOHRI: Communicating Robot Capabilities and Limitations as Augmented Reality Affordances

Human interaction is essential for issuing personalized instructions and assisting robots when failure is likely. However, robots remain largely black boxes, offering users little insight into their evolving capabilities and limitations. To address this gap, we present explainable object-oriented HRI (X-OOHRI), an augmented reality (AR) interface that conveys robot action possibilities and constraints through visual signifiers, radial menus, color coding, and explanation tags. Our system encodes object properties and robot limits into object-oriented structures using a vision-language model, allowing explanation generation on the fly and direct manipulation of virtual twins spatially aligned within a simulated environment. We integrate the end-to-end pipeline with a physical robot and showcase diverse use cases ranging from low-level pick-and-place to high-level instructions. Finally, we evaluate X-OOHRI through a user study and find that participants effectively issue object-oriented commands, develop accurate mental models of robot limitations, and engage in mixed-initiative resolution.

cs.HC↗

arXiv2025

STAR: Smartphone-analogous Typing in Augmented Reality

While text entry is an essential and frequent task in Augmented Reality (AR) applications, devising an efficient and easy-to-use text entry method for AR remains an open challenge. This research presents STAR, a smartphone-analogous AR text entry technique that leverages a user's familiarity with smartphone two-thumb typing. With STAR, a user performs thumb typing on a virtual QWERTY keyboard that is overlain on the skin of their hands. During an evaluation study of STAR, participants achieved a mean typing speed of 21.9 WPM (i.e., 56% of their smartphone typing speed), and a mean error rate of 0.3% after 30 minutes of practice. We further analyze the major factors implicated in the performance gap between STAR and smartphone typing, and discuss ways this gap could be narrowed.

cs.HC↗

arXiv2025

GhostObjects: Instructing Robots by Manipulating Spatially Aligned Virtual Twins in Augmented Reality

Robots are increasingly capable of autonomous operations, yet human interaction remains essential for issuing personalized instructions. Instead of directly controlling robots through Programming by Demonstration (PbD) or teleoperation, we propose giving instructions by interacting with GhostObjects-world-aligned, life-size virtual twins of physical objects-in augmented reality (AR). By direct manipulation of GhostObjects, users can precisely specify physical goals and spatial parameters, with features including real-world lasso selection of multiple objects and snapping back to default positions, enabling tasks beyond simple pick-and-place.

cs.HC↗

arXiv2025

Hapster: Using Apple Watch Haptics to Enable Live Low-Friction Student Feedback in the Physical Classroom

The benefits of student response systems (SRSs) for in-person lectures are well-researched. However, all current SRSs only rely on a visual interface to relay information to the instructor. We describe the design and evaluation of Hapster, a prototype system that uses an Apple Watch to deliver live, aggregated student feedback to the instructor via both visual and vibro-tactile modalities. We evaluated this system with 6 instructors and 155 students at a U.S. university. Participants reported that the system was effective at delivering live student feedback and facilitating better engagement from both the instructor and the students. However, instructors also noted several challenges with differentiating and perceiving the haptic sequences while lecturing. We conclude by discussing the tradeoff between system flexibility and abuse potential while identifying opportunities for further research regarding accessibility, content moderation, and additional interaction modalities. Our results suggest that haptics can be used as an effective live feedback mechanism for instructors in the physical classroom.

cs.HC↗

arXiv2025

Breaking the Plane: Exploring Real-Time Visualization of 3D Surfaces in Augmented Reality with Handwritten Input

We introduce Breaking the Plane, an augmented reality (AR) application built for AR headsets that enables users to visualize 3D mathematical functions using handwritten input. Researchers have demonstrated overlaying 3D visualizations of mathematical concepts through AR enhances learning motivation and comprehension, and equation parsing makes the authoring of teaching materials more time-efficient for instructors. Previous works have developed AR systems that separately employ equation parsing and 3D mathematical visualizations, but work has yet to be done to combine those features by enabling real-time interactions and dynamic visualizations that help users learn in situ. We explore this by developing an AR system featuring handwritten equation parsing, graph manipulation, and a 3D function plotter. We found that our system significantly surpassed other systems in engagement, achieved comparable ease of use to a popular visualization tool, was considered the most effective in aiding problem-solving, and was highly preferred by participants for future use.

cs.HC↗

arXiv2025

Interactivity x Explainability: Toward Understanding How Interactivity Can Improve Computer Vision Explanations

Explanations for computer vision models are important tools for interpreting how the underlying models work. However, they are often presented in static formats, which pose challenges for users, including information overload, a gap between semantic and pixel-level information, and limited opportunities for exploration. We investigate interactivity as a mechanism for tackling these issues in three common explanation types: heatmap-based, concept-based, and prototype-based explanations. We conducted a study (N=24), using a bird identification task, involving participants with diverse technical and domain expertise. We found that while interactivity enhances user control, facilitates rapid convergence to relevant information, and allows users to expand their understanding of the model and explanation, it also introduces new challenges. To address these, we provide design recommendations for interactive computer vision explanations, including carefully selected default views, independent input controls, and constrained output spaces.

cs.HC↗

arXiv2022

Beyond Being Real: A Sensorimotor Control Perspective on Interactions in Virtual Reality

We can create Virtual Reality (VR) interactions that have no equivalent in the real world by remapping spacetime or altering users' body representation, such as stretching the user's virtual arm for manipulation of distant objects or scaling up the user's avatar to enable rapid locomotion. Prior research has leveraged such approaches, what we call beyond-real techniques, to make interactions in VR more practical, efficient, ergonomic, and accessible. We present a survey categorizing prior movement-based VR interaction literature as reality-based, illusory, or beyond-real interactions. We survey relevant conferences (CHI, IEEE VR, VRST, UIST, and DIS) while focusing on selection, manipulation, locomotion, and navigation in VR. For beyond-real interactions, we describe the transformations that have been used by prior works to create novel remappings. We discuss open research questions through the lens of the human sensorimotor control system and highlight challenges that need to be addressed for effective utilization of beyond-real interactions in future VR applications, including plausibility, control, long-term adaptation, and individual differences.

cs.HC↗