Prerna Khanna

dblp:274/6423 · DBLP profile ↗
← Back
8ranked-venue papers
3as first author
8since 2021 · last 2025
0000-0003-0162-0052ORCID · verified

Domains — the database's venue-derived domains; a paper can count in several

Computer networks · 5 · 1 first-author · 5 since 2021Human-computer interaction and ubiquitous computing · 2 · 2 first-author · 2 since 2021Applied, interdisciplinary, general and emerging computing · 1 · 1 since 2021
YearPublicationVenuePosition
2025 GestureVoice: Enabling Multimodal Text Editing for Blind Users Using Gestures and Voice
abstract
Text editing on smartphones presents substantial difficulties for blind users, particularly in mobile situations where using the smartphone touch screen is challenging.While voice input allows for hands-free text creation, editing the text typically requires physical interaction with the touchscreen, negating the benefits of the hands-free input mechanism.This paper introduces GestureVoice, a novel multimodal approach that enables screen-free text editing for blind users.By leveraging smartwatch-based hand gestures for navigation and voice commands for correction, GestureVoice allows users to edit text without any contact with their smartphones.GestureVoice replaces cumbersome screen-based interaction for choosing the navigation granularity with an intuitive mid-air hand gesture.It also introduces an adaptive crown cursor (rotating the physical dial of the watch) to smoothly navigate to the edit location.A preliminary study highlighted the significant time spent by blind users correcting text errors using traditional methods.In contrast, our evaluation with 8 blind users demonstrates that Ges-tureVoice achieves a 53.80% reduction in text editing time, offering a more efficient, intuitive, and screen-free solution for blind users.
Prerna Khanna, Monalika Padma Reddy, I. V. Ramakrishnan, Xiaojun Bi 0001, Aruna Balasubramanian
ASSETS1
2024 Hand Gesture Recognition for Blind Users by Tracking 3D Gesture Trajectory
abstract
Hand gestures provide an alternate interaction modality for blind users and can be supported using commodity smartwatches without requiring specialized sensors. The enabling technology is an accurate gesture recognition algorithm, but almost all algorithms are designed for sighted users. Our study shows that blind user gestures are considerably diferent from sighted users, rendering current recognition algorithms unsuitable. Blind user gestures have high inter-user variance, making learning gesture patterns difcult without large-scale training data. Instead, we design a gesture recognition algorithm that works on a 3D representation of the gesture trajectory, capturing motion in free space. Our insight is to extract a micro-movement in the gesture that is user-invariant and use this micro-movement for gesture classifcation. To this end, we develop an ensemble classifer that combines image classifcation with geometric properties of the gesture. Our evaluation demonstrates a 92% classifcation accuracy, surpassing the next best state-of-the-art which has an accuracy of 82%.
Prerna Khanna, I. V. Ramakrishnan, Shubham Jain 0003, Xiaojun Bi 0001, Aruna Balasubramanian
CHI1
2024 Enabling Accessible and Ubiquitous Interaction in Next-Generation Wearables: An Unvoiced Speech Approach
abstract
As wearable devices increase, there's a growing need for intuitive, private, and accessible interaction methods. This position paper builds on the research on unvoiced speech interaction and authentication to propose a vision for interaction in next-generation wearables. This paper draws upon our previous work on unvoiced speech interfaces that leverage jaw movements and facial vibrations for command recognition and user authentication. We argue that unvoiced speech interaction can provide a robust, privacy-preserving, and noise-resistant alternative to traditional interfaces, enhancing accessibility and offering discrete interaction in public spaces. We discuss the potential integration of these systems into commercial devices and explore gesture-based interactions as an alternative to touch. Additionally, we discuss the future direction of unvoiced speech interfaces. This paper sets the stage for implementing unvoiced speech and gesture-based interaction in mainstream wearables in our daily interactions with technology.
Tanmay Srivastava, Prerna Khanna, Shijia Pan, V. P. Nguyen, Shubham Jain 0003
MobiCom2
2024 Unvoiced: Designing an LLM-assisted Unvoiced User Interface using Earables
abstract
We present Unvoiced, a novel unvoiced user interface that leverages jaw motion to enable users to silently interact with their devices using earables. The core idea is to translate low-frequency jaw motion signals into high-frequency information-rich mel spectrograms. Our proposed cross-modal translation incorporates phonetic, contextual, and syntactic information, while the specialized loss function optimizes for these linguistic features. This ensures that the generated spectrograms capture nuanced speech characteristics. Evaluated for 19 users across four tasks, Unvoiced demonstrates >94% task completion rate and <9% word error rate for over 90% of phrases. Further, Unvoiced maintains >90% task completion rate in noisy conditions.
Tanmay Srivastava, Prerna Khanna, Shijia Pan, Phuc Nguyen 0002, Shubham Jain 0003
SenSys2
2024 Poster Unvoiced: Designing an Unvoiced User Interface using Earables and LLMs
abstract
This poster presents the design and implementation of Unvoiced, a silent speech interaction system. Unvoiced transforms subtle jaw movements into rich speech spectrograms, enabling seamless and private device interaction. Our system captures low-frequency jaw motion signals using ear-worn IMUs and translates them into high-fidelity mel-spectrograms through cross-modal translation techniques. By incorporating phonetic, contextual, and syntactic information, Unvoiced generates high-fidelity spectrograms that existing speech recognition systems can process. In our evaluation with 19 users across four common tasks, Unvoiced achieved a remarkable >94% task completion rate and <9% Word Error Rate (WER) for over 90% of phrases, maintaining robust performance even in noisy conditions.
Tanmay Srivastava, Prerna Khanna, Shijia Pan, Phuc Nguyen 0002, Shubham Jain 0003
SenSys2
2023 AccessWear: Making Smartphone Applications Accessible to Blind Users
abstract
In this paper, we present AccessWear, a system that improves the accessibility of smartphone touchscreen interactions for blind users using smartwatch gestures. Our system design is human-centered, namely, it incorporates the design goals that were learned from a formative user study with 9 blind participants. The formative study showed that blind users liked the idea of using smartwatch gestures as an alternative: 4 participants liked that when using smart-watch gestures, they did not have to bring their expensive phones out in public and 6 participants liked that smart-watch gestures can be performed with one-hand, as the other hand is usually occupied in holding a cane or a guide dog. Even though there are several advantages to smartwatch gestures, our study also shows that gestures performed by blind users have different patterns compared to sighted users, making gesture recognition more challenging. To this end, AccessWear makes two contributions. The first is a gesture recognition system that works specifically for blind users that is lightweight and does not require per-person training. The second is a near-zero-effort gesture replacement system that does not require any changes to the original application. AccessWear uses input virtualization techniques so that a given gesture can replace the touchscreen input seamlessly. We implement AccessWear on an Android smartphone and Android watch. We perform a quantitative and qualitative study with 8 blind participants. Our study shows that AccessWear can recognize gestures with a 92% accuracy and the end-to-end latency when using an alternate gesture was 53 msec on average. The qualitative study shows that when participants perform a task, consisting of a series of gestures, the system is robust, does not have perceived delays, and does not add physical or mental load on the users.
Prerna Khanna, Shirin Feiz, Jian Xu 0013, I. V. Ramakrishnan, Shubham Jain 0003, Xiaojun Bi 0001, Aruna Balasubramanian
MobiCom1
2023 SpiroMask: Measuring Lung Function Using Consumer-Grade Masks
abstract
According to the World Health Organisation (WHO), 235 million people suffer from respiratory illnesses which causes four million deaths annually. Regular lung health monitoring can lead to prognoses about deteriorating lung health conditions. This article presents our system SpiroMask that retrofits a microphone in consumer-grade masks (N95 and cloth masks) for continuous lung health monitoring. We evaluate our approach on 48 participants (including 14 with lung health issues) and find that we can estimate parameters such as lung volume and respiration rate within the approved error range by the American Thoracic Society (ATS). Further, we show that our approach is robust to sensor placement inside the mask.
Rishiraj Adhikary, Dhruvi Lodhavia, Chris Francis, Rohit Patil, Tanmay Srivastava, Prerna Khanna, Nipun Batra 0001, Joseph Breda, Jacob Peplinski, Shwetak N. Patel
ACM Trans. Comput. Heal.6
2022 Leveraging earables for unvoiced command recognition
abstract
We demonstrate an ear-worn technology that recognizes unvoiced human commands by tracking jaw motion. The ear-worn system is designed to achieve continual unvoiced command recognition for robust human-computer interaction (HCI) applications. First, the system reliably extracts the jaw motion signals buried under the noise caused by head motion, walking, and other motion artifacts to track single secondary voice articulator (i.e., word). Then, learning from linguistics and human speech anatomy, we design a novel algorithm that localizes the phonemes in the command, and reconstructs the word. We evaluate the proposed system in real-world experiments with 15 volunteers. Our preliminary results show that the proposed system obtains a word recognition accuracy of 95.6% in noise-free conditions and 93.2% and 91.6%, while head nodding and walking.
Tanmay Srivastava, Prerna Khanna, Shijia Pan, Phuc Nguyen 0002, Shubham Jain 0003
MobiSys2