# Sitemap

A list of all the posts and pages found on the site. For you robots out there is an XML version available for digesting as well.

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## NeckFace: Continuously Tracking Full Facial Expressions on Neck-mounted Wearables

Published in Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies, 2021

Facial expressions are highly informative for computers to understand and interpret a person’s mental and physical activities. However, continuously tracking facial expressions, especially when the user is in motion, is challenging. This paper presents NeckFace, a wearable sensing technology that can continuously track the full facial expressions using a neck-piece embedded with infrared (IR) cameras. A customized deep learning pipeline called NeckNet based on Resnet34 is developed to learn the captured infrared (IR) images of the chin and face and output 52 parameters representing the facial expressions. We demonstrated NeckFace on two common neck-mounted form factors: a necklace and a neckband (e.g., neck-mounted headphones), which was evaluated in a user study with 13 participants. The study results showed that NeckFace worked well when the participants were sitting, walking, or after remounting the device. We discuss the challenges and opportunities of using NeckFace in real-world applications.

Tuochao Chen, Yaxuan Li, Songyun Tao, Hyunchul Lim, Mose Sakashita, Ruidong Zhang, Francois Guimbretiere, and Cheng Zhang. 2021. NeckFace: Continuously Tracking Full Facial Expressions on Neck-mounted Wearables. Proc. ACM Interact. Mob. Wearable Ubiquitous Technol. 5, 2, Article 58 (June 2021), 31 pages. DOI:https://doi.org/10.1145/3463511 https://doi.org/10.1145/3463511

## SpeeChin: A Smart Necklace for Silent Speech Recognition

Published in Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies, 2021

This paper presents SpeeChin, a smart necklace that can recognize 54 English and 44 Chinese silent speech commands. A customized infrared (IR) imaging system is mounted on a necklace to capture images of the neck and face from under the chin. These images are first pre-processed and then deep learned by an end-to-end deep convolutional-recurrent-neural-network (CRNN) model to infer different silent speech commands. A user study with 20 participants (10 participants for each language) showed that SpeeChin could recognize 54 English and 44 Chinese silent speech commands with average cross-session accuracies of 90.5% and 91.6%, respectively. To further investigate the potential of SpeeChin in recognizing other silent speech commands, we conducted another study with 10 participants distinguishing between 72 one-syllable nonwords. Based on the results from the user studies, we further discuss the challenges and opportunities of deploying SpeeChin in real-world applications.

Ruidong Zhang, Mingyang Chen, Benjamin Steeper, Yaxuan Li, Zihan Yan, Yizhuo Chen, Songyun Tao, Tuochao Chen, Hyunchul Lim, and Cheng Zhang. 2022. SpeeChin: A Smart Necklace for Silent Speech Recognition. Proc. ACM Interact. Mob. Wearable Ubiquitous Technol. 5, 4, Article 192 (Dec 2021), 23 pages. https://doi.org/10.1145/3494987 https://doi.org/10.1145/3494987

## EarIO: A Low-power Acoustic Sensing Earable for Continuously Tracking Detailed Facial Movements

Published in Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies, 2022

This paper presents EarIO, an AI-powered acoustic sensing technology that allows an earable (e.g., earphone) to continuously track facial expressions using two pairs of microphone and speaker (one on each side), which are widely available in commodity earphones. It emits acoustic signals from a speaker on an earable towards the face. Depending on facial expressions, the muscles, tissues, and skin around the ear would deform differently, resulting in unique echo profiles in the reflected signals captured by an on-device microphone. These received acoustic signals are processed and learned by a customized deep learning pipeline to continuously infer the full facial expressions represented by 52 parameters captured using a TruthDepth camera. Compared to similar technologies, it has significantly lower power consumption, as it can sample at 86 Hz with a power signature of 154 mW. A user study with 16 participants under three different scenarios, showed that EarIO can reliably estimate the detailed facial movements when the participants were sitting, walking or after remounting the device. Based on the encouraging results, we further discuss the potential opportunities and challenges on applying EarIO on future ear-mounted wearables.

Ke Li, Ruidong Zhang, Bo Liang, François Guimbretière, and Cheng Zhang. 2022. EarIO: A Low-power Acoustic Sensing Earable for Continuously Tracking Detailed Facial Movements. Proc. ACM Interact. Mob. Wearable Ubiquitous Technol. 6, 2, Article 62 (July 2022), 24 pages. https://doi.org/10.1145/3534621 https://doi.org/10.1145/3534621

## BodyTrak: Inferring Full-body Poses from Body Silhouettes Using a Miniature Camera on a Wristband

Published in Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies, 2022

In this paper, we present BodyTrak, an intelligent sensing technology that can estimate full body poses on a wristband. It only requires one miniature RGB camera to capture the body silhouettes, which are learned by a customized deep learning model to estimate the 3D positions of 14 joints on arms, legs, torso, and head. We conducted a user study with 9 participants in which each participant performed 12 daily activities such as walking, sitting, or exercising, in varying scenarios (wearing different clothes, outdoors/indoors) with a different number of camera settings on the wrist. The results show that our system can infer the full body pose (3D positions of 14 joints) with an average error of 6.9 cm using only one miniature RGB camera (11.5mm x 9.5mm) on the wrist pointing towards the body. Based on the results, we disscuss the possible application, challenges, and limitations to deploy our system in real-world scenarios.

Hyunchul Lim, Yaxuan Li, Matthew Dressa, Fang Hu, Jae Hoon Kim, Ruidong Zhang, and Cheng Zhang. 2022. BodyTrak: Inferring Full-body Poses from Body Silhouettes Using a Miniature Camera on a Wristband. Proc. ACM Interact. Mob. Wearable Ubiquitous Technol. 6, 3, Article 154 (September 2022), 21 pages. https://doi.org/10.1145/3552312 https://doi.org/10.1145/3552312

## EatingTrak: Detecting fine-grained eating moments in the wild using a wrist-mounted IMU

Published in Proceedings of the ACM on Human-Computer Interaction, 2022

In this paper, we present EatingTrak, an AI-powered sensing system using a wrist-mounted inertial measurement unit (IMU) to recognize eating moments in a near-free-living semi-wild setup. It significantly improves the SOTA in time resolution using similar hardware on identifying eating moments, from over five minutes to three seconds. Different from prior work which directly learns from raw IMU data, it proposes intelligent algorithms which can estimate the arm posture in 3D in the wild and then learns the detailed eating moments from the series of estimated arm postures. To evaluate the system, we collected eating activity data from 9 participants in semi-wild scenarios for over 113 hours. Results showed that it was able to recognize eating moments at three time-resolutions: 3 seconds and 15 minutes with F-1 scores of 73.7% and 83.8%, respectively. EatingTrak would introduce new opportunities in sensing detailed eating behavior information requiring high time resolution, such as eating frequency, snack-taking, on-site behavior intervention. We also discuss the opportunities and challenges in deploying EatingTrak on commodity devices at scale.

Ruidong Zhang, Jihai Zhang, Nitish Gade, Peng Cao, Seyun Kim, Junchi Yan, and Cheng Zhang. 2022. EatingTrak: Detecting Fine-grained Eating Moments in the Wild Using a Wrist-mounted IMU. Proc. ACM Hum.-Comput. Interact. 6, MHCI, Article 214 (September 2022), 22 pages. https://doi.org/10.1145/3546749 https://doi.org/10.1145/3546749

## D-Touch: Recognizing and Predicting Fine-grained Hand-face Touching Activities Using a Neck-mounted Wearable

Published in Proceedings of the 28th International Conference on Intelligent User Interfaces, 2023

This paper presents D-Touch, a neck-mounted wearable sensing system that can recognize and predict how a hand touches the face. It uses a neck-mounted infrared camera (IR), which takes pictures of the head from the neck. These IR camera images are processed and used to train a deep-learning model to recognize and predict touch time and positions. The study showed D-Touch distinguished 17 Facial related Activity (FrA), including 11 face touch positions and 6 other activities, with over 92.1% accuracy and predict the hand-touching T-zone from other FrA activities with an accuracy of 82.12% within 150 ms after the hand appeared in the camera. A study with 10 participants conducted in their homes without any constraints on participants showed that D-Touch can predict the hand-touching T-zone from other FrA activities with an accuracy of 72.3% within 150 ms after the camera saw the hand. Based on the study results, we further discuss the opportunities and challenges of deploying D-Touch in real-world scenarios.

Hyunchul Lim, Ruidong Zhang, Samhita Pendyal, Jeyeon Jo, and Cheng Zhang. 2023. D-Touch: Recognizing and Predicting Fine-grained Hand-face Touching Activities Using a Neck-mounted Wearable. In Proceedings of the 24th International Conference on Intelligent User Interfaces (to appear)

## ReMotion: Supporting Remote Collaboration in Open Space with Automatic Robotic Embodiment

Published in Proceedings of the 2023 CHI Conference on Human Factors in Computing Systems, 2023

Design activities, such as brainstorming or critique, often take place in open spaces combining whiteboards and tables to present artefacts. In co-located settings, peripheral awareness enables participants to understand each other’s locus of attention with ease. However, these spatial cues are mostly lost while using videoconferencing tools. Telepresence robots could bring back a sense of presence, but controlling them is distracting. To address this problem, we present ReMotion, a fully automatic robotic proxy designed to explore a new way of supporting non-collocated open-space design activities. ReMotion combines a commodity body tracker (Kinect) to capture a user’s location and orientation over a wide area with a minimally invasive wearable system (NeckFace) to capture facial expressions. Due to its omnidirectional platform, ReMotion embodiment can render a wide range of body movements. The formative evaluation indicates that our system enhances the sharing of attention and the sense of co-presence enabling seamless moving-in-space experience.

Mose Sakashita, Xiaoyi Li, Ruidong Zhang, Hyunju Kim, Michael Russo III, Malte F Jung, Cheng Zhang, and François Guimbretière. 2023. ReMotion: Supporting Remote Collaboration in Open Space with Automatic Robotic Embodiment. In Proceedings of the 2023 CHI Conference on Human Factors in Computing Systems (CHI '23) (to appear).

## EchoSpeech: Continuous Silent Speech Recognition on Minimally-obtrusive Eyewear Powered by Acoustic Sensing

Published in Proceedings of the 2023 CHI Conference on Human Factors in Computing Systems, 2023

We present EchoSpeech, a minimally-obtrusive silent speech interface (SSI) powered by low-power active acoustic sensing. EchoSpeech uses speakers and microphones mounted on a glass-frame and emits inaudible sound waves towards the skin. By analyzing echos from multiple paths, EchoSpeech captures subtle skin deformations caused by silent utterances and uses them to infer silent speech. With a user study of 12 participants, we demonstrate that EchoSpeech can recognize 31 isolated commands and 3-6 figure connected digits with 4.5% (std 3.5%) and 6.1% (std 4.2%) Word Error Rate (WER), respectively. We further evaluated EchoSpeech under scenarios including walking and noise injection to test its robustness. We then demonstrated using EchoSpeech in four demo applications in real-time operating at 73.3mW, where the real-time pipeline was implemented on a smartphone with only 1-6 minutes of training data. We believe that EchoSpeech takes a solid step towards minimally-obtrusive wearable SSI for real-life deployment.

Ruidong Zhang, Ke Li, Yihong Hao, Yufan Wang, Zhengnan Lai, François Guimbretière, and Cheng Zhang. 2023. EchoSpeech: Continuous Silent Speech Recognition on Minimally-obtrusive Eyewear Powered by Acoustic Sensing. In Proceedings of the 2023 CHI Conference on Human Factors in Computing Systems (CHI '23) (to appear).

## Talk 1 on Relevant Topic in Your Field

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## Conference Proceeding talk 3 on Relevant Topic in Your Field

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## INFO 4320/5321: Introduction to Rapid Prototyping and Physical Computing (Spring 2022 - Spring 2023)

Teaching assistant for undergraduate/graduate course, Department of Information Science, Cornell University, 2022

The course covers the basics of rapid prototyping and hardware computing including laser cutting, 3D printing, mechanics and micro-controller. My duty as a TA includes helping students with their questions in class, holding office hours and mentoring students in their individual and team projects.