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liwei chan

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Financial Engines Services Inc., Ltd

Sosuke Ichihashi

Georgia Institute of Technology

Assunta Matassa

Università degli Studi di Torino

Omar Abou Khaled

University of Applied Sciences Western Switzerland

Universität Passau

Graz University of Technology

Gabriel-Miro Muntean

Dublin City University

Marianna Obrist

University of Duisburg-Essen

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Papers by liwei chan

The Third Workshop on Multiple Input Modalities and Sensations for VR/AR Interactions (MIMSVAI)

Adjunct Proceedings of the 2023 ACM International Joint Conference on Pervasive and Ubiquitous Computing & the 2023 ACM International Symposium on Wearable Computing

Rapid technological advances are expanding the practical applicability of virtual reality and/or ... more Rapid technological advances are expanding the practical applicability of virtual reality and/or augmented reality (VR/AR); however, the degree to which new users are able to interact with these technologies is limited by current input modalities. Gaining an intuitive grasp of VR/AR applications requires that users be immersed in the virtual environment, which in turn depends on the integration of multiple realistic sensory feedback mechanisms. This workshop will bring together researchers from the fields of UbiComp and VR/AR to explore alternative input modalities and sensory feedback systems to facilitate the design of coherent and engaging VR/AR experiences comparable to those in the real world. CCS CONCEPTS • Human-centered computing → Ubiquitous and mobile computing systems and tools.

Kinect estimated eyes positions depth image a b c d Figure 1: Dart-It is a lightweight system tha... more Kinect estimated eyes positions depth image a b c d Figure 1: Dart-It is a lightweight system that allows users to throw their finger touch to a remote display. In the matching game, a user can (a) lift his arm and (b) rapidly select a target without a cursor, and then (c) swipe to make a match. (d) Occlusion-free eye-tracking based on optical-flow.

Design of Vibrotactile Direction Feedbacks on Wrist for Three-Dimensional Spatial Guidance

Lecture Notes in Computer Science, 2020

A wrist-worn vibrotactile interface was previously studied but was aimed at low-resolution naviga... more A wrist-worn vibrotactile interface was previously studied but was aimed at low-resolution navigation tasks such as driving. The previous design had achieved up to six directions for three-dimensional navigation. We argue that the expressivity of vibrotactile navigation on the wrist has not been fully explored, and we address how three-dimensional direction cues can be packed into a wrist-form tactile interface. We present an 8-tactor cuboid worn in wrist form to generate high-density three-dimensional direction feedback around the wrist. This sparse arrangement of 8 vibrotactors allows up to 26 directions to be presented, when benefitting from phantom illusion. We conducted a study with 36 participants to inform the effective design of the interface regarding two factors: the cuboid shape (e.g., the length along the wrist), by comparing 4-cm, 6-cm, and 8-cm configurations, and the direction feedback, which includes point stimuli and motion stimuli. The results show that 6 cm strikes a balance between form and recognition rate. The direction feedbacks made with motion stimuli (80.2%) are generally more discernible than those made with point stimuli (69.6%).

DLWV2: A Deep Learning-Based Wearable Vision-System with Vibrotactile-Feedback for Visually Impaired People to Reach Objects

We develop a Deep Learning-based Wearable Vision-system with Vibrotactile-feedback (DLWV2) to gui... more We develop a Deep Learning-based Wearable Vision-system with Vibrotactile-feedback (DLWV2) to guide Blind and Visually Impaired (BVI) people to reach objects. The system achieves high accuracy in object detection and tracking in 3-D using an extended deep learning-based 2.5-D detector and a 3-D object tracker with the ability to track 3-D object locations even outside the camera field-of-view. We train our detector with a large number of images with 2.5-D object ground-truth (i.e., 2-D object bounding boxes and distance from the camera to objects). A novel combination of HTC Vive Tracker with our system enables us to automatically obtain the ground-truth labels for training while requiring very little human effort to set up the system. Moreover, our system processes frames in real-time through a client-server computing platform such that BVI people can receive realtime vibrotactile guidance. We conduct a thorough user study on 12 BVI people in new environments with object instances which are unseen during training. Our system outperforms the non-assistive guiding strategy with statistic significance in both time and the number of contacting irrelevant objects. Finally, the interview with BVI users confirms that our system with distance-based vibrotactile feedback is mostly preferred, especially for objects requiring gentle manipulation such as a bottle with water inside.

Novel projector calibration approaches of multi-resolution display

This paper proposes convenient and useful approaches to automatically calibrate the projectors of... more This paper proposes convenient and useful approaches to automatically calibrate the projectors of a multi-resolution display. The proposed approaches estimate both the keystone effect and misalignment of the projections with an assistance of a color camera. Structured light patterns are employed to construct the geometric relationship between projectors and the projection surface, and then pre-warp the images so that they appear undistorted as a result. Experimental results demonstrate that the proposed approaches successfully reduce the human-effort and lower the calibration time of multi-resolution display calibration task.

To move or not to move

Previous studies have outlined the advantages of multi-resolution large-area displays over their ... more Previous studies have outlined the advantages of multi-resolution large-area displays over their fixed-resolution counterparts, however the mobility of the focus region has up until the present time received little attention. To study this phenomenon further, we have developed a multi-resolution tabletop display system with a steerable high resolution focus region to compare the performance between steerable and fixed focus region

“Do you get déjà vu”: Persuasiveness Effects of Communicating with an Avatar of Similar Appearance in Social Virtual Reality

Extended Abstracts of the 2023 CHI Conference on Human Factors in Computing Systems

Design of Vibrotactile Direction Feedbacks on Wrist for Three-Dimensional Spatial Guidance

Cross-Cultural Design. User Experience of Products, Services, and Intelligent Environments, 2020

A wrist-worn vibrotactile interface was previously studied but was aimed at low-resolution naviga... more A wrist-worn vibrotactile interface was previously studied but was aimed at low-resolution navigation tasks such as driving. The previous design had achieved up to six directions for three-dimensional navigation. We argue that the expressivity of vibrotactile navigation on the wrist has not been fully explored, and we address how three-dimensional direction cues can be packed into a wrist-form tactile interface. We present an 8-tactor cuboid worn in wrist form to generate high-density three-dimensional direction feedback around the wrist. This sparse arrangement of 8 vibrotactors allows up to 26 directions to be presented, when benefitting from phantom illusion. We conducted a study with 36 participants to inform the effective design of the interface regarding two factors: the cuboid shape (e.g., the length along the wrist), by comparing 4-cm, 6-cm, and 8-cm configurations, and the direction feedback, which includes point stimuli and motion stimuli. The results show that 6 cm strikes a balance between form and recognition rate. The direction feedbacks made with motion stimuli (80.2%) are generally more discernible than those made with point stimuli (69.6%).

Projector Calibration of Multi-Resolution Display

Advances in display and input technologies have led to growing desire for creating a more immersi... more Advances in display and input technologies have led to growing desire for creating a more immersive visual experience in interactive display systems. Research on constructing a large-scale, high-resolution display environment based on multi-projector mosaic has also become increasingly important to meet the costeffective consideration. In our previous work, we had developed a system called i-m-Top, which integrated one steerable fovea projector for high-resolution projection and another fixed wideangle projector for low-resolution. The touch-sensing is on the basis of diffused illumination and analyzed by computer vision approach. In this paper, we propose a fast, low-cost method for automatic projector calibration with the assistance of one color camera, to eliminate both the keystone effect and misalignment of the projections. Structured light patterns are projected to construct the geometric relationship between projectors and the projection surface, and then pre-warp the images ...

Thermocons

Proceedings of the 29th Annual Symposium on User Interface Software and Technology, 2016

Thermocons describes our work in progress for evaluating thermal haptic feedback on the forehead ... more Thermocons describes our work in progress for evaluating thermal haptic feedback on the forehead as a viable feedback modality for integration with head mounted devices. The purpose was to identify the thermal perception for simultaneous feedback at three locations of the forehead. We provided hot-only, cold-only and hot/cold-mixed thermal stimulations at these location to identify the sensitivity for accurate perception. Our evaluation with 9 participants indicated that perceiving cold-only stimulations were significantly better with an accuracy of 88%. The perception accuracy for hot-only and hot/cold-mixed stimulations were 66% and 65% respectively.

FacePush

SIGGRAPH Asia 2018 Emerging Technologies, 2018

Simulated haptics is a key component to enhance immersion in virtual environments. Previous resea... more Simulated haptics is a key component to enhance immersion in virtual environments. Previous research has proposed various mechanisms to generate different haptic feedbacks. While many were deployed on limbs e.g., through wearable interfaces or handheld controllers, recent researches started to explore displaying haptics directly through HMDs. Examples include thermal [Peiris et al. 2017], vibrotactile [de Jesus Oliveira et al. 2017] and force [Gugenheimer et al. 2016] feedbacks. We present FacePush, a pulley system incorporated with a HMD to display pressure forces on user face. Unlike GyroVR [Gugenheimer et al. 2016] which enabled tangential/rotational force on user head, FacePush's pulley system creates normal force on the face region covered by the HMD. The main concept of FacePush is shifting torque provided by the two motors to a normal force pushing on face. As displayed in Figure 1. This normal force triggered by the motors pushes the HMD into user face resulting in pressure feedbacks on the face.

ThermalBracelet

Proceedings of the 2019 CHI Conference on Human Factors in Computing Systems, 2019

Smartwatches enable the wrist to be used as an ideal location to provide always-available haptic ... more Smartwatches enable the wrist to be used as an ideal location to provide always-available haptic notifications as they are constantly worn with direct contact with the skin. With the wrist straps, the haptic feedback can be extended to the full space around the wrist to provide more spatial and enriched feedback. With ThermalBracelet, we investigate thermal feedback as a haptic feedback modality around the wrist. We present three studies that lead to the development of a smartwatch-integratable thermal bracelet that stimulates six locations around the wrist. Our initial evaluation reports on the selection of the thermal module configurations. Secondly, with the selected six-module configuration, we explore its usability in a real-world scenarios such as walking and reading. Thirdly, we investigate its capability of providing spatio temporal feedback while engaged in distracting tasks. Finally we present application scenarios that demonstrates its usability.

DigitSpace

Proceedings of the 2016 CHI Conference on Human Factors in Computing Systems, 2016

Thumb-to-fingers interfaces augment touch widgets on fingers, which are manipulated by the thumb.... more Thumb-to-fingers interfaces augment touch widgets on fingers, which are manipulated by the thumb. Such interfaces are ideal for one-handed eyes-free input since touch widgets on the fingers enable easy access by the stylus thumb. This study presents DigitSpace, a thumb-to-fingers interface that addresses two ergonomic factors: hand anatomy and touch precision. Hand anatomy restricts possible movements of a thumb, which further influences the physical comfort during the interactions. Touch precision is a human factor that determines how precisely users can manipulate touch widgets set on fingers, which determines effective layouts of the widgets. Buttons and touchpads were considered in our studies to enable discrete and continuous input in an eyes-free manner. The first study explores the regions of fingers where the interactions can be comfortably performed. According to the comfort regions, the second and third studies explore effective layouts for button and touchpad widgets. The experimental results indicate that participants could discriminate at least 16 buttons on their fingers. For touchpad, participants were asked to perform unistrokes. Our results revealed that since individual participant performed a coherent writing behavior, personalized $1 recognizers could offer 92% accuracy on a cross-finger touchpad. A series of design guidelines are proposed for designers, and a DigitSpace prototype that uses magnetic-tracking methods is demonstrated.

HMD Light: Sharing In-VR Experience via Head-Mounted Projector for Asymmetric Interaction

Proceedings of the 33rd Annual ACM Symposium on User Interface Software and Technology, 2020

We present HMD Light, a proof-of-concept Head-Mounted Display (HMD) implementation that reveals t... more We present HMD Light, a proof-of-concept Head-Mounted Display (HMD) implementation that reveals the Virtual Reality (VR) user's experience in the physical environment to facilitate communication between VR and external users in a mobile VR context. While previous work externalized the VR user's experience through an on-HMD display, HMD Light places the display into the physical environment to enable larger display and interaction area. This work explores the interaction design space of HMD Light and presents four applications to demonstrate its versatility. Our exploratory user study observed participant pairs experience applications with HMD Light and evaluated usability, accessibility and social presence between users. From the results, we distill design insights for HMD Light and asymmetric VR collaboration.

LiquidReality: Wetness Sensations on the Face for Virtual Reality

Haptics: Science, Technology, and Applications, 2018

We present LiquidReality, a wearable system that simulates wetness sensations directly on the use... more We present LiquidReality, a wearable system that simulates wetness sensations directly on the user’s face for immersive virtual reality applications. The LiquidReality system consists of a headmounted display integrated with thermal and vibrotactile modules that provides co-located haptic feedback with the displayed visuals. With this system, we conducted a preliminary study that evaluated nine types of thermal and thermal/vibrotactile stimuli to induce a wetness sensation on the user’s face. Our results indicate that thermal only stimuli and low frequency vibrotactile stimuli (combined with thermal) induced better wetness perception. Next, using the results from this preliminary study, we evaluated the immersion enhancement when using the LiquidReality system in combination with related visuals. The results indicate that using the LiquidReality system with related visuals, enhances the level of immersion for the user.

ACM SIGGRAPH 2016 VR Village, 2016

Figure 1: a) 360 video projected as planet, b) stepping on planet view to trigger light, c) audie... more

Touch Control Virtual Screen Apparatus

Collaborative Localization: Enhancing WiFi-Based Position Estimation with Neighborhood Links in Clusters

Lecture Notes in Computer Science, 2006

Location-aware services can benefit from accurate and reliable indoor location tracking. The wide... more Location-aware services can benefit from accurate and reliable indoor location tracking. The widespread adoption of 802.11x wireless LAN as the network infrastructure creates the opportunity to deploy WiFi-based location services with few additional hardware costs. While recent research has demonstrated adequate performance, localization error increases significantly in crowded and dynamic situations due to electromagnetic interferences. This paper proposes collaborative localization as an approach to enhance position estimation by leveraging more accurate location information from nearby neighbors within the same cluster. The current implementation utilizes ZigBee radio as the neighbor-detection sensor. This paper introduces the basic model and algorithm for collaborative localization. We also report experiments to evaluate its performance under a variety of clustering scenarios. Our results have shown 28.2-56% accuracy improvement over the baseline system Ekahau, a commercial WiFi localization system.

Novel projector calibration approaches of multi-resolution display

2011 IEEE International Conference on Multimedia and Expo, 2011

This paper proposes convenient and useful approaches to automatically calibrate the projectors of... more This paper proposes convenient and useful approaches to automatically calibrate the projectors of a multi-resolution display. The proposed approaches estimate both the keystone effect and misalignment of the projections with an assistance of a color camera. Structured light patterns are employed to construct the geometric relationship between projectors and the projection surface, and then pre-warp the images so that they appear undistorted as a result. Experimental results demonstrate that the proposed approaches successfully reduce the human-effort and lower the calibration time of multi-resolution display calibration task.

Moodlog: Touring in mood of place

2008 First IEEE International Conference on Ubi-Media Computing, 2008

This paper presents an interdisciplinary study on social science and computing technology to buil... more This paper presents an interdisciplinary study on social science and computing technology to build a novel touring system toward representing the inner mood of place for the tourists. Ordinary touring systems are generally considering touring as introducing a place with descriptive information. Instead, the proposed system, Moodlog, brings "mood of place" into an ordinary touring scheme, opening up a new aspect of touring, leading to a deeper understanding of a place for tourists. This research introduces three design principles for Moodlog which are: (1) Place Regarded as Human, (2) Experiencing a Great Diversity of Place, and (3) Touring in Mood of Place. The basic idea of the work is we treating a place as a human being to communicate with the tourists. Specifically, Moodlog collects "mood of place" by information tagged by people living and travelling there. People have unique sense of place, which is able to contribute to the place by tagging their mood with digital media such as music, and photo and video taken there. This makes the place have its own mood, turning a passive place to be active as a human. Expressing the mood of place to a tourist's first visiting is just like the place being a human talking about its feeling and the stories it experienced to the tourist. Notably, the place is considered with multiple personalities because tourists have distinct feelings to the same place. Experiencing each personality of the place is just like talking to many people. For mood representation, music, color, photos, and videos are used to create a meaningful atmosphere for the user to easily get immersed in mood of place. Moodlog is implemented with a location-aware orientation-aware camera PDA held by the user during a tour. Additionally, a panorama-based user interface is introduced to help the user interact with the physical environment and the virtual memory of the place. A preliminary study for the system deploying in a university campus shows that the participants are interested in the new touring experience.

The Third Workshop on Multiple Input Modalities and Sensations for VR/AR Interactions (MIMSVAI)

Adjunct Proceedings of the 2023 ACM International Joint Conference on Pervasive and Ubiquitous Computing & the 2023 ACM International Symposium on Wearable Computing

Rapid technological advances are expanding the practical applicability of virtual reality and/or ... more Rapid technological advances are expanding the practical applicability of virtual reality and/or augmented reality (VR/AR); however, the degree to which new users are able to interact with these technologies is limited by current input modalities. Gaining an intuitive grasp of VR/AR applications requires that users be immersed in the virtual environment, which in turn depends on the integration of multiple realistic sensory feedback mechanisms. This workshop will bring together researchers from the fields of UbiComp and VR/AR to explore alternative input modalities and sensory feedback systems to facilitate the design of coherent and engaging VR/AR experiences comparable to those in the real world. CCS CONCEPTS • Human-centered computing → Ubiquitous and mobile computing systems and tools.

Kinect estimated eyes positions depth image a b c d Figure 1: Dart-It is a lightweight system tha... more Kinect estimated eyes positions depth image a b c d Figure 1: Dart-It is a lightweight system that allows users to throw their finger touch to a remote display. In the matching game, a user can (a) lift his arm and (b) rapidly select a target without a cursor, and then (c) swipe to make a match. (d) Occlusion-free eye-tracking based on optical-flow.

Design of Vibrotactile Direction Feedbacks on Wrist for Three-Dimensional Spatial Guidance

Lecture Notes in Computer Science, 2020

A wrist-worn vibrotactile interface was previously studied but was aimed at low-resolution naviga... more A wrist-worn vibrotactile interface was previously studied but was aimed at low-resolution navigation tasks such as driving. The previous design had achieved up to six directions for three-dimensional navigation. We argue that the expressivity of vibrotactile navigation on the wrist has not been fully explored, and we address how three-dimensional direction cues can be packed into a wrist-form tactile interface. We present an 8-tactor cuboid worn in wrist form to generate high-density three-dimensional direction feedback around the wrist. This sparse arrangement of 8 vibrotactors allows up to 26 directions to be presented, when benefitting from phantom illusion. We conducted a study with 36 participants to inform the effective design of the interface regarding two factors: the cuboid shape (e.g., the length along the wrist), by comparing 4-cm, 6-cm, and 8-cm configurations, and the direction feedback, which includes point stimuli and motion stimuli. The results show that 6 cm strikes a balance between form and recognition rate. The direction feedbacks made with motion stimuli (80.2%) are generally more discernible than those made with point stimuli (69.6%).

DLWV2: A Deep Learning-Based Wearable Vision-System with Vibrotactile-Feedback for Visually Impaired People to Reach Objects

We develop a Deep Learning-based Wearable Vision-system with Vibrotactile-feedback (DLWV2) to gui... more We develop a Deep Learning-based Wearable Vision-system with Vibrotactile-feedback (DLWV2) to guide Blind and Visually Impaired (BVI) people to reach objects. The system achieves high accuracy in object detection and tracking in 3-D using an extended deep learning-based 2.5-D detector and a 3-D object tracker with the ability to track 3-D object locations even outside the camera field-of-view. We train our detector with a large number of images with 2.5-D object ground-truth (i.e., 2-D object bounding boxes and distance from the camera to objects). A novel combination of HTC Vive Tracker with our system enables us to automatically obtain the ground-truth labels for training while requiring very little human effort to set up the system. Moreover, our system processes frames in real-time through a client-server computing platform such that BVI people can receive realtime vibrotactile guidance. We conduct a thorough user study on 12 BVI people in new environments with object instances which are unseen during training. Our system outperforms the non-assistive guiding strategy with statistic significance in both time and the number of contacting irrelevant objects. Finally, the interview with BVI users confirms that our system with distance-based vibrotactile feedback is mostly preferred, especially for objects requiring gentle manipulation such as a bottle with water inside.

Novel projector calibration approaches of multi-resolution display

This paper proposes convenient and useful approaches to automatically calibrate the projectors of... more This paper proposes convenient and useful approaches to automatically calibrate the projectors of a multi-resolution display. The proposed approaches estimate both the keystone effect and misalignment of the projections with an assistance of a color camera. Structured light patterns are employed to construct the geometric relationship between projectors and the projection surface, and then pre-warp the images so that they appear undistorted as a result. Experimental results demonstrate that the proposed approaches successfully reduce the human-effort and lower the calibration time of multi-resolution display calibration task.

To move or not to move

Previous studies have outlined the advantages of multi-resolution large-area displays over their ... more Previous studies have outlined the advantages of multi-resolution large-area displays over their fixed-resolution counterparts, however the mobility of the focus region has up until the present time received little attention. To study this phenomenon further, we have developed a multi-resolution tabletop display system with a steerable high resolution focus region to compare the performance between steerable and fixed focus region

“Do you get déjà vu”: Persuasiveness Effects of Communicating with an Avatar of Similar Appearance in Social Virtual Reality

Extended Abstracts of the 2023 CHI Conference on Human Factors in Computing Systems

Design of Vibrotactile Direction Feedbacks on Wrist for Three-Dimensional Spatial Guidance

Cross-Cultural Design. User Experience of Products, Services, and Intelligent Environments, 2020

A wrist-worn vibrotactile interface was previously studied but was aimed at low-resolution naviga... more A wrist-worn vibrotactile interface was previously studied but was aimed at low-resolution navigation tasks such as driving. The previous design had achieved up to six directions for three-dimensional navigation. We argue that the expressivity of vibrotactile navigation on the wrist has not been fully explored, and we address how three-dimensional direction cues can be packed into a wrist-form tactile interface. We present an 8-tactor cuboid worn in wrist form to generate high-density three-dimensional direction feedback around the wrist. This sparse arrangement of 8 vibrotactors allows up to 26 directions to be presented, when benefitting from phantom illusion. We conducted a study with 36 participants to inform the effective design of the interface regarding two factors: the cuboid shape (e.g., the length along the wrist), by comparing 4-cm, 6-cm, and 8-cm configurations, and the direction feedback, which includes point stimuli and motion stimuli. The results show that 6 cm strikes a balance between form and recognition rate. The direction feedbacks made with motion stimuli (80.2%) are generally more discernible than those made with point stimuli (69.6%).

Projector Calibration of Multi-Resolution Display

Advances in display and input technologies have led to growing desire for creating a more immersi... more Advances in display and input technologies have led to growing desire for creating a more immersive visual experience in interactive display systems. Research on constructing a large-scale, high-resolution display environment based on multi-projector mosaic has also become increasingly important to meet the costeffective consideration. In our previous work, we had developed a system called i-m-Top, which integrated one steerable fovea projector for high-resolution projection and another fixed wideangle projector for low-resolution. The touch-sensing is on the basis of diffused illumination and analyzed by computer vision approach. In this paper, we propose a fast, low-cost method for automatic projector calibration with the assistance of one color camera, to eliminate both the keystone effect and misalignment of the projections. Structured light patterns are projected to construct the geometric relationship between projectors and the projection surface, and then pre-warp the images ...

Thermocons

Proceedings of the 29th Annual Symposium on User Interface Software and Technology, 2016

Thermocons describes our work in progress for evaluating thermal haptic feedback on the forehead ... more Thermocons describes our work in progress for evaluating thermal haptic feedback on the forehead as a viable feedback modality for integration with head mounted devices. The purpose was to identify the thermal perception for simultaneous feedback at three locations of the forehead. We provided hot-only, cold-only and hot/cold-mixed thermal stimulations at these location to identify the sensitivity for accurate perception. Our evaluation with 9 participants indicated that perceiving cold-only stimulations were significantly better with an accuracy of 88%. The perception accuracy for hot-only and hot/cold-mixed stimulations were 66% and 65% respectively.

FacePush

SIGGRAPH Asia 2018 Emerging Technologies, 2018

Simulated haptics is a key component to enhance immersion in virtual environments. Previous resea... more Simulated haptics is a key component to enhance immersion in virtual environments. Previous research has proposed various mechanisms to generate different haptic feedbacks. While many were deployed on limbs e.g., through wearable interfaces or handheld controllers, recent researches started to explore displaying haptics directly through HMDs. Examples include thermal [Peiris et al. 2017], vibrotactile [de Jesus Oliveira et al. 2017] and force [Gugenheimer et al. 2016] feedbacks. We present FacePush, a pulley system incorporated with a HMD to display pressure forces on user face. Unlike GyroVR [Gugenheimer et al. 2016] which enabled tangential/rotational force on user head, FacePush's pulley system creates normal force on the face region covered by the HMD. The main concept of FacePush is shifting torque provided by the two motors to a normal force pushing on face. As displayed in Figure 1. This normal force triggered by the motors pushes the HMD into user face resulting in pressure feedbacks on the face.

ThermalBracelet

Proceedings of the 2019 CHI Conference on Human Factors in Computing Systems, 2019

Smartwatches enable the wrist to be used as an ideal location to provide always-available haptic ... more Smartwatches enable the wrist to be used as an ideal location to provide always-available haptic notifications as they are constantly worn with direct contact with the skin. With the wrist straps, the haptic feedback can be extended to the full space around the wrist to provide more spatial and enriched feedback. With ThermalBracelet, we investigate thermal feedback as a haptic feedback modality around the wrist. We present three studies that lead to the development of a smartwatch-integratable thermal bracelet that stimulates six locations around the wrist. Our initial evaluation reports on the selection of the thermal module configurations. Secondly, with the selected six-module configuration, we explore its usability in a real-world scenarios such as walking and reading. Thirdly, we investigate its capability of providing spatio temporal feedback while engaged in distracting tasks. Finally we present application scenarios that demonstrates its usability.

DigitSpace

Proceedings of the 2016 CHI Conference on Human Factors in Computing Systems, 2016

Thumb-to-fingers interfaces augment touch widgets on fingers, which are manipulated by the thumb.... more Thumb-to-fingers interfaces augment touch widgets on fingers, which are manipulated by the thumb. Such interfaces are ideal for one-handed eyes-free input since touch widgets on the fingers enable easy access by the stylus thumb. This study presents DigitSpace, a thumb-to-fingers interface that addresses two ergonomic factors: hand anatomy and touch precision. Hand anatomy restricts possible movements of a thumb, which further influences the physical comfort during the interactions. Touch precision is a human factor that determines how precisely users can manipulate touch widgets set on fingers, which determines effective layouts of the widgets. Buttons and touchpads were considered in our studies to enable discrete and continuous input in an eyes-free manner. The first study explores the regions of fingers where the interactions can be comfortably performed. According to the comfort regions, the second and third studies explore effective layouts for button and touchpad widgets. The experimental results indicate that participants could discriminate at least 16 buttons on their fingers. For touchpad, participants were asked to perform unistrokes. Our results revealed that since individual participant performed a coherent writing behavior, personalized $1 recognizers could offer 92% accuracy on a cross-finger touchpad. A series of design guidelines are proposed for designers, and a DigitSpace prototype that uses magnetic-tracking methods is demonstrated.

HMD Light: Sharing In-VR Experience via Head-Mounted Projector for Asymmetric Interaction

Proceedings of the 33rd Annual ACM Symposium on User Interface Software and Technology, 2020

We present HMD Light, a proof-of-concept Head-Mounted Display (HMD) implementation that reveals t... more We present HMD Light, a proof-of-concept Head-Mounted Display (HMD) implementation that reveals the Virtual Reality (VR) user's experience in the physical environment to facilitate communication between VR and external users in a mobile VR context. While previous work externalized the VR user's experience through an on-HMD display, HMD Light places the display into the physical environment to enable larger display and interaction area. This work explores the interaction design space of HMD Light and presents four applications to demonstrate its versatility. Our exploratory user study observed participant pairs experience applications with HMD Light and evaluated usability, accessibility and social presence between users. From the results, we distill design insights for HMD Light and asymmetric VR collaboration.

LiquidReality: Wetness Sensations on the Face for Virtual Reality

Haptics: Science, Technology, and Applications, 2018

We present LiquidReality, a wearable system that simulates wetness sensations directly on the use... more We present LiquidReality, a wearable system that simulates wetness sensations directly on the user’s face for immersive virtual reality applications. The LiquidReality system consists of a headmounted display integrated with thermal and vibrotactile modules that provides co-located haptic feedback with the displayed visuals. With this system, we conducted a preliminary study that evaluated nine types of thermal and thermal/vibrotactile stimuli to induce a wetness sensation on the user’s face. Our results indicate that thermal only stimuli and low frequency vibrotactile stimuli (combined with thermal) induced better wetness perception. Next, using the results from this preliminary study, we evaluated the immersion enhancement when using the LiquidReality system in combination with related visuals. The results indicate that using the LiquidReality system with related visuals, enhances the level of immersion for the user.

ACM SIGGRAPH 2016 VR Village, 2016

Figure 1: a) 360 video projected as planet, b) stepping on planet view to trigger light, c) audie... more

Touch Control Virtual Screen Apparatus

Collaborative Localization: Enhancing WiFi-Based Position Estimation with Neighborhood Links in Clusters

Lecture Notes in Computer Science, 2006

Location-aware services can benefit from accurate and reliable indoor location tracking. The wide... more Location-aware services can benefit from accurate and reliable indoor location tracking. The widespread adoption of 802.11x wireless LAN as the network infrastructure creates the opportunity to deploy WiFi-based location services with few additional hardware costs. While recent research has demonstrated adequate performance, localization error increases significantly in crowded and dynamic situations due to electromagnetic interferences. This paper proposes collaborative localization as an approach to enhance position estimation by leveraging more accurate location information from nearby neighbors within the same cluster. The current implementation utilizes ZigBee radio as the neighbor-detection sensor. This paper introduces the basic model and algorithm for collaborative localization. We also report experiments to evaluate its performance under a variety of clustering scenarios. Our results have shown 28.2-56% accuracy improvement over the baseline system Ekahau, a commercial WiFi localization system.

Novel projector calibration approaches of multi-resolution display

2011 IEEE International Conference on Multimedia and Expo, 2011

This paper proposes convenient and useful approaches to automatically calibrate the projectors of... more This paper proposes convenient and useful approaches to automatically calibrate the projectors of a multi-resolution display. The proposed approaches estimate both the keystone effect and misalignment of the projections with an assistance of a color camera. Structured light patterns are employed to construct the geometric relationship between projectors and the projection surface, and then pre-warp the images so that they appear undistorted as a result. Experimental results demonstrate that the proposed approaches successfully reduce the human-effort and lower the calibration time of multi-resolution display calibration task.

Moodlog: Touring in mood of place

2008 First IEEE International Conference on Ubi-Media Computing, 2008

This paper presents an interdisciplinary study on social science and computing technology to buil... more This paper presents an interdisciplinary study on social science and computing technology to build a novel touring system toward representing the inner mood of place for the tourists. Ordinary touring systems are generally considering touring as introducing a place with descriptive information. Instead, the proposed system, Moodlog, brings "mood of place" into an ordinary touring scheme, opening up a new aspect of touring, leading to a deeper understanding of a place for tourists. This research introduces three design principles for Moodlog which are: (1) Place Regarded as Human, (2) Experiencing a Great Diversity of Place, and (3) Touring in Mood of Place. The basic idea of the work is we treating a place as a human being to communicate with the tourists. Specifically, Moodlog collects "mood of place" by information tagged by people living and travelling there. People have unique sense of place, which is able to contribute to the place by tagging their mood with digital media such as music, and photo and video taken there. This makes the place have its own mood, turning a passive place to be active as a human. Expressing the mood of place to a tourist's first visiting is just like the place being a human talking about its feeling and the stories it experienced to the tourist. Notably, the place is considered with multiple personalities because tourists have distinct feelings to the same place. Experiencing each personality of the place is just like talking to many people. For mood representation, music, color, photos, and videos are used to create a meaningful atmosphere for the user to easily get immersed in mood of place. Moodlog is implemented with a location-aware orientation-aware camera PDA held by the user during a tour. Additionally, a panorama-based user interface is introduced to help the user interact with the physical environment and the virtual memory of the place. A preliminary study for the system deploying in a university campus shows that the participants are interested in the new touring experience.