Rethinking Eye-blink: Assessing Task Difficulty through Physiological Representation of Spontaneous Blinking

Continuous assessment of task difficulty and mental workload is essential in improving the usability and accessibility of interactive systems. Eye tracking data has often been investigated to achieve this ability, with reports on the limited role of standard blink metrics. Here, we propose a new approach to the analysis of eye-blink responses for automated estimation of task difficulty. The core module is a time-frequency representation of eye-blink, which aims to capture the richness of information reflected on blinking. In our first study, we show that this method significantly improves the sensitivity to task difficulty. We then demonstrate how to form a framework where the represented patterns are analyzed with multi-dimensional Long Short-Term Memory recurrent neural networks for their non-linear mapping onto difficulty-related parameters. This framework outperformed other methods that used hand-engineered features. This approach works with any built-in camera, without requiring specialized devices. We conclude by discussing how Rethinking Eye-blink can benefit real-world applications.Comment: [Accepted version] In Proceedings of CHI Conference on Human Factors in Computing Systems (CHI '21), May 8-13, 2021, Yokohama, Japan. ACM, New York, NY, USA. 19 Pages. https://doi.org/10.1145/3411764.344557

Expressive haptics for enhanced usability of mobile interfaces in situations of impairments

Designing for situational awareness could lead to better solutions for disabled people, likewise, exploring the needs of disabled people could lead to innovations that can address situational impairments. This in turn can create non-stigmatising assistive technology for disabled people from which eventually everyone could benefit. In this paper, we investigate the potential for advanced haptics to compliment the graphical user interface of mobile devices, thereby enhancing user experiences of all people in some situations (e.g. sunlight interfering with interaction) and visually impaired people. We explore technical solutions to this problem space and demonstrate our justification for a focus on the creation of kinaesthetic force feedback. We propose initial design concepts and studies, with a view to co-create delightful and expressive haptic interactions with potential users motivated by scenarios of situational and permanent impairments.Comment: Presented at the CHI'19 Workshop: Addressing the Challenges of Situationally-Induced Impairments and Disabilities in Mobile Interaction, 2019 (arXiv:1904.05382

Exploring Artistic Visualization of Physiological Signals for Mindfulness and Relaxation: A Pilot Study

Mindfulness and relaxation techniques for mental health are increasingly being explored in the human-computer interaction community. Physiological signals and their visualization have often been exploited together in a form of biofeedback with other intervention methods. Here, we aim to contribute to the body of existing work on biofeedback interfaces for mindfulness, with a particular focus on incorporating artistic effects into physiological signal visualization. With an implemented artistic biofeedback interface, we conduct a pilot study where 10 participants attend stress-induction sessions followed by two biofeedback mindfulness sessions: classic biofeedback and artistic visualization. The result demonstrates that artistic visualization-driven biofeedback significantly improves the effectiveness of biofeedback in helping users feel relaxed in comparison with a classic graphical form of biofeedback. Also, it shows that the artistic effect makes it easy to understand what biofeedback represents. Future work includes exploring how advanced physiological computing methods can improve its efficiency and performance

Nose Heat: Exploring Stress-induced Nasal Thermal Variability through Mobile Thermal Imaging

Automatically monitoring and quantifying stress-induced thermal dynamic information in real-world settings is an extremely important but challenging problem. In this paper, we explore whether we can use mobile thermal imaging to measure the rich physiological cues of mental stress that can be deduced from a person's nose temperature. To answer this question we build i) a framework for monitoring nasal thermal variable patterns continuously and ii) a novel set of thermal variability metrics to capture a richness of the dynamic information. We evaluated our approach in a series of studies including laboratory-based psychosocial stress-induction tasks and real-world factory settings. We demonstrate our approach has the potential for assessing stress responses beyond controlled laboratory settings

Mobile Thermography-based Physiological Computing for Automatic Recognition of a Person’s Mental Stress

This thesis explores the use of Mobile Thermography1, a significantly less investigated sensing capability, with the aim of reliably extracting a person’s multiple physiological signatures and recognising mental stress in an automatic, contactless manner. Mobile thermography has greater potentials for real-world applications because of its light-weight, low computation-cost characteristics. In addition, thermography itself does not necessarily require the sensors to be worn directly on the skin. It raises less privacy concerns and is less sensitive to ambient lighting conditions. The work presented in this thesis is structured through a three-stage approach that aims to address the following challenges: i) thermal image processing for mobile thermography in variable thermal range scenes; ii) creation of rich and robust physiology measurements; and iii) automated stress recognition based on such measurements. Through the first stage (Chapter 4), this thesis contributes new processing techniques to address negative effects of environmental temperature changes upon automatic tracking of regions-of-interest and measuring of surface temperature patterns. In the second stage (Chapters 5,6,7), the main contributions are: robustness in tracking respiratory and cardiovascular thermal signatures both in constrained and unconstrained settings (e.g. respiration: strong correlation with ground truth, r=0.9987), and investigation of novel cortical thermal signatures associated with mental stress. The final stage (Chapters 8,9) contributes automatic stress inference systems that focus on capturing richer dynamic information of physiological variability: firstly, a novel respiration representation-based system (which has achieved state-of-the-art performance: 84.59% accuracy, two stress levels), and secondly, a novel cardiovascular representation-based system using short-term measurements of nasal thermal variability and heartrate variability from another sensing channel (78.33% accuracy achieved from 20seconds measurements). Finally, this thesis contributes software libraries and incrementally built labelled datasets of thermal images in both constrained and everyday ubiquitous settings. These are used to evaluate performance of our proposed computational methods across the three-stages

On Quick Measurement of Airborne Ultrasound Pressure Fields

While ultrasound has long been used in the medical field in solid and liquid mediums, it's use in air has been less thoroughly researched due to a previous lack of applications. Recently it has been used for new applications such as mid-air haptics and the levitation of small particles. These applications require accurate acoustic holograms to be generated in mid-air. In order to do so it is vital to measure accurately these pressure fields, but also quickly in order to allow for quick iteration on work, or even real-time feedback. In addition to this it is of benefit to measure the sound field without interfering with it, which microphone set ups often do due to reflections of the device used to move the microphone. This work finds these methods currently lacking, though there are techniques used in place of hydrophones in water that could be adapted to work for the in-air context such as thermography