Hand gesture recognition is becoming a more prevalent mode of human-computer interaction, especially as cameras proliferate across everyday devices. Despite continued progress in this field, gesture customization is often underexplored. Customization is crucial since it enables users to define and demonstrate gestures that are more natural, memorable, and accessible. However, customization requires efficient usage of user-provided data. We introduce a method that enables users to easily design bespoke gestures with a monocular camera from one demonstration. We employ transformers and meta-learning techniques to address few-shot learning challenges. Unlike prior work, our method supports any combination of one-handed, two-handed, static, and dynamic gestures, including different viewpoints, and the ability to handle irrelevant hand movements. We implement three real-world applications using our customization method, conduct a user study, and achieve up to 94% average recognition accuracy from one demonstration. Our work provides a viable path for vision-based gesture customization, laying the foundation for future advancements in this domain.

Speech is inappropriate in many situations, limiting when voice control can be used. Most unvoiced speech text entry systems can not be used while on-the-go due to movement artifacts. Using a dental retainer with capacitive touch sensors, SilentSpeller tracks tongue movement, enabling users to type by spelling words without voicing. SilentSpeller achieves an average 97% character accuracy in offline isolated word testing on a 1164-word dictionary. Walking has little effect on accuracy; average offline character accuracy was roughly equivalent on 107 phrases entered while walking (97.5%) or seated (96.5%). To demonstrate extensibility, the system was tested on 100 unseen words, leading to an average 94% accuracy. Live text entry speeds for seven participants averaged 37 words per minute at 87% accuracy. Comparing silent spelling to current practice suggests that SilentSpeller may be a viable alternative for silent mobile text entry.

The ultimate goal of automatic diet monitoring systems (ADM) is to make food journaling as easy as counting steps with a smartwatch. To achieve this goal, it is essential to understand the utility and usability of ADM systems in real-world settings. However, this has been challenging since many ADM systems perform poorly outside the research labs. Therefore, one of the main focuses of ADM research has been on improving ecological validity. This paper presents an evaluation of ADM’s utility and usability using an end-to-end system, FitNibble. FitNibble is robust to many challenges that real-world settings pose and provides just-in-time notifications to remind users to journal as soon as they start eating. We conducted a long-term field study to compare traditional self-report journaling and journaling with ADM in this evaluation. We recruited 13 participants from various backgrounds and asked them to try each journaling method for nine days. Our results showed that FitNibble improved adherence by significantly reducing the number of missed events (19.6% improvement, p =.0132). Results have shown that participants were highly dependent on FitNibble in maintaining their journals. Participants also reported increased awareness of their dietary patterns, especially with snacking. All these results highlight the potential of ADM in improving the food journaling experience.

In an attempt to help users reach their health goals and practitioners understand the relationship between diet and disease, researchers have proposed many wearable systems to automatically monitor food consumption. When a person consumes food, he/she brings the food close to their mouth, take a sip or bite and chew, and then swallow. Most diet monitoring approaches focus on one of these aspects of food intake, but this narrow reliance requires high precision and often fails in noisy and unconstrained situations common in a person's daily life. In this paper, we introduce FitByte, a multi-modal sensing approach on a pair of eyeglasses that tracks all phases of food intake. FitByte contains a set of inertial and optical sensors that allow it to reliably detect food intake events in noisy environments. It also has an on-board camera that opportunistically captures visuals of the food as the user consumes it. We evaluated the system in two studies with decreasing environmental constraints with 23 participants. On average, FitByte achieved 89% F1-score in detecting eating and drinking episodes.

The touchscreen has been the dominant input surface for smartphones and smartwatches. However, its small size compared to a phone limits the richness of the input gestures that can be supported. We present TapSkin, an interaction technique that recognizes up to 11 distinct tap gestures on the skin around the watch using only the inertial sensors and microphone on a commodity smartwatch. An evaluation with 12 participants shows our system can provide classification accuracies from 90.69% to 97.32% in three gesture families -- number pad, d-pad, and corner taps. We discuss the opportunities and remaining challenges for widespread use of this technique to increase input richness on a smartwatch without requiring further on-body instrumentation.

We explore using the Outer Ear Interface (OEI) to recognize eating activities. OEI contains a 3D gyroscope and a set of proximity sensors encapsulated in an off-the-shelf earpiece to monitor jaw movement by measuring ear canal deformation. In a laboratory setting with 20 participants, OEI could distinguish eating from other activities, such as walking, talking, and silently reading, with over 90% accuracy (user independent). In a second study, six subjects wore the system for 6 hours each while performing their normal daily activities. OEI correctly classified five minute segments of time as eating or non-eating with 93% accuracy (user dependent).