Abstract— Nutrition-related diseases are nowadays a main
threat to human health and pose great challenges to medical
care. A crucial step to solve the problems is to monitor the
daily food intake of a person precisely and conveniently. For this
purpose, we present AutoDietary, a wearable system to monitor
and recognize food intakes in daily life. An embedded hardware
prototype is developed to collect food intake sensor data, which is
highlighted by a high-fidelity microphone worn on the subject’s
neck to precisely record acoustic signals during eating in a noninvasive
manner. The acoustic data are preprocessed and then sent
to a smartphone via Bluetooth, where food types are recognized.
In particular, we use hidden Markov models to identify chewing
or swallowing events, which are then processed to extract their
time/frequency-domain and nonlinear features. A lightweight
decision-tree-based algorithm is adopted to recognize the type of
food. We also developed an application on the smartphone, which
aggregates the food intake recognition results in a user-friendly
way and provides suggestions on healthier eating, such as better
eating habits or nutrition balance. Experiments show that the
accuracy of food-type recognition by AutoDietary is 84.9%, and
those to classify liquid and solid food intakes are up to 97.6%
and 99.7%, respectively. To evaluate real-life user experience, we
conducted a survey, which collects rating from 53 participants
on wear comfort and functionalities of AutoDietary. Results show
that the current design is acceptable to most of the users.