Privacy-Aware Gait Identification With Ultralow-Dimensional Data Using a Distance Sensor

As one of the most natural user behaviors, walking has been widely focused on developing personal identification systems due to its unique biometric authentication features. Popular visual solutions are usually affected by various environmental conditions, and their redundant user information (e.g., body type and appearance) makes it more challenging for users to maintain privacy and security. This article proposes a distance sensor-based gait identification system that uses only 1-D data with a simple system structure. Specifically, a time-of-flight (ToF) sensor was placed in front of a walking person, and a time series of distances was acquired. We extracted gait features from the data by calculating the velocity and acceleration curves and identifying individuals using a random forest (RF) classifier. We evaluated our system on ten users using leave-one-out cross validation. The average identification accuracy was 91.05% for ten users. This study shows that gait recognition is possible using only 1-D time-series data with a noncontact sensor. It can be used as a contactless identification, reducing the computational resources required for low-cost and low-power-consumption edge computing.