Comparison of Step Length Estimators from Wearable Accelerometer Devices

Abstract

Video-based gait analysis, and other measurement devices such as force-plates, electrogoniometers, or electrodes to measure EMG signals are adequate for laboratory studies but are not designed for usability in ambulatory applications. Conversely, accelerometers provide easily portable systems that supply real-time data, which is why they are widely used in ambulatory diagnostic devices. However, such systems do not provide direct measure of several spatio-temporal parameters of interest such as step length, walking distance, or walking velocity. Instead, they have to be estimated with a mathematical model from indirect sensor measurements. Specifically, in this chapter we are concerned with the accelerometry- based estimation of the step length in straight-line human walking.