A smart phone based gait monitor system

Gait analysis is the study of human locomotion and is able to provide useful information in various areas such as health care, therapy, sports training, and characteristic recognition. This paper presents a smartphone based system to collect and calculate gait parameters. These parameters consisted of step length, velocity, cadence, motion intensity, and walking regularity are calculated from the sensor data collected by the inertial sensor of a smart-phone. A prototype of gait parameter collection and visualization system was developed on a laptop and cell phone. The proposed system collects accelerometer data from a smart-phone and calculates the gait parameters related to walking activity. All the parameters are displayed on a customized Matlab graphic user interface on the laptop. The fall detection function is also integrated into the system. Once the user fall down, an alarm message will be sent to preset contact. The experiments are carried out on 4 subjects to test the stability and accuracy of the system. The system shows high accuracy and reliability on counting steps (error<5.47%) and walking duration (error<4.55%). Based on the gait monitor system, an anomaly data detection method is presented. Four independent gait parameters include cadence, and triaxel motion intensity parameters are chosen from previous results during normal activity. If the latest data deviates from the normal activity model too far, the data will be set as an abnormal event.