Sensor fusion and calibration for motion captures using accelerometers

A low cost motion capture system for the human body is handled. This system is based on low cost accelerometers. By extracting the gravity-related term from sensor data, we relate the sensor data with body configuration in real-time. One sensor unit is composed of 3 accelerometers and is capable of identifying 2 rotating angles of joints with 2 degrees of freedom. A geometric fusion technique is applied to cope with the uncertainty of sensor data. A practical calibration technique is also proposed to handle the error in aligning the sensing axis with coordination axis. In the case where motion acceleration is not negligible compared with the gravity acceleration, a compensation technique to extract gravity acceleration from sensor data is proposed. Experimental results of human motion capturing are also described with graphics.