Testing and evaluation of a pen input device using an interial/magnetic sensor module

Abstract

In this thesis, the feasibility of developing a pen input device using an inertial/magnetic sensor module is investigated. The emphasis is on testing and evaluation of algorithms for computing handwriting trajectories based on accelerometer measurement data. This research starts by placing the inertial/magnetic sensor in a 2-D plane and writing alphanumeric characters. Before continuing to evaluate the 3-D writing, a calibration algorithm is implemented for computing the length between the nose of the pen input device and the point where the inertial/magnetic sensor is attached to the pen. A velocity correction algorithm is also applied by recognizing the pause phases in the writing in order to eliminate the drift in acceleration measurements and accurately reproduce handwriting trajectories. Extensive experiments conducted for 2-D and 3-D writings indicate that it is possible to develop a pen input device to track handwriting using an inertial/magnetic sensor module. However, the performance of the handwriting tracking depends on the accuracy of the sensor module and the speed of the writing motion.