Line of Sight Estimation from EOG Signal withVariation of Electrode Position for Human Machine Interface

Electro-oculogram (EOG) is such kind of sensitive biosignal that comes from eyes activities. Using the NF Instrument as the sensor to obtain the signal from gaze motion, the optimum electrode positions in order to distinguish the distance of vertical and horizontal movement were observed based on the magnitude and the stability of EOG signal. There were twelve electrode positions, each six beside and below the eye, as the candidate for the suitable electrode position to acquire the EOG. Another experiment to compare the signal difference between left and right eye was also investigated in horizontal and vertical eye movement. The result shows that the position number 2 satisfies the desired condition for horizontal movement and position number 11 leads in magnitude and stability of the EOG signal in vertical movement. Position number 10 is available for vertical and horizontal gaze motion for the alternative option. These positions were tested by finding the relationship between displacement (pixel) and EOG signal(μV). The result shows that linear approaching to this condition successfully detect the system not only in horizontal or vertical case but also in diagonal gaze motion with average error pixel around 80 pixels or 1.6 cm. Based on this result, we concluded that although we can get easily the EOG signal around the eyes, but not all positions can give a clear figure, so it is very important to determine the suitable electrode position