A Simple Gaze Tracker for Computer Operation by the Disabled in Education

Resumo

A compact gaze tracker was developed which consists of a head band and electrodes which process the Electro-Oculo-Gram (EOG) reflecting the patient´s eye movements. We have confirmed that the processed EOG signal correlates well with gaze angle, and we show that the instrument we designed enables a child to move a target on a screen up to 40 degrees left-right from central sight. To achieve this, a signal processing circuit was designed and placed on a head band to minimize noise. Further processing is based on the identification of saccadic eye movements and on the educated calculation of the estimated gaze angle as a result of angle change in both directions. A 75% success rate was achieved to detect transitions of eye positions in 5° steps from +40° to -40°. First tests by normal children suggest that the device may prove useful for communication by the disabled (e.g. patients with no control on hand movements). In such cases, extensive personal training will tap on neurological plasticity to achieve the required performance level for computer mouse command of educational games and for interactive applications in general.