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시선응시 방법과 시각도가 P300 문자입력기의 정확도에 미치는 영향

The effects of the methods of eye gaze and visual angles on accuracy of P300 speller

  • 엄진섭 (충남대학교 심리학과/뇌과학연구소) ;
  • 손진훈 (충남대학교 심리학과/뇌과학연구소)
  • Eom, Jin-Sup (Department of Psychology, Brain Research Institute, Chungnam National University) ;
  • Sohn, Jin-Hun (Department of Psychology, Brain Research Institute, Chungnam National University)
  • 투고 : 2014.06.16
  • 심사 : 2014.06.30
  • 발행 : 2014.06.30

초록

본 연구에서는 P300 문자입력기의 물리적 특성에 해당하는 문자판의 시각도와 사용자의 개인적 특성에 해당하는 시선응시 방법이 P300 문자입력기의 정확도에 미치는 영향을 검증하였다. 문자판의 시각도는 사용자와 문자판 간의 거리로 조작하였으며, 60 cm 집단과 100 cm 집단, 150 cm 집단으로 구성하였다. 시선응시방법은 세 조건으로 반복측정하였다. 머리 조건은 머리를 움직여서 시선을 두는 조건이었으며, 눈동자 조건은 머리는 고정한 채 눈동자를 움직여서 시선을 두는 조건이었고, 시선고정 조건은 시선을 문자입력기의 중앙에 고정시킨 조건이었다. 이요인설계에 의한 실험결과, 문자입력의 정확도가 시선응시방법에 따라 유의한 차이가 있었다. 머리 조건의 정확도가 눈동자 조건의 정확도 보다 높았으며, 눈동자 조건의 정확도가 시선고정 조건의 정확도 보다 높았다. 그러나 문자판의 시각도와 상호작용효과는 모두 유의하지 않았다. 시선응시방법에 따라 목표문자의 P300 진폭을 측정한 결과, 머리조건의 P300이 눈동자 조건의 P300보다 더 컸다. 머리조건과 눈동자 조건 간에는 오류분포에서 큰 차이가 없었지만, 시선고정 조건은 나머지 두 조건과 큰 차이를 보였다. 머리조건과 눈동자 조건에서는 오류가 주로 목표문자와 인접한 문자에서 나타난 반면, 시선고정 조건은 오류가 상대적으로 넓게 분포하였으며, 문자판의 중심에서 멀리 떨어져 있는 문자들에서 오류가 많이 발생하였다.

This study was to examine how visual angle of matrix corresponding to the physical properties of P300 speller and eye gaze corresponding to the user's personal characteristics influence on the accuracy of P300. Visual angle of the matrix was operated as the distance between the user and the matrix and three groups were composed: 60 cm group, 100 cm groups, and 150 cm group. Eye gaze methods was consisted three conditions. Head moving condition was putting eye gaze using head, pupil moving condition was moving pupil with the head fixed, while the eye fixed condition is to fix the eye gaze at the center of the matrix. The results showed that there was significant difference in the accuracy of P300 speller according to the eye gaze method. The accuracy of the head moving condition was higher than the accuracy of pupil moving conditions, accuracy of pupil moving conditions was higher than the accuracy of the eye fixed conditions. However, the effect of visual angle of matrix and interaction effect were not significant. When P300 amplitude of target character was measured depending on how you stare at the target character, P300 amplitude of the head moving condition was greater than P300 amplitude of the pupil moving condition. There was no significant difference in the error distribution in head moving condition and pupil moving condition, while there was a significant difference between two eye gaze conditions and fixed gaze condition. The error was located at the neighboring characters of the target character in head moving condition and pupil moving condition, while the error was relatively distributed widely in fixed eye condition, error was occurred with high rate in characters far away from the center of matrix.

키워드

참고문헌

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