In this study, according to the reference setting based on the runoff video of 9:00 where the highest water level of 3.94 m has been recorded during the runoff of Cheon-mi Stream in Jeju Island by the attack of Typhoon no. 16 Sanba on September 17th, 2012, the error rate of long-distance and short-distance velocimetry and real-distance change rate by input error have been calculated and the input range value of reference point by stream has been suggested. In the reference setting process, if a long-distance reference point input error occurs, the real-distance change rate of 0.35 m in the x-axis direction and 1.35 m in y-axis direction is incurred by the subtle input error of 2~11 pixels, and if a short-distance reference point input error occurs, the real-distance change rate of 0.02 m in the x-axis direction and 0.81 m in y-axis direction is incurred by the subtle input error of 1~11 pixels. According to the long-distance reference point setting variable, the velocity error rate showed the range of fluctuation of at least 14.36% to at most 76.06%, and when calculating flux, it showed a great range of fluctuation of at least 20.48% to at most 78.81%.

Abstract
 1. 서 론
 2. 표면영상유속계(SIV)의 참조점 설정 원리
 3. 연구방법
  3.1. 대상하천
  3.2. 관측자료
  3.3. 참조점 설정에 따른 원거리, 근거리의 변수계산
 4. 결과 및 고찰
  4.1. 원거리, 근거리 변화에 의한 실거리 변화율 계산
  4.2. 표면영상유속계와 Kalesto의 산정유량 비교
 5. 결 론
 감사의 글
 REFERENCES

• 김용석(제주대학교 토목공학과, Department of Civil Engineering, Jeju National University) | Yong-Seok Kim
• 양성기(제주대학교 토목공학과, Department of Civil Engineering, Jeju National University) | Sung-Kee Yang Corresponding author