DOI QR코드

DOI QR Code

A Test of a Far Infrared Camera for Development of New Surface Image Velocimeter for Day and Night Measurement

주야간 겸용 표면영상유속계 개발을 위한 원적외선 카메라의 적용성 검토

  • Yu, Kwonkyu (Dept. of Civil Eng., Dong-eui University) ;
  • Kim, Seojun (Dept. of Civil & Environmental Eng, Dankook University) ;
  • Yoo, Byeongnam (Dept. of Civil Eng., Dong-eui University) ;
  • Bae, Inhyuk (Dept. of Civil & Environmental Eng, Myongji University)
  • 류권규 (동의대학교 토목공학과) ;
  • 김서준 (단국대학교 토목환경공학과 연구전담) ;
  • 유병남 (동의대학교 토목공학과) ;
  • 배인혁 (명지대학교 토목공학과)
  • Received : 2015.03.20
  • Accepted : 2015.07.07
  • Published : 2015.08.31

Abstract

In flow velocity measurement of natural rivers, taking images with proper image quality is the fundamental and the most important step. Since flood peaks generally occur in night time, it is very difficult to capture proper images in that time. The present study aims to test a far infra-red camera as a adequate alternative to resolve the various problems in measuring flood discharges. The far infra-red cameras are able to capture images in night time without help of any extra illuminations. Futhermore they are not affected by fog nor smoke, hence they can be adapted for a fixed-type surface image velocimeters. For comparison, a commercial camcorder and a near infra-red cameras were used together. The test images were taken at a day time and a night time, and the image acquisition work were performed at an artificial flow channel of the Andong River Experiment Station. The analyzed results showed that the far infra-red camera would be a good instrument for surface image velocimeters, since they were able to capture regardless light condition. There are, however, a few minor problems in their accuracy of the analyzed results. About their accuracy a more study would be required.

홍수시 하천의 유속 측정을 위한 표면영상유속계에서 가장 기본이 되는 단계는 적절한 영상을 취득하는 것이다. 하지만 영상 획득에 있어 야간에 발생하는 홍수 흐름을 촬영하는 것은 매우 어렵다. 이에 본 연구에서는 표면영상 유속계의 야간 영상 획득 장치로 원적외선 카메라를 이용하는 방안을 검토하였다. 원적외선 카메라는 별도의 조명을 필요로 하지 않으므로, 주야간 모두 영상을 획득할 수 있는 장점이 있다. 또한 안개나 연기의 영향을 받지 않아서 고정식 표면영상유속계를 구성하는 좋은 대안이 될 수 있다. 원적외선 영상을 이용한 유속 산정의 결과를 비교하기 위해, 보통의 가시광 카메라와 근적외선 카메라를 이용한 동시 촬영을 하여 영상을 분석하였다. 아울러 소형 프로펠러 유속계에 의한 유속 측정 자료와 비교하였다. 정확도 분석 결과 원적외선의 주간 영상을 이용할 경우 최소-9%에서 최대 -19%의 오차를 나타냈고, 야간 영상을 이용할 경우 최소 -10%에서 최대 -23%의 오차를 나타냈다. 또한 일반캠코더를 이용한 경우와 비교하여 최대 10% 이내의 차이를 보였기 때문에 주야간 유속 측정에 원적외선 카메라의 적용이 가능한 것을 확인하였다. 다만 주간 영상에 비해 야간 영상이 약간 흐려지는 경향이 있기 때문에, 이러한 영상을 적절히 분석하기 위한 지속적인 연구가 필요할 것으로 생각한다.

Keywords

References

  1. Bigun, J. (2006). Vision with direction, a systematic introduction to image processing and computer vision, Springer.
  2. Etoh, G., Takehara, K., Takano, Y., Fujita, I., Sakai, N., Aya, S., Tamai, M., Miyamoto, H., and Muto, Y. (2002). "Infrared particle tracking velocimetry for applications to measurements of surface velocity fields of rivers." Journal of River Technology, Vol. 8, pp. 465-470. (in Japanese)
  3. Ettema, R., Fujita, I., Muste, M., and Kruger, A. (1997). "Particle-image velocimetry for whole-field measurement of ice velocities." Cold Regions Science and Technology, Vol. 26, pp. 97-112. https://doi.org/10.1016/S0165-232X(97)00011-6
  4. Fujita, I. (2013). "Utilization of far-infrared-ray camera for image-based measurement of river flow and discharge." Nagare, Vol. 32, pp. 347-352. (in Japanese).
  5. Fujita, I., and Tsubaki, R. (2002). "A novel free-surface velocity measurement method using spatio-temporal images." Proc. of Hydraulic Measurements and Experimental Methods, ASCE, on CDROM.
  6. Fujita, I., Hara, H., and Yorozuya, A. (2011). "Measurement accuracy of non-contact discharge measurement method using river monitoring movie and development of quasi real time measurement system." Annual Journal of Hydraulic Engineering, Japan Society of Civil Engineers, Vol. 55, pp. S1177-S1182. (in Japanese).
  7. Fujita, I., Kosaka, Y., Honda, M., Yorozuya, A., and Motonaga, Y. (2013a). "Day and night measurements of snow melt floods by STIV with a far infrared camera." Proceedings of 2013 IAHR Congress.
  8. Fujita, I., Kosaka, Y., Yorozuya, A., and Motonaga, Y. (2013b). "Surface flow measurement of snow melt flood by using a far infrared camera." Journal of Japan Society of Civil Engineers, B1, Vol. 69, No. 4, pp. I_703-I_708. (in Japanese)
  9. Fujita, I., Watanabe, H., and Tsubaki, R. (2005). "Efficient image analysis method for river flow measurement using space-time images." Proc. of XXXI IAHR Congress, pp. 422-428.
  10. Hara, H., and Fujita, I. (2010). "Application of two dimensional Fast Fourier Transform to rive surface flow measurement with space time image." Annual Journal of Hydraulic Engineering, Japan Society of Civil Engineers, Vol. 54, pp. 1105-1110. (in Japanese)
  11. Jahne, B. (1993). Spatio-Temporal Image Processing, Springer, pp. 150-152.
  12. Kim, S., Yu, K. and Yoon, B., (2011). "Real-time discharge measurement of the river using fixed-type surface image velocimetry." Journal of Korea Water Resources Association, Vol. 44, pp. 377-388. (in Korean) https://doi.org/10.3741/JKWRA.2011.44.5.377
  13. Kim, S., Yu, K., and Yoon, B. (2010). "Development of a velocity measurement method at night time using an infrared camera." Proc. of 2010 Annual Conference, KWRA. (in Korean)
  14. Kim, Y., Noh, J. and Choi, K. (2014) "Development of microwave water surface current meter for general use to increase efficiency of measurements of river discharges," Journal of the Korean Society of Limnology, Vol. 47, No. 3, pp. 225-231 (in Korean)
  15. Kim, Y., Yang, S., Yu, K., and Kim, D. (2015). "Comparative Analysis of Day and Night Time Video Accuracy to Calculate the Flood Runoff Using Surface Image Velocimeter (SIV)." Journal of Environmental Science International, Vol. 24, No. 4, pp. 359-369. (in Korean) https://doi.org/10.5322/JESI.2015.24.4.359
  16. K-Water (1994). Development of measurement facilities for stream discharge (Development of a microwave surface velocity meter and supersonic correlation current meter). WRRI-WR-94-1. (in Korean)
  17. K-Water (2008). Development of All-time Discharge Measuring System Using Microwave Water Surface Current Meter (2nd yr). KIWE-HRC-08-01. (in Korean)
  18. K-Water (2010). Improvement of Accuracy on Discharge Measurement Using Surface Velocity, KWI-WR-10-01. (in Korean)
  19. Miyamoto, H. (2007). "Basic performance evaluation of water-surface ripples as a visualization tracer for the local remote sensing of river flows." Journal of the Japan Society of Civil Engineers, Vol. B63, No. 4, pp. 357-367. (in Japanese)
  20. Raffel, M., Willert, C., Wereley, S., and Kompenhans, J. (2007). Particle image velocimetry, a practical guide, Springer.
  21. Saito, H., Hagihara, T., Hatanaka, K., and Sawai, T. (2007). "Development of pedestrian detection system using far-infrared-ray (FIR) camera." SEI Technical Review, Vol. 171, pp. 80-85.
  22. Yamaguchi, T., and Niizato, K. (1994). "Flood discharge observation using radio current meter." Journal of Japan Society of Civil Engineers, No. 497/II-28, pp. 41-50. (in Japanese)
  23. Yu, K., Kim, S., and Yoon, B. (2014). "Measurement of two-dimensional velocity distribution of spatiotemporal image velocimeter using cross-correlation analysis." Journal of Korea Water Resources Association, Vol. 47, No. 6, pp. 537-546. (in Korean) https://doi.org/10.3741/JKWRA.2014.47.6.537

Cited by

  1. Development of a real-time surface image velocimeter using an android smartphone vol.49, pp.6, 2016, https://doi.org/10.3741/JKWRA.2016.49.6.469
  2. Applications of unmanned aerial vehicles in fluvial remote sensing: An overview of recent achievements 2017, https://doi.org/10.1007/s12205-017-1862-5