Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
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Predicting Unsaturated Soil Water Content Using CIELAB Color System-based Soil Color

CIELAB 색 표시계 기반 토색을 활용한 불포화토 함수비 예측 연구

  • Baek, Sung-Ha (School of Civil and Environmental Engineering & Construction Engineering Research Institute, Hankyong National Univ.) ;
  • Park, Ka-Hyun (Korea Institute of Civil Engr. and Building Tech.) ;
  • Jeon, Jun-Seo (Korea Institute of Civil Engr. and Building Tech.) ;
  • Kwak, Tae-Young (Korea Institute of Civil Engr. and Building Tech.)
  • 백성하 (한경대학교 건설환경공학부) ;
  • 박가현 (한국건설기술연구원 지반연구본부) ;
  • 전준서 (한국건설기술연구원 지반연구본부) ;
  • 곽태영 (한국건설기술연구원 지반연구본부)
  • Received : 2023.01.31
  • Accepted : 2023.02.07
  • Published : 2023.02.28
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Abstract

A study was conducted to use soil color obtained from digital im ages as an indicator of soil water content. Digital images of Jumoonjin standard sand with five different water contents were captured under nine different lighting conditions. Through digital image processing, the soil color of the sample was obtained based on the CIELAB color system, and the effect of lighting conditions and water content on the soil color was analyzed. The results indicated that L* showed a high correlation with illuminance, whereas a* and b* showed a high correlation with color temperature. As the water content increased, L*, which represents the brightness of the soil color, decreased, and a* and b* increased. Therefore, the soil color changed from green and blue to red and yellow. Based on the regression analysis results of lighting conditions, water content, and soil color, a water content predicting method based on the soil color of silica-based sand photographed under irregular light conditions was proposed. The proposed method can predict the water content with a m axim um error of 0.29%.

본 연구는 흙의 디지털 이미지로부터 획득된 토색을 기반으로 함수비를 예측하기 위한 기초단계로서 수행되었다. 서로 다른 다섯 가지 함수비로 조성된 주문진표준사 시료를 대상으로 광조건을 아홉 번 씩 바꿔가며 디지털 이미지를 촬영했다. 디지털 이미지 프로세싱을 통해 촬영된 시료의 토색을 CIELAB 색 표시계를 기반으로 획득하고, 광조건과 함수비에 따른 토색 변화를 분석했다. 그 결과, 불포화토의 토색 L* 값은 조명의 조도와 높은 상관성을 보였고 a*와 b* 값은 조명의 색온도와 높은 상관성을 보였다. 또한 함수비가 증가하면 토색의 밝기를 나타내는 L*가 감소하고, a*와 b*는 증가하여 토색이 초록과 파랑에서 멀어지고 빨강과 노랑에 가까워졌다. 광조건 및 함수비와 토색의 회귀분석 결과를 종합해 불규칙한 광조건에서 촬영된 실리카 계열의 모래의 토색을 기반으로 함수비를 예측하는 방법을 제안했으며, 제안된 방법을 통해 최대 오차 0.29% 수준으로 함수비를 예측할 수 있음을 확인했다.

Keywords

Acknowledgement

본 연구는 과학기술정보통신부 한국건설기술연구원 연구운영비지원(주요사업)사업으로 수행되었으며(과제번호 20230096-001, 지반분야 재난재해 대응과 미래 건설산업 신성장을 위한 지반 기술 연구), 이에 깊은 감사를 드립니다.

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