ArUco 마커를 활용한 영상기반 구조물의 변위 계측 및 동특성 평가 = Vision-Based Structural Displacement Measurement and Dynamic Characteristic Evaluation Using Aruco Markers

다국어 초록 (Multilingual Abstract)

Recently, vision-based measurement techniques have gained attention as an alternative to conventional contact type sensors for structural health monitoring due to their advantages in non-contact measurement, low cost, and ease of installation. This study developed a vision-based displacement measurement system using ArUco markers and evaluated its applicability for measuring structural displacement and extracting structural dynamic characteristics.
To improve measurement accuracy, camera calibration was performed using OpenCV and checkerboard patterns. The calibration results showed an average reprojection error of approximately 0.3069 pixels. Laboratory experiments were conducted using an Al6061 simply supported beam specimen equipped with an ArUco marker, Laser Doppler Vibrometer, and accelerometer. Static loading tests demonstrated strong agreement between vision based and LDV measurements. Dynamic response tests and FFT analysis showed dominant frequencies of approximately 20Hz, with less than 0.23% difference between acceleration based and vision based measurements.
To validate the experimental results, modal analysis was performed using Abaqus. The predicted natural frequencies showed less than 2% difference from the experimental results. Furthermore, field load tests were conducted on Tosan Bridge under vehicle speeds of 10 km/h and 20 km/h. The vision-based measurements exhibited similar displacement responses and natural frequency results compared with conventional sensors. In particular, under the 20 km/h condition, the difference between acceleration-based and vision-based natural frequencies was approximately 0.03 Hz.
The results indicate that the proposed ArUco marker-based vision measurement system can effectively measure structural displacement and identify structural dynamic characteristics, demonstrating its potential applicability for structural health monitoring of real structures.

목차 (Table of Contents)

• 제 1 장 서 론 1
• 1.1 연구배경 및 목적 1
• 1.2 국내·외 연구동향 2
• 1.3 연구내용 및 방법 4
• 제 2 장 이론적 배경 5
• 2.1 구조물의 진동 및 주파수 해석 5
• 2.1.1 진폭, 진동수 및 위상각 5
• 2.1.2 변위, 속도 및 가속도의 관계 6
• 2.1.3 푸리에 변환 8
• 2.2 영상기반 변위 계측 9
• 2.2.1 영상기반 변위 계측 시스템 9
• 2.2.2 ArUco 마커 기반 변위 추정 기법 11
• 2.2.3 카메라 캘리브레이션 14
• 제 3 장 영상기반 변위 계측 실험 18
• 3.1 실험 개요 18
• 3.2 계측 시스템 구성 18
• 3.2.1 단순보 실험체 18
• 3.2.2 영상기반 변위 계측 19
• 3.2.3 계측장비 21
• 3.3 카메라 캘리브레이션 24
• 3.3.1 카메라 캘리브레이션 결과 27
• 3.3.2 재투영 오차 분석 28
• 3.3.3 캘리브레이션 결과 분석 30
• 3.4 실내 모형 실험 30
• 3.4.1 정적 변위 계측 30
• 3.4.2 동적 응답 계측 및 고유진동수 분석 34
• 3.5 모드해석 41
• 3.5.1 모드해석 개요 41
• 3.5.2 모드해석 결과 42
• 3.5.3 실험 및 모드해석 결과 비교 43
• 3.6 교량 재하시험 44
• 3.6.1 재하시험 개요 44
• 3.6.2 재하시험 결과 48
• 3.6.3 결과분석 및 고찰 53
• 제 4 장 결론 56
• 참 고 문 헌 58