PURPOSES : This study aimed to perform real-time on-site construction volume management by using Internet of things (IoT) technology consisting of 3D scanning, image acquisition, wireless communication systems, and mobile apps for new and maintenance construction of concrete bridge deck overlays. METHODS : LiDAR was used to scan the overlay before and after construction to check the overlay volume. An enhanced inductively coupled plasma (ICP) method was applied to merge the LiDAR data scanned from multiple locations to reduce noise, and an anisotropic filter was applied for efficient three-dimensional shape modeling of the merged LiDAR data. The construction volume counter of the mobile mixer was directly photographed using an IP camera, and the data were transmitted to a central server via the LTE network. The video images were transmitted to the central server and optical character recognition (OCR) was used to recognize the counter number and store it. The system was built such that the stored information could be checked in real time in the field or at the office. RESULTS : As a result of using LiDAR to check the amount of overlay construction, the error from the planned amount was 0.6%. By photographing the counter of the mobile mixer using an IP camera and identifying the number on the counter using OCR to check the quantity, the results showed that there was a 2% difference from the planned quantity. CONCLUSIONS : Although the method for checking the amount of construction on site using LiDAR remains limited, it has the advantage of storing and managing the geometric information of the site more accurately. Through the IoT-based on-site production management system, we were able to identify the amount of concrete used in real time with relative accuracy.

1. 서론
2. LiDAR를 활용한 시공현장의 3D 스캔
    2.1. LiDAR의 원리
    2.2. LiDAR의 자료의 중첩
    2.3. LiDAR 자료의 3D 모델링
    2.4. LiDAR를 통한 3D 스캔 실내 성능평가
3. 광학 문자 인식 및 IoT 기술을 활용한 시공물량의실시간 자료화
    3.1. 광학 문자 인식
    3.2. 실시간 생산량 현장관리를 위한 무선시스템
    3.3. 실시간 생산량 현장관리 및 광학 문자 인식 시스템의 성능평가
4. 현장 시험
    4.1. 현장 시험시공 개요
    4.2. 3D 스캔 시공관리 시스템 현장 성능평가
    4.3. IoT 기반 현장 생산량 관리 시스템의 현장평가
5. 결론
REFERENCES

• 민경환(㈜건설재료시험연구소 책임연구원, 공학박사) | Min Kyunghwan
• 임진선(㈜건설재료시험연구소 이사, 공학박사) | Lim Jinsun
• 이시욱(숭실사이버대학교 건설시스템공학과 조교수, 공학박사) | Lee Siwook (Ph.D., Assistant Professor, Dept. of Construction System Engineering, Korea Soongsil Cyber University, Seoul 03132, Korea) Corresponding author