According to the Center for Construction Research and Training (CPWR) and the Korea Occupational Safety & Health Agency (KOSHA), falls from ladders are a leading cause of fatalities. The current safety inspection process to enforce height-related rules is manual and time-consuming. It requires the physical presence of a safety manager, for whom it is sometimes impossible to monitor an entire area in which ladders are being used. Deep learning-based computer vision technology has the potential to capture a large amount of useful information from a digital image. Therefore, this paper presents a deep learning-based height assessment method using a single known value in an image to measure working height, monitor compliance to safety rules, and ensure worker safety. The proposed method comprises (1) extraction of safety rules from the KOSHA database related to the A-type ladder; (2) object detection (Single Shot Multibox Detector SSD) (3) a height-computing module (HCM) to estimate the working height of the worker (how high a worker is from the ground); and (4) classification of worker behavior (using the developed SSD-based HCM) based on the best practices derived from the KOSHA database. The developed algorithm has been tested on four different scenarios based on KOSHA safety rules, with heights ranging from under 1.2 m to over 2 m. Additionally, the proposed method was evaluated on 300 images for binary classification (safe and unsafe) and achieved an overall accuracy of 85.33%, verifying its feasibility for intelligent height estimation and compliance monitoring.
INDEX TERMS Falls from ladders, vision intelligence-based monitoring, construction safety rules, visionbased height estimation, deep learning.
I. INTRODUCTIONConstruction work is likely to expose workers to hazardous situations because of its distinctive, dynamic, and complex nature. Compared with the workers in other industries, those in the construction industry are more prone to occupational accidents that could potentially lead to fatalities [1]-[3]. The most common construction accidents include fall from height (FFH), collision with objects, electrocution, and being stuckThe associate editor coordinating the review of this manuscript and approving it for publication was Turgay Celik . in between machinery. Among these, FFH is the most frequent cause of accidents at construction sites. According to the U.S. Bureau of Labor Statistics, the number of fatalities due to falls to a lower level increased by 26% from 2011 to 2016, which includes ladders (836 fatal injuries) and rooftops (763). The most common height of a fall was reported as 30 ft (658 deaths) [4]. In addition, the Center for Construction Research and Training (CPWR) reports that ladder (93)-related accidents were a leading cause of fatal injuries from 2011 to 2019 [5]. Moreover, in South Korea, industrial accidents are increasing, with accidents at construction sites
