Experimental evaluation of camera position and 3D modeling accuracy in in-air imaging within a simulated culvert environment

Abstract

This study investigates the use of a floating device autonomously propelled by water flow to capture in-air images for 3D modeling of culvert channels, which are challenging to survey due to their confined geometry. The device, equipped with an upward-facing camera, captures images of the interior surfaces to generate 3D point clouds. However, lateral fluctuations in the platform’s position under hydrodynamic forces lead to varying distances between the camera and the interior of the channel, affecting reconstruction accuracy. Experiments were conducted under different camera positions and flow conditions to evaluate spatial coverage and density. Results showed that the extent of point cloud generation varied significantly with camera position, especially at higher speeds. These findings highlight the impact of camera alignment and operational parameters on the completeness and quality of 3D models in culvert inspections.