A modular and low-cost portable vSLAM system for real-time 3D mapping: from indoor and outdoor spaces to underwater environments

The bond with computer vision and robotics is revolutionizing the traditional surveying approaches. Algorithms such as visual odometry and SLAM are embedded in surveying systems to make on-site and processing operations more efficient both in terms of time and quality of the achieved results. In this paper, we present the latest developments on GuPho, a mobile mapping concept based on photogrammetry that leverages a vSLAM solution to provide innovative and unique features supporting the image acquisition and optimising the processing steps. These include visual feedback on ground sample distance and maximum allowed speed to avoid motion blur. Two efficient image acquisition strategies, based on geometric principles, are implemented to optimise the disk storage, avoiding unnecessary redundancy. Moreover, an innovative automatic exposure control that adjusts the shutter speed or gain based on the tracked object in 3D is part of the system. The paper reports the motivations behind the design choices, details the hardware and software components, discusses several case studies to showcase the potentialities of our low-cost, lightweight, and portable modular prototype system.