Development of a Photogrammetric 3D Measurement System for Small Objects Using Raspberry Pi Cameras as Low-Cost Sensors

Abstract

The digitisation of cultural objects in museums presents two distinct opportunities. Firstly, it allows for the preservation of the objects and collections themselves. Secondly, it enables their accessibility to the general public as 3D models in virtual exhibitions on the Internet. Cultural artefacts of significance can be recorded using laser scanners, 3D handheld scanners or photogrammetry employing the structure-from-motion method. In order to efficiently record and model the considerable number of culturally significant objects, automated recording systems and automated evaluation processes are required. This article presents a low-cost photogrammetric measurement system developed at HafenCity University Hamburg. The system comprises 24 Raspberry Pi cameras mounted on an aluminium frame, which enables the automatic and time-synchronous digitisation of small objects. To ascertain the veracity of the point clouds generated for the test objects, a comparison was conducted with the reference data obtained from the high-precision ATOS 5 structure light projection system. It was established that comprehensive coverage and a high degree of precision could only be achieved through the incorporation of a turntable and supplementary images of the objects, necessitated by minor rotations. The configuration of the photogrammetric low-cost measurement system and the requisite camera calibrations are delineated in the article.