Reverse engineering using close range photogrammetry for additive manufactured reproduction of Egyptian artefacts and other objets d'art

Kaufman, John and Rennie, Allan and Clement, Morag (2014) Reverse engineering using close range photogrammetry for additive manufactured reproduction of Egyptian artefacts and other objets d'art. In: Proceedings of the ASME 2014 12th Biennial Conference on Engineering System Design and Analysis (ESDA 2014) : Volume 1: Applied Mechanics; Automotive Systems; Biomedical Biotechnology Engineering; Computational Mechanics; Design; Digital Manufacturing; Ed. American Society of Mechanical Engineers (ASME), DNK. ISBN 9780791845837

Abstract

Photogrammetry has been used for recording objects for well over one hundred and fifty years. This research considers how digital image capture can be used, with the aid of a medium range Digital SLR camera, and transformed into 3D virtual spatial images, and together with additive manufacturing (AM) technology, geometric representations of the original artefact can be fabricated. The research has focused on the use of photogrammetry as opposed to laser scanning (LS), investigating the shift from LS use to a Digital Single Lens Reflex (DSLR) camera exclusively. The basic photogrammetry equipment required is discussed, with the main objective being simplicity of execution for eventual realisation of physical products. As the processing power of computers has increased and become widely available, at affordable prices, software programs have improved, so it is now possible to digitally combine multi-view photographs, taken from 360°, into 3D virtual representational images. This has now led to the possibility of 3D images being created without LS intervention. Two methods of digital data capture are employed and discussed, together with the specific operating conditions in which to photograph the objects. The first part of the process was the acquisition of the digital data images using the DSLR camera. According to the type of processing software employed, some 60 – 150 images were taken from different angles, for the digital data sets needed for processing, ensuring that there was an image overlap of about 10-20%. The images were taken using a mid-range resolution of 4608 x 3074 pixels, on a Nikon 3100 DSLR camera. Three case studies are documented, the first being the reproduction of a small modern clay sculpture, whilst the other two case studies deal with 3000 year old Egyptian clay artefacts from the Kendal Museum, Cumbria (UK). All three objects were successfully recreated using AM technology, one was recreated on a Fused Deposition Modelling (FDM) printer, one on a Selective Laser Sintering (SLS) machine, and the third on a colour Selective Deposition Lamination (SDL) machine. It has been shown that with the use of a standard DSLR camera and the minimum amount of computer software manipulation, 2D images can be converted not only into 3D virtual video replicas but with the use of AM technology, into solid, geometric representation of the originals.