Generating 3D Models of Paintings through the Combination of 2D, 3D and RTI Data

Abstract

The National Gallery in London has recently been testing the potential of 3D scanning technology to record and measure the surface of paintings. To view and interact with the high-resolution scans requires expensive computational hardware. The proposed workflow borrows some of the techniques used in the gaming industry to provide a computationally efficient interactive interface, even suitable for online viewing. The workflow synergises multiple imaging techniques, and therefore provides better texture representation than 3D scanning alone. The process provides a new way of visualising possible relations across paint layers by combining normal maps with existing image based techniques. 3D laser scanning. 3D models. 3D visualisation. Normal maps. Reflectance transformation imaging. Paintings.

Printing the light

“…Some measurement devices work well in acquiring complex geometries but do not provide colour information. Reflectance transformation imaging (RTI) uses computational photography method that captures surface texture and colour of an object and provides 3D virtual information using traditional photographic techniques and presents some opportunity for exploitation for reproduction 5 …”

“…Reflectance transformation imaging (RTI) uses computational photography method that captures surface texture and colour of an object and provides 3D virtual information using traditional photographic techniques and presents some opportunity for exploitation for reproduction. 5 In principle, red, green, and blue are the primary colours from which all the other colours can be derived and mixing these colours produces the (complementary) secondary colours-cyan, magenta, and yellow (CMY) which each reflects one-third of the spectrum. In schools, we are taught red, yellow and blue are the primary colours.…”

A Review of RTI and an Investigation into the Applicability of Micro-RTI as a Tool for the Documentation and Conservation of Modern and Contemporary Paintings

“…The Lucida scanner recorded data from the test painting (15 cm x 22 cm) in one scan in approximately 20 minutes, however this did not include the post processing which took approximately two hours. The post processed data from the Lucida Scanner was converted to an RTI file, to allow a direct comparison of the texture and feature detection of the two systems (Aure et al, 2017). The RTI image obtained from the Lucinda scanner did not contain the smattered blue paint that had leaked over the crisp edge (figure 8), which is clearly visible in the comparative renderings of the same area using micro-RTI.…”

From the Engraved Tablet to the Digital Tablet, History of a 15th-Century Music Score

“…It is a computational photographic method that captures a subject's surface shape and color from a series of frontal photographs under different artificial lighting and enables the interactive re-lighting of the subject from any direction [Malzbender et al 2001]. This technology is particularly useful in the context of objects with light relief such as paintings [Aure et al 2017]. It was thus well suited for the engraved tablet with its very thin carving.…”