Measuring changes in cultural heritage objects with Reflectance Transformation Imaging

Manfredi, Marcello; Williamson, Greg; Kronkright, Dale; Doehne, Eric; Jacobs, Megan; Marengo, Emílio; Bearman, Gregory H.

doi:10.1109/digitalheritage.2013.6743730

Cited by 14 publications

(12 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The recording was conducted using a computational photographic technique called Hemispheral Harmonics (HSH) (Manfredi et al ., ), part of a larger family of techniques known as RTI. Over the past decade, RTI has been shown to be a robust and useful technique for surface imaging of cultural heritage and has been deployed to record a wide spectrum of archaeological and conserved artefacts (Malzbender et al ., ; Hammer et al ., : 9; Freeth et al ., ; Earl et al ., ; Gabov and Bevan, ; Klausmeyer, ).…”

Section: Survey Methodsmentioning

confidence: 99%

Recording and Analysis of Ship Graffiti in St Thomas’ Church and Blackfriars Barn Undercroft in Winchelsea, East Sussex, UK

Dhoop

Cooper

Copeland

2016

International Journal of Nautical Archaeology

View full text Add to dashboard Cite

Two assemblages of ship graffiti were recorded using Reflectance Transformation Imaging in the ancient port town of Winchelsea. The engravings show characteristics common to most medieval ship graffiti in England, while displaying different levels of detail, which encouraged a nuanced interpretation. It is suggested that the ship graffiti demonstrate a multifaceted relationship with the sea. The St Thomas’ church graffiti could have been a means of spiritual protection and a devotional practice that cuts across different communities of practice and social groups. The seascape in Blackfriars Barn undercroft can be interpreted as an occasion of informal remembrance of the mustering of a large naval fleet before setting out.

show abstract

Section: Survey Methodsmentioning

confidence: 99%

Recording and Analysis of Ship Graffiti in St Thomas’ Church and Blackfriars Barn Undercroft in Winchelsea, East Sussex, UK

Dhoop

Cooper

Copeland

2016

International Journal of Nautical Archaeology

View full text Add to dashboard Cite

show abstract

“…Manfredi Marcello and et al [11] developed a reliable RTI method for monitoring changes in cultural heritage objects to get detailed information on the object surface. In this work, they captured the RTI and compared the normal vectors to the limits: the method was able to detect the damage automatically.…”

Section: Related Studymentioning

confidence: 99%

Approach to Analysis the Surface Geometry Change in Cultural Heritage Objects

Saha

Foryś

Martusewicz

et al. 2020

Lecture Notes in Computer Science

View full text Add to dashboard Cite

The three-dimensional digitization of the cultural heritage objects during different stages of the conservation process is an important tool for objective documentation. Further data analysis is also important to monitor, estimate and understand any possible change as accurately as possible. In this work, the cultural heritage (CH) objects were selected for 3D scanning, analysis and visualisation of the change or degradation on their surface over time. The main goal of this work is to develop analysis, and visualization methods for CH object to assess local change in their surface geometry to support conservation processes documentation. The analysis was based on geometrical analysis of change in global distance between before and after chemical cleaning for a chosen object. The new local neighborhood distance histogram has been proposed as a local measure of surface change based on optimized k-neighborhood search algorithm to assess the local geometry change of a focus point.

show abstract

“…Examples of applications are in the representation of coins (Mudge et al, 2005) and in archaeology (Earl et al, 2010). RTI can also provide information on physical changes in the surface geometry of the object itself, such as cockling and distortion of parchment (Manfredi et al, 2013). The photometric 'shape from shading' technique was introduced by Woodham (1980) in the context of computer-based image understanding.…”

Section: Prior Workmentioning

confidence: 99%

Metrology Enabled Reflection Transformation Imaging to Reconstruct Local Detail in Manufactured Surfaces

Robson

MacDonald

Sargeant

2020

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

View full text Add to dashboard Cite

Abstract. Understanding the performance of large high performance manufactured structures can require highly accurate dimensional measurement across large volumes with the often conflicting capability to record critical parts of the structure in fine detail. Examples include turbine blades, aircraft wings and off-site manufactured modular structures assembled on-site for city, energy and transport infrastructure. Established large-volume industrial metrology systems such as laser trackers and photogrammetry partially meet the need through the measurement of targets and reflectors, but are limited in capability to record high density local detail needed to capture the finest manufactured features. Whilst large-volume surface sensing is possible with laser radar, photogrammetric pattern projection and contact probing for example, the detail required at a local level typically demands local sensing which generally takes the form of a tracked sensor such as a triangulation laser scanner or hand held touch probe. Local sensing systems face challenges where surfaces have fine detail of similar magnitude to the local sensing system sampling capability and particularly for optical sensors where the light reflected back to the sensor by the surface includes specular reflections compounded by local geometry. This paper investigates how Reflection Transformation Imaging (RTI) with a dome camera and lighting system might be calibrated, characterised and tracked as an alternative technology that is more robust to material surface properties and capable of very fine surface detail capture. Laboratory results demonstrate the capability to characterise and locate the dome to sub-millimetric accuracy within a large-volume tracked space to achieve local surface sampling at the 30 μm × 30 μm level. A method utilising sparse touch probe points to seed conversion of low and high frequency normal maps into a common 3D surface is explored with local agreement with laser tracker surface probe check points to the order of 30 μm.

show abstract

Measuring changes in cultural heritage objects with Reflectance Transformation Imaging

Cited by 14 publications

References 4 publications

Recording and Analysis of Ship Graffiti in St Thomas’ Church and Blackfriars Barn Undercroft in Winchelsea, East Sussex, UK

Recording and Analysis of Ship Graffiti in St Thomas’ Church and Blackfriars Barn Undercroft in Winchelsea, East Sussex, UK

Approach to Analysis the Surface Geometry Change in Cultural Heritage Objects

Metrology Enabled Reflection Transformation Imaging to Reconstruct Local Detail in Manufactured Surfaces

Contact Info

Product

Resources

About