Articles by Geneviéve Lucet

In this article the authors present a method for obtaining a line-art representation of a mural painting using colour photography. First, the information concerning colour components was separated and then the contours of graphic representations were extracted. The result is an exact copy of the original and this level of precision makes it an important solution to the problem of registering and recording mural paintings. This method has been shown to be a useful solution for the documentation of the state of conservation of paintings, as well as a means for keeping track of restoration work; furthermore, it provides a fundamental method for analysing paint compositions. The approach was developed bearing in mind the possibility of use by non-specialist computer users: no programming knowledge is assumed and the use of shareware software was always preferred.

Besides allowing the visualisation of architecture from the past through the use of images, either virtual or real, virtual restitution in architecture implies the use of analytical methodologies that serve the purpose of a better understanding of architectural space as well as its genesis. The restitution contributes both to the process of building an appropriate tridimensional model adequate for multiple uses, and to the output of new information as the restitution process develops. In the present work, the applied methodological approach is discussed in relation to a virtual restitution of the Mesoamerican archaeological site of Cacaxtla leading to an idealisation of its original condition.

A discussion is made about the problem of the graphic registering of a large mural, symbol of the Mexican culture of the fifties. Vantages of digital information are well known. Nevertheless, digitization of a 3712 m2 mural in order to capture information of the state of the mural before and after restoration, and analyse damages applying image processing tools, oblige to a solution that takes into account the particularities of the problem. The solution must ensure high precision of the survey to be a tool for restorators and must control general snapshot conditions to obtain images with equal characteristic that will allow the repetition of the same algorithm for the "Computer Aided Restoration" step. How were selected pixel definition, image size, camera location, image acquisition and digitization systems, and enlightenment condition was controlled? These are the topics developed in the present work.