Heritage documentation and 3D retouching of virtual objects

In this paper we present some results of the use of digital documentation techniques for the characterization and analysis of Cultural Heritage. The used tools (geographic information systems, digital photogrammetry and computer graphics software) allow us to explore new forms of recovery of digital documentation. The typology of objects where these technologies may be applied is diverse, from public artworks to objects integrated into a museological context. For the performed exercises, which were presented in RECH 3, were given as examples objects from the urban parks in the city of Porto, from the National Museum of Soares dos Reis, from the Major Seminary of Our Lady of the Conception of Porto, from the Church of the Holy Spirit in Évora, and from private collectors, among others. The results show that through current digital techniques it is possible to document and characterize in a hyper-realistic manner the surfaces of the works, analyze the degradation phenomena with high accuracy, annotate technological evidences, develop virtual scenarios with infographic profile, reconstruct missing elements of objects, and even make chromatic reintegration on 3D objects. In practice, the actual virtualization works with digital photogrammetry and with recent techniques of computer processing that provide a handy tool for the documentation of heritage works. This kind of virtualization is a strong alternative to documentation made with laser scanning, often costly. Nonetheless, photogrammetry data capture always requires a high technical accuracy in the photographical acquisition and long post-processing elaboration to develop the 3D models.