Cultural heritage interactive 3D models on the web: An approach using open source and free software

Cultural heritage sites and artefacts get a significant added value from high-resolution 3D models. These models are increasingly available due to improvements in technology and to higher integration of survey techniques such as laser scanning and photogrammetry. In this paper we present a case study on the development of a web-based application for user access and interactive exploration of three-dimensional models by providing integrated geometrical and non-geometrical information into an intuitive interface. The main feature of this interactive system is to provide the user with a completely new visit experience based on a free interactive exploration interface of the object (i.e., not constrained by any predefined pathway) and on the opportunity to get more detailed information on specific parts of interest. A parallel aim achieved was to use, in data processing and in the architecture, open source tools and free software, thus providing full transparency on adopted methodology and data processing methods, and a cost effective solution both for server and client. Furthermore, the aspect of data size has been considered using a segmentation and simplification scheme and server-side data management to keep transmission size to a minimum, thus improving access speed.     

公元439年:河陇地域学术发展的转捩点

永嘉之乱中原流民迁入河陇及北魏太延五年河西士族东迁平城,这两次移民事件,对河陇学术的影响截然不同,这种不同不仅仅局限在人口的迁出与迁入这一层面上。以移民迁入河陇来说,学者们所热衷于讨论的永嘉移民使中原学术转移保存于河陇说,实际上是对陈寅恪学术观点的误读。陈寅恪先生所论是指文化重心转移而非移民所带来的文化之转移。而河西士人东迁平城后,又因他们的境遇很差,对北魏的贡献也大打折扣。相反的,河西士族被竭泽式的迁出,对于河陇,特别是对河西学术的影响却是灾难性的,河陇地域学术五百多年以来所形成的士族模式和地域格局因之发生了转折。     

An integrated and automated segmentation approach to deteriorated regions recognition on 3D reality-based models of cultural heritage artifacts

In the field of Cultural Heritage, image analysis represents an indispensable practice for restorers to collect information about the state of preservation of monuments and artifacts and plan restoration interventions. In addition, during the last two decades, the wide spread of remote sensing technologies and the possibility to build 3D reality-based models of artifacts allow the extension of image analysis to 3D environments. In this context, the purpose of this contribution is to show the results of investigations held in order to provide a methodology for the automatic detection of deteriorated areas within architectures and artifacts using colour images as a field of examination. Using both 2D and 3D segmentation approaches, our methodology aims at speeding and efficiently performing the automatic detection of deteriorated zones within Cultural Heritage and therefore segment 3D digital models acquired using different survey technologies. Within our investigations, we selected case studies concerning recurrent deteriorations, such as, for example, detachments, cracks and chromatic alterations; we run them both to manual and to automatic recognition and selection tests, in order to compare the results obtained using these approaches and evaluate the reliability of the automatic one. Results comparison included computational and user time, quantification of the deteriorated area error between manual and automatically detected zones. Additional parameters characterizing the specific type of deteriorations were also computed for each case study. Comparison between the automatic and the manual procedure showed that the automatic detection is faster and reliable in all our selected case studies, with evident improvements in the efficient evaluation of the entity and extension of deteriorated areas on 3D geometry.