In this paper, we present BoostHDR, a novel method for compressing high dynamic range (HDR) images. The
algorithm leverages on a novel segmentation-based tone mapping operator (TMO) which relaxes the no seams
constraint. Our method can work with both JPEG and JPEG2000 encoders. Moreover, it provides better results
compared to the state of the art in HDR images compression algorithms in terms of bit per pixels (bpp), and
visual quality using objective metrics.
We present a methodology, based on 3D scanned digital models, for measurement and monitoring wood deformations,
caused by weather changes, in the trees of the fossilized Dunarobba forest. The Dunarobba forest, located
in the central part of Italy, was discovered recently after some excavations to dig clay for bricks manufacturing.
The removal of the clay mass exposed the wood to the weather conditions, initiating a process of degradation.
Different conservation methodologies have been proposed and the choice of the best fitting one has to be validated
by means of an objective and measurable methodology. Monitoring the geometric variation of the wood trunks
trough comparison of periodic 3D scanning campaign will be used to evaluate the current degradation rate and
assess the effectiveness of the proposed conservation techniques.
A new prospective for the study, documentation and presentation of Cultural Heritage is opened by the joint usage of the tools for the automatic reconstruction of digital 3D models and the instruments for interactive 3D visualization. New techniques are available to perform high-resolution sampling of both the shape and the multi-band reflection properties of painted surfaces. The digital 3D models produced are extremely accurate and rich of information, as it has been proved in the experiments run on the Leonardo's Madonna of the
Yarnwinder. This paper presents an overview of the techniques needed to build high-quality 3D models from the raw data produced by the scanning devices and describes how to process those models to make them usable in interactive applications. A very critical point is how to integrate the reflection properties with 3D shape models; this integration (based on texture mapping) allows us to produce textured 3D models that allow a joint visualization of shape and color attributes. The interactive visualization tools developed by ISTI-CNR are described, presenting both their features and potential for the visual presentation and analysis of works of art. Examples of the results obtained on the Madonna of the Yarnwinder are presented.
Offine rendering techniques have nowadays reached an astonishing level of realism but paying the cost of a long computational time. The new generation of programmable graphic hardware, on the other hand, gives the possibility to implement in realtime some of the visual effects previously available only for cinematographic production. In a collaboration between the Visual Computing Lab (ISTI-CNR) with the Institute for Creative Technologies of the University of Southern California, has been developed a realtime demo that replicate a sequence from the short movie "The Parthenon" presented at Siggraph 2004. The application is designed to run on an immersive reality system, making possible for a user to perceive the virtual environment with a cinematographic visual quality. In this paper we present the principal ideas of the project, discussing design issues and technical solution used for the realtime demo.
The increasing rate of growth in size of currently available
datasets is a well known issue. The possibility of developing fast
and easy to implement frameworks able to visualize at least part
of a tera-sized volume is a challenging task. Several techniques
have been proposed in recent years ranging from simplification to
wavelet analysis. Subdivision methods have been one of the most
successful techniques applied to the multi-resolution
representation and visualization of surface meshes. Extensions of
these techniques to the volumetric case presents positive effects
and major challenges mainly concerning the generalization of the
combinatorial structure of the refinement procedure and the
analysis of the smoothness of the limit mesh. In this paper we
address mainly the first part of the problem, presenting a
framework that exploits a subdivision scheme suitable for
extension to 3D and higher dimensional meshes. We introduce a
technique that combines the flexibility of a progressive
multi-resolution representation with the advantage of a recursive
subdivision scheme. The main contributions of the paper are: (a) a
progressive algorithm that builds a multi-resolution surface by
successive refinements so that a consistent representation of the
output is always available (b) a multi-resolution representation
where any adaptively selected level of detail is guaranteed to be
consistently embedded in 3D space (no self-intersections).
The measurement of the shape of an artwork usually requires a high-resolution instrumentation, in order to catch small details such as chisel marks, sculptural relieves, surface cracks, etc. 3D scanning techniques, together with new modeling software tools, allow a high fidelity reproduction of an artwork: these can be applied either to support and document its repair or for the realization of 3D archives and virtual museums. Starting from a high-resolution digital model of an object, a further step could be its reproduction by means of fast-prototyping techniques like stereo-lithography or electro-erosion. This work is aimed at showing the performance of a high-resolution laser scanner devoted to Cultural Heritage applications. The device is portable and very versatile, in order to allow in situ applications, accurate and reliable, so to capture intricate details. This laser profilometer has been used in a few surveys, the most significant of which are the monitoring the various phases of the restoration process of an ellenistic bronze (the Minerva of Arezzo, Florence), the cataloguing of some archaeological findings (from the Grotta della Poesia, Lecce) and the documenting of wooden panels surface conditions (the “Madonna del Cardellino” by Raffaello and “La Tebaide” by Beato Angelico).
Modern 3D scanning technologies allow to reconstruct 3D digital representations of Cultural Heritage artifacts in a semi-automatic way, characterized by very high accuracy and wealth of details. The availability of an accurate digital representation opens several possibilities of utilization to experts (restorers, archivists, museum curators), or to ordinary people (students, museum visitors). 3D scanned data are commonly used for the production of animations, interactive visualizations, or virtual reality applications. A much more exciting opportunity is to use these data in the restoration of Cultural Heritage artworks. The integration between 3D graphic and restoration represents an open research field where many new supporting tools are required; the David restoration project has given several starting points and guidelines to the definition and development of innovative solutions. Digital 3D models can be used in two different but not subsidiary modes: as an instrument for the execution of specific investigations and as a supporting media for the archival and integration of all the restoration-related information, gathered with the different studies and analysis performed on the artwork. In this paper we present some recent work done in the framework of the Michelangelo's David restoration project. A 3D model of the David was reconstructed by the Digital Michelangelo Project, using laser-based 3D scanning technology. We have developed some tools to make those data accessible and useful in the restoration. Preliminary results are reported here together with some directions for further research.
SICAR is an internet-based system for the management of the
information gathered during restoration analysis and intervention
(alphanumeric and raster data), which is mapped and geo-referenced
to 2D or 3D models. Joining the skills of a set of multidisciplinary partners, an integrated and innovative system will be developed, to permit to link to an accurate 2D or 3D model of the monument under restoration all the data gathered during the restoration analysis and intervention [raster images, document in TXT format, hypertext (HTML) or semi-structured text (XML)]. As far concerns semi-structured texts, a software module will automatically process documents, extracting their structure. SICAR will be developed to be completely accessible via web, for data entry and displaying, and will be suitable to wireless and intranet connection (GPRS, Bluetooth, etc.), in order to document the status of the objects to be restored, in restoration sites or laboratories. In this way data will be accessible even with low-speed connection.