2013
Doctoral thesis
Restricted
Surface Appearance Estimation from Video Sequences
Palma G.
The realistic virtual reproduction of real world objects using Computer Graphics techniques requires the accurate acquisition and reconstruction of both 3D geometry and surface appearance. Unfortunately, in several application contexts, such as Cultural Heritage (CH), the reflectance acquisition can be very challenging due to the type of object to acquire and the digitization conditions. Although several methods have been proposed for the acquisition of object reflectance, some intrinsic limitations still make its acquisition a complex task for CH artworks: the use of specialized instruments (dome, special setup for camera and light source, etc.); the need of highly controlled acquisition environments, such as a dark room; the difficulty to extend to objects of arbitrary shape and size; the high level of expertise required to assess the quality of the acquisition. The Ph.D. thesis proposes novel solutions for the acquisition and the estimation of the surface appearance in fixed and uncontrolled lighting conditions with several degree of approximations (from a perceived near diffuse color to a SVBRDF), taking advantage of the main features that differentiate a video sequences from an unordered photos collections: the temporal coherence; the data redundancy; the easy of the acquisition, which allows acquisition of many views of the object in a short time. Finally, Reflectance Transformation Imaging (RTI) is an example of widely used technology for the acquisition of the surface appearance in the CH field, even if limited to single view Reflectance Fields of nearly flat objects. In this context, the thesis addresses also two important issues in RTI usage: how to provide better and more flexible virtual inspection capabilities with a set of operators that improve the perception of details, features and overall shape of the artwork; how to increase the possibility to disseminate this data and to support remote visual inspection of both scholar and ordinary public.
Palma G.
The realistic virtual reproduction of real world objects using Computer Graphics techniques requires the accurate acquisition and reconstruction of both 3D geometry and surface appearance. Unfortunately, in several application contexts, such as Cultural Heritage (CH), the reflectance acquisition can be very challenging due to the type of object to acquire and the digitization conditions. Although several methods have been proposed for the acquisition of object reflectance, some intrinsic limitations still make its acquisition a complex task for CH artworks: the use of specialized instruments (dome, special setup for camera and light source, etc.); the need of highly controlled acquisition environments, such as a dark room; the difficulty to extend to objects of arbitrary shape and size; the high level of expertise required to assess the quality of the acquisition. The Ph.D. thesis proposes novel solutions for the acquisition and the estimation of the surface appearance in fixed and uncontrolled lighting conditions with several degree of approximations (from a perceived near diffuse color to a SVBRDF), taking advantage of the main features that differentiate a video sequences from an unordered photos collections: the temporal coherence; the data redundancy; the easy of the acquisition, which allows acquisition of many views of the object in a short time. Finally, Reflectance Transformation Imaging (RTI) is an example of widely used technology for the acquisition of the surface appearance in the CH field, even if limited to single view Reflectance Fields of nearly flat objects. In this context, the thesis addresses also two important issues in RTI usage: how to provide better and more flexible virtual inspection capabilities with a set of operators that improve the perception of details, features and overall shape of the artwork; how to increase the possibility to disseminate this data and to support remote visual inspection of both scholar and ordinary public.
See at:
etd.adm.unipi.it 
| CNR ExploRA
2012
Conference article
Restricted
Insourcing, outsourcing and crowdsourcing 3D collection formation: perspectives for cultural heritage sites
Kaminski J., Echavarria K. R., Arnold D., Palma G., Scopigno R., Proesmans M., Stevenson J.
This paper presents three different propositions for cultural heritage organisations on how to digitise objects in 3D. It is based on the practical evaluation of three different deployment experiments that use different methods and business models for mass 3D-acquisition. These models are: developing the skills of in-house staff within an organisation, the use of external professionals and using crowdsourcing as a mechanism for developing the 3D collection. Furthermore, the paper provides an analysis of these models, lessons learned and practical recommendations for cultural heritage organisations. The analysis includes considerations of issues such as strategy, size of the organisation, skills, equipment, object accessibility and complexity as well as the cost, time and quality of the 3D technology. The paper concludes that most organisations are able to develop 3D collections but variations in the result will be reflected by the strategic approach they place on innovative 3D technologiesSource: The 13th International Symposium on Virtual Reality, Archaeology and Intelligent Cultural Heritage, pp. 81–88, Brighton, 19-21 November 2012
DOI: 10.2312/vast/vast12/081-088
Project(s): 3D-COFORM
Metrics:
Kaminski J., Echavarria K. R., Arnold D., Palma G., Scopigno R., Proesmans M., Stevenson J.
This paper presents three different propositions for cultural heritage organisations on how to digitise objects in 3D. It is based on the practical evaluation of three different deployment experiments that use different methods and business models for mass 3D-acquisition. These models are: developing the skills of in-house staff within an organisation, the use of external professionals and using crowdsourcing as a mechanism for developing the 3D collection. Furthermore, the paper provides an analysis of these models, lessons learned and practical recommendations for cultural heritage organisations. The analysis includes considerations of issues such as strategy, size of the organisation, skills, equipment, object accessibility and complexity as well as the cost, time and quality of the 3D technology. The paper concludes that most organisations are able to develop 3D collections but variations in the result will be reflected by the strategic approach they place on innovative 3D technologiesSource: The 13th International Symposium on Virtual Reality, Archaeology and Intelligent Cultural Heritage, pp. 81–88, Brighton, 19-21 November 2012
DOI: 10.2312/vast/vast12/081-088
Project(s): 3D-COFORM
Metrics:
See at:
diglib.eg.org | CNR ExploRA
2014
Conference article
Unknown
Storytelling of a coin collection by means of RTI images: the case of the Simoneschi Collection in Palazzo Blu
Palma G., Baldassarri M., Favilla M. C., Scopigno R.
Reflectance Transformation Imaging (RTI) is a technique that captures a subject's surface shape and color and enables the interactive re-lighting of the subject from any direction. Although at the beginning this technique was designed to aid Cultural Heritage specialists in the inspection and interpretation process, the recent advances of 3D web visualization platforms are increasing our capability to open this type of visual inspection to the ordinary public. Especially the methodologies for virtual manipulation of Cultural Heritage artifacts through RTI are gaining interest. In this context one of the most interesting kind of objects to acquire and virtually explore by means of RTI images are the ancient coins collections. Typically, a coin is a very small artwork, presented to the public from a distance and visible only from one side. Furthermore, coins have a lot of hidden knowledge that is difficult to transfer to the visitors in an easy, effective and understandable manner. What we present is the use of this new multimedia data, RTI images, in the process of digitalization and virtual presentation of the coin collection of the Palazzo Blu Museum (Pisa, Italy). The main goal of the project was to provide an improved access of ordinary people (visitors of the museum or web surfers) to the exposed numismatic materials. The result of this activity is an interactive kiosk that, integrated with the existing traditional museum exhibition, allows the visitors to interact and virtually explore every coin. The interactive presentation system, developed in HTML5 and designed to be deployed either by a museum kiosk or by a web site, is composed by a presentation section and the interactive viewer of the RTI images of each coin. The presentation part contains the description of the project and the organization of the coins into different subsets, using historical and thematic criteria, with the purpose to provide a presentation to a public of ordinary museum visitors. The RTI viewer offers a set of basic functionalities for the virtual manipulation of the coins using high-resolution images produced by RTI techniques. The RTI image of the coin, generated from a set of images acquired from the same point of view but with different lighting conditions, allows the visitor to change the direction of light in real time, making visible and appreciable details otherwise imperceptible. The virtual manipulation is completed by the free navigation on the coin, with basic operations like pan and zoom, and the possibility to flip the coin, to interact with the reverse, and to explore small areas of interest, identified by some hot spots on the surface and associated with text and pictures that provide additional information about the most interesting and important technical, historical and artistic features of the piece. The kiosk is currently installed inside the Museum Palazzo Blu in Pisa, in the exhibition room of the Ottavio Simoneschi's coin collection, and it will be soon loaded on the museum web site.Source: MWF 2014 - Museums and the Web Florence 2014, pp. 1–7, Florence, Italy, 18-21 February 2014
Project(s): V-MUST.NET
Palma G., Baldassarri M., Favilla M. C., Scopigno R.
Reflectance Transformation Imaging (RTI) is a technique that captures a subject's surface shape and color and enables the interactive re-lighting of the subject from any direction. Although at the beginning this technique was designed to aid Cultural Heritage specialists in the inspection and interpretation process, the recent advances of 3D web visualization platforms are increasing our capability to open this type of visual inspection to the ordinary public. Especially the methodologies for virtual manipulation of Cultural Heritage artifacts through RTI are gaining interest. In this context one of the most interesting kind of objects to acquire and virtually explore by means of RTI images are the ancient coins collections. Typically, a coin is a very small artwork, presented to the public from a distance and visible only from one side. Furthermore, coins have a lot of hidden knowledge that is difficult to transfer to the visitors in an easy, effective and understandable manner. What we present is the use of this new multimedia data, RTI images, in the process of digitalization and virtual presentation of the coin collection of the Palazzo Blu Museum (Pisa, Italy). The main goal of the project was to provide an improved access of ordinary people (visitors of the museum or web surfers) to the exposed numismatic materials. The result of this activity is an interactive kiosk that, integrated with the existing traditional museum exhibition, allows the visitors to interact and virtually explore every coin. The interactive presentation system, developed in HTML5 and designed to be deployed either by a museum kiosk or by a web site, is composed by a presentation section and the interactive viewer of the RTI images of each coin. The presentation part contains the description of the project and the organization of the coins into different subsets, using historical and thematic criteria, with the purpose to provide a presentation to a public of ordinary museum visitors. The RTI viewer offers a set of basic functionalities for the virtual manipulation of the coins using high-resolution images produced by RTI techniques. The RTI image of the coin, generated from a set of images acquired from the same point of view but with different lighting conditions, allows the visitor to change the direction of light in real time, making visible and appreciable details otherwise imperceptible. The virtual manipulation is completed by the free navigation on the coin, with basic operations like pan and zoom, and the possibility to flip the coin, to interact with the reverse, and to explore small areas of interest, identified by some hot spots on the surface and associated with text and pictures that provide additional information about the most interesting and important technical, historical and artistic features of the piece. The kiosk is currently installed inside the Museum Palazzo Blu in Pisa, in the exhibition room of the Ottavio Simoneschi's coin collection, and it will be soon loaded on the museum web site.Source: MWF 2014 - Museums and the Web Florence 2014, pp. 1–7, Florence, Italy, 18-21 February 2014
Project(s): V-MUST.NET
See at: CNR ExploRA
2019
Report
Open Access
Augmented reality experience with physical artefacts
Palma G., Cignoni P.
This technical report presents a system to improve the engagement of the user in a virtual reality experience using economic, physical copies of real artefacts, made with cheap 3D fabrication technologies. Based on a combination of hardware and software components, the proposed system gives the user the possibility to interact with the physical replica in the virtual environment and to see the appearance of the original artefact. In this way, we overcome the current limitation of the cheap 3D fabrication technologies: a faithful appearance reproduction. Moreover using a consumer device for the real-time hand tracking and a custom electronic controller for the capacitive touch sensing, the system permits the creation of virtual experiences where the user with his hand can change the virtual appearance of the object using a set of personalization actions selectable from a physical 3D printed palette.Source: ISTI Technical reports, 2019
Project(s): EMOTIVE
Palma G., Cignoni P.
This technical report presents a system to improve the engagement of the user in a virtual reality experience using economic, physical copies of real artefacts, made with cheap 3D fabrication technologies. Based on a combination of hardware and software components, the proposed system gives the user the possibility to interact with the physical replica in the virtual environment and to see the appearance of the original artefact. In this way, we overcome the current limitation of the cheap 3D fabrication technologies: a faithful appearance reproduction. Moreover using a consumer device for the real-time hand tracking and a custom electronic controller for the capacitive touch sensing, the system permits the creation of virtual experiences where the user with his hand can change the virtual appearance of the object using a set of personalization actions selectable from a physical 3D printed palette.Source: ISTI Technical reports, 2019
Project(s): EMOTIVE
See at:
ISTI Repository 
| CNR ExploRA
2020
Contribution to book
Closed Access
Una Loggia digitale al tempo del COVID-19
Palma G., Siotto E.
Il capitolo dopo aver illustrato il concepimento e l'evoluzione del progetto "Una loggia digitale per Raffaello e collaboratori in Villa Farnesina, Roma" per conto dell'Accademia Nazionale dei Lincei e del CNR-ISTI, descrive le fasi di progettazione e sviluppo del sistema digitale interattivo, come sono stati acquisiti i dati e come è stato creato il modello e, infine, offre una guida all'uso del sistema interattivo organizzato su due livelli di dettaglio (http://vcg.isti.cnr.it/farnesina/loggia/).Source: Raffaello in Villa Farnesina: Galatea e Psiche, edited by A. Sgamellotti, V. Lapenta, C. Anselmi, C. Seccaroni, pp. 89–96. Roma: Bardi Editore, 2020
Palma G., Siotto E.
Il capitolo dopo aver illustrato il concepimento e l'evoluzione del progetto "Una loggia digitale per Raffaello e collaboratori in Villa Farnesina, Roma" per conto dell'Accademia Nazionale dei Lincei e del CNR-ISTI, descrive le fasi di progettazione e sviluppo del sistema digitale interattivo, come sono stati acquisiti i dati e come è stato creato il modello e, infine, offre una guida all'uso del sistema interattivo organizzato su due livelli di dettaglio (http://vcg.isti.cnr.it/farnesina/loggia/).Source: Raffaello in Villa Farnesina: Galatea e Psiche, edited by A. Sgamellotti, V. Lapenta, C. Anselmi, C. Seccaroni, pp. 89–96. Roma: Bardi Editore, 2020
See at:
vcg.isti.cnr.it | CNR ExploRA
2020
Contribution to book
Closed Access
A digital Loggia at the time of COVID-19
Palma G., Siotto E.
The chapter starts illustrating the conception and evolution of the project "A digital loggia for Raphael and collaborators in Villa Farnesina, Rome" on behalf of the Accademia Nazionale dei Lincei and ISTI-CNR. After it describes the design and development phases of the interactive digital system, how the data were acquired and how the model was created and, finally, offers a guide to the use of the interactive system organized on two levels of detail (http://vcg.isti.cnr.it/farnesina /loggia/).Source: Raphael in Villa Farnesina: Galatea and Psyche, edited by A. Sgamellotti, V. Lapenta, C. Anselmi, C. Seccaroni, pp. 91–98. Roma: Bardi Editore, 2020
Palma G., Siotto E.
The chapter starts illustrating the conception and evolution of the project "A digital loggia for Raphael and collaborators in Villa Farnesina, Rome" on behalf of the Accademia Nazionale dei Lincei and ISTI-CNR. After it describes the design and development phases of the interactive digital system, how the data were acquired and how the model was created and, finally, offers a guide to the use of the interactive system organized on two levels of detail (http://vcg.isti.cnr.it/farnesina /loggia/).Source: Raphael in Villa Farnesina: Galatea and Psyche, edited by A. Sgamellotti, V. Lapenta, C. Anselmi, C. Seccaroni, pp. 91–98. Roma: Bardi Editore, 2020
See at:
vcg.isti.cnr.it | CNR ExploRA
2021
Journal article
Open Access
Augmented virtuality using touch-sensitive 3D-printed objects
Palma G., Perry S., Cignoni P.
Virtual reality (VR) technologies have become more and more affordable and popular in the last five years thanks to hardware and software advancements. A critical issue for these technologies is finding paradigms that allow user interactions in ways that are as similar as possible to the real world, bringing physicality into the experience. Current literature has shown, with different experiments, that the mapping of real objects in virtual reality alongside haptic feedback significantly increases the realism of the experience and user engagement, leading to augmented virtuality. In this paper, we present a system to improve engagement in a VR experience using inexpensive, physical, and sensorized copies of real artefacts made with cheap 3D fabrication technologies. Based on a combination of hardware and software components, the proposed system gives the user the possibility to interact with the physical replica in the virtual environment and to see the appearance of the original cultural heritage artefact. In this way, we overcome one of the main limitations of mainstream 3D fabrication technologies: a faithful appearance reproduction. Using a consumer device for the real-time hand tracking and a custom electronic controller for the capacitive touch sensing, the system permits the creation of augmented experiences where the user with their hands can change the virtual appearance of the real replica object using a set of personalization actions selectable from a physical 3D-printed palette.Source: Remote sensing (Basel) 13 (2021). doi:10.3390/rs13112186
DOI: 10.3390/rs13112186
Project(s): EMOTIVE
Metrics:
Palma G., Perry S., Cignoni P.
Virtual reality (VR) technologies have become more and more affordable and popular in the last five years thanks to hardware and software advancements. A critical issue for these technologies is finding paradigms that allow user interactions in ways that are as similar as possible to the real world, bringing physicality into the experience. Current literature has shown, with different experiments, that the mapping of real objects in virtual reality alongside haptic feedback significantly increases the realism of the experience and user engagement, leading to augmented virtuality. In this paper, we present a system to improve engagement in a VR experience using inexpensive, physical, and sensorized copies of real artefacts made with cheap 3D fabrication technologies. Based on a combination of hardware and software components, the proposed system gives the user the possibility to interact with the physical replica in the virtual environment and to see the appearance of the original cultural heritage artefact. In this way, we overcome one of the main limitations of mainstream 3D fabrication technologies: a faithful appearance reproduction. Using a consumer device for the real-time hand tracking and a custom electronic controller for the capacitive touch sensing, the system permits the creation of augmented experiences where the user with their hands can change the virtual appearance of the real replica object using a set of personalization actions selectable from a physical 3D-printed palette.Source: Remote sensing (Basel) 13 (2021). doi:10.3390/rs13112186
DOI: 10.3390/rs13112186
Project(s): EMOTIVE
Metrics:
See at:
ISTI Repository | www.mdpi.com | CNR ExploRA
2017
Contribution to book
Restricted
Realizzazione del sistema interattivo 'Loggia digitale'
Siotto E., Palma G., Scopigno R.
The VC Lab has developed, in collaboration with the Accademia Nazionale dei Lincei, the Interactive Digital System of the Loggia of Cupid and Psyche within the exhibition 'The Loggia of Cupid and Psyche - Raffaello and Giovanni da Udine - Colours of Prosperity: Fruits from the Old and New World' Villa Farnesina, Rome April 20 - July 20 2017. The system allows access to the 'digital Loggia' and permits the visitor to navigate freely through the high-resolution panoramic image of the painted ceiling, to admire it from a closer point of view and to consult the results of historical, botanical and scientific analyses performed on the selected species. The system is available online and with an interactive kiosk in the Farnesina building.Source: La Loggia di Amore e Psiche - Raffaello e Giovanni da Udine - I colori della prosperità: Frutti dal Vecchio e Nuovo Mondo, pp. 74–77, 2017
Siotto E., Palma G., Scopigno R.
The VC Lab has developed, in collaboration with the Accademia Nazionale dei Lincei, the Interactive Digital System of the Loggia of Cupid and Psyche within the exhibition 'The Loggia of Cupid and Psyche - Raffaello and Giovanni da Udine - Colours of Prosperity: Fruits from the Old and New World' Villa Farnesina, Rome April 20 - July 20 2017. The system allows access to the 'digital Loggia' and permits the visitor to navigate freely through the high-resolution panoramic image of the painted ceiling, to admire it from a closer point of view and to consult the results of historical, botanical and scientific analyses performed on the selected species. The system is available online and with an interactive kiosk in the Farnesina building.Source: La Loggia di Amore e Psiche - Raffaello e Giovanni da Udine - I colori della prosperità: Frutti dal Vecchio e Nuovo Mondo, pp. 74–77, 2017
See at:
vcg.isti.cnr.it | CNR ExploRA
2010
Journal article
Restricted
Dynamic shading enhancement for reflectance transformation imaging
Palma G., Corsini M., Cignoni P., Scopigno R., Mudge M.
We propose a set of dynamic shading enhancement techniques for improving the perception of details, features, and overall shape characteristics from images created with Reflectance Transformation Imaging (RTI) techniques. Selection of these perceptual enhancement filters can significantly improve the user's ability to interactively inspect the content of 2D RTI media by zooming, panning, and changing the illumination direction. In particular, we present two groups of strategies for RTI image enhancement based on two main ideas: exploiting the unsharp masking methodology in the RTI-specific context; and locally optimizing the incident light direction for improved RTI image sharpness and illumination of surface features. The Result section will present a number of datasets and compare them with existing techniques.Source: ACM journal on computing and cultural heritage (Print) 3 (2010): 1–20. doi:10.1145/1841317.1841321
DOI: 10.1145/1841317.1841321
Metrics:
Palma G., Corsini M., Cignoni P., Scopigno R., Mudge M.
We propose a set of dynamic shading enhancement techniques for improving the perception of details, features, and overall shape characteristics from images created with Reflectance Transformation Imaging (RTI) techniques. Selection of these perceptual enhancement filters can significantly improve the user's ability to interactively inspect the content of 2D RTI media by zooming, panning, and changing the illumination direction. In particular, we present two groups of strategies for RTI image enhancement based on two main ideas: exploiting the unsharp masking methodology in the RTI-specific context; and locally optimizing the incident light direction for improved RTI image sharpness and illumination of surface features. The Result section will present a number of datasets and compare them with existing techniques.Source: ACM journal on computing and cultural heritage (Print) 3 (2010): 1–20. doi:10.1145/1841317.1841321
DOI: 10.1145/1841317.1841321
Metrics:
See at:
Journal on Computing and Cultural Heritage | CNR ExploRA
2017
Contribution to book
Restricted
Development of the interactive system 'digital Loggia'
Siotto E., Palma G., Scopigno R.
The VC Lab has developed, in collaboration with the Accademia Nazionale dei Lincei, the Interactive Digital System of the Loggia of Cupid and Psyche within the exhibition 'The Loggia of Cupid and Psyche - Raffaello and Giovanni da Udine - Colours of Prosperity: Fruits from the Old and New World' Villa Farnesina, Rome April 20 - July 20 2017. The system allows access to the 'digital Loggia' and permits the visitor to navigate freely through the high-resolution panoramic image of the painted ceiling, to admire it from a closer point of view and to consult the results of historical, botanical and scientific analyses performed on the selected species. The system is available online and with an interactive kiosk in the Farnesina building.Source: The Loggia of Cupid and Psyche - Raffaello and Giovanni da Udine - Colours of prosperity: Fruits from the Old and New World, pp. 74–77, 2017
Siotto E., Palma G., Scopigno R.
The VC Lab has developed, in collaboration with the Accademia Nazionale dei Lincei, the Interactive Digital System of the Loggia of Cupid and Psyche within the exhibition 'The Loggia of Cupid and Psyche - Raffaello and Giovanni da Udine - Colours of Prosperity: Fruits from the Old and New World' Villa Farnesina, Rome April 20 - July 20 2017. The system allows access to the 'digital Loggia' and permits the visitor to navigate freely through the high-resolution panoramic image of the painted ceiling, to admire it from a closer point of view and to consult the results of historical, botanical and scientific analyses performed on the selected species. The system is available online and with an interactive kiosk in the Farnesina building.Source: The Loggia of Cupid and Psyche - Raffaello and Giovanni da Udine - Colours of prosperity: Fruits from the Old and New World, pp. 74–77, 2017
See at:
vcg.isti.cnr.it | CNR ExploRA
2010
Conference article
Unknown
Improving 2D-3D registration by mutual information using gradient maps
Palma G., Corsini M., Dellepiane M., Scopigno R.
In this paper we propose an extension for the algorithms of image-to-geometry registration by Mutual Information(MI) to improve the performance and the quality of the alignment. Proposed for the registration of multi modal medical images, in the last years MI has been adapted to align a 3D model to a given image by using different renderings of the model and a gray-scale version of the input image. A key aspect is the choice of the rendering process to correlate the 3D model to the image without taking into account the texture data and the lighting conditions. Even if several rendering types for the 3D model have been analyzed, in some cases the alignment fails for two main reasons: the peculiar reflection behavior of the object that we are not able to reproduce in the rendering of the 3D model without knowing the material characteristics of the object and the lighting conditions of the acquisition environment; the characteristics of the image background, especially non uniform background, that can degrade the convergence of the registration. To improve the quality of the registration in these cases we propose to compute the MI between the gradient map of the 3D rendering and the gradient map of the image in order to maximize the shared data between them.Source: Eurographics Italian Chapter Conference 2010, pp. 89–94, Genova, 18/19 novembre 2010
Palma G., Corsini M., Dellepiane M., Scopigno R.
In this paper we propose an extension for the algorithms of image-to-geometry registration by Mutual Information(MI) to improve the performance and the quality of the alignment. Proposed for the registration of multi modal medical images, in the last years MI has been adapted to align a 3D model to a given image by using different renderings of the model and a gray-scale version of the input image. A key aspect is the choice of the rendering process to correlate the 3D model to the image without taking into account the texture data and the lighting conditions. Even if several rendering types for the 3D model have been analyzed, in some cases the alignment fails for two main reasons: the peculiar reflection behavior of the object that we are not able to reproduce in the rendering of the 3D model without knowing the material characteristics of the object and the lighting conditions of the acquisition environment; the characteristics of the image background, especially non uniform background, that can degrade the convergence of the registration. To improve the quality of the registration in these cases we propose to compute the MI between the gradient map of the 3D rendering and the gradient map of the image in order to maximize the shared data between them.Source: Eurographics Italian Chapter Conference 2010, pp. 89–94, Genova, 18/19 novembre 2010
See at: CNR ExploRA
2008
Software
Unknown
RTIViewer - a tool for remote browsing of images created with relectance transformation techniques.
Cignoni P., Corsini M., Palma G., Scopigno R.
The RTI Viewer allows you to load and examine images created with relectance transformation techniques. The tool supports these formats, collectively called RTI files: X Polynomial Texture Maps (PTM files) X Hemispherical Harmonics Maps (HSH files) X Universal Reflectance Transformation Imaging (URTI files) The viewer can display both single-view and multi-view images; a mulit-view RTI is a collection of single-view images together with optical flow data that generates intermediate views.
Cignoni P., Corsini M., Palma G., Scopigno R.
The RTI Viewer allows you to load and examine images created with relectance transformation techniques. The tool supports these formats, collectively called RTI files: X Polynomial Texture Maps (PTM files) X Hemispherical Harmonics Maps (HSH files) X Universal Reflectance Transformation Imaging (URTI files) The viewer can display both single-view and multi-view images; a mulit-view RTI is a collection of single-view images together with optical flow data that generates intermediate views.
See at: CNR ExploRA
2012
Journal article
Open Access
A statistical method for SVBRDF approximation from video sequences in general lighting conditions
Palma G., Callieri M., Dellepiane M., Scopigno R.
We present a statistical method for the estimation of the Spatially Varying Bidirectional Reflectance Distribution Function (SVBRDF) of an object with complex geometry, starting from video sequences acquired with fixed but general lighting conditions. The aim of this work is to define a method that simplifies the acquisition phase of the object surface appearance and allows to reconstruct an approximated SVBRDF. The final output is suitable to be used with a 3D model of the object to obtain accurate and photo-realistic renderings. The method is composed by three steps: the approximation of the environment map of the acquisition scene, using the same object as a probe; the estimation of the diffuse color of the object; the estimation of the specular components of the main materials of the object, by using a Phong model. All the steps are based on statistical analysis of the color samples projected by the video sequences on the surface of the object. Although the method presents some limitations, the trade-off between the easiness of acquisition and the obtained results makes it useful for practical applications.Source: Computer graphics forum (Online) 31 (2012): 1491–1500. doi:10.1111/j.1467-8659.2012.03145.x
DOI: 10.1111/j.1467-8659.2012.03145.x
Project(s): 3D-COFORM
Metrics:
Palma G., Callieri M., Dellepiane M., Scopigno R.
We present a statistical method for the estimation of the Spatially Varying Bidirectional Reflectance Distribution Function (SVBRDF) of an object with complex geometry, starting from video sequences acquired with fixed but general lighting conditions. The aim of this work is to define a method that simplifies the acquisition phase of the object surface appearance and allows to reconstruct an approximated SVBRDF. The final output is suitable to be used with a 3D model of the object to obtain accurate and photo-realistic renderings. The method is composed by three steps: the approximation of the environment map of the acquisition scene, using the same object as a probe; the estimation of the diffuse color of the object; the estimation of the specular components of the main materials of the object, by using a Phong model. All the steps are based on statistical analysis of the color samples projected by the video sequences on the surface of the object. Although the method presents some limitations, the trade-off between the easiness of acquisition and the obtained results makes it useful for practical applications.Source: Computer graphics forum (Online) 31 (2012): 1491–1500. doi:10.1111/j.1467-8659.2012.03145.x
DOI: 10.1111/j.1467-8659.2012.03145.x
Project(s): 3D-COFORM
Metrics:
See at:
Computer Graphics Forum | Computer Graphics Forum | onlinelibrary.wiley.com | CNR ExploRA
2012
Conference article
Unknown
Telling the story of ancient coins by means of interactive RTI images visualization
Palma G., Siotto E., Proesmans M., Baldassarri M., Baracchini C., Batino S., Scopigno R.
Methodologies for virtual examination of Cultural Heritage artifacts through Reflectance Transformation Imaging (RTI) are gaining interest. Although at the beginning this techniques were designed to aid Cultural Heritage specialists in the inspection and interpretation process, the recent advances of 3D web visualization platforms are increasing our capability to open this type of visual inspection to the ordinary public. We present the design and implementation of a system that provide the access of ordinary people (visitors of the museum or web surfers) to a collection of ancient coins, preserved in the San Matteo Museum of Pisa (Italy). Those coins have been digitized to produce RTI representations and are presented to museum visitors together with some data telling their story and explaining their value. The interactive presentation system, designed to be deployed either by a museum kiosk or by a web site, is composed of two integrated sections: a brief introduction to the different subsets of coins; an interactive visualization of the RTI representation of each coin, by means of a specific RTI viewer. The coins are organized in different (possibly overlapping) subsets, to allow us to better present them to a public of inexperienced visitors. Starting from the main theme, the Historical Collection of the coins, we have some subsets about the iconography, the different production techniques (coining or fusion), the value of the coins, etc. After the selection of a specific subset, the user is presented a basic page containing an hypertext description with some basic information, a draggable image gallery with the thumbnails of the coins in the subset and the RTI viewer to display the specific selected coin. The viewer supports visualization and interaction with the RTI image through a basic set of functionalities: changing the light direction, zooming, panning over the image, flipping the coin to switch between the two sides and finally the possibility to show some hot spots, which link specific locations/areas on the coin with descriptive data (presented by means of HTML hypertext page).Source: Computer Applications and Qualitative Methods in Archaeology, pp. 177–185, Southamptom, UK, 26-29 March 2012
Palma G., Siotto E., Proesmans M., Baldassarri M., Baracchini C., Batino S., Scopigno R.
Methodologies for virtual examination of Cultural Heritage artifacts through Reflectance Transformation Imaging (RTI) are gaining interest. Although at the beginning this techniques were designed to aid Cultural Heritage specialists in the inspection and interpretation process, the recent advances of 3D web visualization platforms are increasing our capability to open this type of visual inspection to the ordinary public. We present the design and implementation of a system that provide the access of ordinary people (visitors of the museum or web surfers) to a collection of ancient coins, preserved in the San Matteo Museum of Pisa (Italy). Those coins have been digitized to produce RTI representations and are presented to museum visitors together with some data telling their story and explaining their value. The interactive presentation system, designed to be deployed either by a museum kiosk or by a web site, is composed of two integrated sections: a brief introduction to the different subsets of coins; an interactive visualization of the RTI representation of each coin, by means of a specific RTI viewer. The coins are organized in different (possibly overlapping) subsets, to allow us to better present them to a public of inexperienced visitors. Starting from the main theme, the Historical Collection of the coins, we have some subsets about the iconography, the different production techniques (coining or fusion), the value of the coins, etc. After the selection of a specific subset, the user is presented a basic page containing an hypertext description with some basic information, a draggable image gallery with the thumbnails of the coins in the subset and the RTI viewer to display the specific selected coin. The viewer supports visualization and interaction with the RTI image through a basic set of functionalities: changing the light direction, zooming, panning over the image, flipping the coin to switch between the two sides and finally the possibility to show some hot spots, which link specific locations/areas on the coin with descriptive data (presented by means of HTML hypertext page).Source: Computer Applications and Qualitative Methods in Archaeology, pp. 177–185, Southamptom, UK, 26-29 March 2012
See at: CNR ExploRA
2013
Conference article
Unknown
Surface light field from video acquired in uncontrolled settings
Palma G., Desogus N., Cignoni P., Scopigno R.
This paper presents an algorithm for the estimation of the Surface Light Field using video sequences acquired moving the camera around the object. Unlike other state of the art methods, it does not require a uniform sampling density of the view directions, but it is able to build an approximation of the Surface Light Field starting from a biased video acquisition: dense along the camera path and completely missing in the other directions. The main idea is to separate the estimation of two components: the diffuse color, computed using statistical operations that allow the estimation of a rough approximation of the direction of the main light sources in the acquisition environment; the other residual Surface Light Field effects,modeled as linear combination of spherical functions. From qualitative and numerical evaluations, the final rendering results show a high fidelity and similarity with the input video frames, without ringing and banding effects.Source: Digital Heritage 2013, pp. 31–38, Marseille, France, 28 October - 1 November 2013
Project(s): HARVEST4D
Palma G., Desogus N., Cignoni P., Scopigno R.
This paper presents an algorithm for the estimation of the Surface Light Field using video sequences acquired moving the camera around the object. Unlike other state of the art methods, it does not require a uniform sampling density of the view directions, but it is able to build an approximation of the Surface Light Field starting from a biased video acquisition: dense along the camera path and completely missing in the other directions. The main idea is to separate the estimation of two components: the diffuse color, computed using statistical operations that allow the estimation of a rough approximation of the direction of the main light sources in the acquisition environment; the other residual Surface Light Field effects,modeled as linear combination of spherical functions. From qualitative and numerical evaluations, the final rendering results show a high fidelity and similarity with the input video frames, without ringing and banding effects.Source: Digital Heritage 2013, pp. 31–38, Marseille, France, 28 October - 1 November 2013
Project(s): HARVEST4D
See at: CNR ExploRA
2014
Report
Unknown
Automatic detection of geometric changes in time varying point clouds
Palma G., Cignoni P., Tamy B., Scopigno R.
The detection of the geometric changes in 4D data is an important task for all the applications interested in the segmentation of the input geometry between the static and dynamic areas, for the example the cleaning of the input clouds from the objects that are moved or disappear in one of the time step or the analysis and the study of the dynamic part to model the type of change. In this paper we present a novel algorithm to solve this problem that takes in input two point clouds of the same environments acquired in different moments. The core of the method is the computation of the differences between the point clouds using a multi-scale comparison of the implicit surface defined using the Growing Least Square framework. Then the obtained results are further processed to make the segmentation more robust in some critical geometrical configurations that are very common in man-made environments. The final segmentation shows an accurate detection of the real changes in the scene.Source: ISTI Technical reports, 2014
Project(s): HARVEST4D
Palma G., Cignoni P., Tamy B., Scopigno R.
The detection of the geometric changes in 4D data is an important task for all the applications interested in the segmentation of the input geometry between the static and dynamic areas, for the example the cleaning of the input clouds from the objects that are moved or disappear in one of the time step or the analysis and the study of the dynamic part to model the type of change. In this paper we present a novel algorithm to solve this problem that takes in input two point clouds of the same environments acquired in different moments. The core of the method is the computation of the differences between the point clouds using a multi-scale comparison of the implicit surface defined using the Growing Least Square framework. Then the obtained results are further processed to make the segmentation more robust in some critical geometrical configurations that are very common in man-made environments. The final segmentation shows an accurate detection of the real changes in the scene.Source: ISTI Technical reports, 2014
Project(s): HARVEST4D
See at: CNR ExploRA
2015
Conference article
Restricted
Digital Study and Web-based Documentation of the Colour and Gilding on Ancient Marble Artworks
Siotto E., Palma G., Potenziani M., Scopigno R.
Greek and Roman marble artworks have been deeply studied from a typological and stylistic point of view, while there is still a limited knowledge on the pigments, dyes, binders and technical expedients used by Roman artists. In a renewed scientific interest towards the ancient polychromy (colour and gilding), a digital methodological and multidisciplinary approach can provide valuable information to better investigate and understand this fundamental aspect and to get a complete sense on Greek and Roman marble artworks. Following this research direction, the paper proposes a systematic methodological process defined to detect, document and visualize the preserved (and in some cases the digital reconstructed) original colour and gilding on Roman marble sarcophagi (II-IV century AD). The process defines a working pipeline that, starting from the selection of the artefact to study, proposes a set of investigation steps to improve our knowledge of its original painting. These steps include the direct virtual inspection, the archaeological and historical research, the on-site scientific investigation by multispectral imaging, spectroscopic and elemental analysis (eventually supported by micro-invasive techniques performed in laboratory), the accurate polychrome surface acquisition by colour calibrated 2D images. All the data produced are integrated with a high-resolution 3D model to support enhanced analysis and comparison and to create a digital 3D polychrome reconstruction by virtual painting. Finally, all those data are also made accessible on the web by using a cutting edge platform for visual media publication and interactive 3D visualization. This systematic and multidisciplinary process was tested on the so-called 'Annona sarcophagus' (Museo Nazionale Romano - Palazzo Massimo, inv. no. 40799).Source: Digital Heritage International Congress, pp. 239–246, Granada, 28/09/2015-02/10/2015
DOI: 10.1109/digitalheritage.2015.7413877
Project(s): ARIADNE
Metrics:
Siotto E., Palma G., Potenziani M., Scopigno R.
Greek and Roman marble artworks have been deeply studied from a typological and stylistic point of view, while there is still a limited knowledge on the pigments, dyes, binders and technical expedients used by Roman artists. In a renewed scientific interest towards the ancient polychromy (colour and gilding), a digital methodological and multidisciplinary approach can provide valuable information to better investigate and understand this fundamental aspect and to get a complete sense on Greek and Roman marble artworks. Following this research direction, the paper proposes a systematic methodological process defined to detect, document and visualize the preserved (and in some cases the digital reconstructed) original colour and gilding on Roman marble sarcophagi (II-IV century AD). The process defines a working pipeline that, starting from the selection of the artefact to study, proposes a set of investigation steps to improve our knowledge of its original painting. These steps include the direct virtual inspection, the archaeological and historical research, the on-site scientific investigation by multispectral imaging, spectroscopic and elemental analysis (eventually supported by micro-invasive techniques performed in laboratory), the accurate polychrome surface acquisition by colour calibrated 2D images. All the data produced are integrated with a high-resolution 3D model to support enhanced analysis and comparison and to create a digital 3D polychrome reconstruction by virtual painting. Finally, all those data are also made accessible on the web by using a cutting edge platform for visual media publication and interactive 3D visualization. This systematic and multidisciplinary process was tested on the so-called 'Annona sarcophagus' (Museo Nazionale Romano - Palazzo Massimo, inv. no. 40799).Source: Digital Heritage International Congress, pp. 239–246, Granada, 28/09/2015-02/10/2015
DOI: 10.1109/digitalheritage.2015.7413877
Project(s): ARIADNE
Metrics:
See at:
doi.org | ieeexplore.ieee.org | CNR ExploRA
2016
Report
Unknown
Temporal appearance change detection using multi-view image acquisition
Palma G., Banterle F., Cignoni P.
Appearance change detection is a very important task for applications monitoring the degradation process of a surface. This is especially true in Cultural Heritage (CH), where the main goal is to control the preservation condition of an artifact. We propose an automatic solution based on the estimation of an explicit parametric reflectance model that can help the user in the detection of the regions that are affected by appearance changes. The idea is to acquire multi-view photo datasets at different times and to compute the 3D model and the Surface Light Field (SLF) of the object for each acquisition. Then, we compare the SLF in the time using a weighting scheme, which takes account of small lighting variations and small misalignments. The obtained results give several cues on the changed areas. In addition, we believe that these can be used as good starting point for further investigations.Source: ISTI Technical reports, 2016
Project(s): HARVEST4D
Palma G., Banterle F., Cignoni P.
Appearance change detection is a very important task for applications monitoring the degradation process of a surface. This is especially true in Cultural Heritage (CH), where the main goal is to control the preservation condition of an artifact. We propose an automatic solution based on the estimation of an explicit parametric reflectance model that can help the user in the detection of the regions that are affected by appearance changes. The idea is to acquire multi-view photo datasets at different times and to compute the 3D model and the Surface Light Field (SLF) of the object for each acquisition. Then, we compare the SLF in the time using a weighting scheme, which takes account of small lighting variations and small misalignments. The obtained results give several cues on the changed areas. In addition, we believe that these can be used as good starting point for further investigations.Source: ISTI Technical reports, 2016
Project(s): HARVEST4D
See at: CNR ExploRA
2016
Journal article
Open Access
Detection of geometric temporal changes in point clouds
Palma G., Cignoni P., Boubekeur T., Scopigno R.
Detecting geometric changes between two 3D captures of the same location performed at different moments is a critical operation for all systems requiring a precise segmentation between change and no-change regions. Such application scenarios include 3D surface reconstruction, environment monitoring, natural events management and forensic science. Unfortunately, typical 3D scanning setups cannot provide any one-to-one mapping between measured samples in static regions: in particular, both extrinsic and intrinsic sensor parameters may vary over time while sensor noise and outliers additionally corrupt the data. In this paper, we adopt a multi-scale approach to robustly tackle these issues. Starting from two point clouds, we first remove outliers using a probabilistic operator. Then, we detect the actual change using the implicit surface defined by the point clouds under a Growing Least Square reconstruction that, compared to the classical proximity measure, offers a more robust change/no-change characterization near the temporal intersection of the scans and in the areas exhibiting different sampling density and direction. The resulting classification is enhanced with a spatial reasoning step to solve critical geometric configurations that are common in man-made environments. We validate our approach on a synthetic test case and on a collection of real data sets acquired using commodity hardware. Finally, we show how 3D reconstruction benefits from the resulting precise change/no-change segmentation.Source: Computer graphics forum (Print) 35 (2016): 33–45. doi:10.1111/cgf.12730
DOI: 10.1111/cgf.12730
Project(s): HARVEST4D
Metrics:
Palma G., Cignoni P., Boubekeur T., Scopigno R.
Detecting geometric changes between two 3D captures of the same location performed at different moments is a critical operation for all systems requiring a precise segmentation between change and no-change regions. Such application scenarios include 3D surface reconstruction, environment monitoring, natural events management and forensic science. Unfortunately, typical 3D scanning setups cannot provide any one-to-one mapping between measured samples in static regions: in particular, both extrinsic and intrinsic sensor parameters may vary over time while sensor noise and outliers additionally corrupt the data. In this paper, we adopt a multi-scale approach to robustly tackle these issues. Starting from two point clouds, we first remove outliers using a probabilistic operator. Then, we detect the actual change using the implicit surface defined by the point clouds under a Growing Least Square reconstruction that, compared to the classical proximity measure, offers a more robust change/no-change characterization near the temporal intersection of the scans and in the areas exhibiting different sampling density and direction. The resulting classification is enhanced with a spatial reasoning step to solve critical geometric configurations that are common in man-made environments. We validate our approach on a synthetic test case and on a collection of real data sets acquired using commodity hardware. Finally, we show how 3D reconstruction benefits from the resulting precise change/no-change segmentation.Source: Computer graphics forum (Print) 35 (2016): 33–45. doi:10.1111/cgf.12730
DOI: 10.1111/cgf.12730
Project(s): HARVEST4D
Metrics:
See at:
ISTI Repository | Computer Graphics Forum | onlinelibrary.wiley.com | CNR ExploRA
2016
Conference article
Restricted
Multi-view ambient occlusion for enhancing visualization of raw scanning data
Sabbadin M., Palma G., Cignoni P., Scopigno R.
The correct understanding of the 3D shape is a crucial aspect to improve the 3D scanning process, especially in order to perform high quality and as complete as possible 3D acquisitions on the field. The paper proposes a new technique to enhance the visualization of raw scanning data based on the definition in device space of a Multi-View Ambient Occlusion (MVAO). The approach allows improving the comprehension of the 3D shape of the input geometry and, requiring almost no preprocessing, it can be directly applied to raw captured point clouds. The algorithm has been tested on different datasets: high resolution Time-of-Flight scans and streams of low quality range maps from a depth camera. The results enhance the details perception in the 3D geometry using the multi-view information to make more robust the ambient occlusion estimationSource: Eurographics Workshop on Graphics and Cultural Heritage, pp. 23–32, Genova, Italy, 5-7 ottobre 2016
DOI: 10.2312/gch.20161379
Project(s): HARVEST4D
Metrics:
Sabbadin M., Palma G., Cignoni P., Scopigno R.
The correct understanding of the 3D shape is a crucial aspect to improve the 3D scanning process, especially in order to perform high quality and as complete as possible 3D acquisitions on the field. The paper proposes a new technique to enhance the visualization of raw scanning data based on the definition in device space of a Multi-View Ambient Occlusion (MVAO). The approach allows improving the comprehension of the 3D shape of the input geometry and, requiring almost no preprocessing, it can be directly applied to raw captured point clouds. The algorithm has been tested on different datasets: high resolution Time-of-Flight scans and streams of low quality range maps from a depth camera. The results enhance the details perception in the 3D geometry using the multi-view information to make more robust the ambient occlusion estimationSource: Eurographics Workshop on Graphics and Cultural Heritage, pp. 23–32, Genova, Italy, 5-7 ottobre 2016
DOI: 10.2312/gch.20161379
Project(s): HARVEST4D
Metrics:
See at:
diglib.eg.org | CNR ExploRA