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- PERSONAL DATA:Born Domodossola, Italy, 21st December 1981 EDUCATION:February, 2011: PhD in Geomatics and Infrastructu... morePERSONAL DATA:Born Domodossola, Italy, 21st December 1981 EDUCATION:February, 2011: PhD in Geomatics and InfrastructuresDecember, 2006: Master degree in Civil Engineering - Surveying and MonitoringJuly, 2004: Bachelor degree in Civil Engineeringedit
Currently, the commercial market offers several tools for digital documentation of historic sites and buildings. Photogrammetry and laser scanning play a fundamental role in the acquisition of metric information, which is then processed... more
Currently, the commercial market offers several tools for digital documentation of historic sites and buildings. Photogrammetry and laser scanning play a fundamental role in the acquisition of metric information, which is then processed to generate reliable records particularly useful also in the built heritage conservation field. Although potentially very fast and accurate, such techniques require expert operators to produce reliable results, especially in the case of complex and large sites. The aim of this paper is to present the digital workflow developed for data acquisition and processing of the Shaikh Isa Bin Ali house in Muharraq, Bahrain. This historic structure is an outstanding example of Bahrain architecture as well as tangible memory of the country history, with strong connotations in the Bahrain cultural identity. The building has been documented employing several digital techniques, including: aerial (drone) and terrestrial photogrammetry, rectifying photography, total station and laser scanning. The documentation project has been developed for the Bahrain Authority for Culture and Antiquities (BACA) by a multidisciplinary team of experts from Carleton Immersive Media Studio (CIMS, Carleton University, Canada) and Gicarus Lab (Politecnico di Milano, Italy).
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Documenting the physical characteristics of historic structures is the first step for any preventive maintenance, monitoring, conservation, planning and promotion action. Metric documentation supports informative decision-making process... more
Documenting the physical characteristics of historic structures is the first step for any preventive maintenance, monitoring, conservation, planning and promotion action. Metric documentation supports informative decision-making process for property owners, site managers, public officials, and conservators. This information serves also a broader purpose, over time, it becomes the primary means by which scholars, heritage professionals, and the general public understand a site that radically changed or disappeared. Further, documentation supports monitoring as well as the character-defining elements analysis, relevant to define the values of the building for the local and international community. The awareness of these concepts oriented the digital documentation and training activities, developed between 2016 and 2017, for the Bahrain Authority for Culture and Antiquities (BACA) in Bahrain. The developed activities had two main aims: a) support the local staff in using specific recor...
The goal of this study was to analyze the filtering performance of LiDAR data of an algorithm implemented by our group of research. The algorithm is completely automatic and needs only the raw data classified as first and last pulses. It... more
The goal of this study was to analyze the filtering performance of LiDAR data of an algorithm implemented by our group of research. The algorithm is completely automatic and needs only the raw data classified as first and last pulses. It was implemented in the open source software GRASS and it is composed of three functions that have to be
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Radiometric image normalization is one of the basic pre-processing methods used in satellite time series analysis. This paper presents a new multi-image approach able to estimate the parameters of relative radiometric normalization... more
Radiometric image normalization is one of the basic pre-processing methods used in satellite time series analysis. This paper presents a new multi-image approach able to estimate the parameters of relative radiometric normalization through a multiple and simultaneous regression with a dataset of a generic number of images. The method was developed to overcome the typical drawbacks of standard one-to-one techniques, where image pairs are independently processed. The proposed solution is based on multi-image pseudo-invariant features incorporated into a unique regression solved via Least Squares. Results for both simulated and real data are presented and discussed.
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Nowadays commercial software able to automatically create an accurate 3D model from any sequence of terrestrial images is not available. This paper presents a methodology which is capable of processing markerless block of terrestrial... more
Nowadays commercial software able to automatically create an accurate 3D model from any sequence of terrestrial images is not available. This paper presents a methodology which is capable of processing markerless block of terrestrial digital images to perform a twofold task: (i) determine the exterior orientation parameters by using a progressive robust feature-based matching followed by a Least Squares Matching refining and a bundle adjustment; (ii) extract a dense point-clouds by using a multi-image matching based on diverse image primitives. The final result is an accurate surface model with characteristics similar to those achievable with range-based sensors. In the whole processing workflow the natural texture of the object is used, thus images and calibration parameters are the only inputs. The method exploits Computer Vision and Photogrammetric techniques and combines their advantages in order to automate the process. At the same time it ensures a precise and reliable solution. To verify the accuracy of the developed methodology, several comparisons with manual measurements, total station data and 3D laser scanner were also carried out.
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It is normal for tourists to take photos during their holidays, which are then printed, loaded into digital frames or shared on the Internet. This paper describes a new methodology to obtain accurate 3D digital models and material... more
It is normal for tourists to take photos during their holidays, which are then printed, loaded into digital frames or shared on the Internet. This paper describes a new methodology to obtain accurate 3D digital models and material replicas of real objects, starting from digital images acquired with consumer and professional cameras. The implemented software is completely automatic and provides detailed reconstructions. It stands out from other existing approaches for the high metric accuracy of the final product, the level of detail obtainable, the speed of the algorithms and its adaptability under different viewing conditions. Several examples relating to an actual trip to Rome are reported and discussed, showing what a tourist can obtain with this package. Obviously, the method can be used for many other applications in which accurate models are needed.
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This paper wants to explore the application of the theory of reliability, which has become largely popular in the analysis of geodetic and photogrammetric networks, to the multiple co-registration of satellite time-series of images... more
This paper wants to explore the application of the theory of reliability, which has become largely popular in the analysis of geodetic and photogrammetric networks, to the multiple co-registration of satellite time-series of images through block adjustment. Indeed the current and future availability of long series of satellite imagery can be exploited for the purpose of change detection and soil monitoring along time. Due to the large overlap between images, the multiple coregistration is a feasible task that may result in an increased reliability of the observations. On the other hand, to deal with such big data sets, automatic procedures have been developed for co-registration of satellite time-series. Due to the presence of residual errors in such procedures, the error analysis during the final block adjustment plays a key-role. Consequently, the background on the theory of reliability has been introduced here, and three simulated examples have been created in order to check the efficiency of the reliability analysis when dealing with time-series of medium resolution satellite imagery.
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Image sequence analysis for 3-D modeling is an aim of primary importance in Photogrammetry and Computer Vision. Both disciplines approach this issue, but with different procedures. The result is the reconstruction of a 3-D model of the... more
Image sequence analysis for 3-D modeling is an aim of primary importance in Photogrammetry and Computer Vision. Both disciplines approach this issue, but with different procedures. The result is the reconstruction of a 3-D model of the captured object featuring different characteristics in terms of accuracy and time needed to built it up. The goal of this work is the
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My �� Sn Sanctuary comprehends several ancient Hindu temples and is the most foremost heritage site of this nature in Vietnam. Part of the complex is today seriously damaged and needs restoration works. The temple G1 addressed in this... more
My �� Sn Sanctuary comprehends several ancient Hindu temples and is the most foremost heritage site of this nature in Vietnam. Part of the complex is today seriously damaged and needs restoration works. The temple G1 addressed in this work represents a pilot case to establish a workflow for both documentation and conservation purposes. Both aims required as primary need
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Nowadays orthophotos from satellite and aerial imagery are very requested products, considering their low cost motivated by the highly automated production chain. The generation of orthophotos requires a block of oriented images and a... more
Nowadays orthophotos from satellite and aerial imagery are very requested products, considering their low cost motivated by the highly automated production chain. The generation of orthophotos requires a block of oriented images and a digital model of the ground (DTM or DSM). In case a DTM is adopted, the lackness of information about buildings results in distortions. The availability of a LiDAR DDSM allows to overcome this problem, even though if the spatial resolution is not very high, some problems in correspondence of building contour might arise. To solve for this drawback, a method based on thickening a LiDAR DDSM from an initial grid of 2×2 m2 to a 0.2×0.2 m2 one is proposed here. This method has been implemented by exploiting the availability of a spatial DB of the same area, which allows to classify all points of the thickened DDSM in two categories: those belonging to a building and those not. A test of the method has been carried out on a photogrammetric block taken over ...
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It is normal for tourists to take photos during their holidays, which are then printed, loaded into digital frames or shared on the Internet. This paper describes a new methodology to obtain accurate 3D digital models and material... more
It is normal for tourists to take photos during their holidays, which are then printed, loaded into digital frames or shared on the Internet. This paper describes a new methodology to obtain accurate 3D digital models and material replicas of real objects, starting from digital images acquired with consumer and professional cameras. The implemented software is completely automatic and provides detailed reconstructions. It stands out from other existing approaches for the high metric accuracy of the final product, the level of detail obtainable, the speed of the algorithms and its adaptability under different viewing conditions. Several examples relating to an actual trip to Rome are reported and discussed, showing what a tourist can obtain with this package. Obviously, the method can be used for many other applications in which accurate models are needed.
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ABSTRACT In this paper an automated procedure for surface reconstruction that can be used for surveying and monitoring rock and ground slopes is presented. This method has been developed for geological and engineering applications, where... more
ABSTRACT In this paper an automated procedure for surface reconstruction that can be used for surveying and monitoring rock and ground slopes is presented. This method has been developed for geological and engineering applications, where accuracy and completeness are factors of primary importance for the final 3D model, which must provide a detailed metric survey and not only a visual reconstruction of the scene. The proposed procedure integrates two image matching techniques. The first one is used to automatically extract a set of tie points that are needed for computing the exterior orientation parameters of all images through a photogrammetric bundle adjustment. Such tie oints are also exploited to obtain a preliminary seed model that is then enriched based on Multi-photo Least Squares Matching. During this second stage, the surface model is improved in terms of point density and accuracy. Different strategies were implemented to successfully combine both techniques, along with some new improvements. The presented procedure has been tested in two different applications: geometric modelling of rock cliffs and evaluation of weathering of a ground slope. In both cases the obtained results presented accuracy sufficient for geological investigation. Moreover, outcomes were comparable to the ones from laser scanning surveying and other photogrammetric implementations.
... Sequence name image res. # images RMSE self-calibration # 3D points accuracy Navona 4000×3000 px 92 0.7 px no ca 18300 1:6900 Sequence name image res. # images RMSE self-calibration # 3D points accuracy Campidoglio 4416×3312 52 1.19... more
... Sequence name image res. # images RMSE self-calibration # 3D points accuracy Navona 4000×3000 px 92 0.7 px no ca 18300 1:6900 Sequence name image res. # images RMSE self-calibration # 3D points accuracy Campidoglio 4416×3312 52 1.19 px yes ca 11720 1:1200 ...
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The identification of a parallelogram in the image plane, along with the knowledge of camera parameters, allows metric properties to be recovered. This paper presents a methodology capable of estimating a rectifying homography for images... more
The identification of a parallelogram in the image plane, along with the knowledge of camera parameters, allows metric properties to be recovered. This paper presents a methodology capable of estimating a rectifying homography for images of planar objects without taking any measurement on the world plane. The rectified image will have only an overall scale ambiguity. The method was implemented to create a photogrammetric package for the estimation of the proposed projective transformation. This package was also extended to compute homographic transformations with standard techniques, such as ground control points, rectangles with a known length ratio, and squares. Examples are presented using synthetic and real data acquired for different purposes, including HDR and panoramic photography. Finally, a practical test with two photogrammetric staffs was carried out to check the accuracy of the procedure, starting from the same quantities measured with an optical level.
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Multi-temporal and multi-source images gathered from satellite platforms are nowadays a fundamental source of information in several domains. One of the main challenges in the fusion of different data sets consists in the registration... more
Multi-temporal and multi-source images gathered from satellite platforms are nowadays a fundamental source of information in several domains. One of the main challenges in the fusion of different data sets consists in the registration issue, i.e., the integration into the same framework of images collected with different spatial resolution and acquisition geometry. This paper presents a novel methodology to accomplish this task on the basis of a method that stands out from existing approaches. The whole data (time series) set is simultaneously co-registered with a two-dimensional multiple Least Squares adjustment with different geometric transformations implemented. Some tests were carried out with different geometric transformation models (including similarity, affine, and polynomial) and variable matching thresholds. They showed a sub-pixel precision after the computation of multiple adjustment. The use of multi-image corresponding points allowed the improvement of the registratio...
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ABSTRACT Image-to-image co-registration is one of the preprocessing steps needed for the analysis of satellite time series. This chapter presents a new approach where all the available images are simultaneously co-registered, overcoming... more
ABSTRACT Image-to-image co-registration is one of the preprocessing steps needed for the analysis of satellite time series. This chapter presents a new approach where all the available images are simultaneously co-registered, overcoming the limits of traditional techniques. This method was tested on the flood and landslide that occurred in Valtellina (northern Italy) during summer of 1987, resulting in the large rockslide of Val Pola. A data set made up of 13 medium-resolution satellite images collected with Landsat-4 and Landsat-5 Thematic Mapper over a period of 30 years was automatically processed. Results showed that the new approach can provide subpixel accuracy close to manual measurements, which today are considered the most accurate method for image registration. The multi-image co-registration method also demonstrated to be atmospheric resistant and robust against land-cover changes, snow, and cloud cover.
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... Raffaella BRUMANA, Daniela ORENI, Mario ALBA, Luigi BARAZZETTI, Branka CUCA, and Marco SCAIONI Politecnico di Milano, piazza Leonardo Da Vinci 32, Milan, Italy. {raffaella.brumana, daniela.oreni, mario.alba, luigi ...
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This paper presents an automated methodology for the accurate reconstruction of surfaces and 3D objects. This method was developed for close-range photogrammetric applications, with a particular attention to terrestrial free-form objects... more
This paper presents an automated methodology for the accurate reconstruction of surfaces and 3D objects. This method was developed for close-range photogrammetric applications, with a particular attention to terrestrial free-form objects that can be modeled with point clouds extracted from high resolution images. The image orientation phase is carried out using an automatic procedure based on a rigorous bundle adjustment.
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ABSTRACT
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This paper presents two methodologies able to map a block of IR thermal and RGB images on 3D models derived from terrestrial laser scanning surveying. Proposed methods stand out from other traditional approaches that are mainly based on... more
This paper presents two methodologies able to map a block of IR thermal and RGB images on 3D models derived from terrestrial laser scanning surveying. Proposed methods stand out from other traditional approaches that are mainly based on the projection of single ...
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ABSTRACT Two-dimensional Digital Image Correlation (DIC) is widely accepted and commonly used in the field of experimental mechanics as a practical and effective tool for quantitative in-plane deformation measurement of an object surface.... more
ABSTRACT Two-dimensional Digital Image Correlation (DIC) is widely accepted and commonly used in the field of experimental mechanics as a practical and effective tool for quantitative in-plane deformation measurement of an object surface. Cross-Correlation and Least Square Matching are the two most popular techniques for the extraction of image correspondences based on similarities between grey values. A comparative analysis between these two approaches is presented performing a simple test on a traditional brick for construction mounted on a micrometric sledge. Performance analysis in cases where good image data cannot be assumed (e.g. being the specimen surface not properly patterned and/or the camera used gives low quality images) are considered in particular.
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ABSTRACT Image-based deformation measurement (IBDM) techniques entail the use of image sequences for extracting metric information to be compared over time. Their applications may concern several domains, such as civil and mechanical... more
ABSTRACT Image-based deformation measurement (IBDM) techniques entail the use of image sequences for extracting metric information to be compared over time. Their applications may concern several domains, such as civil and mechanical engineering as well as geosciences. The rationale behind IBDM and the methodological classification are discussed in the paper along with some examples of application derived from the experience of the authors. The main advantages of IBDM techniques are the non-contact observational capability, the large coverage on the object along with high acquisition rate, as well as an improvement of the degree of image processing automation. In addition, IBDM is generally a relatively low-cost approach. After a short review of the current state of the art, applications are organized into three main categories: (1) photogrammetric coded-target measurements, (2) surface-point tracking to reconstruct dense displacement fields, and (3) comparison of surfaces obtained from dense image matching. Different camera configurations and geometric models to transform points from the image space to the object space are also discussed.