PHOTOGRAMMETRIC PROCESSING AND FRUITION OF PRODUCTS IN OPEN-SOURCE ENVIRONMENT APPLIED TO THE CASE STUDY OF THE ARCHAEOLOGICAL PARK OF POMPEII

Abstract. The paper presents the geomatic survey campaign carried out in the Domus V of Pompeii Archaeological site, the photogrammetric processing of the collected images and the following fruition of the deriving products deploying open-source software. Among all the produced results, the orthophotos of the vertical walls of one of the Domus V rooms are made available through a "master/slave" GIS environment, where each orthophoto is uploaded in a "slave" project whose visualization is triggered by querying the corresponding geometry representing the wall in the "master" project. This strategy allows to include the display of the third dimension, i.e., the altimetric one, within a traditional GIS environment, so to constitute a 3D GIS representation. This is particularly useful to realize a catalogue of all the archaeological site in the future to be viewed, queried and exploited also by non-specialists in geomatics or archaeology fields of knowledge

U.ph.o and mago: Two useful instruments in support of photogrammetric uav survey

In emergency and critical scenarios, the UAV could play a key role in accessing unreachable sites in a safe and rapid way, guaranteeing at the same time the necessary accuracy and precision of the survey. In this context, UAV survey campaigns have been performed by the authors in Norcia (Italy), hit by tragic seismic events in August and October 2016. The surveys were motivated by the artistic and historical value of monuments, the need to plan and design the restoring and retrofitting of buildings, and also to quantify and manage the ruins. Goal of such surveys was the description of the structures geometry with a centimetric precision and a high level of reliability. Recently, the authors have conceived two tools, U.Ph.O (Unmanned Photogrammetric Office) and MAGO (Adaptive Mesh for Orthophoto Generation), dedicated to the planning and restitution phases of the survey, respectively. U.Ph.O. and MAGO are here applied to two different buildings in Norcia, i.e. the Civic Tower of Norcia and San Salvatore Church of Campi di Norcia. The former is a standing-out structure, surrounded by the complex of the historical centre, while the latter is located in an isolated site in the countryside. These features make the survey planning and the orthophoto reconstruction completely different, mainly due to the different optimal shooting geometry and the presence or absence of obstructions

MAGO: A NEW APPROACH FOR ORTHOPHOTOS PRODUCTION BASED ON ADAPTIVE MESH RECONSTRUCTION

Orthophotos are one of the most common and typical products of a photogrammetric post-processing and, since the diffusion of specific software, their generation and usage have become even more widespread. In spite of it, some issues remain on the accuracy of orthophoto reconstruction, which is often downgraded by the introduction of meshes and Digital Surface Models to be used as surfaces representing the object. The use of a more accurate and reliable input, such as a point cloud, makes these approximations avoidable. For this reason, a new approach, termed MAGO (Adaptive Mesh for Orthophoto Reconstruction), is here delineated and proposed. The input data of the procedure are the user-defined orthophoto plane, the image and its internal and external orientation parameters, and a point cloud representing the object. Each pixel of the image is projected on the orthophoto plane at its original resolution via an iterative process, which builds an adaptive mesh, defined by means of the three best fitting points, where the collinearity rays and the point cloud intersect. After an overview on the method and its innovative features, an example on a test case is reported, together with a comparison between MAGO’s and another photogrammetric software results

Use of UAS for the conservation of historical buildings in case of emergencies

The task of conservation and management of cultural heritage is quite central in Italy, which lists a high number of beautiful architectures. A quick and precise survey may be requested in case of calamity. In the present paper, the most commonly used survey techniques are discussed, focusing on their applications for the conservation of the artistic heritage in case of emergency. Particular attention is given to Unmanned Aerial Systems (UAS) photogrammetry and its potentiality in obtaining good results in terms of speed, cheapness, precision and accuracy, assuring at the same time the safety of the operators in critical situations (e.g. natural disasters). A case study, realized at the Castle of Casalbagliano (Alessandria, Italy), is discussed. Different image block configurations and acquisition geometries (nadiral and oblique images) have been exploited, with the aim of defining useful guidelines for emergencies UAS survey of partially collapsed structures. An application to a significative case study is introduced

Algorithm Portfolios for Noisy Optimization: Compare Solvers Early

International audienceNoisy optimization is the optimization of objective functions corrupted by noise. A portfolio of algorithms is a set of algorithms equipped with an algorithm selection tool for distributing the compu- tational power among them. We study portfolios of noisy optimization solvers, show that different settings lead to dramatically different perfor- mances, obtain mathematically proved adaptivity by an ad hoc selection algorithm dedicated to noisy optimization. A somehow surprising result is that it is better to compare solvers with some lag; i.e., recommend the current recommendation of the best solver, selected from a comparison based on their recommendations earlier in the run

MAGO approach for semantic segmentation: the case study of UAVid benchmark dataset

The present work is focused on a semantic segmentation strategy implemented in the workflow of the tool MAGO (standing for \u201cAdaptive Mesh for Orthophoto Generation\u201d), considering the contribution of the 3D geometry and the colour information, both deriving from the point cloud of the scene. Moreover, the 2D source imagery, previously used to obtain the photogrammetric point cloud, is employed even to enhance the procedure with the recognition of moving objects, comparing the evolution of epochs. The analysed context is an urban scene, deriving from the UAVid dataset proposed for the ISPRS benchmark. In particular, the so-called \u201cseq18\u201d, a set of high-resolution oblique images taken by UAV (Unmanned Aerial Vehicle), has been used to test the semantic segmentation. The workflow includes the production of two Digital Surface Models (DSMs), containing the geometric and radiometric information, respectively, and their processing by means of the Harris corner detector, allowing the understanding of the image variability. Then, starting from the source geometry and colour information and combining them with their variability mapping, a preliminary classification is performed. Further criteria allow the segmentation of the humans and cars present in the scene. In particular, static objects are identified according to the content of the neighbour pixels in a certain kernel, while the evolution in time of moving elements is recognized by means of the comparison of the projected images belonging to the different epochs. The presented preliminary achievements show some criticalities that require further attention and improvement. In particular, the strategy could be enriched getting more information from the source 2D images, which at the moment are directly used only for the comparison of consecutive epochs

APPLICAZIONE DEL RILEVAMENTO GEOMATICO ALLA DOMUS DELLA REGINA D’INGHILTERRA A POMPEI (VII, 14, 5): RISULTATI PRELIMINARI

This work arises from the collaboration between the Laboratory of Archaeological Research Methodologies and the Laboratory of Geomatics of the University of Genoa, based on a multidisciplinary approach, combining archaeological and engineering skills. Since 2016, the team of archaeologists from the University of Genoa has been working inside the Pompeii Archaeological Park in the shops of insula 14 of Regio VII, an important area within the urban context as it overlooks Via dell'Abbondanza, the most important road, and it is located in a central position, in proximity to the main public areas, such as the Forum. From the beginning of the project to the present day, the archaeology team has analysed the tabernae from a stratigraphic point of view. So, simultaneously with the excavation activity, a stratigraphic analysis of the walls and coatings was carried out, involving both the commercial establishments being excavated and the three large houses of the insula, mainly focusing on the most western one, named 'Casa della Regina d'Inghilterra'. In September 2020, a survey campaign was carried out by geomatics engineers aiming to applying innovative survey methodologies to the architectural complex of the entire insula and, specifically, to the 'Casa della Regina d'Inghilterra'. In particular, the survey data were collected by total station, GNSS, laser scanner, combined with terrestrial and UAV photogrammetry. This paper presents the preliminary results obtained from the geomatic survey campaign, leading to the creation of an accurate photogrammetric model which can be used as a basis for a reconstructive model, whose hypotheses will be confirmed or denied by a future structural analysis

Educational Experiences for Geomatics Scientific Dissemination

The present work aims to illustrate the experience in geomatic dissemination, gained by actively participating and contributing to seminars, lectures and educational workshops, applying both traditional and innovative teaching methods. The main focus is on two educational workshops: one on altitude, its measurement techniques, issues and the evolution of the instrumentation employed; the second on photogrammetry applied to various environments and scenarios, such as securing buildings and ruins in emergencies or underwater analyses, mapping and surveying of coral reefs. In both workshops, the authors begin by capturing the attention with simple examples of every-day experiences related to the workshop\u2019s main theme, then give explanations using posters, videos, simple games and practical experiences that can improve understanding. The authors scientific dissemination highlights the concrete application of Geomatics in every-day life and enhances the audience emotional involvement. The workshops\u2019 main goal is to stimulate the audience curiosity to understand the basic concepts, starting from intuitive considerations and questions from the audience itself. This allows the introduction of the main concepts of Geomatics and highlights its full potential

Phase noise performances of a cross-coupled CMOS VCO with resistor tail biasing

The voltage controlled oscillator (VCO) is a fundamental block in RF IC architectures. Today's wireless communication applications do require a high level of performances from such a circuit, and specifically its phase noise figure and its power consumption. In fact, modern standards often demand for phase noise level better than -95 dBc/Hz at 100 KHz in the vast majority of cases, with supply voltages approaching the 1 V range. This paper presents the design challenges of a cross-coupled 1.8 GHz CMOS voltage controlled oscillator with a tuning range of 7%, and a phase noise figure of -113 dBc/Hz at an offset frequency of 100 KHz. It employs a resistor for biasing, avoiding in this way the common tail current source based on active circuitry (e.g. current mirrors in CMOS designs). This choice prevents the 1/f device noise upconversion, leading to an improved spectral purity. Since phase noise also varies with the reciprocal of the tail current, a trade-off can be established between noise performances and power consumption by simply changing the biasing resistor. The same circuit topology may thus be useful for building VCOs whose applications range from high performance wireless standards where an extremely low phase noise is mandatory, to low-cost portable systems where the reduced power drain is of major concern

Differential Cross-Coupled CMOS VCOs with Resistive and Inductive Tail Biasing

Todays Wireless Communication Systems need very high performance VCOs. In many cases, phase noise levels better than -100 dBc/Hz@100 kHz have to be reached with a power consumption lower than 10 mW. This work presents a 1.8 GHz CMOS VCO with a phase noise of -113 dBc/Hz@100 kHz, where a bias resistor avoids the MOS active current source and its related noise, while a tail inductor allows truly differential operation