Alberto Guarnieri

University of Padova | UNIPD · Department of Land, Environment, Agriculture and Forestry TESAF

Despite GNSS (Global Navigation Satellite System) enables positioning, navigation and timing (PNT) almost everywhere, the development of applications like self-driving vehicles and indoor navigation requires extending accurate positioning to scenarios where GNSS either is not reliable or does garantee a sufficiently precise solution. Integrating in...

Point clouds are collected nowadays from a plethora of sensors, some having higher accuracies and higher costs, some having lower accuracies but also lower costs. Not only there is a large choice for different sensors, but also these can be transported by different platforms, which can provide different scan geometries. In this work we test the ext...

The development of autonomous vehicles, both terrestrial and aerial ones (unmanned aerial system (UAS)), is causing the need of properly formulating appropriate solutions for ensuring a safe interaction between them, human beings and the infrastructures and environment in their operating area. To such aim, the knowledge of the positions of differen...

Massive point clouds have now become a common product from surveys using passive (photogrammetry) or active (laser scanning) technologies. A common question is what is the difference in terms of accuracy and precision of different technologies and processing options. In this work four ultra-dense point-clouds (PCs) from drone surveys are compared....

Despite the availability of GNSS on consumer devices enabled personal navigation for most of the World population in most of the outdoor conditions, the problem of precise pedestrian positioning is still quite challenging when indoors or, more in general, in GNSS-challenging working conditions. Furthermore, the covid-19 pandemic also raised of pede...

Point cloud semantic segmentation is a key step for automatically deriving an informative building model from the 3D data reconstruction obtained by 3D surveying tools, such as laser scanners and photogrammetry. Such representation increases the richness of the information available of the represented building, leading to an at least rough interpre...

Tracking locations is practical and speditive with smartphones, as they are omnipresent devices, relatively cheap, and have the necessary sensors for positioning and networking integrated in the same box. Nowadays recent models have GNSS antennas capable of receiving multiple constellations. In the proposed work we test the hypothesis that GNSS pos...

3D building modeling is becoming an important support in civil engineering, architecture and cultural heritage applications. Despite static laser scanning can be considered as the state-of-the-art in such kind of applications, mobile mapping techniques can be considered as a suitable alternative to quickly gather geospatial information. Outdoor mob...

The development and availability on consumer devices of the global navigation satellite systems (GNSS) have dramatically changed the everyday-life of most of the human population, enabling real time navigation on almost any smart device produced in the last years. However, such strong dependence on the availability of the GNSS limits the further sp...

Tracking locations is practical and speditive with smartphones, as they are omnipresent devices, relatively cheap, and have the necessary sensors for positioning and networking integrated in the same box. Nowadays recent models have GNSS antennas capable of receiving multiple constellations. In the proposed work we test the hypothesis that GNSS pos...

Mobile mapping system have been used in a wide range of applications during the last decades, most of the times with the goal of quickly and quite reliably acquiring georeferenced spatial information of relatively large areas of interest. Indeed, such kind of systems are often preferred to static surveying techniques when dealing with relatively la...

Nowadays time-of-flight (ToF) cameras and multiple RGB cameras are being embedded in an increasing number of high-end smartphones: despite their integration in mobile devices is mostly motivated by photographic applications, their availability can be exploited to enable 3D reconstructions directly on smartphones. Furthermore, even when a ToF camera...

Given the worldwide spread of smartphones, photogram-metric surveying with mobile devices is becoming of significant interest in the research community for providing low cost three-dimensional (3D) models. Since the photogram-metric procedure applied to images produces a projective model, some external information is needed in order to obtain a 3D...

Despite photogrammetry has been longly used for 3D model production, the recent development of structure from motion based reconstructions and the spread of unmanned aerial vehicles (UAV) are increasing its usage even further. Actually, the combined use of nadir and oblique UAV photogrammetry allows to cross the bridge between close range and aeria...

The Worldwide spread of relatively low cost mobile devices embedded with dual rear cameras enables the possibility of exploiting smartphone stereo vision for producing 3D models. Despite such idea is quite attractive, the small baseline between the two cameras restricts the depth discrimination ability of this kind of stereo vision systems. This pa...

Photogrammetry is one of the most used techniques for monitoring and surveying. It is widely used in several applications and in different working conditions. Accuracy of photogrammetry reconstruction methods may change depending on the working conditions (e.g. the number of acquired images, lighting conditions, baselines between images), and it is...

The subject of photogrammetric surveying with mobile devices, in particular smartphones, is becoming of significant interest in the research community. Nowadays, the process of providing 3D point clouds with photogrammetric procedures is well known. However, external information is still typically needed in order to move from the point cloud obtain...

During the past dozen years, several mobile mapping systems based on the use of imaging and positioning sensors mounted on terrestrial (and aerial) vehicles have been developed. Recently, systems characterized by an increased portability have been proposed in order to enable mobile mapping in environments that are difficult to access for vehicles,...

Photogrammetry has been widely used in the recent years in a number of applications, e.g. cultural heritage, surveying buildings and infrastructures. Despite nowadays its use is quite common, most of the used photogrammetric softwares are commercial. This paper aims at comparing the use of a free Matlab tool that is being developed at the Universit...

This paper considers Leica backpack and photogrammetric surveys of a mediaeval bastion in Padua, Italy. Furhtermore, terrestrial laser scanning (TLS) survey is considered in order to provide a state of the art reconstruction of the bastion. Despite control points are typically used to avoid deformations in photogrammetric surveys and ensure correct...

It is a matter of fact that 3D visualisation and proper documentation of cultural objects helps to preserve the history and memories of historic buildings, archaeological sites and cultural landscapes, and supports economic growth by stimulating cultural tourism. Preservation, visualisation and recreation of valuable historical and architectural ob...

In the last decade advances in the fields of close-range photogrammetry, terrestrial laser scanning (TLS) and computer vision (CV) have enabled to collect different kind of information about a Cultural Heritage objects and to carry out highly accurate 3D models. Additionally, the integration between laser scanning technology and Finite Element Anal...

This paper considers the use of a low cost mobile device in order to develop a mobile mapping system (MMS), which exploits only sensors embedded in the device. The goal is to make this MMS usable and reliable even in difficult environments (e.g. emergency conditions, when also WiFi connection might not work). For this aim, a navigation system able...

In this paper we present the results of the development of a Web-based archiving and documenting system aimed to the management of multisource and multitemporal data related to cultural heritage. As case study we selected the building complex of Villa Revedin Bolasco in Castefranco Veneto (Treviso, Italy) and its park. Buildings and park were built...

In this paper we present the results of the development of a Web-based archiving and documenting system aimed to the management of multisource and multitemporal data related to cultural heritage. As case study we selected the building complex of Villa Revedin Bolasco in Castefranco Veneto (Treviso, Italy) and its park. Buildings and park were built...

Nowadays photogrammetry and laser scanning methods are the most wide spread surveying techniques. Laser scanning methods usually allow to obtain more accurate results with respect to photogrammetry, but their use have some issues, e.g. related to the high cost of the instrumentation and the typical need of high qualified personnel to acquire experi...

Nowadays photogrammetry and laser scanning methods are the most wide spread surveying techniques. Laser scanning methods usually allow to obtain more accurate results with respect to photogrammetry, but their use have some issues, e.g. related to the high cost of the instrumentation and the typical need of high qualified personnel to acquire experi...

In recent years, Unmanned Aerial Vehicles (UAVs) are attracting more and more attention in both the research and industrial communities: indeed, the possibility to use them in a wide range of remote sensing applications makes them a very flexible and attractive solution in both civil and commercial cases (e.g. precision agriculture, security and co...

Due to the effect of climate factors, natural phenomena and human usage, buildings and infrastructures are subject of progressive degradation. The deterioration of these structures has to be monitored in order to avoid hazards for human beings and for the natural environment in their neighborhood. Hence, on the one hand, monitoring such infrastruct...

Recently, several works have been proposed in the literature to take advantage of the diffusion of smartphones to improve people experience during museum visits. The rationale is that of substituting traditional written/audio guides with interactive electronic guides usable on a mobile phone. Augmented reality systems are usually considered to make...

In accordance with recent studies, most of the observed natural hazards throughout the globe are related to the dynamics of hydrological variability. This determines the fundamental importance of studies related to hydrogeological risk assessment, in terms of both prevention and mitigation of damages; science shall provide the modelling and forecas...

This paper deals with the study of the dynamics of a landslide from two different but complementary point of views. The landslide is situated within the Miozza basin, an area of approximately 10.7 km² located in the Alpine region of Carnia (Italy). In the first part of the paper, the macro-scale analysis of volumetric changes occurred after the rea...

Different high-resolution techniques can be employed to obtain information about the 3D surface of glaciers. This is typically carried out using efficient, but also expensive and logistically demanding, light detection and ranging (LiDAR) technologies, such as airborne scanners and terrestrial laser scanners (TLSs). Recent technological improvement...

In this chapter, we evaluate the movement of 6 points near a landslide body, which were surveyed with GNSS receivers over time. We apply Bayesian inference to identify the areas on the ground with statistically significant vertical (downwards) shifts. Traditional statistical methods work well only when point displacements between different survey e...

This paper considers the problem of indoor navigation by means of low-cost mobile devices. The required accuracy, the low reliability of low-cost sensor measurements and the typical unavailability of the GPS signal make indoor navigation a challenging problem. In this paper, a particle filtering approach is presented in order to obtain good navigat...

The continuous technological improvement of mobile devices opens the frontiers of Mobile Mapping systems to very compact systems, i.e. a smartphone or a tablet. This motivates the development of efficient 3D reconstruction techniques based on the sensors typically embedded in such devices, i.e. imaging sensors, GPS and Inertial Navigation System (I...

The objective of this report is to present and discuss a work-flow for extracting, from full-waveform (FW) lidar data, formats which are compatible with common information systems (GIS) and statistical software packages. Full-waveform, specifically for forestry, got attention from the scientific community because a more in-depth analysis can add va...

The development of Mobile Mapping systems over the last decades allowed to quickly collect georeferenced spatial measurements by means of sensors mounted on mobile vehicles. Despite the large number of applications that can potentially take advantage of such systems, because of their cost their use is currently typically limited to certain speciali...

Digital elevation models (DEMs) of glaciated terrain are commonly used to measure changes in geometry and hence infer the mass balance of glaciers. Different tools and methods exist to obtain information about the 3D geometry of terrain. Recent improvements on the quality and performance of digital cameras for close-range photogrammetry, and the de...

Digital elevation models (DEMs) of glaciated terrain are commonly used to measure changes in geometry and hence infer the mass balance of glaciers. Different tools and methods exist to obtain information about the 3D geometry of terrain. Recent improvements on the quality and performance of digital cameras for close-range photogrammetry, and the de...

Discriminating laser scanner data points belonging to ground from points above-ground (vegetation or buildings) is a key issue in research. Methods for filtering points into ground and non-ground classes have been widely studied mostly on datasets derived from airborne laser scanners, less so for terrestrial laser scanners. Recent developments in t...

In this article, we present an investigation regarding the differences between a full-waveform and a discrete-return terrestrial laser scanner employed in a survey of a mountain area with dense vegetation. The Riegl LMS-Z620 provides discrete returns whereas the Riegl VZ-400 provides multiple returns with associated width and amplitude of the peaks...

For a correct use of metrics derived from processing of the full-waveform return signal from airborne laser scanner sensors any correlation which is not related to properties of the reflecting target must be known and, if possible, removed. In the following article we report on an analysis of correlation between several metrics extracted from the f...

In the last decades, the topic of coastal erosion and the derived risk have been subject of a growing interest for public authorities and researchers. Recent major natural events, such as hurricanes, tsunamis, and sea level rising, called the attention of media and society, underlining serious concerns about such problems. In a high-density populat...

Smaller glaciers (<0.5 km2) react quickly to environmental changes and typically show a large scatter in their individual response. Accounting for these ice bodies is essential for assessing regional glacier change, given their high number and contribution to the total loss of glacier area in mountain regions. However, studying small glaciers using...

The possibility to identify with significant accuracy the position of a vehicle in a mapping reference frame for driving directions and best-route analysis is a topic which is attracting a lot of interest from the research and development sector. To reach the objective of accurate vehicle positioning and integrate response events, it is necessary t...

The demand for high-definition surveys within cultural heritage-related projects represents one of the main factors that promoted the use of laser scanning technology and photogrammetry. By measuring millions of points within relatively short time periods, terrestrial laser scanners (TLS) allows to researchers to derive complete and very detailed t...

In this paper we present the results related to several field campaigns conducted in the last three years in a small (4.4 km2) wilderness basin in Carnia, a tectonically active alpine region in northeast Italy. The study area is a typical alpine debris-flow dominated catchment where several landslides, including a significantly large one, were obse...

Laser scanner technology can be very useful for applications relative to surveying river-beds with high and very high resolution (sampling heights at one meter spacing or less). A 3D model of structures including the river-bed, sides and contiguous areas allows to develop rigorous hydraulic models relative to flooding predictions and to the estimat...

Full-waveform is becoming increasingly available in today's LiDAR systems and the analysis of the full return signal can provide additional information on the reflecting surfaces. In this paper we present the results of an assessment on full-waveform analysis, as opposed to the more classic discrete return analysis, for discerning vegetation cover...

In this paper we present the results of the comparison between two terrestrial laser scanners (TLS), a discrete return system (Riegl LMS-Z620) and an echo-digitizing system (Riegl VZ-400), employed for the survey of a dense forested area, in the italian Alps. The site is actually undergoing a strong debate among the inhabitants and local government...

A great number of papers have been so far published about the comparison and the integration between terrestrial laser scanning and digital photogrammetry, as surveying and 3D modeling techniques. Though most of the works report about their application to Cultural Heritage, achieved results have shown that these two technologies can supplement each...

Distinguishing vegetation characteristics in a terrestrial laser scanner dataset is an interesting issue for environmental assessment. Methods for filtering vegetation points to distinguish them from ground class have been widely studied mostly on datasets derived from airborne laser scanner, less so for terrestrial laser scanners (TLS). Recent dev...

In this paper we present the first part of a potential project aimed at the development of an autonomous model helicopter. Such vehicle will be used for land photogrammetric surveying, for documentation of archeological sites, for detection of polluted areas at sea and for many other situations where remote surveying is a definite advantage due to...

Full waveform airborne laser scanning for mapping morphometric parameters in terrain with varying vegetation cover

Both Terrestrial Laser Scanner (TLS) and Airborne Laser Swath Mapping technology (ALSM), using LiDAR (Light Detection And Ranging) technology, provide high resolution topographic data with notable advantages over traditional survey techniques. This technology found increasing application on glaciers in the last decade, since it provides detailed in...

Terrestrial laser scanning technique has represented one of the more advances occurred in the last years in the field of data acquisition. Time-of-Flight (TOF) systems provide a fast and reliable tool to measure millions of 3D points allowing a very effective and dense measurement of the surface geometry. Nowadays, the generation of high quality 3D...

Abstract This article presents a methodology for designing a WebGIS framework intended for automatically analyzing spatial data and updating statistics of interest with new information inserted daily by multiple users via a Web portal. A practical example is used on vehicle accident data for assessing risk in specific road segments. Two main blocks...

Cultural heritage sites and artefacts get a significant added value from high-resolution 3D models. These models are increasingly available due to improvements in technology and to higher integration of survey techniques such as laser scanning and photogrammetry. In this paper we present a case study on the development of a web-based application fo...

This paper reports the results of a comparative analysis between airborne discrete return lidar and satellite waveform lidar. Morphological and vegetation indices extracted from the two types of lidar have been analyzed to assess correlation, considering the discrete return lidar as reference because of its higher resolution. For each waveform lida...

In recent years, the integration between laser scanning technology and photogrammetry has been proven to be a very effective methodology to provide high-resolution 3D models of heritage sites and cultural artifacts. Furthermore, the availability for faster connections to the Internet and for more performing servers and browsers have pushed the deve...

In the last years UAV (Unmanned Aerial Vehicle) systems are become very actractive for various commercial, industrial, public, scientific and military operations. The tasks include pipeline inspection, dam surveillance, photogrammetric survey, infrastructure maintenance, inspection of flooded areas, fire fighting, terrain monitoring, volcano observ...

Road accidents have a definite impact in terms of lives, welfare and traffic congestion, especially with increase in mobility and number of overall vehicles. Prevention policies can greatly benefit from data analysis of positions and accident characteristics. This work presents a practical integration of open source software for the implementation...

Marshes are ubiquitous landforms in estuaries and lagoons, where important hydrological, morphological and ecological processes take place. These areas attenuate sea action on the coast and act as sediment trapping zones. Due to their ecosystem functions and effects on coastal stabilization, marshes are crucial structures in tidal environments, bot...

Nowadays earth survey tends to get increasingly automated using mobile mapping systems integrated with Global Positioning System (OPS) geographic reference frame (WGS84). Very common cartographic representations are the ones which use an aphylactic because it represents the areas of objects with very little error and is thus very useful for the cad...

In the last years, unmanned aerial vehicle (UAV) systems have become very attractive for various commercial, industrial, public, scientific, and military operations. Potential tasks include pipeline inspection, dam surveillance, photogrammetric survey, infrastructure maintenance, inspection of flooded areas, fire fighting, terrain monitoring, volca...

This paper reports an analysis of results from processing return signals from canopy covers using a artificial neural network to find if there is an improvement on detecting tree height and position compared to a more classic local maximum filter approach. The hypothesis taken into consideration is that a neural network permits to insert several us...

In this paper we present the preliminary results of a study aimed to assess the stability of a complex historical structure such as the Anatomy Theatre. The construction occupies the two upper floors on the north west side of Palazzo del Bo', the building seat of the University of Padua. The Anatomy Theatre is certainly one of the oldest, most impo...

The plenty of works presented in last two years about the use of 3D models in the field of Cultural Heritage witness the great interest of surveyors, engineers, architects and archaeologists towards the laser scanning technique as an invaluable surveying mean for asbuilt documentation, digital archiving and restoration of important elements belongi...

Over the years, MMS systems have demonstrated that accuracies suitable for all but the most demanding cadastral and engineering applications can be achieved. This result, combined with a reduction in both the time and cost of data collection, made MMS a very interesting technology potentially able to meet the demand of GIS operators for rapid spati...

RIASSUNTO Negli anni recenti, la possibilità offerta dal laser scanner terrestre di acquisire grandi quantità di dati in tempi relativamente brevi, con un grado di precisione e dettaglio elevati, ha spinto l'interesse di topografi, ingegneri, architetti e archeologi a considerare il laser a scansione come uno strumento di rilevamento fondamentale p...

Observational fluvial geomorphology has greatly benefited in the last decades from the wide availability of digital terrain data obtained by orthophotos and by means of accurate airborne laser scanner data (LiDAR). On the contrary, the spatially-distributed study of the geomorphology of intertidal areas, such as tidal flats and marshes, remains pro...