27 research outputs found
Terrestrial mobile mapping: photogrammetric simulator
No full textNowadays many types of sensors are used for terrestrial mobile mapping (TMM): IMU, odometers, GNSS, cameras, etc., and it is essential to understand how these sensors can improve the solution in terms of precision, accuracy and reliability. TMM issues are characterized by many variables: vehicle trajectory, the height of the buildings and the distance between them, traffic conditions, the presence or absence of trees, the level of illumination, etc. The aim of this study is to determine how photogrammetric measurements can improve the quality of TMM solution at least concerning magnitude and error propagation when there is no GNSS signal (for example in an urban canyon). Another purpose of the study was to determine the most suitable design project for a specific relief in order to obtain the best possible photogrammetric results. By analyzing the error propagation in the various components of relative orientation along the trajectory and considering a sequence of images characterized by an overlap varying between 60 to 90% and the same number of tie points, results were obtained which confirmed the reliability of the data produced by the simulator. These results are shown in this pape
ODOMETRY AND LOW-COST SENSOR FUSION IN TMM DATASET
No full textThe aim of this study is to identify the most powerful motion model and filtering technique to represent an urban terrestrial mobile
mapping (TMM) survey and ultimately to obtain the best representation of the car trajectory. The authors want to test how far a
motion model and a more or less refined filtering technique could bring benefits in the determination of the car trajectory.
To achieve the necessary data for the application of the motion models and the filtering techniques described in the article, the
authors realized a TMM survey in the urban centre of Turin by equipping a vehicle with various instruments: a low-cost action-cam
also able to record the GPS trace of the vehicle even in the presence of obstructions, an inertial measurement system and an
odometer.
The results of analysis show in the article indicate that the Unscented Kalman Filter (UKF) technique provides good results in the
determination of the vehicle trajectory, especially if the motion model considers more states (such as the positions, the tangential
velocity, the angular velocity, the heading, the acceleration). The authors also compared the results obtained with a motion model
characterized by four, five and six states.
A natural corollary to this work would be the introduction to the UKF of the photogrammetric information obtained by the same
camera placed on board the vehicle. These data would permit to establish how photogrammetric measurements can improve the
quality of TMM solutions, especially in the absence of GPS signals (like urban canyons)
Real-time monitoring for fast deformations using GNSS low-cost receivers
No full textLandslides are one of the major geo-hazards which have constantly affected Italy especially over the last few years. In fact 82% of the Italian territory is affected by this phenomenon which destroys the environment and often causes deaths: therefore it is necessary to monitor these effects in order to detect and prevent these risks. Nowadays, most of this type of monitoring is carried out by using traditional topographic instruments (e.g. total stations) or satellite techniques such as GNSS receivers. The level of accuracy obtainable with these instruments is sub-centimetrical in post-processing and centimetrical in real-time however there are very high costs (many thousands of euros). The rapid diffusion of GNSS networks has lead to an increase of using mass-market receivers for real-time positioning. In this paper, the performances of GNSS mass-market receiver are reported with the aim of verifying if this type of sensor can be used for real-time landslide monitoring: for this purpose a special slide was used for simulating a landslide, since it enabled us to give manual displacements thanks to a micrometre screw. These experiments were also carried out by considering a specific statistical test (a modified Chow test) which enabled us to understand if there were any displacements from a statistical point of view in real time. The tests, the algorithm and results are reported in this paper
Figure. 1 Dendrapta nasicola n in Dendrapta nasicola n. sp. (Copepoda: Siphonostomatoida: Lernaeopodidae) a parasite from the olfactory sacs of Bathyraja scaphiops (Norman, 1937) in the South Western Atlantic
No full textFigure. 1 Dendrapta nasicola n. sp. (adult female) from Bathyraja scaphiops (Arhynchobatidae). a general habitus (lateral view), composite drawing. b general habitus (ventral view) c antennule. d mandible. e antenna. f maxillule. g maxilliped. Scale bars: a, b = 2.5 mm; c–g = 50 μm.Published as part of Irrigoitia, Manuel M., Taglioretti, Verónica & Timi, Juan T., 2020, Dendrapta nasicola n. sp. (Copepoda: Siphonostomatoida: Lernaeopodidae) a parasite from the olfactory sacs of Bathyraja scaphiops (Norman, 1937) in the South Western Atlantic, pp. 1-8 in Annals of the Brazilian Academy of Sciences 92 on page 4, DOI: 10.1590/0001-3765202020180933, http://zenodo.org/record/462380
Il posizionamento NRTK in alta quota: applicazioni e risultati nell'ambito del progetto Helidem
No full textIl presente lavoro si colloca nel progetto INTERREG Italia-Svizzera 2007-2013 HELIDEM. In tale ambito era prevista ed è stata istituita una rete di stazioni permanenti a copertura delle aree alpine di Piemonte, Lombardia e parte della Svizzera. Tale rete costituisce un prototipo, seppur limitato a una piccola area, di servizio di posizionamento transnazionale ottenuto mediante unificazione di reti regionali già installate: inoltre, nell'ambito del progetto, fornirà il sistema di riferimento per rilievi (in tempo reale e post-elaborati) finalizzati all'unificazione dei Modelli Digitali dei Terreno e del modello delle altezze (geoide) per le aree di progetto. Nel presente lavoro viene descritta la rete e le modalità con cui è stata inquadrata nel sistema di riferimento ETRF2000. Vengono inoltre discussi i primi test di posizionamento cinematico, sia in tempo reale sia post-elaborato, appoggiato alla rete. Particolarmente interessanti sono i confronti fra risultati in bassa e alta quota, che permettono considerazioni non intuitiv
On outlier detection in a photogrammetric mobile mapping dataset
No full textVarious types of technology are used for Terrestrial Mobile Mapping (TMM) such as IMU, cameras, odometers, laser scanner etc., which are integrated in order to determine the attitude and the position of the vehicle in use, especially in the absence of GNSS signal i.e. in an urban canyon. The aim of this study is to use only photogrammetric measurements obtained with a low cost camera (with a reduced focal length and small frames) located on the vehicle, in order to improve the quality of TMM solution in the absence of a GNSS signal. It is essential to have good quality frames in order to solve this problem. In fact it is generally quite easy to extract a large number of common points between the frames (the so-called 'tie points'), but this does not necessarily imply the goodness of the matching quality, which might be uncorrected due to the presence of obstacles that may occlude the camera sight. The Authors used two different methods for solving the problem of the presence of outliers: RANSAC and the Forward Search. In this article the Authors show the results obtainable with good quality frames (frames without occlusions) and under difficult conditions that simulate better realit
Figure. 3 Dendrapta nasicola n in Dendrapta nasicola n. sp. (Copepoda: Siphonostomatoida: Lernaeopodidae) a parasite from the olfactory sacs of Bathyraja scaphiops (Norman, 1937) in the South Western Atlantic
No full textFigure. 3 Dendrapta nasicola n. sp. (adult female) from Bathyraja scaphiops (Arhynchobatidae), scanning electron micrographs (SEM). a cephalothorax (ventral view). b buccal appendices (ventral view). c buccal appendices (lateral view). d mouth cone detail (lateral view). e antenna. f maxillule. g maxilla. h bulla. Abbreviations: A1 Antennule. A2 Antenna. MC Mouth cone. Mx1 Maxillule. Mx2 Maxilla Mxp Maxilliped. Scale bars: a = 500 μm; b, c = 100 μm; d, h = 10 μm; e = 50 μm; f = 20 μm; g = 1 mm.Published as part of Irrigoitia, Manuel M., Taglioretti, Verónica & Timi, Juan T., 2020, Dendrapta nasicola n. sp. (Copepoda: Siphonostomatoida: Lernaeopodidae) a parasite from the olfactory sacs of Bathyraja scaphiops (Norman, 1937) in the South Western Atlantic, pp. 1-8 in Annals of the Brazilian Academy of Sciences 92 on page 6, DOI: 10.1590/0001-3765202020180933, http://zenodo.org/record/462380
Prenatal invasive diagnosis for congenital Toxoplasmosis by PCR for specific DNA Toxoplasma sequences
No full textnon disponibil
Progetto Riswagest: individuazione delle aree della Lomellina più vocate ad adottare la tecnica irrigua dell’AWD
No full text
