549 research outputs found
Geodetic datums of the Italian cadastral systems
No full textThe geodetic datum, and its possible descriptions, of the Italian cadastral networks are analyzed, in order to provide a solution to fit the cadastral sheets to modern map contents and grids, using just their corner crosshair data. Analyzing the extension of the Genova 1902 datum to the whole Italian territory, it occured that the transformation error is acceptable only in the original survey area of the respective triangulation net. For Souther Italy and Sicily (Sicilia), the errors exceed the 20 meters. The Molodensky-type transformation parameters of the Castanea della Furie 1910 and the Guardia Vecchia (Sardinia) datums are provided using only their fundamental point coordinates, without error estimation. While these datums are not correctly checked at their whole application are, we suggest to define local datums of the Bessel ellipsoid, using the Bessel and WGS84coordinates of the respective cadastral grid origins and use them for geo-reference as a basis of the local Cassini grids
Proposal of an abridged procedure to manage Cadastral maps in an open GIS package
No full textCadastral cartography, born after unification of Italy in 1870, is an important source of large scale geographic
information.
Cadastral maps represent the result of the largest scale survey of on the whole national territory. Because of
their large scale, their creation is extremely expensive and the updating of the cadastre claim considerable
funds from the state budgets. That’s why the coordinate system, the geodetic basis of a cadastral work, is
rarely changed.
Even if Gauss-Boaga grid system based on ROMA40 datum was introduced and applied at some smaller
parts of the country, the cartographic coordinates manly used in the cadastral maps are based on CassiniSoldner
projection and cadastral datum Bessel-Genova; Bessel_Monte Mario and Bessel Castanea delle
Furie.
In the Cassini-Soldner projection, the whole Italian territory is subdivided in 31 major ("grandi origini") and
more than 800 local ("piccole origini") cadastral systems.
Nowadays, it is fundamental the implementation of a fast and free procedure for the updating of cadastral
maps from Italian cadastral datum to modern WGS84.
The two main goals of this paper are: the identification of a suitable set of points with coordinates known in
both datums and the computation of Abridging Molodensky parameters from Cassini-Soldner cadastral
datum to WGS84. The test area selected is the district of Rome called “Città metropolitana di Roma
Capitale” .
The data set of points suitable for the least-square estimation is extracted from the information available on
the website www.globogis.it/fiduciali.it.
The "globogis" database includes a selection of trigonometric points, with coordinates expressed in the
WGS84 datum, and a selection of cadastral points ("punti fiduciali") with coordinates expressed in the
Bessel-Genova 1902 datum. The whole database is analysed in order to provide the correct association
between cadastral and trigonometric points.
Known the dataset of points, the Abridging Molodensky parameters are estimated with a least square
principle using a specific package developed by Prof. Timar.
The estimated parameters are implemented and tested in the open source software QGIS. The accuracy of
Abridging Molodensky parameters is tested using an independent set of point with respect to the estimation
points
Luminescence properties of natural muscovite relevant to optical dating of contaminated quartz samples
No full textMuscovite is a mineral commonly found along quartz in sediments, where the latter is the mineral of choice in numerous optically stimulated luminescence (OSL) dating studies. Since muscovite cannot be efficiently eliminated following standard laboratory treatments, it is important to assess its luminescence properties. This study is focused on the investigation of muscovite hand-picked from a quartz sample extracted from loess and of museum specimens of muscovite in order to evaluate their potential implication in the OSL dating of quartz samples contaminated with muscovite grains. The obtained results show that generally applicable luminescence characteristics cannot be described for muscovite. In terms of the thermoluminescence (TL) response, all samples investigated display the same wide peak at 200 °C. The blue light and infrared (IR) sensitivities differ between the samples: 3 out of 5 samples present no or negligible level of OSL and IRSL response, while the other 2 samples are characterised by both blue light (2000–3400 counts in 0.31 s of stimulation for 10 mg of muscovite after irradiation with a dose of 136 Gy) and IR sensitivity (265–320 counts in 0.31 s of stimulation for 10 mg of muscovite after irradiation with a dose of 136 Gy). Based on the samples analysed in this study, aliquots of quartz contaminated with optically (blue light) sensitive muscovite would also be IR sensitive. Hence, potentially problematic aliquots can be identified via the IRSL purity test usually used in the OSL dating of quartz samples for detection of feldspar contamination. The impact of muscovite on dose determination for quartz was also tested and it was concluded that at least in the case of bright quartz, muscovite minerals do not influence the OSL measurements.</p
Uncovering the limits of uniqueness in sampled Gabor phase retrieval: A dense set of counterexamples in L2(ℝ)
No full textSampled Gabor phase retrieval — the problem of recovering a square-integrable signal from the magnitude of its Gabor transform sampled on a lattice — is a fundamental problem in signal processing, with important applications in areas such as imaging and audio processing. Recently, a classification of square-integrable signals which are not phase retrievable from Gabor measurements on parallel lines has been presented. This classification was used to exhibit a family of counterexamples to uniqueness in sampled Gabor phase retrieval. Here, we show that the set of counterexamples to uniqueness in sampled Gabor phase retrieval is dense in L2(ℝ), but is not equal to the whole of L2(ℝ) in general. Overall, our work contributes to a better understanding of the fundamental limits of sampled Gabor phase retrieval.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Analysi
Gabor Frames for Model Sets
No full textWe generalize three main concepts of Gabor analysis for lattices to the setting of model sets: fundamental identity of Gabor analysis, Janssen’s representation of the frame operator and Wexler–Raz biorthogonality relations. Utilizing the connection between model sets and almost periodic functions, as well as Poisson’s summations formula for model sets we develop a form of a bracket product that plays a central role in our approach. Furthermore, we show that, if a Gabor system for a model set admits a dual which is of Gabor type, then the density of the model set has to be greater than one.© The Author(s) 201
A fast learning algorithm for Gabor transformation
No full textAn adaptive learning approach for the computation of the coefficients of the generalized nonorthogonal 2-D Gabor transform representation is introduced in this correspondence. The algorithm uses a recursive least squares (RLS) type algorithm. The aim is to achieve minimum mean squared error for the reconstructed image from the set of the Gabor coefficients. The proposed RLS learning offers better accuracy and faster convergence behavior when compared with the least mean squares (LMS)-based algorithms. Applications of this scheme in image data reduction are also demonstrated
Palmprint Identification Using Gabor and Wide Principal Line Features
No full textAbstractIn this paper proposed palmprint identification using Gabor features, Gabor and Wide Principal Line Image (WPLI) features. Extracted a fixed size ROI from palmprint images. Resize the extracted ROI into 64 x 64. Apply the Gabor filters to extract the features from the resized ROI. Dissimilarity distance is used to measure the dissimilarity between the query palmprint and database palmprint images. Experiments were conducted on Polyu Palmprint Database using Gabor features, Gabor and WPLI features. Experimental results shows that the proposed approach using Gabor and WPLI features obtains better results compared with the existing methods
The Mind/Body Connection
No full textPhysician and award winning author, Dr Gabor Mate, discusses his research at the intersection of addiction, science, psychology, and compassionhttps://digitalcommons.ciis.edu/publicprograms/1030/thumbnail.jp
Density of Gabor Systems Via the Short Time Fourier Transform
No full textWe apply a new approach to the study of the density of Gabor systems, and obtain a simple and straightforward proof to Ramanathan and Steger’s well-known result regarding the density of Gabor frames and Gabor Riesz sequences. Moreover, this point of view allows us to extend this result in several directions. The approach we use was first observed by Olevskii and the third author in their study of exponential systems, here we develop and simplify it further
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