Pietro Ferraro

Bio: Pietro Ferraro is an academic researcher from National Research Council. The author has contributed to research in topics: Digital holography & Holography. The author has an hindex of 61, co-authored 653 publications receiving 12666 citations. Previous affiliations of Pietro Ferraro include Aeritalia & Centre national de la recherche scientifique.

Processing of optically-captured digital holograms for three-dimensional display

Abstract: In digital holography, holograms are usually optically captured and then two-dimensional slices of the reconstruction volume are reconstructed by computer and displayed on a two-dimensional display. When the recording is of a three-dimensional scene then such two-dimensional display becomes restrictive. We outline our progress on capturing larger ranges of perspectives of three-dimensional scenes, and our progress on four approaches to better visualise this three-dimensional information encoded in the digital holograms. The research has been performed within a European Commission funded research project dedicated the capture, processing, transmission, and display of real-world 3D and 4D scenes using digital holography.

A comparison of centrality measures and their role in controlling the spread in epidemic networks

Abstract: The ranking of nodes in a network according to their ``importance'' is a classic problem that has attracted the interest of different scientific communities in the last decades. The current COVID-19 pandemic has recently rejuvenated the interest in this problem, as it is related to the selection of which individuals should be tested in a population of asymptomatic individuals, or which individuals should be vaccinated first. Motivated by the COVID-19 spreading dynamics, in this paper we review the most popular methods for node ranking in undirected unweighted graphs, and compare their performance in a benchmark realistic network, that takes into account the community-based structure of society. Also, we generalize a classic benchmark network originally proposed by Newman for ranking nodes in unweighted graphs, to show how ranks change in the weighted case.

Lateral shearing interferometer for measuring refractive index of silicon

Abstract: A simple lateral shearing interferometer is proposed for measuring refractive index of thin parallel plate silicon sample. The rotating sample works as lateral shearing element. As the sample rotates a continuous lateral shearing is obtained owing to the change of the optical path difference (OPD) between the transmitted beam and that first reflected by the surface sample. The recorded interferometric signal is Fourier-transform analyzed and the phase change is determined as a function of the rotating angle. If the thickness of the silicon sample is known the method provides accurate measurement of the refractive index. ( Summary only available )

Infrared digital holography

Abstract: We describe a long-wavelength Mach-Zehnder interferometer for digital off-axis Fresnel holography with a pyro-electric detector array used to record digital holograms of an extended object at 10.6 μm. We show that, although the spatial resolution of the pyro-electric detector array is much less than that of typical CCD cameras working in the visible region, good reconstruction of the amplitude and phase of the object wavefield can be obtained. The principle of Fresnel reconstruction in digital holography is described and results of reconstruction process for object size of the order of 700 μm are presented and discussed.

Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry

Abstract: A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

Fiber grating sensors

Abstract: We review the recent developments in the area of optical fiber grating sensors, including quasi-distributed strain sensing using Bragg gratings, systems based on chirped gratings, intragrating sensing concepts, long period-based grating sensors, fiber grating laser-based systems, and interferometric sensor systems based on grating reflectors.