Prof. Paulo Torrão Fiadeiro Profile

Prof. Paulo Torrão Fiadeiro

Physics Researcher at Univ de Beira Interior

SPIE Involvement:

Author

Proceedings Article | 3 October 2019 Paper

Three-dimensional surface reconstruction for evaluation of wrinkling on textile fabrics

António de O. Mendes, Paulo Fiadeiro, Rui A. L. Miguel, José M. Lucas, Manuel J. dos Santos Silva

Proceedings Volume 11207, 1120703 (2019) https://doi.org/10.1117/12.2524510

KEYWORDS: 3D image processing, Statistical analysis, Image processing, Visualization, 3D image reconstruction, Image analysis, 3D vision, Inspection, 3D scanning

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Proceedings Article | 3 October 2019 Paper

Influence of pupil function in pseudophakia

Elsa S. Fonseca, Paulo Fiadeiro, Renato Gomes, Angel Sanchez Trancon, António M. Baptista, Pedro Serra

Proceedings Volume 11207, 112071N (2019) https://doi.org/10.1117/12.2527412

KEYWORDS: Eye models, Eye, Visualization, Data modeling, Visual process modeling, Image quality, Spherical lenses, Statistical modeling, Modulation transfer functions, Surgery

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Proceedings Article | 17 September 2018 Presentation + Paper

A digital hologram compression scheme for representation on the object plane

Marco Bernardo, Elsa Fonseca, Paulo Fiadeiro, António Pinheiro, Manuela Pereira

Proceedings Volume 10752, 107520J (2018) https://doi.org/10.1117/12.2323442

KEYWORDS: Holograms, Digital holography, Holography, Computer generated holography, Image compression

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Digital holography is a growing field that owes its success to the provided three-dimensional imaging representation. This is achieved by encoding the wave field transmitted or scattered by an object in the form of an interference pattern with a reference beam. While in conventional imaging systems it is usually impossible to recover the correct focused image from a defocused one, with digital holography the image can be numerically retrieved at any distance from the hologram. Digital holography also allows the reconstruction of multiple objects at different depths. In a previous study, the benchmark of the main available image coding standard solutions JPEG, JPEG-XT, JPEG 2000 and the HEVC intra mode was performed for digital holographic data represented on the object plane. The HEVC intra main coding profile outperforms the other standards while JPEG 2000 results in very similar compression performance. In the current work, a scheme based on the HEVC intra mode codec for holographic information compression on the object plane is proposed. In the base layer, a 2D version of the object (amplitude information on object plane) is coded with HEVC intra main coding profile. Previously was observed that the phase information requires much higher bit rates than the amplitude information, as standardized codecs are not adapted for the compression of this type of information. In this paper we propose a model where the amplitude information is encoded with the HEVC intra mode codec, while the phase is represented by encoding the real information and the signal of the imaginary information. The real information is also encoded using the HEVC intra mode as it already revealed appropriate for compression of this type of information. The imaginary information signal is encoded with JBIG. The advantage of this scheme is that the amplitude information provides a direct 2D representation of the hologram while the phase information can be considered as a 3D enhancement layer. The results show that the proposed scheme outperforms the state of the art in holography compression, while allowing compatibility with the current standards and direct 2D visualization.

Proceedings Article | 22 August 2014 Paper

Revisiting grating orientation effects on visual contrast sensitivity using optical interferometry

P. Serra, L. Santos, J. Corte-Real, P. Fiadeiro

Proceedings Volume 9286, 92864E (2014) https://doi.org/10.1117/12.2063728

KEYWORDS: Contrast sensitivity, Spatial frequencies, Eye, Visualization, Fringe analysis, Interferometers, Visual optics, Phase modulation, Visual system, Retina

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Proceedings Article | 22 August 2014 Paper

Study of repeatability of an optical laser system for characterization of the paper fiber distribution and mass density

António de O. Mendes, Paulo Fiadeiro, Ana Costa, Maria Amaral, Mohamed Belgacem

Proceedings Volume 9286, 92862Y (2014) https://doi.org/10.1117/12.2062697

KEYWORDS: Laser optics, Anisotropy, Statistical analysis, Fiber lasers, Laser systems engineering, Image transmission, Image sensors, Sensors, Visualization, Telecommunications

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Proceedings Article | 18 November 2013 Paper

Study of the ink-paper interaction by image analysis: surface and bulk inspection

Paulo Fiadeiro, António de O. Mendes, Ana M. Ramos, Sónia L. de Sousa

Proceedings Volume 8785, 8785BV (2013) https://doi.org/10.1117/12.2024991

KEYWORDS: Inspection, Image analysis, Statistical analysis, Image sensors, Sensors, Optical design, Image processing, Quantitative analysis, Analytical research, Image acquisition

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Proceedings Article | 18 November 2013 Paper

Retro-diffusion and transmission of laser radiation to characterize the paper fiber distribution and mass density

António de O. Mendes, Paulo Fiadeiro, Ana Costa, Maria Amaral, Mohamed Belgacem

Proceedings Volume 8785, 8785AY (2013) https://doi.org/10.1117/12.2022367

KEYWORDS: Anisotropy, Fiber lasers, Image sensors, Sensors, Statistical analysis, Fiber characterization, Laser optics, Image transmission, Laser development, Image processing

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Proceedings Article | 26 September 2013 Paper

Digital hologram recording and stereo reconstruction from a single hologram

Angelo Arrifano, Marc Antonini, Paulo Fiadeiro, Manuela Pereira

Proceedings Volume 8856, 88561J (2013) https://doi.org/10.1117/12.2025294

KEYWORDS: Holograms, Digital holography, Cameras, Sensors, Holography, Spatial frequencies, Digital recording, Transmittance, Information visualization, 3D image reconstruction

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Proceedings Article | 26 January 2006 Paper

Three-dimensional surface reconstruction for evaluation of the abrasion effects on textile fabrics

A. Mendes, P. Fiadeiro, R. Miguel

Proceedings Volume 6056, 60560F (2006) https://doi.org/10.1117/12.640438

KEYWORDS: Sensors, Image sensors, Data acquisition, Statistical analysis, CCD cameras, Image processing, CCD image sensors, Reflectivity, Error analysis, Algorithm development

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Proceedings Article | 26 November 2001 Paper

Paper surface diffraction to characterize the fiber orientation distribution

Mario Pereira, Jose Teixeira, Paulo Fiadeiro, Jacques Silvy

Proceedings Volume 4448, (2001) https://doi.org/10.1117/12.449373

KEYWORDS: Anisotropy, Diffraction, Ultrasonics, Structured optical fibers, Fiber characterization, Manufacturing, Compact discs, Optics manufacturing, Charge-coupled devices, Surface plasmons

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Proceedings Article | 6 January 1997 Paper

Satellite remote sensing adaptive optic system phase characteristic measurement

Paulo Fiadeiro, Alexandre Smirnov

Proceedings Volume 2956, (1997) https://doi.org/10.1117/12.263173

KEYWORDS: Phase measurement, Adaptive optics, Remote sensing, Satellites, Sensors, Signal processing, Feedback loops, Image analysis, Light, Image quality

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Proceedings Article | 29 September 1995 Paper

Phase retrieval in computer generation of schlieren images

Paulo Fiadeiro, David Emmony

Proceedings Volume 2546, (1995) https://doi.org/10.1117/12.221537

KEYWORDS: Diffraction, Refractive index, Image processing, Phase retrieval, Schlieren techniques, Fourier transforms, Computer simulations, Sensors, Image acquisition, Reconstruction algorithms

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Showing 5 of 12 publications

Conference Committee Involvement (1)

Third International Conference on Applications of Optics and Photonics

8 May 2017 | Faro, Portugal

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