M. Victoria Collados

Dr. M. Victoria Collados

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Research Focus & Metrics

Academic Career Length

18Years (2009-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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25 July 2016 in Energies
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Journal Article
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JSJulia Marin Saez
Julia Marin Saez
Daniel ChemisanaDaniel Chemisana
Daniel Chemisana
ABAlex Moreno Bellostes
Alex Moreno Bellostes
ARAlberto Riverola
Alberto Riverola
JAJesús Atencia
Jesús Atencia
MCM. Victoria Collados
M. Victoria Collados
A building integrated holographic concentrating photovoltaic-thermal system has been optically and energetically simulated. The system has been designed to be superimposed into a solar shading louvre; in this way the concentrating unit takes profit of the solar altitude tracking, which the shading blinds already have, to increase system performance. A dynamic energy simulation has been conducted in two different locations—Sde Boker (Israel) and Avignon (France)—both with adequate annual irradiances for solar applications, but with different weather and energy demand characteristics. The simulation engine utilized has been TRNSYS, coupled with MATLAB (where the ray-tracing algorithm to simulate the holographic optical performance has been implemented). The concentrator achieves annual mean optical efficiencies of 30.3% for Sde Boker and 43.0% for the case of Avignon. Regarding the energy production, in both locations the thermal energy produced meets almost 100% of the domestic hot water demand as this has been considered a priority in the system control. On the other hand, the space heating demands are covered by a percentage ranging from 15% (Avignon) to 20% (Sde Boker). Finally, the electricity produced in both places covers 7.4% of the electrical demand profile for Sde Boker and 9.1% for Avignon.

22 July 2009 in Applied Optics
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Journal Article
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AVAyalid Villamarín
Ayalid Villamarín
JAJesús Atencia
Jesús Atencia
MCM. Victoria Collados
M. Victoria Collados
MQManuel Quintanilla
Manuel Quintanilla
We characterize Slavich PFG-04 dichromated gelatin plates to make transmission volume holographic elements recorded with a 532 nm laser source, obtaining high efficiency gratings with a high signal to noise ratio. The linear dynamic range of the material is studied by measuring the efficiency of multiplexed gratings. Results obtained are applied to the recording of holographic elements with high efficiency when they are illuminated with a 800 nm light source.

16 April 2021 in Journal of Imaging
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Francisco Avila GomezFrancisco Avila Gomez
Francisco Avila Gomez
JAJORGE ARES
JORGE ARES
CMConcepción Vidosa Marcellán
Concepción Vidosa Marcellán
MCM. Victoria Collados
M. Victoria Collados
LRLaura Remón
Laura Remón
The optical quality of an image depends on both the optical properties of the imaging system and the physical properties of the medium in which the light travels from the object to the final imaging sensor. The analysis of the point spread function of the optical system is an objective way to quantify the image degradation. In retinal imaging, the presence of corneal or cristalline lens opacifications spread the light at wide angular distributions. If the mathematical operator that degrades the image is known, the image can be restored through deconvolution methods. In the particular case of retinal imaging, this operator may be unknown (or partially) due to the presence of cataracts, corneal edema, or vitreous opacification. In those cases, blind deconvolution theory provides useful results to restore important spatial information of the image. In this work, a new semi-blind deconvolution method has been developed by training an iterative process with the Glare Spread Function kernel based on the Richardson-Lucy deconvolution algorithm to compensate a veiling glare effect in retinal images due to intraocular straylight. The method was first tested with simulated retinal images generated from a straylight eye model and applied to a real retinal image dataset composed of healthy subjects and patients with glaucoma and diabetic retinopathy. Results showed the capacity of the algorithm to detect and compensate the veiling glare degradation and improving the image sharpness up to 1000% in the case of healthy subjects and up to 700% in the pathological retinal images. This image quality improvement allows performing image segmentation processing with restored hidden spatial information after deconvolution.

22 October 2021 in Photonics
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MSMarina Sevilla
Marina Sevilla
JSJulia Marin Saez
Julia Marin Saez
Daniel ChemisanaDaniel Chemisana
Daniel Chemisana
MCM. Victoria Collados
M. Victoria Collados
JAJesús Atencia
Jesús Atencia
A wavelength multiplexing procedure for color transmission volume holograms of diffusing objects recorded in Bayfol® HX200 photopolymer is proposed. For the recording, three lasers of 442 nm, 532 nm and 633 nm, and a Spectralon® diffusing object were used for monochromatic and polychromatic calibration. Monochromatic calibration shows that the maximum index modulation obtained for each wavelength was not enough to give 100% efficiency, although the efficiency values achieved in the case of monochromatic recordings with diffusing objects were high, at around 90% for 633 nm and 532 nm recordings, and 60% for 442 nm. The efficiency values obtained for multiplexed holograms were 19.1% for the 442 nm hologram, 25.9% for the 532 nm hologram and 15.2% for the 633 nm.

27 October 2023 in Sensors
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Journal Article
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IPIoana Adriana Potarniche
Ioana Adriana Potarniche
JSJulia Marin Saez
Julia Marin Saez
MCM. Victoria Collados
M. Victoria Collados
JAJesús Atencia
Jesús Atencia
This paper presents a holographic sensor based on reflection holograms recorded in the commercial photopolymer Bayfol® HX 200. The recording geometry and index modulation of the hologram were optimised to improve accuracy for this specific application. The sensor was subjected to tests using various analytes, and it exhibited sensitivity to acetic acid and ethanol. The measurements revealed a correlation between the concentration of the analyte in contact with the sensor’s surface and the resulting wavelength shift of the diffracted light. The minimum detectable concentrations were determined to be above 0.09 mol/dm3 for acetic acid and 5% (v/v) for ethanol. Notably, the sensors demonstrated a rapid response time. Given that ethanol serves as a base for alcoholic beverages, and acetic acid is commonly found in commercial vinegar, these sensors hold promise for applications in food quality control.