ELECTRON - ArtículosELECTRON - Artículoshttp://hdl.handle.net/10017/2562024-03-28T22:35:23Z2024-03-28T22:35:23ZMillimetric spatial resolution time-expanded ϕ-OTDRSoriano Amat, MiguelGuay, PhilippeFidalgo Martins, HugoMartín López, SoniaGonzález Herráez, MiguelFernández Ruiz, María del RosarioGenest, Jeromehttp://hdl.handle.net/10017/610052024-03-08T01:17:42Z2023-10-24T00:00:00ZMillimetric spatial resolution time-expanded ϕ-OTDR
Soriano Amat, Miguel; Guay, Philippe; Fidalgo Martins, Hugo; Martín López, Sonia; González Herráez, Miguel; Fernández Ruiz, María del Rosario; Genest, Jerome
Time-expanded phase-sensitive optical time-domain reflectometry is a distributed optical fiber sensing technology based on dual-frequency combs that allows for dynamic and high spatial resolution measurements while maintaining reduced detection requirements. Since the formalization of the technique, different experimental schemes have been satisfactorily tested, with a general performance of cm-scale spatial resolution over hundreds of meters. In this article, we present an optimized scheme with enhanced energy and spectral efficiencies that allows reaching 5 mm spatial resolution. As compared to previous experimental approaches, the presented architecture is based on a free-running dual comb setup generated through pure electro-optical phase modulation. Besides, the introduction of an optical hybrid in the detection stage allows for doubling the spatial resolution while keeping the refresh rate and the sensing range unchanged.
2023-10-24T00:00:00ZNoise analysis in direct detection and coherent detection phase-sensitive optical time-domain reflectometry systemsVidal Moreno, Pedro JoseBecerril, Carlos ErnestoFernández Ruiz, María Del RosarioFidalgo Martins, HugoMartín López, SoniaGonzález Herráez, Miguelhttp://hdl.handle.net/10017/610042024-03-08T01:17:42Z2023-08-14T00:00:00ZNoise analysis in direct detection and coherent detection phase-sensitive optical time-domain reflectometry systems
Vidal Moreno, Pedro Jose; Becerril, Carlos Ernesto; Fernández Ruiz, María Del Rosario; Fidalgo Martins, Hugo; Martín López, Sonia; González Herráez, Miguel
This study compares noise and signal-to-noise ratio (SNR) in direct detection and coherent detection fiber-based distributed acoustic sensing (DAS) systems. Both detection schemes employ the dynamic analysis of Rayleigh-backscattered light in phase-sensitive optical time-domain reflectometry (ΦOTDR) systems. Through theoretical and experimental analysis, it is determined that for photodetection filters with a sufficiently narrow bandwidth, the SNR performance of both detection schemes is comparable. However, for filters with poor selectivity, coherent detection was found to exhibit superior performance. These findings provide crucial guidelines for the design of high-performance time-domain DAS systems.
2023-08-14T00:00:00ZDiagnosis of multiple sclerosis using optical coherence tomography supported by explainable artificial intelligenceDongil Moreno, Francisco JavierOrtiz del Castillo, MiguelPueyo, AnaBoquete Vázquez, LucianoSánchez Morla, Eva MaríaJimeno Huete, DanielMiguel Jiménez, Juan ManuelBarea Navarro, RafaelVilades, EGarcia-Martín , E.http://hdl.handle.net/10017/609962024-03-19T17:47:49Z2024-01-31T00:00:00ZDiagnosis of multiple sclerosis using optical coherence tomography supported by explainable artificial intelligence
Dongil Moreno, Francisco Javier; Ortiz del Castillo, Miguel; Pueyo, Ana; Boquete Vázquez, Luciano; Sánchez Morla, Eva María; Jimeno Huete, Daniel; Miguel Jiménez, Juan Manuel; Barea Navarro, Rafael; Vilades, E; Garcia-Martín , E.
BACKGROUND/OBJECTIVES: Study of retinal structure based on optical coherence tomography (OCT) data can facilitate early
diagnosis of relapsing-remitting multiple sclerosis (RRMS). Although artificial intelligence can provide highly reliable diagnoses, the
results obtained must be explainable.
SUBJECTS/METHODS: The study included 79 recently diagnosed RRMS patients and 69 age matched healthy control subjects.
Thickness (Avg) and inter-eye difference (Diff) features are obtained in 4 retinal layers using the posterior pole protocol. Each layer
is divided into six analysis zones. The Support Vector Machine plus Recursive Feature Elimination with Leave-One-Out Cross
Validation (SVM-RFE-LOOCV) approach is used to find the subset of features that reduces dimensionality and optimises the
performance of the classifier.
RESULTS: SVM-RFE-LOOCV was used to identify OCT features with greatest capacity for early diagnosis, determining the area of
the papillomacular bundle to be the most influential. A correlation was observed between loss of layer thickness and increase in
functional disability. There was also greater functional deterioration in patients with greater asymmetry between left and right
eyes. The classifier based on the top-ranked features obtained sensitivity = 0.86 and specificity = 0.90.
CONCLUSIONS: There was consistency between the features identified as relevant by the SVM-RFE-LOOCV approach and the
retinotopic distribution of the retinal nerve fibres and the optic nerve head. This simple method contributes to implementation of
an assisted diagnosis system and its accuracy exceeds that achieved with magnetic resonance imaging of the central nervous
system, the current gold standard. This paper provides novel insights into RRMS affectation of the neuroretina.
2024-01-31T00:00:00ZHighly flexible strain sensors based on CNT-reinforced Ecoflex silicone rubber for wireless facemask breathing monitoring via BluetoothBosque, Antonio delFernández Sánchez-Romate, Xoan XoséLlana Calvo, Álvaro de laFernández Barbosa, Pedro RafaelBorromeo, SusanaSánchez, MaríaUreña, Alejandrohttp://hdl.handle.net/10017/609512024-03-02T01:19:12Z2023-09-05T00:00:00ZHighly flexible strain sensors based on CNT-reinforced Ecoflex silicone rubber for wireless facemask breathing monitoring via Bluetooth
Bosque, Antonio del; Fernández Sánchez-Romate, Xoan Xosé; Llana Calvo, Álvaro de la; Fernández Barbosa, Pedro Rafael; Borromeo, Susana; Sánchez, María; Ureña, Alejandro
Highly stretchable strain sensors based on carbon nanotube (CNT)-reinforced Ecoflex silicone rubber are developed for breathing monitoring purposes. The addition of CNTs promotes an improvement in electrical conductivity and mechanical properties (Young’s modulus and tensile strength) due to its good dispersion in Ecoflex. The evaluation of strain monitoring response, in both tensile and compression conditions, indicates a wide strain detection range and an ultrasensitive response at high strain levels, reaching a gauge factor of around 104 at 70% or 105 at 300% for 0.3 and 0.7 wt % CNT-reinforced sensors, respectively. They show a quite stable electrical response under 2000 cycling loads and different levels of frequencies. Moreover, the response and recovery times are in the range of milliseconds (∼600 and ∼800 ms, respectively). Finally, a proof-of-concept of wireless facemask breathing monitoring was carried out with Bluetooth Low Energy technology and a platform that has been developed to acquire, filter, visualize, and store the breathing signal. With this, the respiration rate can be unequivocally monitored as well as the difference between inspiration and expiration. Thus, this type of trial is proposed for breath monitoring in medical analysis, emergency teams, or first aid.
2023-09-05T00:00:00Z