Developing a Robust Acquisition System for Fringe Projection Profilometry

Since Fringe Projection Profilometry (FPP) is an intensity-based coding strategy, it is prone to improper optical setup arrangement, surface texture and reflectance, uneven illumination distribution, among others. These conditions introduce errors in phase retrieval which lead to an inaccurate 3-D reconstruction. In this paper, we describe a dynamic approach toward a robust FPP acquisition in challenging scenes and objects. Our aim is to acquire the best possible fringe pattern image by adjusting the object closer to an ideal system-object setup. We describe the software implementation of our method and the interface design using LabVIEW. Experimental results demonstrate that the proposed method greatly reduces sources of error in 3-D reconstruction. © Published under licence by IOP Publishing Ltd.Universidad Tecnológica de Pereira, UTP: C2018P018, C2018P005 538871552485 Departamento Administrativo de Ciencia, Tecnología e Innovación, COLCIENCIASThis work has been partly funded by Colciencias (Fondo Nacional de Financiamiento para la Ciencia, la Tecnología y la Innovación Francisco José de Caldas) project 538871552485, and by Universidad Tecnológica de Bolívar projects C2018P005 and C2018P018. Authors thank Dirección de Investigaciones, Universidad Tecnológica de Bolívar for the support. J. Pineda thanks Universidad Tecnológica de Bolívar for a Masters degree scholarship

A Structure-from-Motion Pipeline for Generating Digital Elevation Models for Surface-Runoff Analysis

Digital Elevation Models (DEMs) are used to derive information from the morphology of a land. The topographic attributes obtained from the DEM data allow the construction of watershed delineation useful for predicting the behavior of systems and for studying hydrological processes. Imagery acquired from Unmanned Aerial Vehicles (UAVs) and 3D photogrammetry techniques offer cost-effective advantages over other remote sensing methods such as LIDAR or RADAR. In particular, a high spatial resolution for measuring the terrain microtopography. In this work, we propose a Structure from Motion (SfM) pipeline using UAVs for generating high-resolution, high-quality DEMs for developing a rainfall-runoff model to study flood areas. SfM is a computer vision technique that simultaneously estimates the 3D coordinates of a scene and the pose of a camera that moves around it. The result is a 3D point cloud which we process to obtain a georeference model from the GPS information of the camera and ground control points. The pipeline is based on open source software OpenSfM and OpenDroneMap. Encouraging experimental results on a test land show that the produced DEMs meet the metrological requirements for developing a surface-runoff model. © Published under licence by IOP Publishing Ltd.This work has been partly funded by Universidad Tecnológica de Bolívar project (FI2006T2001). The authors thank Direccion de Investigaciones Universidad Tecnologica de Bolivar for their support

Fringe quality map for fringe projection profilometry in LabVIEW

The phase retrieval process is mainly affected by local shadows, irregular surface brightness and fringe discontinuities. To overcome these problems, image-processing strategies are carried out such as binary masks, interpolation techniques, and filtering. Similarly, many unwrapping algorithms have been developed to handle phase unwrapping errors in two-dimensional regions. The presence of error-prone areas can be visualized during the acquisition stage avoiding the use of image processing strategies and sophisticated phase unwrapping algorithms, which in many cases represent high computational costs and long execution times. To help overcome these problems, we propose a Fringe Quality Map based on a phase residue analysis to estimate error-prone areas during acquisition. The software was fully implemented in LabVIEW, and we provide the software as supplementary material. Experimental results demonstrate that the proposed method estimates areas with poor contrast, which lead to unwrapping errors, as well as phase errors in a more complex 3D shape. © Sociedad Española de Óptica

Métodos de calibración cámara-proyector con compensación de distorsiones geométricas en perfilometría por proyección de franjas: Un estudio comparativo

The calibration methods most used in fringe projection profilometry are based on models of least squares adjustment and stereo vision techniques. However, the geometric distortions of the projector and camera lenses introduce imprecision in certain regions of the 3D reconstruction. In this paper, we perform a comparative study between the second order polynomial adjustment method and the stereo calibration method applying lens distortion compensation. The experimental results show that in the stereo calibration the incidence of the distortions in the 3D reconstruction is significant. In contrast, in the proposed polynomial calibration, reconstruction errors are associated with the calibrated volume, typically low within the calibration volume. © Sociedad Española de óptica.Los métodos de calibración más usados en perfilometría por proyección de franjas están basados en modelos de ajustes por mínimos cuadrados y técnicas de visión estéreo. Sin embargo, las distorsiones geométricas de los lentes del proyector y de la cámara introducen imprecisión en ciertas regiones de la reconstrucción 3D. En este trabajo realizamos un estudio comparativo entre el método de ajuste polinomial de segundo orden y el método de calibración estéreo aplicando compensación de distorsiones. Los resultados experimentales muestran que en la calibración estéreo la incidencia de las distorsiones en la reconstrucción 3D es significativa. En cambio, en la calibración polinomial propuesta, los errores de reconstrucción están asociados al volumen calibrado. © Sociedad Española de óptica

Synchrotron emission from secondary leptons in microquasar jets

We present a model to estimate the synchrotron radio emission generated in microquasar (MQ) jets due to secondary pairs created via decay of charged pions produced in proton-proton collisions between stellar wind ions and jet relativistic protons. Signatures of electrons/positrons are obtained from consistent particle energy distributions that take into account energy losses due to synchrotron and inverse Compton (IC) processes, as well as adiabatic expansion. The space parameter for the model is explored and the corresponding spectral energy distributions (SEDs) are presented. We conclude that secondary leptonic emission represents a significant though hardly dominant contribution to the total radio emission in MQs, with observational consequences that can be used to test some still unknown processes occurring in these objects as well as the nature of the matter outflowing in their jets

Robust automated reading of the skin prick test via 3D imaging and parametric surface fitting

The conventional reading of the skin prick test (SPT) for diagnosing allergies is prone to inter- and intra-observer variations. Drawing the contours of the skin wheals from the SPT and scanning them for computer processing is cumbersome. However, 3D scanning technology promises the best results in terms of accuracy, fast acquisition, and processing. In this work, we present a wide-field 3D imaging system for the 3D reconstruction of the SPT, and we propose an automated method for the measurement of the skin wheals. The automated measurement is based on pyramidal decomposition and parametric 3D surface fitting for estimating the sizes of the wheals directly. We proposed two parametric models for the diameter estimation. Model 1 is based on an inverted Elliptical Paraboloid function, and model 2 on a super-Gaussian function. The accuracy of the 3D imaging system was evaluated with validation objects obtaining transversal and depth accuracies within ± 0.1 mm and ± 0.01 mm, respectively. We tested the method on 80 SPTs conducted in volunteer subjects, which resulted in 61 detected wheals. We analyzed the accuracy of the models against manual reference measurements from a physician and obtained that the parametric model 2 on average yields diameters closer to the reference measurements (model 1: -0.398 mm vs. model 2: -0.339 mm) with narrower 95% limits of agreement (model 1: [-1.58, 0.78] mm vs. model 2: [-1.39, 0.71] mm) in a Bland-Altman analysis. In one subject, we tested the reproducibility of the method by registering the forearm under five different poses obtaining a maximum coefficient of variation of 5.24% in the estimated wheal diameters. The proposed method delivers accurate and reproducible measurements of the SPT. © 2019 Pineda et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Departamento Administrativo de Ciencia, Tecnología e Innovación (COLCIENCIAS), COLCIENCIAS: 538871552485 C2018P018, C2018P005This study was supported by Colciencias (www.colciencias.gov.co, Grant 538871552485) and by Universidad Tecnol?gica de Bolivar (www.utb.edu.co, Grants C2018P005 and C2018P018), Colombia

Uncovering the chemical structure of the pulsating low-mass white dwarf SDSS J115219.99+024814.4

Pulsating low-mass white dwarf stars are white dwarfs with stellar masses between 0.30 M⊙ and 0.45 M⊙ that show photometric variability due to gravity-mode pulsations. Within this mass range, they can harbour both a helium- and hybrid-core, depending if the progenitor experienced helium-core burning during the pre-white dwarf evolution. SDSS J115219.99+024814.4 is an eclipsing binary system where both components are low-mass white dwarfs, with stellar masses of 0.362±0.014 M⊙ and 0.325±0.013 M⊙. In particular, the less massive component is a pulsating star, showing at least three pulsation periods of ∼1314 s, ∼1069 s and ∼582.9 s. This opens the way to use asteroseismology as a tool to uncover its inner chemical structure, in combination with the information obtained using the light-curve modelling of the eclipses. To this end, using binary evolutionary models leading to helium- and hybrid-core white dwarfs, we compute adiabatic pulsations for ℓ = 1 and ℓ = 2 gravity modes with Gyre. We found that the pulsating component of the SDSS J115219.99+024814.4 system must have a hydrogen envelope thinner that the value obtained from binary evolution computations, independently of the inner composition. Finally, from our asteroseismological study, we find a best fit model characterised by Teff = 10 917 K, M=0.338 M⊙, MH = 10−6 M⊙ with the inner composition of a hybrid WD

Role of a cryptic tRNA gene operon in survival under translational stress

As compared to eukaryotes, bacteria have a reduced tRNA gene set encoding between 30 and 220 tRNAs. Although in most bacterial phyla tRNA genes are dispersed in the genome, many species from distinct phyla also show genes forming arrays. Here, we show that two types of arrays with distinct evolutionary origins exist. This work focuses on long tRNA gene arrays (L-arrays) that encompass up to 43 genes, which disseminate by horizontal gene transfer and contribute supernumerary tRNA genes to the host. Although in the few cases previously studied these arrays were reported to be poorly transcribed, here we show that the L-array of the model cyanobacterium Anabaena sp. PCC 7120, encoding 23 functional tRNAs, is largely induced upon impairment of the translation machinery. The cellular response to this challenge involves a global reprogramming of the transcriptome in two phases. tRNAs encoded in the array are induced in the second phase of the response, directly contributing to cell survival. Results presented here show that in some bacteria the tRNA gene set may be partitioned between a housekeeping subset, which constantly sustains translation, and an inducible subset that is generally silent but can provide functionality under particular conditions.Ministerio de Ciencia, Innovación y Universidades [BFU2016-77097-P to I.L., A.H.; BIO2017-84066-R to F.J.R-C.]; Agencia Estatal de Investigación [PID2019-104784RJ-100/AEI/10.13039/501100011033 to R.L.I.]; National Science Foundation [MCB-1715840 to M.I.]. RB-M's lab at University of Alicante is a member of Proteored, PRB3 and is supported by grant PT17/0019, of the PE I+D+i 2013-2016, funded by ISCIII and ERDF. Funding for open access charge: Consejo Superior de Investigaciones Científicas

PrevenBox: Evaluation of concomitant use of preventive medications with OnabotulinumtoxinA in migraine

P114 Background: OnabotulinumtoxinA is an effective, tolerable and safepreventive treatment for chronic migraine (CM). Other than a reduc-tion in headache frequency or disability, in CM the withdrawal ofconcomitant preventive medication indicates treatment effectivenessand quality of life improvement. Objective: To characterize the change in the use of oral preventivemedication after treatment with OnabotulinumtoxinA in patientswith migraine. Methods: This is a multicentre study. We consecutively included pa-tients with migraine (ICHD-3) that were on preventive treatment withOnabotulinumtoxinA. We retrospectively collected demographic data, diagnosis of migraine, frequency and intensity changes, number ofcycle and OnabotulinumtoxinA dose. In addition, we listed the initialand current preventive treatment (number of drugs and group) andthe number and cycle of medications withdrawn. We performed aunivariate and logistic regression analysis. Results: We included 542 patients: 87.6% women, mean age 47.6 ±11.7 years. A 89.3% had chronic migraine and 10.8% had high fre-quency episodic migraine. The mean reduction in frequency aftertreatment was 13.4±8.2 headache days/month. At baseline, a 91.3%took other preventives and during treatment with Onabotulinumtox-inA a 58.6% withdrew at least one drug, 25.8% stopped completelyall oral preventive drugs. Factors associated with withdrawal were:being male, having >50% response in frequency and intensity, thenumber of infiltrations and a shorter chronification period until thefirst OnabotulinumtoxinA administration (p <0.05). The multivariateanalysis showed that a better response in intensity (OR:1.8 [1.4-2.2], p<0.001), a greater number of infiltrations (OR:1.1 [1.0-1.2], p<0.001)and a shorter chronification period (OR:0.994 [0.992-0.997], p<0.001)were predictors of withdrawal. The ROC curve, showed that 6 Onabo-tulinumtoxinA cycles was the cut-off point that better predicted oralpreventive medication withdrawal (p <0.001). Conclusions: Treatment with OnabotulinumtoxinA reduces the use ofother preventive medications for migraine. The highest probability ofwithdrawal occurs after 6 cycles of treatment