Andrés G MarrugoUniversidad Tecnológica de Bolívar · Ingeniería mecánica y mecatrónica
Andrés G Marrugo
PhD
About
115
Publications
31,493
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Introduction
Dr. Andrés Marrugo is an Associate Professor in the Dept. of Mechanical and Mechatronics Engineering at the Universidad Tecnológica de Bolívar (UTB), Colombia, where he did his B.Eng. in Mechatronics Engineering (Summa Cum Laude). He received his Ph.D. in Optical Engineering (Cum Laude) and his M.Sc. in Photonics from the Universitat Politècnica de Catalunya, Spain. He was the recipient of the Honours Diploma for Young Researchers from the Spanish Optical Society (SEDOPTICA) and the SPIE DCS Rising Researcher award. At UTB, Professor Marrugo's lab is called Laboratorio de Óptica y Procesamiento de Imágenes (OPI-Lab), and together with his team they innovate in optical technologies and develop methods for 2D and 3D image acquisition/analysis for biomedical and industrial applications.
Additional affiliations
May 2013 - present
October 2008 - February 2013
Publications
Publications (115)
Purpose
The aim of this study was to evaluate the efficacy of artificial intelligence–derived morphometric parameters in characterizing Fuchs corneal endothelial dystrophy (FECD) from specular microscopy images.
Methods
This cross-sectional study recruited patients diagnosed with FECD, who underwent ophthalmologic evaluations, including slit-lamp...
Editor-in-Chief Andres G. Marrugo discusses the complexities of academic publishing and the crucial role of broad-based learning in a graduate course on scientific writing. The editorial highlights the need for effective communication and comprehension of publishing models to prepare emerging researchers for the academic world.
Computerized medical evaluation of the corneal endothelium is challenging because it requires costly equipment and specialized personnel, not to mention that conventional techniques require manual annotations that are difficult to acquire. This study aims to obtain reliable segmentations without requiring large data sets labeled by expert personnel...
Las experiencias docentes resultantes (seis experiencias), diversas entre sí, hicieron posible atender al desafío de la enseñanza y el aprendizaje en medio de la realidad emergente. Algunas de ellas lograron, asimismo, desarrollar de manera intencional, a través de metodologías activas del aprendizaje, habilidades favorables
para la consolidación d...
Editor-in-Chief Andres Marrugo discusses the role of Large Language Models, like ChatGPT, in academic publishing, highlighting some practical applications, potential pitfalls, and the ethical considerations required for their responsible use in academia.
This Letter presents a novel structured light system model that effectively considers local lens distortion by pixel-wise rational functions. We leverage the stereo method for initial calibration and then estimate the rational model for each pixel. Our proposed model can achieve high measurement accuracy within and outside the calibration volume, d...
This Letter presents a novel structured light system model that effectively considers local lens distortion by pixel-wise rational functions. We leverage the stereo method for initial calibration and then estimate the rational model for each pixel. Our proposed model can achieve high measurement accuracy within and outside the calibration volume, d...
Editor-in-Chief Andres Marrugo discusses the latest developments in the journal.
Specular microscopy assessment of the human corneal endothelium (CE) in Fuchs’ dystrophy is challenging due to the presence of dark image regions called guttae. This paper proposes a UNet-based segmentation approach that requires minimal post-processing and achieves reliable CE morphometric assessment and guttae identification across all degrees of...
The convolutional neural networks (CNNs) as tools for ultrasound image segmentation often have their performance affected by the low signal-to-noise ratio of the images. This prevents a correct classification and extraction of relevant information and therefore affects clinical diagnosis. We propose a study of the effect of different speckle filter...
Specular microscopy assessment of the human corneal endothelium (CE) in Fuchs' dystrophy is challenging due to the presence of dark image regions called guttae. This paper proposes a UNet-based segmentation approach that requires minimal post-processing and achieves reliable CE morphometric assessment and guttae identification across all degrees of...
The development of techniques for synthesizing graphene and its derivatives, as well as currently available nanocomposite fabrication techniques, coupled with the diverse applications of strain and pressure sensors, has made this field of growing interest in the last decade. This article provides an overview of conventional strain sensor manufactur...
The need for fast, inexpensive, and robust medical technology is now more crucial than ever [...]
Although there is a perception in the community that the state of optics research in Colombia has reached a mature state with international recognition, to date, there is no study that supports this view quantitatively. We aimed to assess the state of optics research in Colombia based on international journal publications. Therefore, we determined...
This special issue of Optica Pura y Aplicada (OPA) on Optics in Colombia compiles peer-reviewed articles by optics and photonics researchers from Colombia. The call for papers was made in May 2021 through a call published on the page of the Sociedad Red Colombiana de Óptica and was open to contributions from professionals with affiliation in Colomb...
We explore the possibility of extending the depth of focus of an imaging lens with an asymmetric quartic phase-mask, while keeping the aberration within a relatively low level. This can be intended, for instance, for ophthalmic applications, where no further digital processing can take place, relying instead on the patient’s neural adaptation to th...
We propose modeling a structured light system with open-source computer graphics software to perform experimental verifications independently of the physical system. Encouraging experimental results show the capabilities of the digital twin.
We generate synthetic images with a generative adversarial network (GAN) model trained with image patches from specular microscopy corneal endothelial cells. Preliminary results show it may be a suitable approach for reliable cell segmentation.
Although there is a perception in the community that the state of optics research in Colombia has reached a mature state with international recognition, to date, there is no study that supports this view quantitatively. We aimed to assess the state of optics research in Colombia based on international journal publications. Therefore, we determined...
Despite the attention marker-less pose estimation has attracted in recent years, marker-based approaches still provide unbeatable accuracy under controlled environmental conditions. Thus, they are used in many fields such as robotics or biomedical applications but are primarily implemented through classical approaches, which require lots of heurist...
The pose estimation of a surgical instrument is a common problem in the new needs of medical science. Many instrument tracking methods use markers with a known geometry that allows for solving the instrument pose as detected by a camera. However, marker occlusion happens, and it hinders correct pose estimation. In this work, we propose an adaptable...
We propose a three-dimensional (3D) multimodal medical imaging system that combines freehand ultrasound and structured light 3D reconstruction in a single coordinate system without requiring registration. To the best of our knowledge, these techniques have not been combined before as a multimodal imaging technique. The system complements the intern...
We propose a three-dimensional (3D) multimodal medical imaging system that combines freehand ultrasound and structured light 3D reconstruction in a single coordinate system without requiring registration. To the best of our knowledge, these techniques have not been combined as a multimodal imaging technique. The system complements the internal 3D i...
We propose a multi-stage calibration method for increasing the overall accuracy of a large-scale structured light system by leveraging the conventional stereo calibration approach using a pinhole model. We first calibrate the intrinsic parameters at a near distance and then the extrinsic parameters with a low-cost large-calibration target at the de...
Despite the attention marker-less pose estimation has attracted in recent years, marker-based approaches still provide unbeatable accuracy under controlled environmental conditions. Thus, they are used in many fields such as robotics or biomedical applications but are primarily implemented through classical approaches, which require lots of heurist...
Automated cell counting in in-vivo specular microscopy images is challenging, especially in situations where single-cell segmentation methods fail due to pathological conditions. This work aims to obtain reliable cell segmentation from specular microscopy images of both healthy and pathological corneas. We cast the problem of cell segmentation as a...
This paper reviews recent developments of non-contact three-dimensional (3D) surface metrology using an active structured optical probe. We focus primarily on those active non-contact 3D surface measurement techniques that could be applicable to the manufacturing industry. We discuss principles of each technology, and its advantageous characteristi...
Accurate endothelial cell density with specular microscopy is essential for correct clinical assessment of the cornea. Commercial specular microscopes incorporate automated cell segmentation methods to estimate cell density. However, these methods are prone to false cell detections in pathological corneas. This project aims to obtain a reliable aut...
The implementation and generation of synthetic data for testing algorithms in optical metrology are often difficult to reproduce. In this work, we propose a framework for the generation of reproducible synthetic surface data. We present two study cases using the Code Ocean platform, which is based on Docker and Linux container technologies to turn...
WRPGEN is a framework to generate reproducible synthetic phase data. The simulated data is simultaneously corrupted by noise and phase dislocations. The algorithm relies on Gaussian-Laplacian pyramids to preserve surface features on different scales. The implementation of our algorithms can be accessed and executed through a Code Ocean compute caps...
WLSIGEN is a framework to generate reproducible synthetic interference microscopy images. The algorithm simulates a rough surface and the acquisition of its microscopy image with the interference pattern as recorded with a Mirau-type interference microscope using a white light source.
Computer vision tracking systems are used in many medical and industrial applications. Understanding and modeling the tracking errors for a given system aids in the correct implementation and operation for optimal measurement results. This project aims to simulate and experimentally validate a tracking system for medical imaging. In this work, we d...
It has become customary to calibrate a camera-projector pair in a structured light (SL) system as a stereo-vision setup. The 3D reconstruction is carried out by triangulation from the detected point at the camera sensor and its correspondence at the projector DMD. There are several algebraic formulations to obtain the coordinates of the 3D point, e...
This work shows the results of a numerical model developed to simulate the CBMS technique for the production of the Fe78Si9B13 metallic magnetic ribbons for application in electronics. The model proposes a numerical approximation to a Vogel-Fulcher-Tammann (VFT) expression as a method in the solidification process. This approximation is introduced...
The key to accurate 3D shape measurement in fringe projection profilometry (FPP) is the proper calibration of the measurement system. Current calibration techniques rely on phase-coordinate mapping (PCM) or back-projection stereo vision (SV) methods. PCM methods are cumbersome to implement as they require precise positioning of the calibration targ...
Recent methods for phase unwrapping in the presence of noise include denoising algorithms to filter out noise as a preprocessing stage. However, including a denoising stage increases the overall computational complexity resulting in long execution times. In this paper, we present a noniterative simultaneous phase unwrapping and denoising algorithm...
The key to accurate 3D shape measurement in Fringe Projection Profilometry (FPP) is the proper calibration of the measurement system. Current calibration techniques rely on phase-coordinate mapping (PCM) or back-projection stereo-vision (SV) methods. PCM methods are cumbersome to implement as they require precise positioning of the calibration targ...
SPUD is a Simultaneous Phase Unwrapping and Denoising Algorithm for Phase Imaging. The algorithm relies on the least squares discrete cosine transform (DCT) solution for phase unwrapping with an additional sparsity constraint on the DCT coefficients of the unwrapped solution. Simulation results with different levels of noise and wrapped phase fring...
The growing need to perform surgical procedures, monitoring, and intervention of greater precision have led to the development of multimodal medical imaging systems. Multimodal images are a strategy to overcome the limitations of medical imaging technologies by combining the strengths of individual modalities or technologies. In this work, we propo...
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 processin...
We propose a method to obtain a fringe-free extended focused image in white light scanning interference microscopy based on processing the stack of images over a range within the coherence length of the source.
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 dynami...
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 photog...
The problem of phase unwrapping from a noisy and also incomplete wrapped phase map arises in many optics and image processing applications. In this work, we propose a noise-robust approach for processing regional phase dislocations. Our approach combines phase unwrapping and sparse-based inpainting with dictionary learning to recover the continuous...
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 i...