Guardiola Garcia, Jose Luis

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0000-0002-1100-4950
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https://panorama.upv.es/es/ipublic/researcher/340446
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Author: Pérez Jiménez, Alberto José × Subject: 3D reconstruction ×

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Now showing 1 - 4 of 4
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    Publication
    A System for In-Line 3D Inspection without Hidden Surfaces
    (MDPI AG, 2018) Perez-Cortes, Juan-Carlos; Pérez Jiménez, Alberto José; Sáez Barona, Sergio; Guardiola Garcia, Jose Luis; Salvador Igual, Ismael; Instituto Universitario Mixto de Tecnología de Informática; Departamento de Informática de Sistemas y Computadores; Escuela Técnica Superior de Ingeniería Informática; Institut Valencià de Competitivitat Empresarial; European Regional Development Fund
    [EN] This work presents a 3D scanner able to reconstruct a complete object without occlusions, including its surface appearance. The technique presents a number of differences in relation to current scanners: it does not require mechanical handling like robot arms or spinning plates, it is free of occlusions since the scanned part is not resting on any surface and, unlike stereo-based methods, the object does not need to have visual singularities on its surface. This system, among other applications, allows its integration in production lines that require the inspection of a large volume of parts or products, especially if there is an important variability of the objects to be inspected, since there is no mechanical manipulation. The scanner consists of a variable number of industrial quality cameras conveniently distributed so that they can capture all the surfaces of the object without any blind spot. The object is dropped through the common visual field of all the cameras, so no surface or tool occludes the views that are captured simultaneously when the part is in the center of the visible volume. A carving procedure that uses the silhouettes segmented from each image gives rise to a volumetric representation and, by means of isosurface generation techniques, to a 3D model. These techniques have certain limitations on the reconstruction of object regions with particular geometric configurations. Estimating the inherent maximum error in each area is important to bound the precision of the reconstruction. A number of experiments are presented reporting the differences between ideal and reconstructed objects in the system.
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    Publication
    Alignment and Improvement of Shape-From-Silhouette Reconstructed 3D Objects
    (Institute of Electrical and Electronics Engineers, 2024) Pérez Jiménez, Alberto José; Perez-Soler, Javier; Pérez Cortés, Juan Carlos; Guardiola Garcia, Jose Luis; Instituto Universitario Mixto de Tecnología de Informática; Departamento de Informática de Sistemas y Computadores; Escuela Técnica Superior de Ingeniería Informática; European Commission; Institut Valencià de Competitivitat Empresarial
    [EN] 3D object alignment is essential in multiple fields. For instance, to allow precise measurements in metrology, to perform surface/volumetric checks or quality control in industrial inspection, to align partial captures of a 3D object during object scanning, to simplify object recognition or classification in pattern recognition, accuracy and speed, being opposed, are desirable features of those algorithms. Nevertheless, they can be more or less critical depending on the application area. In the present work, we propose a methodology to improve the alignment of 3D objects reconstructed using shape-from-silhouette techniques. This reconstruction technique produces objects with small synthetic bulges, making them more difficult to align accurately. On the one hand, prealignment and branch-and-bound techniques are used to improve the convergence and speed of the alignment algorithms. On the other hand, a method to obtain a precise alignment even in the presence of bulges is presented. Finally, a refinement of the shape-from-silhouettes technique is shown. This technique uses multiple captures to refine object reconstruction and reduce or eliminate, among other improvements, synthetic bulges.
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    Probabilistic Evaluation of 3D Surfaces Using Statistical Shape Models (SSM)
    (MDPI AG, 2020-11) Pérez, Javier; Guardiola Garcia, Jose Luis; Pérez Jiménez, Alberto José; Pérez Cortés, Juan Carlos; Instituto Universitario Mixto de Tecnología de Informática; Departamento de Informática de Sistemas y Computadores; Escuela Técnica Superior de Ingeniería Informática; Institut Valencià de Competitivitat Empresarial
    [EN] Inspecting a 3D object which shape has elastic manufacturing tolerances in order to find defects is a challenging and time-consuming task. This task usually involves humans, either in the specification stage followed by some automatic measurements, or in other points along the process. Even when a detailed inspection is performed, the measurements are limited to a few dimensions instead of a complete examination of the object. In this work, a probabilistic method to evaluate 3D surfaces is presented. This algorithm relies on a training stage to learn the shape of the object building a statistical shape model. Making use of this model, any inspected object can be evaluated obtaining a probability that the whole object or any of its dimensions are compatible with the model, thus allowing to easily find defective objects. Results in simulated and real environments are presented and compared to two different alternatives.
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    Publication
    Simple and precise multi-view camera calibration for 3D reconstruction
    (Elsevier, 2020-12) Pérez Jiménez, Alberto José; Pérez Cortés, Juan Carlos; Guardiola Garcia, Jose Luis; Instituto Universitario Mixto de Tecnología de Informática; Departamento de Informática de Sistemas y Computadores; Escuela Técnica Superior de Ingeniería Informática
    [EN] A precise calibration in multi-view camera environments allows to perform accurate 3D object reconstruction, precise tracking of objects and accurate pose estimation. Those techniques are of high value in the industry today in fields as quality control or automation. In the present work, an improvement of a simple existing multi-view camera calibration method is presented. The improved method employs a specially developed reference token to overcome some issues in the original algorithm. We prove that the new method overcomes those problems thus attaining a higher accuracy while keeping the process simple and the implementation costs low. This last aspects makes the method interesting for the industry but specially suitable for SMEs typical in traditional sectors.