Epipolarización de un par fotogramétrico sin parámetros de orientación

La reconstrucción de escenas mediante procesamiento de imagen resulta un trabajo habitual en fotogrametría. En aquellos casos que requieran 2D, el procesamiento de imágenes aisladas puede resultar suficiente, mientras que la generación de escenas 3D requiere del uso de múltiples imágenes. Una técnica habitual de trabajo para generar escenas 3D es la epipolarización. Habitualmente estas técnicas requieren del uso de parámetros de orientación interna, lo que implica la calibración de la/s cámara/s. Así mismo, también resulta necesario conocer la orientación relativa entre los fotogramas. En este trabajo se presenta un algoritmo completamente geométrico que permite la generación de diferentes modelos 3D, con un único par fotogramétrico, sin ningún parámetro de orientación y sin preseñalización de puntos de control. El algoritmo permite la generación de modelos 3D con imágenes provenientes de cámaras desconocidas, escaneadas de un libro o video frames. Los modelos 3D obtenidos están libres de paralajes y presentan un ajuste mejor a 0,5 pixels

Limitaciones en el levantamiento digital de bienes patrimoniales con tipología de torre

[EN] Digital terrestrial survey techniques such as photogrammetry (SfM) and 3D laser scanning have certain limitations. These depend on the tools used, geometry, lighting conditions and distance from the element which is being surveyed. Therefore, the aim of this study is to describe a method for the correct digital survey of high elements (with tower typology) when working with such restrictions, as well as to verify the relevance of its usefulness. This methodology is applied to two bell towers located in Ravenna (Italy) allowing a series of tests and reasoning on geometric accuracy and quality of the texture obtained in final models.[ES] Las técnicas de levantamiento digital terrestres como la fotogrametría (SfM) y el láser escáner 3D (TLS) poseen ciertas limitaciones en función de las herramientas utilizadas y de la geometría, condiciones de iluminación y distancia del elemento con el que se trabaja. Por ello, el objetivo de este estudio es describir un método para el correcto levantamiento digital de elementos altos (con tipología de torre) cuando se trabaja con dichas restricciones, así como verificar la pertinencia de su utilidad. Dicha metodología se aplica a dos torres campanario situadas en Ravenna (Italia) permitiendo realizar una serie de ensayos y razonamientos sobre la precisión y la calidad de la textura obtenida en los modelos finales.Molina Sánchez, S.; Juan Vidal, F.; Cipriani, L.; Denia Ríos, JL. (2021). Limitations in the digital survey of heritage assets with tower typology. EGA Expresión Gráfica Arquitectónica. 26(42):76-89. https://doi.org/10.4995/ega.2021.14749OJS7689264

Determining image distortion and PBS (point of best symmetry) in digital images using straight line matrices

[EN] It is impossible to take accurate measurements in photogrammetry without first removing the distortion in images. This paper presents a methodology for correcting radial and tangential distortion and for determining the PBS (Point of Best Symmetry) without knowledge of the interior orientation parameters (IOPs). An analytical plumb-line calibration method is used, measuring only the coordinates of points on straight lines, regardless of the position and direction of these lines within the image. Points belonging to multiple lines can also be used since the effects on their X and Y coordinates are calculated independently. The results obtained on an image of a common scene, taken with a handheld non-metric camera, show a high degree of accuracy even with a minimum number of observables. And its application on a calibrated grid for engineering purposes with a semi-metric camera, results optimal even using a single image. (C) 2016 Elsevier Ltd. All rights reserved.The authors wish to thank CITES Espana and Direccion General de Bienes Culturales y Ensenanzas Artisticas, de la Consejeria de Educacion, Cultura y Universidades de la Comunidad Autonoma de la Region de Murcia, Museo Nacional de Arqueologia Subacuatica. Financial support is gratefully acknowledged from Spanish "I + D + I MINECO" projects CTQ2011-28079-CO3-01 and 02 and CTQ2014-53736-C3-1-P supported by ERDEF funds. The authors also wish to thank Mr. Manuel Planes and Dr. Jose Luis Moya, technical supervisors of the Electron Microscopy Service of the Universitat Politecnica de Valencia.Herráez Boquera, J.; Denia Ríos, JL.; Navarro Esteve, PJ.; Rodríguez Pereña, J.; Martín Sánchez, MT. (2016). Determining image distortion and PBS (point of best symmetry) in digital images using straight line matrices. Measurement. 91:641-650. https://doi.org/10.1016/j.measurement.2016.05.051S6416509

APPLICATIONS OF THREE-DIMENSIONAL SCANNING TECHNOLOGY FOR THE COORDINATION OF HISTORICAL MONUMENTS OF NATIONAL INSTITUTE OF ARCHAEOLOGY AND HISTORY (INAH) IN MEXICO CITY. (2009 AND 2010)

[EN] The National Institute of Archaeology and History manages the documentation and preservation of the patrimony of Mexico, a country with an area of ??1.959.000 square kilometers, which is almost four times the size of Spain. To attend on all this patrimony, INAH has several departments. The National Coordination of Historical Monuments manages the monuments and architecture built from the colonial era. Inside the Coordination, the Technical Support Division manages the teams and the tools necessary for the survey[ES] El Instituto Nacional de Arqueología e Historia gestiona la documentación y conservación del patrimonio de México un país con una extensión de 1.959000 kilómetros cuadrados, que casi cuadriplica la extensión de España. Para atender todo este Patrimonio el INAH cuenta con diversos departamentos. La Coordinación Nacional de Monumentos Históricos gestiona los monumentos y arquitecturas construidos a partir de la época virreinal. Dentro de la Coordinación, la Dirección de Apoyo Técnico gestiona los equipos e instrumentos necesarios para el levantamiento.Navarro Esteve, P.; Herráez Boquera, J.; Mora Flores, Á.; Barros E Costa, H.; Denia Ríos, JL. (2011). APLICACIONES DE LA TECNOLOGÍA DE DIGITALIZACIÓN TRIDIMENSIONAL POR LA COORDINACIÓN DE MONUMENTOS HISTÓRICOS DEL INSTITUTO NACIONAL DE ARQUEOLOGÍA E HISTORIA (INAH) EN MÉXICO DF. (2009 Y 2010). EGA. Revista de Expresión Gráfica Arquitectónica. 16(17). doi:10.4995/ega.2011.882SWORD4253161

Epipolar image rectification through geometric algorithms with unknown parameters

Herráez Boquera, J., Denia Rios, J.L., Navarro Esteve, P.J., Rodríguez Pereña, J., Martín Sánchez M.T."Epipolar image rectification through geometric algorithms with unknown parameters". JJ. Electron. Imaging. 22(4), 043021 (Dec 02, 2013). © (2013) Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited. http://dx.doi.org/10.1117/1.JEI.22.4.043021Image processing in photogrammetry is commonly used for scene reconstruction. Although two-dimensional applications can be solved using isolated images, reconstruction of three-dimensional scenes usually requires the use of multiple images simultaneously. Epipolar image rectification is a common technique for this purpose. It typically requires internal orientation parameters and, therefore, knowledge of camera calibration and relative orientation parameters between images. A reparameterization of the fundamental matrix through a completely geometric algorithm of seven parameters that enables the epipolar image rectification of a photogrammetric stereo pair without introducing any orientation parameters and without premarking ground control points is presented. The algorithm enables the generation of different stereoscopic models with a single photogrammetric pair from unknown cameras, scanned from a book, or frames from video sequences. Stereoscopic models with no parallaxes have been obtained with a standard deviation of <0.5 pixels. (C) 2013 SPIE and IS&THerráez Boquera, J.; Denia Rios, JL.; Navarro Esteve, PJ.; Rodríguez Pereña, J.; Martín Sánchez, MT. (2013). Epipolar image rectification through geometric algorithms with unknown parameters. Journal of Electronic Imaging. 22(4). doi:10.1117/1.JEI.22.4.04302104302122

Design and calibration of a drill-guided system by laser for structural strengthening of historic bridge

Restoring the spans of a historic bridge requires installing tensors to ensure the structural and mechanical stability of the rows of stones that form the resistant body of the bridge. Once the positions where the structure-crossing tensors should be installed have been determined, the entry and exit points of each drill hole must be marked on both sides of the bridge. However, the exit point of each drill hole is not visible from the entry point, making it impossible to drill precisely. Here, we present a method based on a calibrated system that combines precision topography with laser technology. Using this method, drill holes longer than 12 m can be achieved with centimetric precision. © 2012 Elsevier Masson SAS. All rights reserved.This project is part of the research project "MOCAIDE", Creation and cartographic feeding of spatial data infrastructures at the Local Administration trough a data model integrating cadastre, urban planning and historic heritage, with reference CSO2008-04808 and financed by the CICYT and European funds.Herráez Boquera, J.; Denia Ríos, JL.; Navarro Esteve, PJ.; Bosch Roig, L.; Bosch Reig, I. (2013). Design and calibration of a drill-guided system by laser for structural strengthening of historic bridge. Journal of Cultural Heritage. 14(3):248-253. https://doi.org/10.1016/j.culher.2012.06.004S24825314

Modeling the thickness of vaults in the church of Santa María de Magdalena (Valencia, Spain) with laser scanning techniques

Restoring cultural heritage is an extremely important job due to its immeasurable value. However, it also requires even greater attention in the case of a building. The actions taken on these constructions not only guarantee their preservation from the point of view of their historical value, but they also guarantee their stability as structures. The need to control historic buildings, analyzing their defects and their possible consequences, is decisive in preventing significant damage. This work demonstrates calculating the thickness of vaults in a church. It is easy to determine the interior and exterior 3D geometry of the church using scanner laser techniques. By combining both geometries, it is easy to determine the difference between the interior vaults and the roof of the church. However, the interior of both geometries is completely unknown, and it is not possible to act on their condition for structural consolidation purposes. This work shows the methods used to determine the interior sections of the vault thicknesses by referencing the internal geometry of both models with the interior of the church, using plumb line system scanning. The results obtained show accuracy better than 6 millimeters. © 2013 Elsevier Masson SAS. All rights reserved.Herráez Boquera, J.; Navarro Esteve, PJ.; Denia Rios, JL.; Martín Sánchez, MT.; Rodríguez Pereña, J. (2013). Modeling the thickness of vaults in the church of Santa María de Magdalena (Valencia, Spain) with laser scanning techniques. Journal of Cultural Heritage. doi:10.1016/j.culher.2013.11.015

Topographic adjustment for the structural consolidation of the Serrano's bridge of Valencia

Se trata de exponer el sistema de orientación adoptado para la realización de perforaciones de gran longitud, en las que el punto de entrada del taladro y el punto de salida de la perforación están prefijados, y donde la precisión es determinante para la obtención de un buen resultado en la realización posterior de los anclajes. Se analizan métodos de orientación directos que permiten dirigir el sistema pero obtienen poca precisión o no admiten una comprobación continua; no permitiendo tener en cuenta las posibles desviaciones por holguras o caída del taladro durante la perforación. El sistema adoptado es una alineación de los controles del taladro, guiada por un replanteo topográfico. Se estudia la geometría de la perforación y su implementación en cualquier posición del espacio para garantizar la máxima precisión en el direccionamiento.This work presents a system to guide the work of making long perforations whose drill entry points and drill exit points are established, and where accuracy is crucial to obtain a good result for subsequent anchorages. Direct guidance methods that allow a control of the system were analysed. However, they proved poorly accurate or did not make continuous verifications possible, and did not allow possible deviations from the drill becoming loose or falling while drilling to be taken into account. The adopted system is an alignment of the drill controls and the topography of the surfaces is reconsidered. The geometry of the drilling and its implementation in any position of the surface is analysed to ensure maximum accuracy in the drilling direction.Bosch Roig, L.; Herráez Boquera, J.; Navarro Esteve, PJ.; Marcenac, V.; Bosch Reig, I.; Denia Ríos, JL. (2008). Ajuste topográfico para la consolidación estructural del puente de Serrano de Valencia. Arché. (3):215-220. http://hdl.handle.net/10251/31847215220