Sensores hiperespectrales aerotransportados: eliminación del efecto de deriva

En este artículo se explican los conceptos básicos de los sensores hiperespectrales rotacionales aerotransportados. Así mismo, se hace una revisión de las diferentes circunstancias causantes de los errores en la formación de las imágenes y se propone una metodología para corregirlas. A continuación, mostramos un ejemplo práctico en el que se observa cómo la consideración y eliminación del efecto de deriva permite georreferenciar con alta precisión imágenes hiperespectrales tomadas con sensores rotacionales

Accuracy analysis of a mobile mapping system for close range photogrammetric projects

[EN] Image-based mapping solutions require accurate exterior orientation parameters independently of the cameras used for a survey. This paper analyses the inclusion of up to two stereo-based geometric constraints in the form of baseline distance and convergence angle between camera axes to boost the integrated sensor orientation performance on outdoor close-range projects. A terrestrial low-cost mobile mapping GNSS/IMU multi-camera system is used to test the performance of the stereo-based geometric constraint on a weak geometric network in a stop-and-go survey. The influence of the number of control points (CPs) is analysed to confirm the performance and usability of the geometric constraints in real live terrestrial projects where far from ideal setups can exist across the survey. Improvements in image residuals up to 9 times and deviation errors better than 1 cm are expected when at least three CPs are incorporated into the adjustmentThe authors gratefully acknowledge the support from the Spanish Ministerio de Economia y Competitividad to the project HAR2014-59873-R. Contributions on direct georeferencing from professors Dr. David Hernandez-Lopez, Dr. Luis Garcia-Asenjo and D. Pascual Garrigues are highly appreciated.Navarro Tarin, S.; Lerma García, JL. (2016). Accuracy analysis of a mobile mapping system for close range photogrammetric projects. Measurement. 93:148-156. https://doi.org/10.1016/j.measurement.2016.07.0301481569

8th. International congress on archaeology computer graphica. Cultural heritage and innovation

El lema del Congreso es: 'Documentación 3D avanzada, modelado y reconstrucción de objetos patrimoniales, monumentos y sitios.Invitamos a investigadores, profesores, arqueólogos, arquitectos, ingenieros, historiadores de arte... que se ocupan del patrimonio cultural desde la arqueología, la informática gráfica y la geomática, a compartir conocimientos y experiencias en el campo de la Arqueología Virtual. La participación de investigadores y empresas de prestigio será muy apreciada. Se ha preparado un atractivo e interesante programa para participantes y visitantes.Lerma García, JL. (2016). 8th. International congress on archaeology computer graphica. Cultural heritage and innovation. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/73708EDITORIA

Spherical harmonics to quantify cranial asymmetry in deformational plagiocephaly

[EN] Cranial deformation and deformational plagiocephaly (DP) in particular affect an important percentage of infants. The assessment and diagnosis of the deformation are commonly carried by manual measurements that provide low interuser accuracy. Another approach is the use of three-dimensional (3D) models. Nevertheless, in most cases, deformation measurements are carried out manually on the 3D model. It is necessary to develop methodologies for the detection of DP that are automatic, accurate and take profit on the high quantity of information of the 3D models. Spherical harmonics are proposed as a new methodology to identify DP from head 3D models. The ideal fitted ellipsoid for each head is computed and the orthogonal distances between head and ellipsoid are obtained. Finally, the distances are modelled using spherical harmonics. Spherical harmonic coefficients of degree 2 and order - 2 are identified as the correct ones to represent the asymmetry characteristic of DP. The obtained coefficient is compared to other anthropometric deformation indexes, such as Asymmetry Index, Oblique Cranial Length Ratio, Posterior Asymmetry Index and Anterior Asymmetry Index. The coefficient of degree 2 and order - 2 with a maximum degree of 4 is found to provide better results than the commonly computed anthropometric indexes in the detection of DP.This article was funded by Instituto de Salud Carlos III and European Regional Development Fund (FEDER) (Grant no. PI18/00881).Grieb, J.; Barbero-García, I.; Lerma, JL. (2022). Spherical harmonics to quantify cranial asymmetry in deformational plagiocephaly. Scientific Reports. 12(1):1-10. https://doi.org/10.1038/s41598-021-04181-z11012

Valoración de la calidad de imágenes panorámicas esféricas

[EN] In recent years, the production of panoramic images has been boosted by the increasing use of digital photographiccameras and mobile phones. However, for highly demanding applications such as long-range deformation monitoring, theaccuracy and quality control of panoramic images and processes used to obtain accurate 3D models should be properlyassessed. Therefore, prior to being applied in real projects, the quality of the spherical panoramic images generated bythree widely used computer programs (Agisoft Metashape, GigaPan Stitch and PTGui) is evaluated using the same imagesof a photogrammetric laboratory full of control points and an outdoor environment by shooting from several stations. Inaddition to the assessment of the geometrical accuracy, the study also includes important aspects for practical efficiencysuch as workflow, speed of processing, user-friendliness, or exporting products and formats available. The results of thecomparisons show that Agisoft Metashape meets the required geometric specifications with higher quality and has clearadvantages in performance if compared to the other two tested programs.[ES] En los últimos años, la producción de imágenes panorámicas se ha visto impulsada por el uso cada vez mayor de cámaras fotográficas digitales y teléfonos móviles. Sin embargo, deben evaluarse adecuadamente en aplicaciones altamente exigentes como la monitorización de deformaciones a grandes distancias, la precisión y el control de calidad de las imágenes panorámicas y los procesos utilizados para obtener modelos 3D precisos. Por consiguiente, antes de ser aplicadas en proyectos reales, se evalúa la calidad de las imágenes panorámicas esféricas generadas por tres programas informáticos ampliamente utilizados (Agisoft Metashape, GigaPan Stitch y PTGui) utilizando las mismas imágenes de un laboratorio fotogramétrico lleno de puntos de apoyo y del exterior desde varias estaciones. Además de la evaluación de la precisión geométrica, el estudio también incluye aspectos importantes para la eficiencia práctica como es el flujo de trabajo, la velocidad de procesamiento, la facilidad de uso o la exportación de productos y los formatos disponibles. Los resultados de las comparaciones muestran que Agisoft Metashape cumple con las especificaciones geométricas requeridas con mayor calidad y tiene claras ventajas de rendimiento si se compara con los otros dos programas testeados.Javadi, P.; Lerma, J.; García-Asenjo, L.; Garrigues, P. (2021). Quality assessment of spherical panoramic images. En Proceedings 3rd Congress in Geomatics Engineering. Editorial Universitat Politècnica de València. 7-14. https://doi.org/10.4995/CiGeo2021.2021.12728OCS71

Updating urban cadastral cartography using LiDAR and GIS

[EN] This paper presents a methodology to automatically update urban cartography using LiDAR (Light Detección And Ranging) data and GIS (Geographic Information Systems). It is worth having access to large scale urban cartography either for the private sector or for the general public; therefore, periodic map updating is requested by local authorities. However, as it is difficult to detect new buildings on outdated plans, most of the times a full update is carried out without considering the related costs of this action. This paper introduces a method to update cartography after detecting changes in LiDAR data. In addition, several algorithms are presented to transform 2D cartography in 3D, making use of a least squares adjustment of the height information delivered by the LiDAR technology.[ES] Este artículo presenta una metodología para actualizar cartografía urbana de forma automática utilizando datos LiDAR (Light Detección And Ranging) y SIG (Sistema de Información Geográfica). La gran utilidad de disponer de cartografía urbana a grandes escalas tanto para el sector privado como público motiva la actualización periódica de la misma por parte de las administraciones locales. No obstante, dada la dificultad de detectar nuevas edificaciones en la cartografía obsoleta, en la mayoría de los casos se opta por su renovación completa con los costes asociados que ello conlleva. El presente artículo muestra una metodología para actualizar cartografía, previa detección de cambios utilizando datos LiDAR. Además, se exponen distintos algoritmos para transformar cartografía 2D a 3D a partir de un ajuste mínimo cuadrático utilizando la información altimétrica que proporciona la tecnología LiDAR.Sánchez Lopera, J.; Lerma García, JL. (2012). Actualización de cartografía catastral urbana mediante LiDAR y SIG. GeoFocus. 12:53-70. http://hdl.handle.net/10251/4364453701

Fully automatic smartphone-based photogrammetric 3D modelling of infant¿s heads for cranial deformation analysis

[EN] Image-based and range-based solutions can be used for the acquisition of valuable data in medicine. However, most of these methods are not valid for non-static patients. Cranial deformation is a problem with high prevalence among infants and image-based solutions can be used to assess the degree of deformation and monitor the evolution of patients. However, it is required to deal with infants normal movement during the assessment in order to avoid sedation. Some high-end multiple-sensor image-based solutions allow the achievement of accurate 3D data for medical applications under unpredicted dynamic conditions in consultation. In this paper, a novel, single photogrammetric smartphone-based solution for cranial deformation assessment is presented. A coded cap is placed on the infant's head and a guided smartphone app is used by the user to acquire the information, that is later processed on a server to obtain the 3D model. The smartphone app is designed to guide users with no knowledge of photogrammetry, computer vision or 3D modelling. The processing is fully automatic offline. The photogrammetric tool is also non-invasive, reacting well with quick and sudden infant's movements. Therefore, it does not require sedation. This paper tackles the accuracy and repeatability analysis tested both for a single user (intrauser) and multiple non-expert user (interuser) on 3D printed head models. The results allow us to confirm an accuracy below 1.5 mm, which makes the system suitable for clinical practice by medical staff. The basic automatically-derived anthropometric linear magnitudes are also tested obtaining a mean variability of 0.6 +/- 0.6 mm for the longitudinal and transversal distances and 1.4 +/- 1.3 mm for the maximum perimeter.This project is funded by Instituto de Salud Carlos III and European Regional Development Fund (FEDER), project number PI18/00881, and by Generalitat Valenciana, grant number ACIF/2017/056.Barbero-García, I.; Lerma, JL.; Mora Navarro, JG. (2020). Fully automatic smartphone-based photogrammetric 3D modelling of infant¿s heads for cranial deformation analysis. ISPRS Journal of Photogrammetry and Remote Sensing. 166:268-277. https://doi.org/10.1016/j.isprsjprs.2020.06.013S268277166Aldridge, K., Boyadjiev, S. A., Capone, G. T., DeLeon, V. B., & Richtsmeier, J. T. (2005). Precision and error of three-dimensional phenotypic measures acquired from 3dMD photogrammetric images. American Journal of Medical Genetics Part A, 138A(3), 247-253. doi:10.1002/ajmg.a.30959Argenta, L. (2004). Clinical Classification of Positional Plagiocephaly. Journal of Craniofacial Surgery, 15(3), 368-372. doi:10.1097/00001665-200405000-00004Ballardini, E., Sisti, M., Basaglia, N., Benedetto, M., Baldan, A., Borgna-Pignatti, C., & Garani, G. (2018). Prevalence and characteristics of positional plagiocephaly in healthy full-term infants at 8–12 weeks of life. European Journal of Pediatrics, 177(10), 1547-1554. doi:10.1007/s00431-018-3212-0Barbero-García, I., Cabrelles, M., Lerma, J. L., & Marqués-Mateu, Á. (2018). Smartphone-based close-range photogrammetric assessment of spherical objects. The Photogrammetric Record, 33(162), 283-299. doi:10.1111/phor.12243Barbero-García, I., Lerma, J. L., Marqués-Mateu, Á., & Miranda, P. (2017). Low-Cost Smartphone-Based Photogrammetry for the Analysis of Cranial Deformation in Infants. World Neurosurgery, 102, 545-554. doi:10.1016/j.wneu.2017.03.015Barbero-García, I., Lerma, J. L., Miranda, P., & Marqués-Mateu, Á. (2019). Smartphone-based photogrammetric 3D modelling assessment by comparison with radiological medical imaging for cranial deformation analysis. Measurement, 131, 372-379. doi:10.1016/j.measurement.2018.08.059Bay, H., Ess, A., Tuytelaars, T., Gool, L. Van, 2007. Speeded-Up Robust Features (SURF). https://doi.org/10.1016/j.cviu.2007.09.014.Bernardini, F., Mittleman, J., Rushmeier, H., Silva, C., & Taubin, G. (1999). The ball-pivoting algorithm for surface reconstruction. IEEE Transactions on Visualization and Computer Graphics, 5(4), 349-359. doi:10.1109/2945.817351Besl, P.J., McKay, N.D., 1992. Method for registation of 3-D shapes. In: Schenker, P.S. (Ed.), Sensor Fusion IV: Control Paradigms and Data Structures. SPIE, pp. 586–606. https://doi.org/10.1117/12.57955.Camison, L., Bykowski, M., Lee, W. W., Carlson, J. C., Roosenboom, J., Goldstein, J. A., … Weinberg, S. M. (2018). Validation of the Vectra H1 portable three-dimensional photogrammetry system for facial imaging. International Journal of Oral and Maxillofacial Surgery, 47(3), 403-410. doi:10.1016/j.ijom.2017.08.008Caple, J. M., Stephan, C. N., Gregory, L. S., & MacGregor, D. M. (2015). Effect of Head Position on Facial Soft Tissue Depth Measurements Obtained Using Computed Tomography. Journal of Forensic Sciences, 61(1), 147-152. doi:10.1111/1556-4029.12896Cignoni, P., Callieri, M., Corsini, M., Dellepiane, M., Ganovelli, F., Ranzuglia, G., 2008. MeshLab: an Open-Source Mesh Processing Tool. In: Scarano, V., Chiara, R. De, Erra, U. (Eds.), Eurographics Italian Chapter Conference. The Eurographics Association. https://doi.org/10.2312/LocalChapterEvents/ItalChap/ItalianChapConf2008/129-136.Collett, B. R., Wallace, E. R., Kartin, D., Cunningham, M. L., & Speltz, M. L. (2019). Cognitive Outcomes and Positional Plagiocephaly. Pediatrics, 143(2), e20182373. doi:10.1542/peds.2018-2373De Jong, G., Tolhuisen, M., Meulstee, J., van der Heijden, F., van Lindert, E., Borstlap, W., … Delye, H. (2017). Radiation-free 3D head shape and volume evaluation after endoscopically assisted strip craniectomy followed by helmet therapy for trigonocephaly. Journal of Cranio-Maxillofacial Surgery, 45(5), 661-671. doi:10.1016/j.jcms.2017.02.007De Jong, G. A., Maal, T. J. J., & Delye, H. (2015). The computed cranial focal point. Journal of Cranio-Maxillofacial Surgery, 43(9), 1737-1742. doi:10.1016/j.jcms.2015.08.023Dörhage, K. W. W., Wiltfang, J., von Grabe, V., Sonntag, A., Becker, S. T., & Beck-Broichsitter, B. E. (2018). Effect of head orthoses on skull deformities in positional plagiocephaly: Evaluation of a 3-dimensional approach. Journal of Cranio-Maxillofacial Surgery, 46(6), 953-957. doi:10.1016/j.jcms.2018.03.013Farkas, L.G., 1994. Anthropometry of the Head and Face. Raven Pr.Garrido-Jurado, S., Muñoz-Salinas, R., Madrid-Cuevas, F. J., & Medina-Carnicer, R. (2016). Generation of fiducial marker dictionaries using Mixed Integer Linear Programming. Pattern Recognition, 51, 481-491. doi:10.1016/j.patcog.2015.09.023Goebbels, S., Pohle-Fröhlich, R., Pricken, P., 2019. Iterative closest point algorithm for accurate registration of coarsely registered point clouds with CityGML models. In: ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences. pp. 201–208. https://doi.org/10.5194/isprs-annals-IV-2-W5-201-2019.Grazioso, S., Selvaggio, M., Caporaso, T., & Di Gironimo, G. (2019). A Digital Photogrammetric Method to Enhance the Fabrication of Custom-Made Spinal Orthoses. JPO Journal of Prosthetics and Orthotics, 31(2), 133-139. doi:10.1097/jpo.0000000000000244Heymsfield, S.B., Bourgeois, B., Ng, B.K., Sommer, M.J., Li, X., Shepherd, J.A., 2018. Digital anthropometry: A critical review. In: European Journal of Clinical Nutrition. Nature Publishing Group, pp. 680–687. https://doi.org/10.1038/s41430-018-0145-7.Hsu, C.-K., Hallac, R. R., Denadai, R., Wang, S.-W., Kane, A. A., Lo, L.-J., & Chou, P.-Y. (2019). Quantifying normal head form and craniofacial asymmetry of elementary school students in Taiwan. Journal of Plastic, Reconstructive & Aesthetic Surgery, 72(12), 2033-2040. doi:10.1016/j.bjps.2019.09.005Jodeh, D. S., Curtis, H., Cray, J. J., Ford, J., Decker, S., & Rottgers, S. A. (2018). Anthropometric Evaluation of Periorbital Region and Facial Projection Using Three-Dimensional Photogrammetry. Journal of Craniofacial Surgery, 29(8), 2017-2020. doi:10.1097/scs.0000000000004761Khormi, Y., Chiu, M., Goodluck Tyndall, R., Mortenson, P., Smith, D., & Steinbok, P. (2019). Safety and efficacy of independent allied healthcare professionals in the assessment and management of plagiocephaly patients. Child’s Nervous System, 36(2), 373-377. doi:10.1007/s00381-019-04400-zKournoutas, I., Vigo, V., Chae, R., Wang, M., Gurrola, J., Abla, A. A., … Rubio, R. R. (2019). Acquisition of Volumetric Models of Skull Base Anatomy Using Endoscopic Endonasal Approaches: 3D Scanning of Deep Corridors Via Photogrammetry. World Neurosurgery, 129, 372-377. doi:10.1016/j.wneu.2019.05.251Lopes Alho, E.J., Rondinoni, C., Furokawa, F.O., Monaco, B.A., 2019. Computer-assisted craniometric evaluation for diagnosis and follow-up of craniofacial asymmetries: SymMetric v. 1.0. Child’s Nerv. Syst. 1–7. https://doi.org/10.1007/s00381-019-04451-2.Lowe, D.G., 1999. Object recognition from local scale-invariant features. In: Proceedings of the International Conference on Computer Vision-Volume 2 - Volume 2, ICCV ’99. IEEE Computer Society, Washington, DC, USA, p. 1150.Lübbers, H.-T., Medinger, L., Kruse, A., Grätz, K. W., & Matthews, F. (2010). Precision and Accuracy of the 3dMD Photogrammetric System in Craniomaxillofacial Application. Journal of Craniofacial Surgery, 21(3), 763-767. doi:10.1097/scs.0b013e3181d841f7Martiniuk, A. L. C., Vujovich-Dunn, C., Park, M., Yu, W., & Lucas, B. R. (2017). Plagiocephaly and Developmental Delay: A Systematic Review. Journal of Developmental & Behavioral Pediatrics, 38(1), 67-78. doi:10.1097/dbp.0000000000000376Meulstee, J. W., Verhamme, L. M., Borstlap, W. A., Van der Heijden, F., De Jong, G. A., Xi, T., … Maal, T. J. J. (2017). A new method for three-dimensional evaluation of the cranial shape and the automatic identification of craniosynostosis using 3D stereophotogrammetry. International Journal of Oral and Maxillofacial Surgery, 46(7), 819-826. doi:10.1016/j.ijom.2017.03.017Mitchell, H. ., & Newton, I. (2002). Medical photogrammetric measurement: overview and prospects. ISPRS Journal of Photogrammetry and Remote Sensing, 56(5-6), 286-294. doi:10.1016/s0924-2716(02)00065-5Mortenson, P. A., & Steinbok, P. (2006). Quantifying Positional Plagiocephaly. Journal of Craniofacial Surgery, 17(3), 413-419. doi:10.1097/00001665-200605000-00005Munn, L., & Stephan, C. N. (2018). Changes in face topography from supine-to-upright position—And soft tissue correction values for craniofacial identification. Forensic Science International, 289, 40-50. doi:10.1016/j.forsciint.2018.05.016Muñoz-Salinas, R., Marín-Jimenez, M. J., Yeguas-Bolivar, E., & Medina-Carnicer, R. (2018). Mapping and localization from planar markers. Pattern Recognition, 73, 158-171. doi:10.1016/j.patcog.2017.08.010Nahles, S., Klein, M., Yacoub, A., & Neyer, J. (2018). Evaluation of positional plagiocephaly: Conventional anthropometric measurement versus laser scanning method. Journal of Cranio-Maxillofacial Surgery, 46(1), 11-21. doi:10.1016/j.jcms.2017.10.010Nocerino, E., Poiesi, F., Locher, A., Tefera, Y.T., Remondino, F., Chippendale, P., Van Gool, L., 2017. 3D Reconstruction with a Collaborative Approach Based on Smartphones and a Cloud-based Server. ISPRS - Int. Arch. Photogramm. Remote Sens. Spat. Inf. Sci. 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Análisis de repetibilidad en videogrametría para la evaluación de la deformación craneal en niños

[EN] Cranial deformation affects a large number of infants. The methodologies commonly employed to measure the deformation include, among others, calliper measurements and visual assessment for mild cases and radiological imaging for severe cases, where surgical intervention is considered. Visual assessment and calliper measurements usually lack the required level of accuracy to evaluate the deformation. Radiological imaging, including Computed Tomography (CT) and Magnetic Resonance Imaging (MRI), are costly and highly invasive. The use of smartphones to record videos that can be used for three-dimensional (3D) modelling of the head has emerged as a low-cost, noninvasive methodology to extract 3D information of the patient. To be able to analyse the deformation, a novel technique is employed: the obtained model is compared with an ideal head. In this study we have tested the repeatability of the process. For this purpose, several models of two patients have been obtained and the differences between them are evaluated. The results show that the differences in the ellipsoid semiaxis for the same patient are usually below 4 mm, although they increase up to 6.4 mm in some cases. The variability in the distances to the ideal head, which are the values used to evaluate deformity, reaches a maximum value of 2.7 mm. The errors obtained are comparable to those of classical measurement techniques and show the potential of the methodology in development.[ES] La deformación craneal afecta a un elevado porcentaje de lactantes, a pesar de esto, no existen estándares para su medición. Existen diversas metodologías empleadas para el análisis de este tipo de deformación, que van desde el análisis visual o la medición con calibre en casos leves, a pruebas radiológicas en casos más graves, en los que se plantea la posibilidad de una intervención quirúrgica. El análisis visual y la medición con calibre a menudo carecen de la precisión requerida para evaluar la deformación, mientras que las pruebas radiológicas (Tomografía Axial Computarizada, TAC, o Resonancia Magnética, RM) son altamente invasivas y tienen un alto coste. Otras soluciones como la fotografía tridimensional (3D) incluyen complejos sistemas de varias cámaras, lo que también supone un coste elevado. La posibilidad de utilizar videos tomados con teléfonos inteligentes para la creación de modelos 3D craneales se ha convertido en una posibilidad para obtener información 3D del paciente de forma precisa y con un coste bajo. Para analizar la deformación se ha planteado una metodología que consiste en calcular las distancias entre el modelo generado y una forma craneal ideal. En este estudio se ha llevado a cabo el análisis de la repetibilidad del proceso de obtención del modelo y de la cabeza ideal ajustada, para ello se han obtenido varios modelos 3D de dos pacientes y se han evaluado las diferencias entre ellos. Los resultados muestran unas diferencias en los semiejes de los elipsoides de aproximadamente 4 mm, aunque este error llega a incrementarse hasta 6.4 mm en algunos casos. La variabilidad en las distancias del modelo a la cabeza ideal, empleadas para medir la deformidad tienen un máximo de 2.7 mm. Las precisiones obtenidas con esta metodología son comparables a las obtenidas mediante técnicas de análisis tradicionales y muestran el potencial de la metodología en desarrollo.This work was supported by Subprogram C (No. C10) for the development of coordinated actions between the UPV and the IIS La Fe.Barbero García, I.; Lerma García, JL.; Marqués Mateu, Á.; Miranda, P. (2017). Analysis of repeatability on videogrammetry for infants' cranial deformation. En Primer Congreso en Ingeniería Geomática. Libro de actas. Editorial Universitat Politècnica de València. 15-19. https://doi.org/10.4995/CIGeo2017.2017.6604OCS151

Desarrollo de software para el tratamiento de datos colorimétricos y espectrales: pycolourimetry

[EN] Archaeological documentation is a complex process where the technical measurement and specification of colour is a key aspect. In the last years heritage documentation processes have largely benefited from the application of digital recording methods, imagery analysis software and technologies that offers great advantages over the traditional methods. The rigorous processing of colourimetric data requires software packages with specific colourimetric technical characteristics. In this paper we report on our in-house pyColourimetry software that was developed and tested taking into account the recommendations of the Commission Internationale de l'Éclairage (CIE). The objective is to apply a rigorous procedure for the characterisation of cameras based a priori on polynomial models. Most of the digital cameras capture colour information in the well-known RGB format, but the signals generated by the digital camera are device dependent. By means of the characterisation we establish the relationship between device dependent RGB values and the tristimulus coordinates defined by the CIE standard colourimetric observer. Once the camera is characterised, users have the potential to obtain output images in the sRGB space that is independent of the sensor of the camera. pyColourimetry software allows users to control the entire digital image processing and the colourimetric data workflow proposed. We applied the methodology on a set of pictures targeting Levantine rock art motifs in Cova dels Cavalls (Castellón, Spain) which is considered part of a UNESCO World Heritage Site. The outcomes obtained are satisfactory and very promising for proper colour documentation in cultural heritage estudies.[ES] La documentación del patrimonio arqueológico es un proceso complejo donde la correcta medición del color es un aspecto clave. En los últimos años los procesos de documentación se han beneficiado gracias al uso de imágenes digitales, software de tratamiento de imágenes, así como de otras tecnologías frente a los métodos tradicionales. El procesamiento riguroso de datos colorimétricos requiere paquetes de software con características técnicas específicas. En este artículo presentamos un informe sobre el software pyColourimetry, desarrollado y testado teniendo en cuenta las recomendaciones de la Comisión Internacional de la Iluminación (CIE). Mediante este software el susuario puede caracterizar cámaras digitales a partir de modelos polinomiales. La mayoría de cámaras digitales captan información del color en el conocido sistema RGB. Sin embargo, la señal generada depende del dispositivo. A partir de la caracterización establecemos la relación entre los valores RGB dependientes y las coordenadas independientes CIE triestímulo. Una vez caracterizada la cámara se obtienen imágenes en el espacio sRGB, independiente del sensor empleado. El software pyColourimetry permite a los usuarios controlar todo el procesamiento digital de imágenes y el flujo de trabajo de datos colorimétricos propuesto. Aplicamos la metodología a un conjunto de imágenes que contienen motivos de arte rupestre levantino pertenecientes a la Cova dels Cavalls (Castellón, España), considerada parte del Patrimonio de la Humanidad por la UNESCO. Los resultados obtenidos son satisfactorios y muy prometedores para la correcta documentación del color en estudios de patrimonio cultural.The authors gratefully acknowledge the support from the Spanish Ministerio de Economía y Competitividad to the project HAR2014-59873-R. The authors would like also to acknowledge comments from the colleagues at the Photogrammetry & Laser Scanning Research Group (GIFLE).Molada Tebar, A.; Lerma García, JL.; Marqués-Mateu, Á. (2017). Software development for colourimetric and spectral data processing: pycolourimetry. En Primer Congreso en Ingeniería Geomática. Libro de actas. Editorial Universitat Politècnica de València. 48-53. https://doi.org/10.4995/CIGeo2017.2017.6568OCS485

EL LEVANTAMIENTO, LA REPRESENTACIÓN Y EL MODELADO ESTRUCTURAL DE UN PUENTE ANTICUADO

[EN] The in opera concrete bridges characterize often the landscapes crossed by old roads and railways. In particular the arch bridges represent a product of human genius and, in some cases, of his art. In the last few years, at the SmartLab laboratory of the University of Calabria, there were developed activities in the field of surveying, monitoring and representation of structures. In the framework of these activities, Geomatics techniques for the surveying of bridges are widely used since 2014. The results of the measurements are used for documentation and representation purposes, as well as for the reconstruction of the constructive procedures. The finite element modeling of the structures has been obtained to simulate their behavior in case of earthquake. This article describes the activities relating to a bridge dated back to the 50s of the twentieth century: it is an arch bridge made of reinforced concrete. The surveying is aimed to determine the exact reconstruction of the geometry, the identification of the foundation settlement as well as the Finite Element Modeling (FEM) in order to allow structural identification and reverse engineering process. The instruments and techniques used for surveying and modeling operations, along with the deviations between models and "as built" are described.[ES] Los puentes de hormigón in opera caracterizan a menudo los paisajes atravesados por los antiguos caminos y las vías férreas. En particular, los puentes de arco, representan un producto del ingenio humano y, en algunos casos, de su arte. En los últimos años, en el laboratorio SmartLab de la Universidad de Calabria, se desarrollaron actividades en el campo de la topografia, el monitoreo y la representación de estructuras. En el marco de estas actividades, las técnicas geomáticas relativas al levantamiento de puentes se utilizan ampliamente desde 2014. Se utilizan los resultados de las mediciones con fines de documentación y de representación, así como para la reconstrucción de los procedimientos constructivos. La modelización mediante elementos finitos de la estructura se ha obtenido para simular su comportamiento en caso de terremoto. El artículo describe las actividades relativas a un puente que data de los años 50 del siglo XX: es un puente en arco de hormigón armado. El levantamiento está dirigido a la reconstrucción exacta de la geometría, la identificación de asentamiento de la cimentación y el modelado de elementos finitos que permiten la identificación de estructuras y el proceso de ingeniería inversa. Se describen las herramientas y las técnicas utilizadas durante el levantamiento con escéner làser y las operaciones de modelado, junto con las desviaciones entre los modelos y el como fue construido "as built"Artese, S.; Lerma García, JL.; Zagari, G.; Zinno, R. (2016). THE SURVEY, THE REPRESENTATION AND THE STRUCTURAL MODELING OF A DATED BRIDGE. En 8th International congress on archaeology, computer graphics, cultural heritage and innovation. Editorial Universitat Politècnica de València. 162-168. https://doi.org/10.4995/arqueologica8.2016.3559OCS16216