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

Macro Photogrammetry & Surface Features Extraction for Paleolithic Portable Art Documentation

[EN] In this article, we propose a methodology for the archaeological documentation of limestone plaquettes decorated with faint paintings and fine engravings. The plaquette number 16330 is presented, belonging to the portable art collection in Cova del Parpalló (Gandía, Spain), one of the most important Paleolithic sites in the UNESCO¿s Rock Art of the Mediterranean Basin on the Iberian Peninsula. Macro photogrammetry is used to generate a 3D model and basic treatments on raster images. The resulting 3D model has a spatial resolution of tens of microns and was used to generate a digital elevation model (DEM) and orthorectified macro photographs for documenting the engravings and paintings. All stages of the workflow are detailed in-depth, specifying the data collection parameters and the configuration used in the subsequent processing with HyperCube and DStretch software. The resulting documentation is accurate, reproducible, and objective and allows the reinterpretation of the available graphic documentation started in the 1990s.This research was funded by Generalitat Valenciana (PROMETEO/2017/060) and Ministerio de la Ciencia e Innovación (HAR2017-85153-P).Cabrelles, M.; Lerma, JL.; Villaverde, V. (2020). Macro Photogrammetry & Surface Features Extraction for Paleolithic Portable Art Documentation. Applied Sciences. 10:1-16. https://doi.org/10.3390/app10196908S11610Porter, S. T., Huber, N., Hoyer, C., & Floss, H. (2016). Portable and low-cost solutions to the imaging of Paleolithic art objects: A comparison of photogrammetry and reflectance transformation imaging. Journal of Archaeological Science: Reports, 10, 859-863. doi:10.1016/j.jasrep.2016.07.013Cassen, S., Lescop, L., Grimaud, V., & Robin, G. (2014). Complementarity of acquisition techniques for the documentation of Neolithic engravings: lasergrammetric and photographic recording in Gavrinis passage tomb (Brittany, France). Journal of Archaeological Science, 45, 126-140. doi:10.1016/j.jas.2014.02.019López-Menchero Bendicho, V. M., Marchante Ortega, Á., Vincent, M., Cárdenas Martín-Buitrago, Á. J., & Onrubia Pintado, J. (2017). Uso combinado de la fotografía digital nocturna y de la fotogrametría en los procesos de documentación de petroglifos: el caso de Alcázar de San Juan (Ciudad Real, España). Virtual Archaeology Review, 8(17), 64. doi:10.4995/var.2017.6820Jalandoni, A., & Kottermair, M. (2018). Rock art as microtopography. Geoarchaeology, 33(5), 579-593. doi:10.1002/gea.21677Defrasne, C. (2014). Digital image enhancement for recording rupestrian engravings: applications to an alpine rockshelter. Journal of Archaeological Science, 50, 31-38. doi:10.1016/j.jas.2014.06.010Le Quellec, J.-L., Duquesnoy, F., & Defrasne, C. (2015). Digital image enhancement with DStretch ® : Is complexity always necessary for efficiency? Digital Applications in Archaeology and Cultural Heritage, 2(2-3), 55-67. doi:10.1016/j.daach.2015.01.003Evans, L., & Mourad, A.-L. (2018). DStretch® and Egyptian tomb paintings: A case study from Beni Hassan. Journal of Archaeological Science: Reports, 18, 78-84. doi:10.1016/j.jasrep.2018.01.011Rodríguez González, E., Pastor, S. C., & Casals, J. R. (2019). Lost colours: Photogrammetry, image analysis using the DStretch plugin, and 3-D modelling of post-firing painted pottery from the south west Iberian Peninsula. Digital Applications in Archaeology and Cultural Heritage, 13, e00093. doi:10.1016/j.daach.2019.e00093Domingo, I., García-Argüelles, P., Nadal, J., Fullola, J. M., Lerma, J. L., & Cabrelles, M. (2019). Humanizing European Paleolithic art: A new visual evidence of human/bird interactions at L’Hort de la Boquera site (Margalef de Montsant, Tarragona, Spain). L’Anthropologie, 123(1), 1-18. doi:10.1016/j.anthro.2019.01.001Menna, F., Nocerino, E., Morabito, D., Farella, E. M., Perini, M., & Remondino, F. (2017). AN OPEN SOURCE LOW-COST AUTOMATIC SYSTEM FOR IMAGE-BASED 3D DIGITIZATION. The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, XLII-2/W8, 155-162. doi:10.5194/isprs-archives-xlii-2-w8-155-2017Porter, S. T., Roussel, M., & Soressi, M. (2016). A Simple Photogrammetry Rig for the Reliable Creation of 3D Artifact Models in the Field. Advances in Archaeological Practice, 4(1), 71-86. doi:10.7183/2326-3768.4.1.71Angheluță, L. M., & Rădvan, R. (2019). MACRO PHOTOGRAMMETRY FOR THE DAMAGE ASSESSMENT OF ARTWORK PAINTED SURFACES. The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, XLII-2/W15, 101-107. doi:10.5194/isprs-archives-xlii-2-w15-101-2019Menna, F., Nocerino, E., Remondino, F., Dellepiane, M., Callieri, M., & Scopigno, R. (2016). 3D DIGITIZATION OF AN HERITAGE MASTERPIECE - A CRITICAL ANALYSIS ON QUALITY ASSESSMENT. ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, XLI-B5, 675-683. doi:10.5194/isprsarchives-xli-b5-675-2016Lerma, J. L., Navarro, S., Cabrelles, M., & Seguí, A. E. (2010). Camera Calibration with Baseline Distance Constraints. The Photogrammetric Record, 25(130), 140-158. doi:10.1111/j.1477-9730.2010.00579.xDíaz-Guardamino, M., García Sanjuán, L., Wheatley, D., & Rodríguez Zamora, V. (2015). RTI and the study of engraved rock art: A re-examination of the Iberian south-western stelae of Setefilla and Almadén de la Plata 2 (Seville, Spain). Digital Applications in Archaeology and Cultural Heritage, 2(2-3), 41-54. doi:10.1016/j.daach.2015.07.002Quesada, E., & Harman, J. (2019). A step further in rock art digital enhancements. DStretch on Gigapixel imaging. Digital Applications in Archaeology and Cultural Heritage, 13, e00098. doi:10.1016/j.daach.2019.e0009

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

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

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

Augmented reality application assessment for disseminating rock art

[EN] Currently, marker-based tracking is the most used method to develop augmented reality (AR) applications (apps). However, this method cannot be applied in some complex and outdoor settings such as prehistoric rock art sites owing to the fact that the usage of markers is restricted on site. Thus, natural feature tracking methods have to be used. There is a wide range of libraries to develop AR apps based on natural feature tracking. In this paper, a comparative study of Vuforia and ARToolKit libraries is carried out, analysing factors such as distance, occlusion and lighting conditions that affect user experience in both indoor and outdoor environments, and eventually the app developer. Our analysis confirms that Vuforia¿s user experience indoor is better, faster and flicker-free whether the images are properly enhanced, but it does not work properly on site. Therefore, the development of AR apps for complex outdoor environments such as rock art sites should be performed with ARToolKit.The authors gratefully acknowledge the support from the Spanish Ministerio de Economia y Competitividad to the project HAR2014-59873-R. Similarly, the authors want to express their gratitude to the General Directorate of Culture and Heritage, Conselleria d'Educacio, Investigacio, Cultura i Esport, Generalitat Valenciana for letting us access and carry out research at the archaeological site.Blanco-Pons, S.; Carrión-Ruiz, B.; Lerma, JL. (2018). Augmented reality application assessment for disseminating rock art. Multimedia Tools and Applications. 78(8):10265-10286. https://doi.org/10.1007/s11042-018-6609-xS1026510286788Alahi A., Ortiz R., Vandergheynst P (2012) FREAK: fast retina keypoint. Comput Vis Pattern Recognit 510–517 . doi: https://doi.org/10.1109/CVPR.2012.6247715Amin D, Govilkar S (2015) Comparative study of augmented reality Sdk’S. Int J Comput Sci Appl 5:11–26. https://doi.org/10.1227/01.NEU.0000297044.82035.57ARCore ARCore - Google Developer | ARCore | Google Developers. https://developers.google.com/ar/ . Accessed 26 Jun 2018ARKit ARKit - Apple Developer. https://developer.apple.com/arkit/ . Accessed 26 Jun 2018ARToolkit (2017) ARToolkit. https://archive.artoolkit.org/ . Accessed 2 Oct 2017ARToolkit (2017) About. https://artoolkit.org/about-artoolkit . Accessed 11 Apr 2017ARToolkit (2017) Documentation. https://artoolkit.org/documentation/ . Accessed 12 Apr 2017ArUco ArUco: A minimal library for Augmented Reality applications based on OpenCV | Aplicaciones de la Visión Artificial. https://www.uco.es/investiga/grupos/ava/node/26 . Accessed 19 Apr 2018Azuma R (1997) A survey of augmented reality. Presence Teleoperators Virt Environ 6:355–385 . doi: 10.1.1.30.4999Azuma R, Baillot Y, Feiner S et al (2001) Recent advances in augmented reality. Ieee Comput Graph Appl 34–47. doi: https://doi.org/10.4061/2011/908468Blanco-Novoa O, Fernandez-Carames TM, Fraga-Lamas P, Vilar-Montesinos M (2018) A practical evaluation of commercial industrial augmented reality systems in an industry 4.0 shipyard. IEEE Access 6:1–1. https://doi.org/10.1109/ACCESS.2018.2802699Blanco-Pons S, Carrión-Ruiz B, Lerma JL (2016) Review of augmented reality and virtual reality techniques in rock art. Proc 8th Int Congress Archaeol Comput Graph Cult Herit Innov ‘ARQUEOLÓGICA 2.0L: 176–183Brancati N, Caggianese G, Frucci M et al (2017) Experiencing touchless interaction with augmented content on wearable head-mounted displays in cultural heritage applications. Pers Ubiquitous Comput 21:203–217. https://doi.org/10.1007/s00779-016-0987-8Cagalaban G, Kim S (2010) Multiple object tracking in unprepared environments using combined feature for augmented reality applications. Springer, Berlin, HeidelbergCamera-Calibration Camera Calibration App for Android [ARToolkit]. https://archive.artoolkit.org/documentation/doku.php?id=4_Android:android_camera_calibration . Accessed 16 Oct 2017Carmigniani J, Furht B, Anisetti M et al (2011) Augmented reality technologies, systems and applications. Multimed Tools Appl 51:341–377. https://doi.org/10.1007/s11042-010-0660-6Carrión-Ruiz B, Blanco-Pons S, Lerma JL (2016) Digital image analysis of the visible region through simulation of rock art paintings. Proc 8th Int Congress Archaeol Comput Graph, Cult Heritage Innov ‘ARQUEOLÓGICA 2.0.’: 169–175Chen CY, Chang BR, Sen HP (2014) Multimedia augmented reality information system for museum guidance. Pers Ubiquitous Comput 18:315–322. https://doi.org/10.1007/s00779-013-0647-1CRYENGINE CRYENGINE | The complete solution for next generation game development by Crytek. https://www.cryengine.com/ . Accessed 7 Jun 2017Domingo I, Carrión B, Blanco S, Lerma JL (2015) Evaluating conventional and advanced visible image enhancement solutions to produce digital tracings at el Carche rock art shelter. Digit Appl Archaeol Cult Herit 2:79–88. https://doi.org/10.1016/j.daach.2015.01.001Dos Santos AB, Dourado JB, Bezerra A (2016) ARToolkit and Qualcomm Vuforia: An Analytical Collation. Proc - 18th Symp Virt Augment Real SVR 2016:229–233. https://doi.org/10.1109/SVR.2016.46DroidAR (2017) DroidAR by bitstars. https://bitstars.github.io/droidar/ . Accessed 10 Dec 2017Engine U (2017) Unreal Engine. https://www.unrealengine.com/ . Accessed 10 Oct 2017Fiala M (2005) ARTag, a fiducial marker system using digital techniques. Proc IEEE Comput Soc Conf Comput Vis Pattern Recogn 2:590–596. https://doi.org/10.1109/CVPR.2005.74Fischer J, Eichler M, Bartz D, Straßer W (2007) A hybrid tracking method for surgical augmented reality. Comput Graph 31:39–52. https://doi.org/10.1016/j.cag.2006.09.007González C, Vallejo D, Albusac J, Castro J (2011) Realidad Aumentada. Un enfoque práctico con ARToolKit y Blender. 2–120Gutierrez JM, Molinero MA, Soto-Martín O, Medina CR (2015) Augmented reality technology spreads information about historical graffiti in temple of Debod. Procedia Comput Sci 75:390–397. https://doi.org/10.1016/j.procs.2015.12.262Haladová ZB, Szemzö R, Kovačovský T, Žižka J (2015) Utilizing Multispectral Scanning and Augmented Reality for Enhancement and Visualization of the Wooden Sculpture Restoration Process. Procedia Comput Sci 67:340–347. https://doi.org/10.1016/j.procs.2015.09.278Jamali SS, Shiratuddin MF, Wong KW, Oskam CL (2015) Utilising mobile-augmented reality for learning human anatomy. Procedia - Soc Behav Sci 197:659–668. https://doi.org/10.1016/j.sbspro.2015.07.054Khan D, Ullah S, Rabbi I (2015) Factors affecting the design and tracking of ARToolKit markers. Comput Stand Interf 41:56–66. https://doi.org/10.1016/j.csi.2015.02.006Khan D, Ullah S, Yan D et al (2018) Robust tracking through the design of high quality fiducial markers: an optimization tool for ARToolKit. IEEE Access 4:22421–22433. https://doi.org/10.1109/ACCESS.2018.2801028Kim SL, Suk HJ, Kang JH, et al (2014) Using unity 3D to facilitate mobile augmented reality game development. Internet things (WF-IoT), 2014 IEEE World Forum 21–26 . doi: https://doi.org/10.1109/WF-IoT.2014.6803110Kounavis CD, Kasimati AE, Zamani ED (2012) Enhancing the tourism experience through mobile augmented reality: challenges and prospects. Int J Eng Bus Manag 4:1–6. https://doi.org/10.5772/51644La Delfa GC, Monteleone S, Catania V et al (2016) Performance analysis of visualmarkers for indoor navigation systems. Front Inf Technol Electron Eng 17:730–740. https://doi.org/10.1631/FITEE.1500324Liu S, Ge S, Yu H (2016) Research on Robustness recognition algorithms in augmented reality. 3rd Int Conf Inf Sci Control Eng: 547–552. doi: https://doi.org/10.1109/ICISCE.2016.123Lowe DG (2004) Distinctive image features from scale invariant keypoints. Int J Comput Vis 60:91–11020042. https://doi.org/10.1023/B:VISI.0000029664.99615.94Lytridis C, Tsinakos A, Kazanidis I (2018) ARTutor—an augmented reality platform for interactive distance learning. Educ Sci 8:6. https://doi.org/10.3390/educsci8010006Marchand E, Uchiyama H, Spindler F et al (2016) Pose estimation for augmented reality : a hands-on survey. IEEE Trans Vis Comput Graph 22:2633–2651. https://doi.org/10.1109/TVCG.2015.2513408Martínez R, Villaverde V (2002) La cova dels cavalls en el Barranc de la ValltortaMarto AGR, Sousa AA, de Gonçalves A (2017) DinofelisAR demo augmented reality based on natural features. 12a Conferência Ibérica Sist e Tecnol Informação, Lisboa 64:852–861. https://doi.org/10.1016/j.procs.2015.08.638Moreels P, Perona P (2007) Evaluation of feature detectors and descriptors based on 3D objects. Int J Comput Vis 73:263–284. https://doi.org/10.1007/s11263-006-9967-1Pierdicca R, Frontoni E, Zingaretti P et al (2015) Making visible the invisible. augmented reality visualization for 3D reconstructions of archaeological sites. Augment Virt Real Sec Int Conf AVR 2015 9254:25–37. https://doi.org/10.1007/978-3-319-22888-4Rabbi I, Ullah S, Javed M, Zen K (2014) Analysis of ARToolKit fiducial markers attributes for robust tracking. 1st Int Conf Recent Trends Inf Commun Technol Anal 281–290Radkowski R, Oliver J (2013) Natural feature tracking augmented reality for on-site assembly assistance systems. In: Shumaker R (ed) Virtual, Augmented and Mixed Reality. Systems and Applications. VAMR 2013. Lecture Notes in Computer Science. Springer, Berlin, Heidelberg, pp 281–290Ridel B, Reuter P, Laviole J et al (2014) The revealing flashlight: interactive spatial augmented reality for detail exploration of cultural heritage artifacts. J Comput Cult Herit 7(6):1–6:18. https://doi.org/10.1145/2611376Seo J, Shim J, Choi JH, et al (2011) Enhancing marker-based AR technology. Lect Notes Comput Sci (including Subser Lect Notes Artif Intell Lect Notes Bioinformatics) 6773 LNCS:97–104 . doi: https://doi.org/10.1007/978-3-642-22021-0_12Seo J, Shim J, Choi JH et al (2011) Enhancing marker-based AR technology. In: International conference on virtual and mixed reality. virtual and mixed reality - new trends. Springer, Berlin, Heidelberg, pp 97–104Siltanen S (2015) Diminished reality for augmented reality interior design. Vis Comput 33:1–16. https://doi.org/10.1007/s00371-015-1174-zSörös G, Seichter H, Rautek P, Gröller E (2011) Augmented visualization with natural feature tracking. Proc 10th Int Conf Mob Ubiquitous Multimed 4–12. doi: https://doi.org/10.1145/2107596.2107597Uchiyama H, Marchand E (2012) Object detection and pose tracking for augmented reality: recent approaches. 18th Korea-Japan Jt Work Front Comput Vis 1–8Unity Unity. https://unity3d.com/es . Accessed 12 Oct 2017Vuforia (2017) Vuforia. https://www.vuforia.com/ . Accessed 2 Oct 2017Vuforia (2017) Vuforia-VuMark. https://library.vuforia.com/articles/Training/VuMark . Accessed 4 Apr 2017Vuforia (2017) Image targets. https://library.vuforia.com/articles/Training/Image-Target-Guide . Accessed 11 Apr 2017Wang H, Qin J, Zhang F (2015) A new interaction method for augmented reality based on ARToolKit. 2015 8th Int Congr Image Signal Process 578–583. doi: https://doi.org/10.1109/CISP.2015.7407945Wang G, Wang B, Zhong F et al (2015) Global optimal searching for textureless 3D object tracking. Vis Comput 31:979–988. https://doi.org/10.1007/s00371-015-1098-7Wu S, Oerlemans A, Bakker EM, Lew MS (2017) A comprehensive evaluation of local detectors and descriptors. Signal Process Image Commun 59:150–167. https://doi.org/10.1016/J.IMAGE.2017.06.010Xu Y, Wu Y, Zhou H, View M (2018) Multi-scale Voxel Hashing and Efficient 3D Representation for Mobile Augmented Reality. Cvpr 1618–1625 . doi: https://doi.org/10.1109/CVPRW.2018.0020

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

Heuristic method based on voting for extrinsic orientation through image epipolarization

[EN] Traditionally, the stereo-pair rectification, also known as epipolarization problem, (i.e., the projection of both images onto a common image plane) is solved once both intrinsic (interior) and extrinsic (exterior) orientation parameters are known. A heuristic method is proposed to solve both the extrinsic orientation problem and the epipolarization problem in just one single step. The algorithm uses the main property of a coplanar stereopair as fitness criteria: null vertical parallax between corresponding points to achieve the best stereopair. Using an iterative approach, each pair of corresponding points will vote for a rotation axis that may reduce vertical parallax. The votes will be weighted, the rotation applied, and an iteration will be carried out, until the vertical parallax residual error is below a threshold. The algorithm performance and accuracy are checked using both simulated and real case examples. In addition, its results are compared with those obtained using a traditional nonlinear least-squares adjustment based on the coplanarity condition. The heuristic methodology is robust, fast, and yields optimal results.The authors gratefully acknowledge the support from the Spanish Ministerio de Economia y Competitividad to the Project No. HAR2014-59873-R.Martín, S.; Lerma García, JL.; Uzkeda, H. (2017). Heuristic method based on voting for extrinsic orientation through image epipolarization. Journal of Electronic Imaging. 26(6):063020-1-063020-11. https://doi.org/10.1117/1.JEI.26.6.063020S063020-1063020-1126