Homography-based ground plane detection using a single on-board camera

This study presents a robust method for ground plane detection in vision-based systems with a non-stationary camera. The proposed method is based on the reliable estimation of the homography between ground planes in successive images. This homography is computed using a feature matching approach, which in contrast to classical approaches to on-board motion estimation does not require explicit ego-motion calculation. As opposed to it, a novel homography calculation method based on a linear estimation framework is presented. This framework provides predictions of the ground plane transformation matrix that are dynamically updated with new measurements. The method is specially suited for challenging environments, in particular traffic scenarios, in which the information is scarce and the homography computed from the images is usually inaccurate or erroneous. The proposed estimation framework is able to remove erroneous measurements and to correct those that are inaccurate, hence producing a reliable homography estimate at each instant. It is based on the evaluation of the difference between the predicted and the observed transformations, measured according to the spectral norm of the associated matrix of differences. Moreover, an example is provided on how to use the information extracted from ground plane estimation to achieve object detection and tracking. The method has been successfully demonstrated for the detection of moving vehicles in traffic environments.

Simulation of plasma flows in divergent magnetic nozzles

Images from the simulation code DIMAGNO illustrate the roles of pressure, electric, and magnetic forces in the 2-D plasma expansion in a magnetic nozzle and the generation of thrust

An Efficient Hybrid GO-PWS Algorithm to Analyze Conformal Serrated-Edge Reflectors for Millimeter-Wave Compact Range

A method to analyze parabolic reflectors with arbitrary piecewise rim is presented in this communication. This kind of reflectors, when operating as collimators in compact range facilities, needs to be large in terms of wavelength. Their analysis is very inefficient, when it is carried out with fullwave/MoM techniques, and it is not very appropriate for designing with PO techniques. Also, fast GO formulations do not offer enough accuracy to reach performance results. The proposed algorithm is based on a GO-PWS hybrid scheme, using analytical as well as non-analytical formulations. On one side, an analytical treatment of the polygonal rim reflectors is carried out. On the other side, non-analytical calculi are based on efficient operations, such as M2 order 2-dimensional FFT. A combination of these two techniques in the algorithm ensures real ad-hoc design capabilities, reached through analysis speedup. The purpose of the algorithm is to obtain an optimal conformal serrated-edge reflector design through the analysis of the field quality within the quiet zone that it is able to generate in its forward half space.

An Efficient Multiple Object Detection and Tracking Framework for Automatic Counting and Video Surveillance Applications

Automatic visual object counting and video surveillance have important applications for home and business environments, such as security and management of access points. However, in order to obtain a satisfactory performance these technologies need professional and expensive hardware, complex installations and setups, and the supervision of qualified workers. In this paper, an efficient visual detection and tracking framework is proposed for the tasks of object counting and surveillance, which meets the requirements of the consumer electronics: off-the-shelf equipment, easy installation and configuration, and unsupervised working conditions. This is accomplished by a novel Bayesian tracking model that can manage multimodal distributions without explicitly computing the association between tracked objects and detections. In addition, it is robust to erroneous, distorted and missing detections. The proposed algorithm is compared with a recent work, also focused on consumer electronics, proving its superior performance.

Viaducto para la mejora del trazado de la N-403 Toledo-��vila, entre el pk. 111+050 y el pk. 111+450, t��rmino municipal de San Juan de la Nava (��vila)

Las actuaciones que se definen en el presente Proyecto de Construcci��n consisten en una mejora de trazado de la actual N-403 Toledo-��vila, mediante la construcci��n de un viaducto que une los puntos kilom��tricos 111+050 y 111+450 de dicha carretera, en el t��rmino municipal de San Juan de la Nava (��vila). Esta mejora de trazado nace de la necesidad de aumentar la seguridad de un tramo con unas estad��sticas de accidentalidad y mortalidad superiores a las del resto de la N- 403. Esos altos ��ndices de accidentalidad no se pueden achacar al estado del pavimento ni a posibles desprendimientos de los taludes excavados, sino que se deben a la escasa visibilidad que se produce en ambos puntos kilom��tricos arriba se��alados, en los cuales hay curvas cerradas con visibilidad reducida debido a que los taludes de las m��rgenes son pr��cticamente verticales, al estar ��stos excavados en granito, que permite tales ��ngulos. A esto hay que sumar que la carretera existente es de tipo convencional, con una sola calzada y un carril por sentido, de manera que el riesgo de choque frontal en dichos puntos es elevado. Para resolver esta problem��tica, la Administraci��n impone mejorar el actual trazado con otro recto que salva aquellos puntos kilom��tricos mediante un viaducto.

Idas y venidas. Los viajes de arquitectura en Espa��a entre 1920 y 1960

Esta tesis se propone indagar en las vias por las que la arquitectura espa��ola cambi�� en el periodo comprendido entre 1920 y 1960 y el papel que los viajes tuvieron en dicho cambio. La investigaci��n busca demostrar que, junto a otros factores como la llegada de revistas y libros y las conferencias de arquitectos de la talla de Le Corbusier, Gropius, Mendelsohn, Neutra o Aalto, los viajes tuvieron un papel clave en el proceso de apertura de miras y que provoc�� que, bien a traves de lo publicado en las revistas por los ���arquitectos viajeros��� o por el reflejo que tuvo lo conocido fuera de nuestras fronteras en proyectos y obras concretas, un buen numero de arquitectos, que no tuvieron la posibilidad de viajar, pudieron conocer que exist��a una realidad muy distinta a la que los profesores en la Escuela les hab��an ense��ado o a la que estaban acostumbrados a ver en otros arquitectos de generaciones anteriores basada, en buena medida, en la recuperaci��n de un estilo propio nacional centrandose en los historicismos. A lo largo de la investigaci��n trataremos de ver que efecto produjo la apertura de fronteras y que papel tuvieron los viajes en dicho proceso. Tambi��n nos centraremos en comprobar hasta qu�� punto cambi�� la manera de ver la arquitectura de los protagonistas del viaje y de aquellos que recibieron la informaci��n por ellos encontrada. Veremos c��mo dicha informaci��n es cuantificable, clasificable y demostrable en propuestas concretas. Ser�� importante ver que motiv�� su salida, que buscaban y que encontraron as�� como, entre las influencias recibidas, cuales tuvieron un mayor calado: las propuestas europeas o las americanas, y dentro de las primeras, las holandesas, las alemanas o las francesas. Los objetivos que se persigue conseguir son: contribuir a un mayor conocimiento de la arquitectura entre 1920 y 1960 a trav��s de las conexiones internacionales y el ensanchamiento de horizontes, recopilar, clasificar y analizar todo el material obtenido relacionando los viajes con las biograf��as de los arquitectos protagonistas, estudiar qu�� interesa a los arquitectos espa��oles cuando van fuera y porqu�� (ser�� importante ver qui��nes de entre los arquitectos son m��s abiertos a las corrientes europeas y que motiv�� su salida en busca de nuevos lenguajes), ordenar las reflexiones que exponen los arquitectos a la vuelta de sus viajes y ver en que propuestas y de qu�� forma los arquitectos plasman lo encontrado en su b��squeda en el extranjero. Para conseguir estos objetivos estructuraremos la investigaci��n en tres bloques: En el primero de ellos nos centraremos en profundizar como era la arquitectura espa��ola a principios del siglo XX. Para poder entender mejor las transformaciones que los viajes provocaron ser�� necesario conocer cu��l era la arquitectura predominante en estos a��os que, como veremos, consist��a en la b��squeda de un estilo nacional propio dirigiendo su mirada al pasado. Tambi��n veremos c��mo un grupo de arquitectos (Palacios, Fl��rez, Torres Balb��s o Anasagasti) fueron pioneros en el deseo de mirar fuera de nuestras fronteras as�� como dedicaremos especial atenci��n a c��mo era la formaci��n en la Escuela. El segundo cap��tulo, que abarca desde principios de los a��os 20 hasta la Guerra Civil, tratar�� de demostrar la importancia que tuvo en el proceso de permeabilidad frente a las corrientes extranjeras los viajes que los arquitectos realizaron y que, sumados a la llegada de revistas y las visitas de los principales arquitectos modernos, provocaron una primera apertura como respuesta a los historicismos predominantes. Entre los arquitectos viajeros destacaremos las figuras de Fernando Garc��a Mercadal (incidiendo en su importancia como difusor de la arquitectura moderna), Rafael Bergam��n, Ram��n S��nchez Arcas y Luis Lacasa. Tambi��n nos detendremos en ver la importancia que tuvieron las exposiciones (con especial atenci��n a la de Artes Decorativas de Par��s de 1925 y la de la Deutscher Werkbund en Stuttgart en 1927) que se realizaron estos a��os y como lleg�� la informaci��n a nuestro pa��s. El tercer y ��ltimo cap��tulo arranca con el periodo de posguerra, una ��poca de transici��n pues los viajes que se realizaron fueron escasos y en la mayor��a de las ocasiones no se llevaron a cabo en busca de nuevos caminos. Veremos c��mo tras la Guerra y de la mano de la dictadura se produce, de la misma forma que en la Alemania nazi, una vuelta al inter��s por los historicismos de principios de siglo. Para entender mejor este periodo haremos un repaso a la obra de Luis Guti��rrez Soto por ser explicativa de lo cambiante de las corrientes arquitect��nicas de estos a��os. Tras el an��lisis de los sucedido en posguerra nos dedicaremos a analizar, de la misma forma que en el primer periodo, la manera en que se produjo el rechazo al estilo nacional de nuevo gracias a la llegada de libros y revistas, lo publicado por las revistas espa��olas, las visitas de arquitectos de prestigio as�� como los viajes de un grupo de arquitectos que, de manera individual, salieron al extranjero en busca de apoyo, de referencias en los que cimentar su arquitectura. De este grupo, por la importancia que los propios protagonistas dieron al hecho de viajar como complemento a su formaci��n y por la manera en la que reflejaron lo aprendido en proyectos concretos destacamos a Francisco de As��s Cabrero, Miguel Fisac, Ram��n V��zquez Molez��n y Francisco Javier S��enz de Oiza. De nuevo, igual que en el primer cap��tulo finalizaremos la investigaci��n dedicando un apartado a las exposiciones (fundamentalmente la Interbau de Berl��n de 1957) celebradas en estos a��os. Para finalizar estableceremos las conclusiones que nos llevar��n a comprobar hasta qu�� punto la arquitectura espa��ola en los periodos previo y posterior a la guerra cambi�� y en qu�� medida tuvieron importancia los viajes que los arquitectos espa��oles realizaron al extranjero en dicho cambio��� ABSTRACT This thesis aims to look at the ways which Spanish architecture changed in the period between 1920 and 1960, and the way it was effected by travelling . The research will demonstrate that, together with other factors, such as the arrival of magazines, books, conferences and architects like Le Corbusier, Gropius, Mendelsohn, Neutra or Aalto, travelling played a key role in architecture. Also, it changed the way we look at architecture. Travelling, thanks to the published journals by "travelling architects��� and the influence that they had - known beyond our borders in projects and concrete works, caused the arrival of a new type of architects. Even those who were not able to travel, knew that there was a very different reality than the reality the teachers at the school had taught them. Also, the ���new reality��� was different from the one that they were used to seeing in other architects of earlier generations, based mainly on the recovery of a national style focused on historicism. Throughout the investigation I will try to show the effect that the opening of borders and travelling had on this process. We will also focus on checking how it changed the way we see the architecture, from the point of view of the protagonists of the travels and those who received the information . We will see how that information is quantifiable and demonstrably classifiable into concrete proposals. It will be important to see which led to their departure. They sought and found among the influences, which had a major impact: the proposed European or American, and within the first, Dutch, German or French. The objectives to be achieved are: To contribute to a better understanding of architecture between 1920 to 1960 by the international connections, and widening the horizon. To collect, classify and analyze all obtained materials related to travelling with biographies of architects protagonists. To study what the interests of the Spanish architects were when they went abroad and why ( it will be important to see who among those architects were more open to European trends and prompted their departures for new languages). To order reflections exhibited by architects around his travels and to see what proposals and how architects reflected what they found in their search abroad. To achieve these objectives we will structure this research in three areas: In the first one, we will focus on how the Spanish architecture in the early twentieth century was. To better understand the changes that travelling caused it is necessary to understand that the predominant architecture in these years was in pursuit of its own national style, directing its gaze to the past, like we shall see. We will also see how a group of architects (Palacios, Fl��rez, Torres Balb��s or Anasagasti) pioneered by looking beyond our borders and devote special attention to how the training was in the School. The second chapter, ranging from early 20s to the Civil War, will try to demonstrate the importance that travelling had in the process of diffusion currents. That, together with the arrival of magazines and visits by leading modern architects, led to a first opening in architecture, in response to the prevailing historicism. Among the travelers we highlight architects like Fernando Garc��a Mercadal (stressing his importance as a disseminator of modern architecture), Rafael Bergam��n, Ram��n S��nchez Arcas and Luis Lacasa. We will also stop to see the importance of exhibitions (with special attention to the Decorative Arts in Paris in 1925 and the Deutscher Werkbund in Stuttgart in 1927) that were held over the years and how the information came to our country . The third and final chapter starts with the post war period, a time of transition for the travels, which were scarce and in most cases were not conducted on new roads. We will see that after the war and with the dictatorship, a return to interest in historicism of the century occurred, just as in Nazi Germany. For better understanding of this period we will review the work of Luis Guti��rrez Soto. His work is explanatory of the changing of architectural trends over these years. After analyzing the case in post war, we turn to analyze, in the same way as in the first period, the manner in which rejection occurred in national style again with the arrival of books and magazines. Visits by prestigious architects and group travels of architects who, individually, went abroad in search of support, references on which to base their architecture. In this group of architects, due to the importance that the protagonists gave to the act of traveling to improve their training and the way in which they reflected what they learned in practical projects, I include Francisco de As��s Cabrero, Miguel Fisac, Ramon Vazquez Molez��n and Francisco Javier Saenz de Oiza. Again, as in the first chapter, we will conclude the investigation dedicating a section to the exhibitions held in these years (mainly Interbau Berlin, 1957). Finally establishing conclusions lead us to see how far the Spanish architecture in the pre- and post -war periods changed and how much the trips were important to Spanish architects who performed abroad on the change...