Unconstrained and Contactless Hand Geometry Biometrics

This paper presents a hand biometric system for contact-less, platform-free scenarios, proposing innovative methods in feature extraction, template creation and template matching. The evaluation of the proposed method considers both the use of three contact-less publicly available hand databases, and the comparison of the performance to two competitive pattern recognition techniques existing in literature: namely Support Vector Machines (SVM) and k-Nearest Neighbour (k-NN). Results highlight the fact that the proposed method outcomes existing approaches in literature in terms of computational cost, accuracy in human identification, number of extracted features and number of samples for template creation. The proposed method is a suitable solution for human identification in contact-less scenarios based on hand biometrics, providing a feasible solution to devices with limited hardware requirements like mobile devices

Gaussian Multiscale Aggregation Applied to Segmentation in Hand Biometrics

This paper presents an image segmentation algorithm based on Gaussian multiscale aggregation oriented to hand biometric applications. The method is able to isolate the hand from a wide variety of background textures such as carpets, fabric, glass, grass, soil or stones. The evaluation was carried out by using a publicly available synthetic database with 408,000 hand images in different backgrounds, comparing the performance in terms of accuracy and computational cost to two competitive segmentation methods existing in literature, namely Lossy Data Compression (LDC) and Normalized Cuts (NCuts). The results highlight that the proposed method outperforms current competitive segmentation methods with regard to computational cost, time performance, accuracy and memory usage.

An approach to hand biometrics in mobile devices

This paper focuses on hand biometrics applied to images acquired from a mobile device. The system offers the possibility of identifying individuals based on features extracted from hand pictures obtained with a low-quality camera embedded on a mobile device. Furthermore, the acquisitions have been carried out regardless illumination control, orientation, distance to camera, and similar aspects. In addition, the whole system has been tested with an owned database. Finally, the results obtained (6.0% ± 0.2) and the algorithm structure are both promising in relation to a posterior mobile implementation

Authentication in mobile devices through hand gesture recognition

This article proposes an innovative biometric technique based on the idea of authenticating a person on a mobile device by gesture recognition. To accomplish this aim, a user is prompted to be recognized by a gesture he/she performs moving his/her hand while holding a mobile device with an accelerometer embedded. As users are not able to repeat a gesture exactly in the air, an algorithm based on sequence alignment is developed to correct slight differences between repetitions of the same gesture. The robustness of this biometric technique has been studied within 2 different tests analyzing a database of 100 users with real falsifications. Equal Error Rates of 2.01 and 4.82% have been obtained in a zero-effort and an active impostor attack, respectively. A permanence evaluation is also presented from the analysis of the repetition of the gestures of 25 users in 10 sessions over a month. Furthermore, two different gesture databases have been developed: one made up of 100 genuine identifying 3-D hand gestures and 3 impostors trying to falsify each of them and another with 25 volunteers repeating their identifying 3- D hand gesture in 10 sessions over a month. These databases are the most extensive in published studies, to the best of our knowledge.

Design of a training tool for improving the use of hand-held detectors in humanitarian demining

Purpose – The purpose of this paper is to introduce the design of a training tool intended to improve deminers' technique during close-in detection tasks. Design/methodology/approach – Following an introduction that highlights the impact of mines and improvised explosive devices (IEDs), and the importance of training for enhancing the safety and the efficiency of the deminers, this paper considers the utilization of a sensory tracking system to study the skill of the hand-held detector expert operators. With the compiled information, some critical performance variables can be extracted, assessed, and quantified, so that they can be used afterwards as reference values for the training task. In a second stage, the sensory tracking system is used for analysing the trainee skills. The experimentation phase aims to test the effectiveness of the elements that compose the sensory system to track the hand-held detector during the training sessions. Findings – The proposed training tool will be able to evaluate the deminers' efficiency during the scanning tasks and will provide important information for improving their competences. Originality/value – This paper highlights the need of introducing emerging technologies for enhancing the current training techniques for deminers and proposes a sensory tracking system that can be successfully utilised for evaluating trainees' performance with hand-held detectors.

Influence of air drag on the optimal hand launching of a small, round projectile

Conditions leading to a maximum range for a small, round projectile, fired by hand, are discussed taking into account air drag and the dependence of the initial speed on the mass launched. Both the optimal angle of release for given projectile and initial speed, and the optimal radius for given density (i.e., among a bed of pebbles) are determined; an increase on the height of release is found to always decrease the angle and increase the radius. The influence of the projectile mass on the optimal manner of launching is considered. The validity of the approximations used in the analysis is discussed. Results from very simple measurements show good agreement with theory.

Design, implementation and evaluation of an unconstrained and contactless biometric system based on hand geometry and stress detection

Esta tesis propone un sistema biométrico de geometría de mano orientado a entornos sin contacto junto con un sistema de detección de estrés capaz de decir qué grado de estrés tiene una determinada persona en base a señales fisiológicas Con respecto al sistema biométrico, esta tesis contribuye con el diseño y la implementación de un sistema biométrico de geometría de mano, donde la adquisición se realiza sin ningún tipo de contacto, y el patrón del usuario se crea considerando únicamente datos del propio individuo. Además, esta tesis propone un algoritmo de segmentación multiescala para solucionar los problemas que conlleva la adquisición de manos en entornos reales. Por otro lado, respecto a la extracción de características y su posterior comparación esta tesis tiene una contribución específica, proponiendo esquemas adecuados para llevar a cabo tales tareas con un coste computacional bajo pero con una alta precisión en el reconocimiento de personas. Por último, este sistema es evaluado acorde a la norma estándar ISO/IEC 19795 considerando seis bases de datos públicas. En relación al método de detección de estrés, esta tesis propone un sistema basado en dos señales fisiológicas, concretamente la tasa cardiaca y la conductancia de la piel, así como la creación de un innovador patrón de estrés que recoge el comportamiento de ambas señales bajo las situaciones de estrés y no-estrés. Además, este sistema está basado en lógica difusa para decidir el grado de estrés de un individuo. En general, este sistema es capaz de detectar estrés de forma precisa y en tiempo real, proporcionando una solución adecuada para sistemas biométricos actuales, donde la aplicación del sistema de detección de estrés es directa para evitar situaciónes donde los individuos sean forzados a proporcionar sus datos biométricos. Finalmente, esta tesis incluye un estudio de aceptabilidad del usuario, donde se evalúa cuál es la aceptación del usuario con respecto a la técnica biométrica propuesta por un total de 250 usuarios. Además se incluye un prototipo implementado en un dispositivo móvil y su evaluación. ABSTRACT: This thesis proposes a hand biometric system oriented to unconstrained and contactless scenarios together with a stress detection method able to elucidate to what extent an individual is under stress based on physiological signals. Concerning the biometric system, this thesis contributes with the design and implementation of a hand-based biometric system, where the acquisition is carried out without contact and the template is created only requiring information from a single individual. In addition, this thesis proposes an algorithm based on multiscale aggregation in order to tackle with the problem of segmentation in real unconstrained environments. Furthermore, feature extraction and matching are also a specific contributions of this thesis, providing adequate schemes to carry out both actions with low computational cost but with certain recognition accuracy. Finally, this system is evaluated according to international standard ISO/IEC 19795 considering six public databases. In relation to the stress detection method, this thesis proposes a system based on two physiological signals, namely heart rate and galvanic skin response, with the creation of an innovative stress detection template which gathers the behaviour of both physiological signals under both stressing and non-stressing situations. Besides, this system is based on fuzzy logic to elucidate the level of stress of an individual. As an overview, this system is able to detect stress accurately and in real-time, providing an adequate solution for current biometric systems, where the application of a stress detection system is direct to avoid situations where individuals are forced to provide the biometric data. Finally, this thesis includes a user acceptability evaluation, where the acceptance of the proposed biometric technique is assessed by a total of 250 individuals. In addition, this thesis includes a mobile implementation prototype and its evaluation.

An Inexpensive Method for Kinematic Calibration of a Parallel Robot by Using One Hand-Held Camera as Main Sensor

This paper presents a novel method for the calibration of a parallel robot, which allows a more accurate configuration instead of a configuration based on nominal parameters. It is used, as the main sensor with one camera installed in the robot hand that determines the relative position of the robot with respect to a spherical object fixed in the working area of the robot. The positions of the end effector are related to the incremental positions of resolvers of the robot motors. A kinematic model of the robot is used to find a new group of parameters, which minimizes errors in the kinematic equations. Additionally, properties of the spherical object and intrinsic camera parameters are utilized to model the projection of the object in the image and thereby improve spatial measurements. Finally, several working tests, static and tracking tests are executed in order to verify how the robotic system behaviour improves by using calibrated parameters against nominal parameters. In order to emphasize that, this proposed new method uses neither external nor expensive sensor. That is why new robots are useful in teaching and research activities.

Un'idea nel palmo di una mano = An idea in the palm of a hand

Una idea en la palma de una mano. Texto en italiano e inglés.

Una Idea Bien Cabe en una Mano. Sobre las maquetas pequeñas como síntesis del espacio arquitectónico = An Idea Fits in the Palm of a Hand

Una Idea Bien Cabe en una Mano. Sobre las maquetas pequeñas como síntesis del espacio arquitectónico = An Idea Fits in the Palm of a Hand

An Idea Fits in The Palm of a Hand

Jewish laws prescribed that when a first-born son was presented in the temple shortly after birth, the offering consisted of two turtle doves or pigeons. And if the family were very poor, a handful of wheat would suffice: the wheat that would fit in the palm of one’s hand. That wonderful Jewish custom, which I learnt about when writing this text, moved me deeply on account of what it shares with my proposal of making models capable of fitting into the palm of one’s hand.

Grasp Mapping Between a 3-Finger Haptic Device and a Robotic Hand

This paper presents the implementation of a robust grasp mapping between a 3-finger haptic device (master) and a robotic hand (slave). Mapping is based on a grasp equivalence defined considering the manipulation capabilities of the master and slave devices. The metrics that translate the human hand gesture to the robotic hand workspace are obtained through an analytical user study. This allows a natural control of the robotic hand. The grasp mapping is accomplished defining 4 control modes that encapsulate all the grasps gestures considered.

Estudio de las propiedades de las fábricas históricas de adobe como soporte a intervenciones de rehabilitación

El extenso legado edificado que constituyen las construcciones históricas de fábrica de adobe distribuidas por toda la península encuentra en la región de Aveiro (Portugal) su máxima expresión, tanto desde el punto de vista cuantitativo, un 30% de los edificios existentes en la región, como tipológico, compuesto por un amplio conjunto de diferentes construcciones (edificios residenciales, edificios militares, iglesias, escuelas, teatros, naves industriales, etc.), muchos de los cuales de reconocido valor histórico, arquitectónico y patrimonial. Tras la gradual desaparición del empleo de la fábrica de adobe como técnica constructiva, durante la segunda mitad del siglo XX, la necesaria conservación y/o rehabilitación de los edificios remanentes no se ha tenido en cuenta. Como consecuencia de esta actitud generalizada de pasividad continuada, se verifica el estado actual de deterioro y de daño acusado que presentan una gran parte de estas construcciones, del cual ha resultado el panorama presente de abandono y ruina en el que se encuentran muchas de ellas. Por regla general, la solución adoptada para afrontar el estado actual de los edificios en estas condiciones suele ser la demolición. No obstante lo anterior, en los últimos años, se viene produciendo en el seno de los diferentes agentes que intervienen en la toma de decisiones sobre estos edificios un interés creciente en su preservación, promoviendo la rehabilitación de los mismos. Empieza de este modo a cobrar importancia la necesidad de desarrollar estrategias de intervención que posibiliten alargar la vida útil de estas estructuras, permitiendo, por un lado, establecer metodologías de análisis de sus condiciones de seguridad, que posibiliten determinar las medidas de actuación necesarias para el aseguramiento de las mismas frente a las acciones existentes y, en su caso, a la incorporación de nuevas solicitaciones debidas a cambios de uso o ampliaciones, así como, dando respuesta a los principales mecanismo de daño a los que se encuentran sujetas. Tratándose de estructuras que fueron construidas utilizando técnicas y materiales escasamente estudiados y entre tanto abandonados, se hace también necesario, y con carácter previo a lo anterior, acometer un estudio e investigación multidisciplinares que permitan su caracterización y comprensión, y la par establecer un diagnóstico sobre los principales agentes y procesos patológicos que promueven el deterioro de las mismas. En este contexto, el estudio llevado a cabo tuvo como objetivos ampliar el conocimiento e investigación acerca de las propiedades y parámetros resistentes de las fábricas históricas de adobe, así como, analizar los principales mecanismos de daño asociados a las mismas, a la luz del el estado actual de estas construcciones, y su repercusión en el comportamiento resistente de las fábricas –con especial énfasis para la influencia del agua–. De este modo, se pretendió construir una base de resultados que, por un lado, pueda servir de soporte a intervenciones de rehabilitación y/o consolidación de estas estructuras – permitiendo de forma ágil y a partir de datos y recursos de cálculo expeditos la evaluación de los niveles de seguridad en las fábricas–, y por otro, el estudio de soluciones de mejora o corrección de deficiencias en su comportamiento estructural. The vast edified legacy composed of the historical adobe load-bearing walls which can be found spread all over the Iberian peninsula has, in the region of Aveiro (Portugal), its maximum expression, both from a quantitative point of view (around 30% of the local construction) and a typological point of view, including a considerable number of different types of constructions (residential buildings, military buildings, churches, industrial buildings, etc.), most of which have a recognized high historical, architectural and patrimonial value. The conservation and/or rehabilitation of many of these edifications has been neglected, since its gradual abandonment as constructive technique during the second half of the 20th century. As a consequence of this posture of general passivity, it is nowadays visible the state of pronounced damage manifested by great part of these constructions, which has been leading to their abandonment and state of ruin. In most cases, the option for demolition has been the solution found to face the actual state of these constructions. However, in recent years, a growing interest in the preservation and maintenance of the adobe constructions has become visible by the envolved parties, with the obvious consequence of rehabilitation. By so, it becomes mandatory to develop strategies of intervention that, through rehabilitation, are able to extend the useful life of the existing structures, allowing on one hand, to establish methodologies to analyze their safety state and determine the actions needed to ensure their protection against existing pressures and, when applicable, the occurrence of new demands due to changes of use or extensions, and on the other hand, to give response to the main damage mechanisms to which these structures are exposed. Because these structures were built using not very well know techniques and materials, which have been, in the meantime, abandoned, it is now crucial that these are object of a previous phase of study and multidisciplinary investigation, essential not only to their characterization and comprehension, but also to the diagnosis of the main pathological processes that affect them. In this context, the present study had as main goal to develop the analysis and knowledge regarding the properties and resistant parameters of the adobe masonry as well as bringing to the light of day the actual state of the existing adobe constructions, making evident the main damage mechanisms by which they are affected and analyzing, through their occurrence, the vulnerability of the mentioned properties and resistant parameters. By so, it was objective of the present study the development of a result database which on one hand, supports the execution of rehabilitation interventions and/or strengthening of these constructions and, on other hand, allows the development of improvement solutions in the mechanical characteristics of the adobe masonry which permit corrections of deficiencies in their structural behavior with a special emphasis on the influence of water. Thus, a database of results was developed. Its goal is, on one hand, to support the rehabilitation or consolidation interventions on these structures - allowing for a quick analysis of the safety state of the adobe walls from expedite data and calculus resources and, on the other hand, to study improvement or correction solutions of their structural behavior.

Arquitectura modal o ensamblaje de repertorios, procesos y disposiciones

En muchas ocasiones se ha establecido una crítica sobre la excesiva disposicionalidad estética del arquitecto: el abuso subjetivista, un innatismo desligado del entorno socioambiental o su desafección hacia las necesidades y los requerimientos pertinentes del usuario final, buscando, principalmente, la objetivación cultural como expresión personal e individualista. Criticas que responden a un malestar persistente, que subyace a la práctica arquitectónica. En otras ocasiones se han ideado y propuesto tentativas o aproximaciones para la corrección y regulación de dicho “exceso”. En busca de la “pretendida objetividad”, éstas han recurrido a un pasado prístino, a una tradición inconsciente, colectiva e impersonal, a la ausencia de autoría, a lo artesanal y a lo vernáculo. También hacia un futuro tecnocrático: al mesianismo basado en la máquina, la ciencia, los métodos y el progreso tecnológico. La búsqueda de un lenguaje compartido, de un diseño sistemático y de una adecuación funcional han establecido nuevos excesos –repertoriales-, relegando la creatividad y la concepción estética a un plano casi inexistente, subordinándolo a variables de diseño externas a la autoría y la expresión subjetiva del diseñador. Esta tensión se ha saldado en una pugna de binomios categoriales que reducen la realidad a un dualismo aporético y contrapuesto, difícilmente superable. El propósito articulatorio de dichas posturas, en modelos ontológicos integrales, permite la incorporación de dichas categorías bajo estructuras y ensamblajes que despliegan los modos de relación, mediación y producción arquitectónicas. Estos ensamblajes combinan los distintos agentes –disposicionalidades- y sus repertorios en cada una de las fases del proceso arquitectónico, construyendo modos de acción y relación en base a los acoplamientos diferenciales, que devienen en técnicas y dinámicas de producción arquitectónica. Cada modo integrará diversas variables en base a los modelos propuestos -estratos, períodos y polos- y a la elección intencional –“situada”- de cada práctica: la Autonomía Modal Arquitectónica. El producto final de cada modo –o ensamblaje- será inconmensurable, estableciendo sistemas y métodos diversos para la práctica estética, sin que por ello esté garantizado el valor o éxito del resultado. ABSTRACT On many occasions an aesthetic criticism of the excessive disposition of the architect´s subjectivist abuse, innate posture detached from socioenvironmental issues or disaffection regarding the needs and requirements of who -or what- will finally use it has been brought up mainly in pursuit of a cultural objectification as a personal expression and an individualistic one. It is a criticism which goes hand in hand with a persistent uneasiness which is interwoven in the architectural practice. On other occasions we have seen ideas, attempts and approaches developed and proposed in order to correct, improve or adjust that so-called “excess”. In the search for this " expected objectivity" theorists have resorted to delving into a pristine past, an unconscious tradition both collective and personal, to the absence of authorship, regarding craft and vernacular. The pursuit of a common language, a systematic design and a functional adequacy has established new excesses -repertoires-, leaving behind creativity and aesthetic conception at an almost nonexistent level and subordinating it to variables outside the authoring design and subjective expression of the designer. This tension has resulted in a conflict between categorical binomial, which reduces reality to an aporetic and opposed dualism which is not easily overcome. The purpose of such articulatory positions in comprehensive ontological modals allows for the incorporation of those categories under structures and assemblies which display and unfold different models of relationship, mediation and production of architecture. These assemblies combine different agents - disposition - and their repertoires in each of the phases of the architectural process, building actions and relational modes based on the differential couplings, which become techniques and dynamics in architectural production. Each mode will integrate several variables within the proposed ontological models - strata, periods and poles - based on an intentional choice –“situated knowledge”- of each practice: Architectural Modal Autonomy. The final product of each mode -or assembly- will be immeasurable, establishing different systems and methods for aesthetic practice without the value or success of the outcome ever being guaranteed.

Human-computer interaction based on visual hand-gesture recognition using volumetric spatiograms of local binary patterns

A more natural, intuitive, user-friendly, and less intrusive Human–Computer interface for controlling an application by executing hand gestures is presented. For this purpose, a robust vision-based hand-gesture recognition system has been developed, and a new database has been created to test it. The system is divided into three stages: detection, tracking, and recognition. The detection stage searches in every frame of a video sequence potential hand poses using a binary Support Vector Machine classifier and Local Binary Patterns as feature vectors. These detections are employed as input of a tracker to generate a spatio-temporal trajectory of hand poses. Finally, the recognition stage segments a spatio-temporal volume of data using the obtained trajectories, and compute a video descriptor called Volumetric Spatiograms of Local Binary Patterns (VS-LBP), which is delivered to a bank of SVM classifiers to perform the gesture recognition. The VS-LBP is a novel video descriptor that constitutes one of the most important contributions of the paper, which is able to provide much richer spatio-temporal information than other existing approaches in the state of the art with a manageable computational cost. Excellent results have been obtained outperforming other approaches of the state of the art.