Multidimensional image enhancement from a set of unregistered differently exposed images

If multiple images of a scene are available instead of a single image, we can use the additional information conveyed by the set of images to generate a higher quality image. This can be done along multiple dimensions. Super-resolution algorithms use a set of shifted and rotated low resolution images to create a high resolution image. High dynamic range imaging techniques combine images with different exposure times to generate an image with a higher dynamic range. In this paper, we present a novel method to combine both techniques and construct a high resolution, high dynamic range image from a set of shifted images with varying exposure times. We first estimate the camera response function, and convert each of the input images to an exposure invariant space. Next, we estimate the motion between the input images. Finally, we reconstruct a high resolution, high dynamic range image using an interpolation from the non-uniformly sampled pixels. Applications of such an approach can be found in various domains, such as surveillance cameras, consumer digital cameras, etc

On the generation of high dynamic range images: theory and practice from a statistical perspective

This dissertation studies the problem of high dynamic range (HDR) image generation from a statistical perspective. A thorough analysis of the camera acquisition process leads to a simplified yet realistic statistical model describing raw pixel values. The analysis and methods then proposed are based on this model. First, the theoretical performance bound of the problem is computed for the static case, where the acquisition conditions are controlled. Furthermore, a new method is proposed that, unlike previous methods, improves the reconstructed HDR image by taking into account the information carried by saturated samples. From a more practical perspective, two methods are proposed to generate HDR images in the more realistic and complex case where both objects and camera may exhibit motion. The first one is a multi-image, patch-based method, that simultaneously estimates and denoises the HDR image. The other is a single image approach that makes use of a general restoration method to generate the HDR image. This general restoration method, applicable to a wide range of problems, constitutes the last contribution of this dissertation

ICTs for whose development? A critical analysis of the discourses surrounding an ICT for Development Initiative for a group of microenterprise entrepreneurs operating in the Jamaican tourism industry: Towards the development of methodologies and analytical tools for understanding and explaining the ICT for Development Phenomenon

This is an interdiscliplinary qualitative study which uses an exploratory research design and builds on Fariclough's Critical Discourse Analysis methodology to analyze the discourses surrounding an Information and Communication Technology (ICT) for livelihood development project in Jamaica, introduced by the United Nations Development Programme - the Jamaica Sustainable Development Networking Programme (JSDNP). The primary objective of this project is to provide the poor in Jamaican communities with access to, and training in ICTs. In this research, I specifically focus on the discourses surrounding the JSDNP Cybercentre Project for a group of microenterprise entrepreneurs in the Jamaican tourism industry to access the epistemological assumptions of this project. From the data collected it was found that at one level, the JSDNP Cybercentre Project encouraged specific ways of acting and organizing congruent with the configurations, processes and structures of corporate firms of industrialized countries, by representing the achievement of livelihood expansion through the use of specific ICTs in a particular way which excluded other discourses. The particular ways of acting and organizing promoted by the Cybercentre encouraged the use of non-indigenous technologies, undervalued indigenous technologies and excluded the indigenization of non-indigenous technologies. These discourses were incompatible with the operational and structural configurations of trans-temporal poor entrepretrepreneurs interviewed and were more favourable to the non-poor and spatio-temporal ones. One of the wider implications of the discourse therefore was that they play a fundamental role in perpetuating entrenched inequalities through the preservation of social practices, along with their associated systems and structures. It was also found that these modalities limited the operational processes of all microenterprise entrepreneurs who were exposed to the Cybercentre Project. These entrepreneurs have limited control over the configuration of non-indigenous technologies; their technological and creative capabilities are restricted; their ability to indigenize non-indigenous technologies impaired; and they are highly dependent on non-indigenous technologies (which themselves have a number of limitations)

Platforms for handling and development of audiovisual data

Estágio realizado na MOG Solutions e orientado por Vítor TeixeiraTese de mestrado integrado. Engenharia Informátca e Computação. Faculdade de Engenharia. Universidade do Porto. 200

Human factors in instructional augmented reality for intravehicular spaceflight activities and How gravity influences the setup of interfaces operated by direct object selection

In human spaceflight, advanced user interfaces are becoming an interesting mean to facilitate human-machine interaction, enhancing and guaranteeing the sequences of intravehicular space operations. The efforts made to ease such operations have shown strong interests in novel human-computer interaction like Augmented Reality (AR). The work presented in this thesis is directed towards a user-driven design for AR-assisted space operations, iteratively solving issues arisen from the problem space, which also includes the consideration of the effect of altered gravity on handling such interfaces.Auch in der bemannten Raumfahrt steigt das Interesse an neuartigen Benutzerschnittstellen, um nicht nur die Mensch-Maschine-Interaktion effektiver zu gestalten, sondern auch um einen korrekten Arbeitsablauf sicherzustellen. In der Vergangenheit wurden wiederholt Anstrengungen unternommen, Innenbordarbeiten mit Hilfe von Augmented Reality (AR) zu erleichtern. Diese Arbeit konzentriert sich auf einen nutzerorientierten AR-Ansatz, welcher zum Ziel hat, die Probleme schrittweise in einem iterativen Designprozess zu lösen. Dies erfordert auch die Berücksichtigung veränderter Schwerkraftbedingungen

Sur la génération d'images à grande gamme dynamique. Théorie et pratique : une perspective statistique

This dissertation studies the problem of high dynamic range (HDR) image generation from a statistical perspective. A thorough analysis of the camera acquisition process leads to a simplified yet realistic statistical model describing raw pixel values. The analysis and methods then proposed are based on this model. First, the theoretical performance bound of the problem is computed for the static case, where the acquisition conditions are controlled. Furthermore, a new method is proposed that, unlike previous methods, improves the reconstructed HDR image by taking into account the information carried by saturated samples. From a more practical perspective, two methods are proposed to generate HDR images in the more realistic and complex case where both objects and camera may exhibit motion. The first one is a multi-image, patch-based method, that simultaneously estimates and denoises the HDR image. The other is a single image approach that makes use of a general restoration method to generate the HDR image. This general restoration method, applicable to a wide range of problems, constitutes the last contribution of this dissertation.Cette thèse porte sur le problème de la génération d'images à grande gamme dynamique (HDR pour l'anglais High Dynamic Range). Une analyse approfondie du processus d'acquisition de la caméra conduit tout d'abord à un modèle statistique simplifié mais réaliste décrivant les valeurs brutes des pixels. Les analyses et méthodes proposées par la suite sont fondées sur ce modèle.Nous posons le problème de l'estimation de l'irradiance comme un problème d'estimation statistique et en calculons la borne de performance. Les performances des estimateurs d'irradiance classiques sont comparées à cette borne. Les résultats obtenus justifient l'introduction d'un nouvel estimateur qui, au contraire des méthodes de la littérature, prend en compte les échantillons saturés.D'un point de vue plus pratique, deux méthodes sont proposées pour générer des images HDR dans le cas plus réaliste et complexe de scènes dynamiques. Nous proposons tout d'abord une méthode multi-image qui utilise des voisinages (patches) pour estimer et débruiter l'image HDR de façon simultanée. Nous proposons également une approche qui repose sur l'acquisition d'une seule image. Cette approche repose sur une méthode générique, par patches, de résolution des problèmes inverses pour génerer l'image HDR. Cette méthode de restauration, d'un point de vue plus général et pour une large gamme d'applications, constitue la dernière contribution de cette thèse