A Deep Primal-Dual Network for Guided Depth Super-Resolution

In this paper we present a novel method to increase the spatial resolution of depth images. We combine a deep fully convolutional network with a non-local variational method in a deep primal-dual network. The joint network computes a noise-free, high-resolution estimate from a noisy, low-resolution input depth map. Additionally, a high-resolution intensity image is used to guide the reconstruction in the network. By unrolling the optimization steps of a first-order primal-dual algorithm and formulating it as a network, we can train our joint method end-to-end. This not only enables us to learn the weights of the fully convolutional network, but also to optimize all parameters of the variational method and its optimization procedure. The training of such a deep network requires a large dataset for supervision. Therefore, we generate high-quality depth maps and corresponding color images with a physically based renderer. In an exhaustive evaluation we show that our method outperforms the state-of-the-art on multiple benchmarks.Comment: BMVC 201

No longer Adams in a simple Eden: Culture and clothing in Hermannsberg missions in the western Transvaal, 1864-1910

African Studies Seminar series. Paper presented 24 March 1997Referring to the Hermannsburg station Linokana in the Marico district the Rand Daily Mail commented in 1907, fifty years after the arrival of the first Lutheran missionaries at that spot. But the days of the missionary are over, for no fewer than four storekeepers have come to contest for the favours of the natives, and through them, and also through their intercourse in town with white men, our coloured brethren are no longer Adams in a simple Eden. They have learned to desire the possession of bright and gaudy clothes and tawdry jewellery, and they crowd into the stores bartering mealies and eggs for cheap clothes. The scenario depicted suggests that chaos and moral decay were taking over power where once European missionaries used to work for the creation of humble Christian communities. Economic advance and urban involvement seemed to wield their corruptive influences over rural mission stations thus alienating "Adams" (probably "Eves" were incorporated in that term) from a simple Eden and introducing them to the degenerative effects of urban-style life. Was it indeed African mission residents who no longer lived in a simple Eden or was it rather their European surveyors who lost their paradisiac dream of creating African society according to their vision? The work experiences and perceptions of African communities of Hermannsburg missionaries in the Western Transvaal in the decades between the mid-nineteenth century and the beginning of the twentieth century clearly reflect how within roughly fifty years in South Africa they lost important features of their Edenic vision with which they had once come to the mission field. Working among communities of the Western Transvaal the missionaries developed a radically redefined understanding of African society which they conveyed to their German supporters through articles in the monthly mission journal, Hermannsburger Missionsblatt. Clothing was a topic which loomed large in the descriptions of their experiences. It was an indispensable pre-requisite to prepare pagan Africans for becoming Christians and therefore had to be scrupulously submitted to the control of the self-styled agents of Christian civilisation. The loss of control over African clothing habits consequently resulted in the disapproval not only of African outward appearance but of African mission residents themselves because outward appearance was considered to be the mirror of a person's inner condition. It is the aim of this paper to show how missionary perception of African costume was intimately related to the degree in which missionary families were incorporated into colonial settler society. From newcomers to South Africa with little means and the burning wish to convert pagan Africans to Christianity they developed into esteemed missionary and settler families with strong roots in the farming sector, some of them dwellers on representative mission stations among Boer neighbours, economically successful, living in respectable houses and stubbornly keeping to their German inheritance. The argument to be unfolded in this paper is that their initial appreciation of African clothing can be attributed to the fact that after ten years of failure in their evangelical activities they were prepared to cherish any African who apparently took over their ideas about decent costume. However, towards the turn of the century missionaries developed a much more critical attitude, disapproving of individual self-expression or African imitation of clothing habits which represented the sartorial flair of people in colonial society. Between Hermannsburg missionaries and African converts issues of clothing were a means of conflict in fighting over social status in the congregation. To develop the argument the first part of this paper will refer to the Hermannsburg missionary vision which was closely tied to the German surrounding in which it originated. In a second part missionary entanglement in the realities of their South African work field will be focused on. To illustrate the change in missionary vision and activity special attention will be paid to the relations between Hermannsburg missionaries and the Bakuena ba Mogopa of Rustenburg and Pretoria districts among whom the mission stations of Bethanie and Hebron were located

Relative orientation with limited control in close range Photogrammetry

In close-range photogrammetry, situations can arise in which it is difficult or impossible to establish a network of control points as required for a conventional absolute orientation procedure. The thesis investigates the replacement of the traditional control network by a few control distances measured between well-defined artificial markers or natural feature points. The measured distances must then serve to reduce deformations suffered by the photogrammetric model in the orientation procedures. All investigations are based on analytical rather than analogue photogrammetry. After a review of the concepts of rotation matrices, least squares adjustment and the generation of synthetic image co-ordinate observations, the study is executed in three major steps. A test field of high precision is established by means of space intersection and a camera calibration method for close-range cameras is developed which combines perspective projection with geodetic observations of the lens system parameters. Thus a problem inherent in many camera calibration methods, namely the exact determination of the perspective centre, is largely overcome. Deformation characteristics related to error in elements of interior and relative orientation are determined by the controlled introduction of errors into these elements. The deformations are presented in tabular and diagrammatical form. An analysis of the deformation leads to the conclusions of theoretical and practical relevance for close-range photogrammetry. As a result of the deformation analysis mathematical models are introduced which utilise the measured distances for the reduction of model deformations. The efficiency of homogeneous scaling, affine scaling and convergency correction, as applied individually and in various combinations, is tested. A mathematical formulation of the converging correction as a restraining condition in a least squares adjustment is developed for this purpose. It is shown that a convergency error is less relevant to close-range photogrammetry than generally assumed and that characteristic model deformations in close-range photogrammetry have the character of affine scale errors. Throughout the thesis algorithms are developed which make it possible to execute all computations on computers with limited memory capacity. A program sample for the relative orientation adjustment is given in Appendix IV to demonstrate the memory saving techniques. Finally the results of the investigation are applied to the survey of shoulder height of African elephants in their natural habitat. Equipment and field work are described and results reported

Alternative employment and training projects in Berlin

The research presented in the thesis is a case-study of attempts to develop socially useful and environmentally sound technology (suest), products or services, as undertaken by alternative employment and training projects in West Berlin. The research is important for the exploration of several issues: the limits of training as a process of changing employment patterns and technological practices; the role of the voluntary / alternative sector; the role of "suest" generally. The initiator group and the eight member groups of the Kooperationsverbund Entwicklungswerkstatt comprised the focal point of the research. Findings from the study suggest that the "training" focus has nearly as many limits as the "products" focus: there were internal problems which in part reflect the confusion about the role of training as a social / technological change agent. The fate of these initiatives will depend largely on what happens to the German economy: will it re-expand conventionally or will "alternative" models prevail

Making the case for grid-connected photovoltaics in Brazil

AbstractIn the developed world, grid-connected photovoltaics (PVs) are the fastest-growing segment of the energy market. From 1999 to 2009, this industry had a 42% compound annual growth-rate. From 2009 to 2013, it is expected to grow to 45%, and in 2013 the achievement of grid parity – when the cost of solar electricity becomes competitive with conventional retail (including taxes and charges) grid-supplied electricity – is expected in many places worldwide. Grid-connected PV is usually perceived as an energy technology for developed countries, whereas isolated, stand-alone PV is considered as more suited for applications in developing nations, where so many individuals still lack access to electricity. This rationale is based on the still high costs of PV when compared with conventional electricity. We make the case for grid-connected PV generation in Brazil, showing that with the declining costs of PV and the rising prices of conventional electricity, urban populations in Brazil will also enjoy grid parity in the present decade. We argue that governments in developing nations should act promptly and establish the mandates and necessary conditions for their energy industry to accumulate experience in grid-connected PV, and make the most of this benign technology in the near future

Modelling alluvial channel dynamics in a river reach dominated by alternate bars

River morphodynamics and sediment transportRiver morphology and morphodynamic