4 research outputs found

    Efficient streaming for high fidelity imaging

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    Researchers and practitioners of graphics, visualisation and imaging have an ever-expanding list of technologies to account for, including (but not limited to) HDR, VR, 4K, 360°, light field and wide colour gamut. As these technologies move from theory to practice, the methods of encoding and transmitting this information need to become more advanced and capable year on year, placing greater demands on latency, bandwidth, and encoding performance. High dynamic range (HDR) video is still in its infancy; the tools for capture, transmission and display of true HDR content are still restricted to professional technicians. Meanwhile, computer graphics are nowadays near-ubiquitous, but to achieve the highest fidelity in real or even reasonable time a user must be located at or near a supercomputer or other specialist workstation. These physical requirements mean that it is not always possible to demonstrate these graphics in any given place at any time, and when the graphics in question are intended to provide a virtual reality experience, the constrains on performance and latency are even tighter. This thesis presents an overall framework for adapting upcoming imaging technologies for efficient streaming, constituting novel work across three areas of imaging technology. Over the course of the thesis, high dynamic range capture, transmission and display is considered, before specifically focusing on the transmission and display of high fidelity rendered graphics, including HDR graphics. Finally, this thesis considers the technical challenges posed by incoming head-mounted displays (HMDs). In addition, a full literature review is presented across all three of these areas, detailing state-of-the-art methods for approaching all three problem sets. In the area of high dynamic range capture, transmission and display, a framework is presented and evaluated for efficient processing, streaming and encoding of high dynamic range video using general-purpose graphics processing unit (GPGPU) technologies. For remote rendering, state-of-the-art methods of augmenting a streamed graphical render are adapted to incorporate HDR video and high fidelity graphics rendering, specifically with regards to path tracing. Finally, a novel method is proposed for streaming graphics to a HMD for virtual reality (VR). This method utilises 360° projections to transmit and reproject stereo imagery to a HMD with minimal latency, with an adaptation for the rapid local production of depth maps

    High Dynamic Range Image Deghosting Using Spectral Angle Mapper

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    The generation of high dynamic range (HDR) images in the presence of moving objects results in the appearance of blurred objects. These blurred objects are called ghosts. Over the past decade, numerous deghosting techniques have been proposed for removing blurred objects from HDR images. These methods may try to identify moving objects and maximize dynamic range locally or may focus on removing moving objects and displaying static objects while enhancing the dynamic range. The resultant image may suffer from broken/incomplete objects or noise, depending upon the type of methodology selected. Generally, deghosting methods are computationally intensive; however, a simple deghosting method may provide sufficiently acceptable results while being computationally inexpensive. Inspired by this idea, a simple deghosting method based on the spectral angle mapper (SAM) measure is proposed. The advantage of using SAM is that it is intensity independent and focuses only on identifying the spectral—i.e., color—similarity between two images. The proposed method focuses on removing moving objects while enhancing the dynamic range of static objects. The subjective and objective results demonstrate the effectiveness of the proposed method

    A global analysis of igneous sill dimensions and their effect on sedimentary basins and petroleum system - statistics and modelling of seismic observations

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    Igneous sill intrusion majorly impacts sedimentary basins, causing forced folding of host rocks, thermal maturation of source rocks, and basinal fluid flow changes. However, the detail of these effects has received little study. Similarly, the mechanisms by which sills are emplaced in basins are poorly understood, and emplacement mechanism may influence the aforementioned basinal impacts. The key that ties impacts and mechanisms together is that models explaining both have not been tested due to a lack of data on sill dimensions. Seismic reflection data presents a unique opportunity to collect detailed measurements on sill dimensions. Work presented in this thesis suggests that the number, shape and dimensions of sills have significant differences between sedimentary basins, having major implications for palaeoclimate modelling. Comparing theoretical sill models with measurements of actual sills undermines many models based around linear elastic fracture mechanics. However, intrusion models which incorporate an overlying elastic plate predict far more accurate sill geometries in comparison with seismic measurements. Additionally, several authors have noted that there is a discrepancy between the amplitude of forced folds and the thickness of their underlying sills. This thesis shows that a large proportion of this discrepancy can be explained by compaction of the fold after sill emplacement. While collecting data on forced folds, a seismic reflector in the Northeast Rockall Trough was mapped which displays undulose topography. Multiple observations point to this reflector being an opal A - opal CT transition. Numerical modelling and kinetic parameterization of the opal A-CT indicates that this topography can arise from local lateral temperature variations. Finally, a recently published model for hydrocarbon prospectivity based on fluid flow arising from sill tips is investigated. It is demonstrated that the original study shows no evidence for the validity of the model, prompting new questions on the scale at which intrusions could affect fluid flow. This thesis therefore shows that current paradigms of sill intrusion mechanisms, palaeoclimate model parameterizations, opal A-CT formation mechanisms and intrusion related fluid flow all need to be reexamined
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