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Now showing 1 - 5 of 5
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    Simulating Film Grain using the Noise-Power Spectrum
    (The Eurographics Association, 2007) Stephenson, Ian; Saunders, Arthur; Ik Soo Lim and David Duce
    Film grain is an essential part of real images. The artifacts it introduces add character to images, which can otherwise appear too perfect. This paper considers the synthesis of film grain based upon its noise-power spectrum, producing grain fields which approximate real film over a range of enlargements and densities. We also identify limitations of the noise-power spectrum in that it fails to fully characterize grain. Simulated grain fields have spectra which match real grain, but lack the phase and density correlations required to create the appearance of individual grains at high magnifications.
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    Interactive Relighting for Stage Use
    (The Eurographics Association, 2009) Stephenson, Ian; Wen Tang and John Collomosse
    Re-lighting by combining images taken under known lighting conditions to synthesise new lighting configurations is a simple, but powerful technique capable of producing impressive results. However it has found little practical application. Here we demonstrate the integration of a relighting tool into a typical theatrical lighting system, to provide real time previews both offline when the stage is unavailable, and during performance.
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    Hardware Accelerated Shaders Using FPGAs
    (The Eurographics Association, 2009) Goddard, Luke; Stephenson, Ian; Wen Tang and John Collomosse
    We demonstrate that Field Programable Gate Arrays (FPGAs) can be used to accelerate shading of surfaces for production quality rendering (a task standard interactive graphics hardware is generally ill-suited to) by allowing circuits to be dynamically created at run-time on standard commercial logic boards. By compiling shaders to hardware descriptions, they can be executed on FPGA with the performance of hardware without sacrificing the flexibility of software implementations. The resulting circuits are fully pipelined, and for circuits within the capacity of the FPGA can shade MicroPolygons at a fixed rate independent of shader complexity.
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    Screen Space Re-Rendering for the Simulation of Concert Lighting
    (The Eurographics Association, 2010) Stephenson, Ian; Scanlan, Liam; John Collomosse and Ian Grimstead
    The visualisation of modern concert lighting requires complex illumination models to be calculated at interactive frame rates. Each light may have 20 or more parameters which are all changing in real time. Here we present a technique which allows static scenes with rapidly changing illumination to be re-rendered quickly in graphics hardware, with support for arbitrary geometry, complex BRDFs, shadowing and volumetric fogging. The rendering algorithm is re-factored to allow changing lighting to be applied to scenes which are otherwise fully rendered, minimising the calculation required when lights are moved.
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    Computer Modelling of Theatrical Sets
    (The Eurographics Association, 2010) Stephenson, Ian; Pride, Rebecca; John Collomosse and Ian Grimstead
    Here we discuss the design and implementation of a modelling tool specifically targeted for use by designers of theatrical sets. By applying domain specific knowledge and contraints to the design of the software, we demonstrate a system which can be used without signifigant training, by users with no previous computer graphics experience. We present initial end user experiences of using the tool in designing a real production of The First Arabian Night .