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Item Light Clustering for Dynamic Image Based Lighting(The Eurographics Association, 2012) Staton, Sam; Debattista, Kurt; Bashford-Rogers, Thomas; Chalmers, Alan; Hamish Carr and Silvester CzannerHigh Dynamic Range (HDR) imagery has made it possible to relight virtual objects accurately with the captured lighting. This technique, called Image Based Lighting (IBL), is a commonly used to render scenes using real-world illumination. IBL has mostly been limited to static scenes due to limitations of HDR capture. However, recently there has been progress on developing devices which can capture HDR video sequences. These can be also be used to light virtual environments dynamically. If existing IBL algorithms are applied to this dynamic problem, temporal artifacts viewed as flickering can often arise due to samples being selected from different parts of the environment in consecutive frames. In this paper we present a method for efficiently rendering virtual scenarios with such captured sequences based on spatial and temporal clustering. Our proposed Dynamic IBL (DIBL) method improves temporal quality by suppressing flickering, and we demonstrate the application to fast previews of scenes lit by video environment maps.Item A Calibrated Olfactory Display for High Fidelity Virtual Environments(The Eurographics Association, 2016) Dhokia, Amar; Doukakis, Efstratious; Asadipour, Ali; Harvey, Carlo; Bashford-Rogers, Thomas; Debattista, Kurt; Waterfield, Brian; Chalmers, Alan; Cagatay Turkay and Tao Ruan WanOlfactory displays provide a means to reproduce olfactory stimuli for use in virtual environments. Many of the designs produced by researchers, strive to provide stimuli quickly to users and focus on improving usability and portability, yet concentrate less on providing high levels of accuracy to improve the fidelity of odour delivery. This paper provides the guidance to build a reproducible and low cost olfactory display which is able to provide odours to users in a virtual environment at accurate concentration levels that are typical in everyday interactions; this includes ranges of concentration below parts per million and into parts per billion. This paper investigates build concerns of the olfactometer and its proper calibration in order to ensure concentration accuracy of the device. An analysis is provided on the recovery rates of a specific compound after excitation. This analysis provides insight into how this result can be generalisable to the recovery rates of any volatile organic compound, given knowledge of the specific vapour pressure of the compound.Item Selective BRDFs for High Fidelity Rendering(The Eurographics Association, 2016) Bradley, Tim; Debattista, Kurt; Bashford-Rogers, Thomas; Harvey, Carlo; Doukakis, Stratos; Chalmers, Alan; Cagatay Turkay and Tao Ruan WanHigh fidelity rendering systems rely on accurate material representations to produce a realistic visual appearance. However, these accurate models can be slow to evaluate. This work presents an approach for approximating these high accuracy reflectance models with faster, less complicated functions in regions of an image which possess low visual importance. A subjective rating experiment was conducted in which thirty participants were asked to assess the similarity of scenes rendered with low quality reflectance models, a high quality data-driven model and saliency based hybrids of those images. In two out of the three scenes that were evaluated significant differences were not found between the hybrid and reference images. This implies that in less visually salient regions of an image computational gains can be achieved by approximating computationally expensive materials with simpler analytic models.Item Backwards Compatible JPEG Stereoscopic High Dynamic Range Imaging(The Eurographics Association, 2012) Selmanovic, Elmedin; Debattista, Kurt; Bashford-Rogers, Thomas; Chalmers, Alan; Hamish Carr and Silvester CzannerIn this paper we introduce Stereoscopic High Dynamic Range (SHDR) Imagery which is a novel tecnique that combines high dynamic range imaging and stereoscopy. Stereoscopic imaging captures two images representing the views of both eyes and allows for better depth perception. High dynamic range (HDR) imaging is an emerging technology which allows the capture, storage and display of real world lighting as opposed to traditional imagery which only captures a restricted range of light due to limitation in hardware capture and displays. HDR provides better contrast and more natural looking scenes. One of the main challenges that needs to be overcome for SHDR to be successful is an efficient storage format that compresses the very large sizes obtained by SHDR if left uncompressed; stereoscopic imaging requires the storage of two images and uncompressed HDR requires the storage of a floating point value per colour channel per pixel. In this paper we present a number of SHDR compression methods that are backward compatible with traditional JPEG, stereo JPEG and JPEG-HDR. The proposed methods can encode SHDR content to little more than that of a traditional LDR image and the backward compatibility property encourages early adopters to adopt the format since their content will still be viewable by any of the legacy viewers.Item The Effect of Discretised and Fully Converged Spatialised Sound on Directional Attention and Distraction(The Eurographics Association, 2010) Harvey, Carlo; Walker, Steve; Bashford-Rogers, Thomas; Debattista, Kurt; Chalmers, Alan; John Collomosse and Ian GrimsteadA major challenge in Virtual Reality (VR) is to be able to provide interactive rates of realism. However this is very computationally demanding and only recently has high-fidelity rendering become close to interactive rates through a series of novel exploitations of visual perception; to render parts of the scene that are not currently being attended by the viewer at a much lower quality without the difference being perceived. This paper investigates the effect spatialised directional sounds, both discrete and converged have on the visual attention of the user with and without an auditory cue present in the scene. We verify the worth of investigating subliminal saccade shifts from directional audio impulses via a pilot study to eye track participant's free viewing a scene with an audio impulse and an acoustic identifier and also with an audio impulse and no acoustic identifier versus a control. By selecting look zones, we can identify how long users are spending attending a particular area of a scene in these scenarios. This work also investigates whether the effect prevailed, and if so to what extent, with discretised spatialised sound as opposed to a fully converged audio sample. We also present a novel technique for generating interactive discrete acoustic samples from arbitrary geometry. We show that even without an acoustic identifier in the scene, directional sound provides enough of an impulse to guide subliminal saccade shifts and affect perception in such a way that this can be used to guide selective rendering of the scenes.