Advances in hardware acceleration has resulted in development of a variety of hardware accelerated ray tracing libraries. The purpose of this bachelor thesis is to investigate if a simple ray tracer, based on a hardware accelerated ray tracing library, can achieve acceptable frame rates in rendering simple 3D game-related environments. Games are often associated with fast rasterization-based rendering techniques, but rasterization is limited where instead ray tracing holds many advantages. Background research was done to gain knowledge about related work, state-of-the-art in ray tracing and available hardware accelerated libraries. By using a method similar to Kanban and Scrum [36], the implementation was split up into different tasks, prioritizing the tasks of implementing basic functionalities of a ray tracer. A simple ray tracer was implemented based on the chosen library Embree, a framework developed at Intel Corporation. Results show that the scenes rendered in lower resolutions (800 x 600) are good candidates for having a stable frame rate of 30 FPS, which is not enough in order to render a real game. The standard of games today require high resolution (full HD 1920 x 1080) and complex scenes. Earlier studies show that Embree has potential of higher performance and looking back the performance of real-time ray tracing has improved, but is still limited to low resolutions and simple lighting and shading models. / Framsteg inom hårdvaruacceleration har resulterat i att en rad olika hårdvaruaccelererade bibliotek för strålföljning utvecklats. Syftet med denna kandidat-uppsats är att undersöka om en enkel strålföljare, baserad på ett hårdvaruaccelererat bibliotek för strålföljning, kan uppnå acceptabla bildfrekvenser vid rendering av enkla spel-relaterade miljöer i 3D. Datorspel förknippas ofta med snabba renderingstekniker. Rasteriseringsalgoritmen är dock begränsad där istället strålföljning har många fördelar. En litteraturstudie gjordes för att få kunskap om relaterade arbeten, state-of-the-art i strålföljning och tillgängliga hårdvaruaccelererade bibliotek. Genom att använda en metod som kan liknas vid Kanban och Scrum [36], blev implementationen uppdelad i olika uppgifter (eng. tasks), där implementationen av grundläggande funktioner av en strålföljare hade högsta prioritet. En enkel strålföljare implementerades med det valda biblioteket Embree, ett ramverk som utvecklas hos Intel Corporation. Resultaten visar att scenerna som renderas med lägre upplösningar (800 x 600) är goda kandidater för att uppnå en stabil bildfrekvens med 30 bilder per sekund (eng. frames per second), vilket inte är tillräckligt för att rendera ett riktigt spel. Standarden hos spel idag kräver hög upplösning (full HD 1920 x 1080) och komplexa scener. Tidigare studier visar att Embree har potential för högre prestanda och tidigare resultat visar att prestandan av interaktiv strålföljning har förbättrats, men att den fortfarande är begränsad till låga upplösningar och enklare belysningsmodeller.

The goal of this thesis is to evaluate the usability of hardware accelerated ray tracing in near-future rendering engines. Specifically, DirectX Ray Tracing API and Nvidia Turing architecture are being examined. Design and implementation of a hybrid rendering engine with support for hardware accelerated ray tracing is included and used in implementation of frequently used graphical effects -- hard and soft shadows, reflections, and Ambient Occlusion. The assessment is made in terms of difficulty of integration into a rendering engine, performance of the resulting system and suitability of implementation of chosen graphical effects. Performance parameters -- including number of rays cast per second, time to build acceleration structures and computation time on the GPU -- are tested and discussed.

Black hole visualization is a problem of raytracing over curved spacetimes. This paper discusses the physics of light in curved spacetimes, the geometry of black holes, and the appearance of objects as viewed through a relativistic camera (the Penrose-Terrell effect). It then discusses computational issues of how to generate images of black holes with a computer. A method of determining the most efficient series of steps to calculate the value of a mathematical expression is described and used to improve the speed of the program. The details of raytracing over curved spaces not covered by a single chart are described. A method of generating images of several black holes in the same spacetime is discussed. Finally, a series of images generated by these methods is given and interpreted. / text

Inversion for refraction statics is a key part of three-dimensional (3D) reflection seismic processing. The present thesis has two primary goals directed toward improvement of refraction statics inversion. First, I attempt to improve the quality of the travel-time data right at the beginning of the processing sequence and before any inversion. Any error in the travel times or geometry caused during acquisition or processing would propagate into the resulting model and may harm the resulting image. To implement rigorous, model-independent data quality control, I view the first-arrival travel times as surfaces in 3D, which allows utilization of the travel-time reciprocity condition to check for errors in geometry and in first-arrival picking.<p> The second goal of this study is in development of a new inversion approach for refraction statics specifically for 3D seismic datasets. The first-break travel-times are decomposed by using a ô-p parameterization, which allows an automatic derivation of a high-quality initial subsurface model. This model is further improved by using accurate, multi-layer ray-tracing and inversion techniques to obtain accurate refraction statics. An iterative inversion scheme based on the Simultaneous Iterative Reconstruction Technique is utilized, and its performance is measured and discussed. To assess the quality of the inverse and establish the optimal grid sizes, I use several types of resolution tests. Finally, the surface consistent statics is calculated and applied to a real dataset from southern Saskatchewan. A comparison of the resulting statics model with statics calculated by using standard industry software is made, and the statics correction is incorporated in seismic processing.<p> An overall result of this study is in demonstration that the fully 3D, ô-p based travel-time inversion method works, is applicable to large seismic datasets, and results in detailed shallow subsurface models and reliable statics solutions. Several recommendations for extending and improving the proposed approaches are also made.

Inversion for refraction statics is a key part of three-dimensional (3D) reflection seismic processing. The present thesis has two primary goals directed toward improvement of refraction statics inversion. First, I attempt to improve the quality of the travel-time data right at the beginning of the processing sequence and before any inversion. Any error in the travel times or geometry caused during acquisition or processing would propagate into the resulting model and may harm the resulting image. To implement rigorous, model-independent data quality control, I view the first-arrival travel times as surfaces in 3D, which allows utilization of the travel-time reciprocity condition to check for errors in geometry and in first-arrival picking.<p> The second goal of this study is in development of a new inversion approach for refraction statics specifically for 3D seismic datasets. The first-break travel-times are decomposed by using a ô-p parameterization, which allows an automatic derivation of a high-quality initial subsurface model. This model is further improved by using accurate, multi-layer ray-tracing and inversion techniques to obtain accurate refraction statics. An iterative inversion scheme based on the Simultaneous Iterative Reconstruction Technique is utilized, and its performance is measured and discussed. To assess the quality of the inverse and establish the optimal grid sizes, I use several types of resolution tests. Finally, the surface consistent statics is calculated and applied to a real dataset from southern Saskatchewan. A comparison of the resulting statics model with statics calculated by using standard industry software is made, and the statics correction is incorporated in seismic processing.<p> An overall result of this study is in demonstration that the fully 3D, ô-p based travel-time inversion method works, is applicable to large seismic datasets, and results in detailed shallow subsurface models and reliable statics solutions. Several recommendations for extending and improving the proposed approaches are also made.

Zugl.: Aachen, Techn. Hochsch., Diss., 2009

No description available.

Zugl.: Aachen, Techn. Hochsch., Diss., 2009.

Universiẗat, Diss., 1999--Hamburg.

A three-by-three polarization ray tracing matrix method is developed to calculate the polarization transformations associated with ray paths through optical systems. The relationship between the three-by-three polarization ray tracing matrix P method and the Jones calculus is shown in Chapter 2. The diattenuation, polarization dependent transmittance, is calculated via a singular value decomposition of the P matrix and presented in Chapter 3. In Chapter 4 the concept of retardance is critically analyzed for ray paths through optical systems. Algorithms are presented to separate the effects of retardance from geometric transformations. The parallel transport of vectors is associated with non-polarizing propagation through an optical system. A parallel transport matrix Q establishes a proper relationship between sets of local coordinates along the ray path, a sequence of ray segments. The proper retardance is calculated by removing this geometric transformation from the three-by-three polarization ray trace matrix. Polarization aberration is wavelength and spatial dependent polarization change that occurs as wavefrontspropagate through an optical system. Diattenuation and retardance of interfaces and anisotropic elements are common sources of polarizationaberrations. Two representations of polarization aberrationusing the Jones pupil and a polarization ray tracing matrix pupil, are presentedin Chapter 5. In Chapter 6 a new class of aberration, skew aberration is defined, as a component of polarization aberration. Skew aberration is an intrinsic rotation of polarization states due to the geometric transformation of local coordinates; skew aberration occurs independent of coatings and interface polarization. Skew aberration in a radially symmetric system primarily has the form of a tilt plus circular retardance coma aberration. Skew aberration causes an undesired polarization distribution in the exit pupil. A principal retardance is often defined within (-π, + π] range. In Chapter 7 an algorithm which calculates the principal retardance, horizontal retardance component, 45° retardance component, and circular retardance component for given retarder Jones matrices is presented. A concept of retarder space is introduced to understand apparent discontinuities in phase unwrapped retardance. Dispersion properties of retarders for polychromatic light is used to phase unwrap the principal retardance. Homogeneous and inhomogeneous compound retarder systems are analyzed and examples of multi-order retardance are calculated for thick birefringent plates. Mathematical description of the polarization properties of light and incoherent addition of light is presented in Chapter 8, using a coherence matrix. A three-by-three-by-three-by-three polarization ray tracing tensor method is defined in order to ray trace incoherent light through optical systems with depolarizing surfaces. The polarization ray tracing tensor relates the incident light’s three-by-three coherence matrix to the exiting light’s three-by-three coherence matrix. This tensor method is applicable to illumination systems and polarized stray light calculations where rays at an imaging surface pixel have optical path lengths which vary over many wavelengths. In Chapter 9 3D Stokes parameters are defined by expanding the coherence matrix with Gell-Mann matrices as a basis. The definition of nine-by-nine 3D Mueller matrix is presented. The 3D Mueller matrix relates the incident 3D Stokes parameters to the exiting 3D Stokes parameters. Both the polarization ray tracing tensor and 3D Mueller matrix are defined in global coordinates. In Chapter 10 a summary of my work and future work are presented followed by a conclusion.