Goal of this diploma thesis is to get knowledge about history and evolution of computer graphic in area of realistic image synthesis, get knowledge about rendering system mental ray and about writing shader for it and write several shader. Create manual about writing  shaders for mental ray. Get knowledge about program Maya and create a tutorial hot to get the shader into it.

This thesis deals with one of the global illumination algorithms - the radiosity algorithm. There are handled fundamentals of the radiosity algorithm including basic equations and relations. You can see review of possible solutions of this method in use and description of the implementation based on video card and OpenGL rendering. The thesis tries to explain main problems and attitudes to implementation of radiosity briefly, clearly and comprehensibly.

No description available.

Background. Global illumination is not trivial to compute in real-time computer graphics. One approximate solution is to distribute virtual light sources from a primary light, to then apply direct light calculations to said virtual lights. This can effectively estimate two-bounce illumination. To mitigate artifacts, virtual lights make use of a spherical shape and utilize spherical harmonics to allow for efficient light integration. These indirect light sources are referred to as "harmonics virtual lights" (HVLs). Objectives. The objectives of this thesis are to analyze the data structures, calculations and performance of an HVL implementation in different 3D scenes. Methods. HVLs are implemented using the Vulkan API. Experiments are then performed to evaluate and optimize execution times. Furthermore, different measures are taken to ensure correctness and minimize errors wherever possible. Results. The GPU pass responsible for gathering indirect light contributions from HVLs turned into a heavy bottleneck. A number of different optimization techniques were applied to said pass and analyzed. Seven techniques were found to have a positive effect on performance, each with varying degrees of impact on timings. No optimization compromised on input parameters, visual results or mathematical correctness. Additionally, three techniques were instead worsening performance of the implementation, despite having initial motivations for possible improvements. Conclusions. All optimization techniques with positive effects working in conjunction led to a total speedup of 46.9x in a specific use case of our implementation. There is room for further potential improvements, and a number of different techniques for future work are explained. The final source code for the implementation can be viewed in a public GitHub repository.

In this dissertation, methods utilizing matched illumination theory to optimally design waveforms for enhanced target detection and identification in the context of through-the-wall radar (TWR) are explored. The accuracy of assumptions made in the waveform design process is evaluated through simulation. Additionally, the moisture profile of an adobe wall is investigated, and it is shown that the moisture profile of the wall will introduce significant variations in the matched illumination waveforms and subsequently, affect the resulting ability of the radar system to correctly identify and detect a target behind the wall. Experimental measurements of adobe wall moisture and corresponding dielectric properties confirms the need for accurate moisture profile information when designing radar waveforms which enhance signal-to-interference-plus-noise ratio (SINR) through use of matched illumination waveforms on the wall/target scenario. Furthermore, an evaluation of the ability to produce an optimal, matched illumination waveform for transmission using simple, common radar systems is undertaken and radar performance is evaluated.

No description available.

<pre>The degree of freedom brought about by breaking the directional symmetry of space through the use of anisotropic media finds applications in numerous photonic systems. Almost all these systems are based on physical principles that are generalized extensions of their isotropic counterparts, much in the same way an ellipse is related to a circle. However, as we show, there are examples where, in the presence of loss, disorder or even coupling to the measurement apparatus, emerges a completely new behavior which is qualitatively different from the isotropic case. In this work we study these emergent phenomena found in open anisotropic photonic systems.</pre> <pre><br></pre> <pre>We demonstrate that open systems based on biaxial anisotropic medium can support exceptional points which are singularities in the parameter space of the system where the mode frequencies as well as the modes themselves coalesce. We also show that topological insulators, which are novel materials that behave as dielectric in the bulk but metallic in the surface and exhibit bianisotropy through the coupling of their electric and magnetic response, can emit thermal radiation that carries nonzero spin angular momentum. Next, after describing how the strong anisotropy of hyperbolic metamaterial can support electromagnetic fields propagating with high wavenumbers unbounded by the frequency, we show that a super-resolution imaging scheme based on such material is quite robust against substantial loss and disorder. Finally, we consider an example of an incoherent perfect absorber and show that loss and anisotropy in this case can work together to recover the ideal lossless limit for the absorbing performance. In addition to making new conceptual connections between photonics and other branches of science such as condensed matter physics, biotechnology and quantum mechanics, these new emergent phenomena are shown to have thermal, imaging and sensing applications.</pre>

Naturally occurring biological nanoparticles (BNPs) and synthetic nanoparticles have a significant role in a wide range of biomedical applications. For instance, direct detection of BNPs, such as viruses, can provide new methods of viral diagnostics while synthetic particles can be used as labels to indirectly detect biomarkers for drug discovery. Therefore, developing advanced tools for nanoparticle detection has gained popularity in biotechnological research. One of the most exciting recent developments in BNP detection has been single particle (or digital) counting of individual particles which offers unprecedented sensitivity levels. However, standard optical techniques face a significant challenge for nanoparticle detection, due the weak optical contrast of sub-wavelength particles. Interferometric microscopy, overcomes the limitations imposed by particle size which allows for visualizing unresolved (diffraction-limited) optical signatures of sub-wavelength particles. Single-particle interferometric reflectance imaging sensor (SP-IRIS), is a widefield microscopy platform, developed by our group over the last years. SP-IRIS uses interferometric enhancement and a layered substrate to increase the optical contrast for the target particles of interest. While this microscopy technique has shown remarkable sensitivity levels for numerous applications including detection of viral particles and nucleic acids, it has remained a specialty tool due to the utilization of z-scan measurements for extracting the optical signature of particles. The z-scan measurements that consist of multiple frames acquired at different focal positions impose two major drawbacks. The first is the requirement of repeatable and high resolution scanning optics and the second is the time and computational processing power required to analyze the image stacks. In this thesis we describe a novel imaging method termed `pixel-diversity‘ IRIS (PD-IRIS), which aims to provide a more practical detection method for nanoparticles by eliminating the need for acquiring z-stacks. PD-IRIS is built upon SP-IRIS, however it introduces a paradigm shift for encoding the necessary optical signature of target particles. PD-IRIS compresses the relevant optical information within a single image frame rather than an image stack. This is achieved by using camera sensors that simultaneously record multiple spectral or polarization channels. Therefore, a single image can record distinct spectral responses of target particles with respect to different excitation wavelengths (multi-spectral PD-IRIS) or the distinct scattering characteristics with respect to polarization (polarization PD-IRIS). This dissertation presents a rigorous study for both PD-IRIS modes and demonstrates the practical applications of nanoparticle detection with proof-of-concept measurements. / 2024-01-16T00:00:00Z

The interaction of light in our world is immensely complex, but with mod- ern computers and advanced rendering algorithms, we are beginning to reach the point where photo-realistic renders are truly difficult to separate from real photographs. Achieving realistic or believable global illumination in scenes with participating media is exponentially more expensive compared to our traditional polygonal methods. Light interacts with the particles of a volume, creating com- plex radiance patterns. In this thesis, we introduce an extension to the commonly used point-based color bleeding (PCB) technique, implementing volume scatter contributions. With the addition of this PCB algorithm extension, we are able to render fast, be- lievable in- and out-scattering while building on existing data structures and paradigms. The proposed method achieves results comparable to that of existing Monte Carlo integration methods, obtaining render speeds between 10 and 36 times faster while keeping memory overhead under 5%.

Modeling believable lighting is a crucial component of computer graphics applications, including games and modeling programs. Physically accurate lighting is complex and is not currently feasible to compute in real-time situations. Therefore, much research is focused on investigating efficient ways to approximate light behavior within these real-time constraints. In this thesis, we implement a general purpose algorithm for real-time applications to approximate indirect lighting. Based on voxel cone tracing, we use a filtered representation of a scene to efficiently sample ambient light at each point in the scene. We present an approach to scene voxelization using hardware tessellation and compare it with an approach utilizing hardware rasterization. We also investigate possible methods of warped voxelization. Our contributions include a complete and open-source implementation of voxel cone tracing along with both voxelization algorithms. We find similar performance and quality with both voxelization algorithms.