Context. Text rendering is useful in different contexts, and usually needs to be as sharp as possible. DirectWrite and Direct2D is a good choice when rendering for a 2D environment and can be used with Direct3D. Objectives. This study addresses the problem of aliasing with a study on FXAA or SSAA to find which is the better option to correct jagginess on text. Methods. A number of photos were set up where 26 test subjects had to answer questions about the blurring and jagginess in the photos. Results. The results showed that FXAA and SSAA perform relatively similar in jagginess in how jaggy the pictures is perceived and was significantly better than no anti-aliasing at all. Conclusions. It depends on how the images are displayed on the screen to detect any kind of jagginess or blur.

Procedural textures and image textures are commonplace in graphics today, finding uses in such places as animated movies and video games. Unlike image texture maps, procedural textures typically suffer from minification aliasing. I present a method that, given a procedural texture on a surface, automatically creates an anti-aliased version of the procedural texture. The new procedural texture maintains the original textures details, but reduces minification aliasing artifacts. This new algorithm creates an image pyramid similar to MIP-Maps to represent the texture. Whereas a MIP-Map stores per-texel color, however, my texture hierarchy stores weighted sums of reflectance functions, allowing a wider-range of effects to be anti-aliased. The stored reflectance functions are automatically selected based on an analysis of the different functions found over the surface. When the texture is viewed at close range, the original texture is used, but as the texture footprint grows, the algorithm gradually replaces the textures result with an anti-aliased one. This results in faster development time for writing procedural textures as well as higher visual fidelity and faster rendering. With the optional addition of authoring guidelines, the analysis phase can be sped up by as much as two orders of magnitude. Furthermore, I developed a method for handling pre-filtered integration of reflectance functions to anti-alias specular highlights. The normal-centric BRDF (NBRDF) allows for fast evaluation over a range of normals appearing on the surface of an object. The NBRDF is easy to implement on the GPU for real-time results and can be combined with procedural reduction maps for real-time procedural texture minification anti-aliasing.

[pt] O mapeamento de sombras é uma técnica de renderização amplamente utilizada para a geração de sombras de superfícies arbitrárias em tempo real. No entanto, devido a sua natureza amostrada, apresenta dois problemas de difícil resolução: o aspecto chamuscado de objetos e a aparência serrilhada das bordas das sombras. Em particular, o sombreamento de modelos CAD (Computer-Aided Design) apresenta desafios ainda maiores, devido à existência de objetos estreitos com silhuetas complexas e o elevado grau de complexidade em profundidade. Neste trabalho, fazemos uma análise detalhada dos problemas de chamuscamento e serrilhamento, revisando e completando trabalhos de diferentes autores. Apresentamos ainda algumas propostas para melhoria de algoritmos existentes: o alinhamento de amostras independente de programas de vértice, um parâmetro generalizado para o LiSPSM (Light- Space Perspective Shadow Map), e um esquema de particionamento adaptativo em profundidade. Em seguida, investigamos a eficácia de diferentes algoritmos quando aplicados a modelos CAD, avaliando-os em critérios como facilidade de implementação, qualidade visual e eficiência computacional. / [en] Shadow mapping is a widely used rendering technique for shadow generation on arbitrary surfaces. However, because of the limited resolution available for sampling the scene, the algorithm presents two difficult problems to be solved: the incorrect self-shadowing of objects and the jagged appearance of shadow borders, also known as aliasing. Generating shadows for CAD (Computer-Aided Design) models presents additional challenges, due to the existence of many thin complex-silhouette objects and the high depth complexity. In this work, we present a detailed analysis of self-shadowing and aliasing by reviewing and building on works from different authors. We also propose some impromevents to existing algorithms: sample alignment without vertex shaders, a generalized parameter for the LiSPSM (Light-Space Perspective Shadow Map) algorithm, and an adaptive z- partitioning scheme. Finally, we investigate the effectiveness of different algorithms when applied to CAD models, considering ease of implementation, visual quality and computational efficiency.

<p>What makes an image photorealistic and how to pinpoint and understand how our mind interprets different elements in an image conditions? It is proposed that the phrase "imperfect makes perfect" is the key for the photorealistic goal in today’s 3D. There is a review of all the elements for the creation of one perfect image, such as Global Illumination, Anti-Aliasing and also a basic review of photography, how a scene is set up, color temperature and the nature of the real light. To put different theories to a test, the common three dimensional software 3D Studio Max was used with the V-Ray renderer. On a field trip to IKEA communications, we were assigned a project of a room scene containing a kitchen, with a finished scene model. A kitchen was created and experimented to reach a result where there is no visible difference between a computer generated image and the photography. Our result was not what we had hoped for due to many problems with our scene. We ourselves see this as a first step toward a scientific explanation to photorealism and what makes something photorealistic.</p>

Η παρούσα διπλωματική εργασία πραγματεύεται την μελέτη και κατασκευή μιας διάταξης μετρήσεων για φωτοβολταϊκά συστήματα. Η εργασία αυτή εκπονήθηκε στο Εργαστήριο Ηλεκτρομηχανικής Μετατροπής Ενέργειας του Τμήματος Ηλεκτρολόγων Μηχανικών και Τεχνολογίας Υπολογιστών της Πολυτεχνικής Σχολής του Πανεπιστημίου Πατρών. Σκοπός είναι η υλοποίηση ενός εργαλείου με το οποίο ο χρήστης θα μπορεί να έχει την επίβλεψη των μεγεθών της ηλεκτρικής ενέργειας που διακινούνται από το σύστημα του. Για παράδειγμα να γνωρίζει τα ποσά ισχύος που παράγονται, τα επίπεδα της τάσης και του ρεύματος ακόμα και τα ποσά ισχύος με τα οποία μπορεί να τροφοδοτήσει το δίκτυο της ΔΕΗ αν σκοπεύει να χρησιμοποιεί μέρος της παραγόμενης ενέργειας για της ανάγκες του και να πουλά το περίσσευμα. Αρχικά έγινε η μελέτη και κατασκευή μιας πλακέτας για την προσαρμογή του πραγματικού σήματος του ρεύματος και της τάσης. Ο επεξεργαστής ο οποίος χρησιμοποιείται σε τέτοιου είδους εφαρμογές δεν μπορεί να «διαβάσει» σήματα των οποίων το πλάτος ξεπερνά τα 5 V. Οπότε πρέπει εμείς να φέρουμε τα μεγάλα σήματα σε τέτοια κλίμακα ώστε να είναι διαχειρίσιμα. Ακόμα πρέπει να μετατρέψουμε το σήμα ρεύματος σε σήμα τάσης ανάλογης κλίμακας για να είναι διαχειρίσιμο και αυτό από το υπολογιστικό σύστημα. Στη συνέχεια έγινε μελέτη της διαδικασίας της δειγματοληψίας και αφού υπολογίστηκαν και το SNR, η το ελάχιστο σφάλμα δειγματοληψίας σχεδίασα ένα κατωδιαβατό φίλτρο τύπου Butterworth 4ης τάξης για να περιορίσω τα φαινόμενα aliasing που δημιουργούνται λόγω αλλοίωσης. Το επόμενο βήμα, το οποίο ήταν και το πιο δύσκολο και απαιτητικό, ήταν να σχεδιαστεί ο κώδικας με τον οποίο θα γινόταν η δειγματοληψία και ο υπολογισμός των μεγεθών που μας ενδιέφεραν σε πραγματικό χρόνο (real time). Έγινε πολλαπλασιασμός σε γλώσσα μηχανής (assembly) και χρήση μόνο ακεραίων τιμών για να γίνει ο κώδικας όσο γίνεται πιο γρήγορος μιας και σε ένα τέτοιο σύστημα το βασικότερο που μας απασχολεί είναι η ταχύτητα των πράξεων. Ακόμα χρειάστηκε να συντονιστούν με σήματα interrupt διάφορα περιφερειακά του μικροελεγκτή για να δουλέψει σωστά το σύστημα. Τέλος έγινε προσπάθεια διασύνδεσης του υπάρχοντος προγράμματος με Η/Υ μέσω σειριακής για να γίνει απεικόνιση των αποτελεσμάτων μέσω μιας γραφικής διεπαφής (GUI). / This thesis is about a measuring system for a Photo voltaic Array connected to the grid. In the first chapter there is a survey for the importance of sustainable power sources. Next the project is presented. After that there is a chapter about the sensors that are used. The method of sampling and and filtering the signal is described in the next 3 chapters. Last but not least in the last chapter the user interface is presented

What makes an image photorealistic and how to pinpoint and understand how our mind interprets different elements in an image conditions? It is proposed that the phrase "imperfect makes perfect" is the key for the photorealistic goal in today’s 3D. There is a review of all the elements for the creation of one perfect image, such as Global Illumination, Anti-Aliasing and also a basic review of photography, how a scene is set up, color temperature and the nature of the real light. To put different theories to a test, the common three dimensional software 3D Studio Max was used with the V-Ray renderer. On a field trip to IKEA communications, we were assigned a project of a room scene containing a kitchen, with a finished scene model. A kitchen was created and experimented to reach a result where there is no visible difference between a computer generated image and the photography. Our result was not what we had hoped for due to many problems with our scene. We ourselves see this as a first step toward a scientific explanation to photorealism and what makes something photorealistic.

Fotorealistiska 3d-bilder används idag inom ett brett spektrum av branscher. Framställningen av denna typ av grafik kräver ofta väldigt mycket datorkraft. Vid rendering med renderingsmotorer som använder sig av raytracing algoritmer är aliasing ett medfött problem. Lösningen heter anti-aliasing som arbetar för att undvika aliasing artefakter som jagged edges eller Moiré-effekter med mera. En del av anti-aliasingprocessen är supersampling som ofta kräver mycket datorkraft. Att optimera parametrar för supersampling är därför mycket viktigt. Det är möjligt att genom optimering spara väldigt mycket datorkraft och därmed tid. Detta arbete innehåller resultat från experiment där deltagare får bedöma bilder med olika kvalité av anti-aliasing. Resultaten av dessa experiment kan användas som referens vid optimering av renderingsparametrar för anti-aliasing vid rendering med hjälp av Mental Ray.

Context. Aliasing artifacts are a present problem in both the game industryand the movie industry. With the GCN (Graphics Core Next) architectureused on both new generation of consoles; Xbox One and Playstation 4, aunified Anti-Aliasing solution can be constructed with high performance,temporal stable edges and satisfying visual fidelity. Objective. This thesis aims to implement several prototypes which willbe utilizing GCN architecture to solve aliasing artifacts such as temporalstability. Method. By doing performance measurements, a survey and an experimenton the constructed prototypes and current state of the art solutionsthis thesis will create both a benchmark between given state of the art solutionsfor the industry and at the same time evaluate the new solutions givenin this thesis. Result. With having potential of being the fastest Anti-Aliasing solutionin the field it does not only bring high performance, but also very temporalstable edges and satisfying visual quality. Conclusion. If not used as a standalone solution, the prototype can be decoupledfrom GCN specific features and be a very suitable complement forMulti Sample Anti-Aliasing which can not handle alpha clipped edges.

<p dir="ltr">The CFD-CAA method combines computational fluid dynamics (CFD) and computational aeroacoustics (CAA) techniques to analyze the interaction between fluid flow and the generation and propagation of sound. CFD is primarily concerned with simulating fluid flow patterns, while CAA focuses on predicting noise generation and its propagation in fluids. The CFD-CAA method provides a powerful tool for understanding and predicting the acoustic behavior of turbulent flows. By combining the strengths of CFD and CAA, this approach provides more precise and comprehensive analyses across various fields, thereby contributing to enhanced designs and noise control strategies.</p><p dir="ltr">Within industrial applications, a primary concern is noise source identification. This process enables engineers to locate and quantify the strength of noise sources within a system, facilitating the implementation of more effective strategies during the design process. A novel methodology, computational statistically optimized near-field acoustic holography (C-SONAH), is proposed to virtually identify aeroacoustic sources. Initially, sound pressure is obtained using the CFD-CAA method, followed by the application of the SONAH algorithm to locate acoustic sources and predict the sound field. C-SONAH offers computational advantages over direct CAA methods for simulating sound produced by systems with rotating elements, as CAA analyzes sources on the moving elements, making sound field calculation computationally expensive. The SONAH procedure converts these rotating sources into a series of equivalent stationary planar or cylindrical waves, reducing the number of sources and the time required to compute the sound field from each source. This methodology was demonstrated by characterizing the aerodynamic noise produced by a bladeless fan. The sound pressure level obtained by C-SONAH method was validated by the data predicted by the direct CFD-CAA method. Acoustic maps were reconstructed at different locations and frequencies, revealing that the C-SONAH method can predict noise sources generated by airflow and rotating components within the fan. Thus, it serves as an effective tool for understanding the aeroacoustic noise generation mechanism and guiding the design optimization of similar products.</p><p dir="ltr">The CFD-CAA method is also a powerful tool for design optimization. Computational simulations are typically less expensive and time-consuming than building and maintaining experimental setups, particularly for large or complex projects. Additionally, simulations reduce the need for multiple physical prototypes, which can shorten the development cycle. CFD-CAA simulations provide detailed flow and acoustic field data, including variables that may be difficult or impossible to measure experimentally, such as pressure distributions, velocity fields, and turbulent structures. In this dissertation, aeroacoustic characteristics and flow field information of vortex whistles were investigated using the CFD-CAA method. The simulation results clearly illustrate the swirling motion created in the vortex whistle cylinder and also demonstrate the linear frequency versus flow rate relationship characteristic of the whistle. The design of the vortex whistle was optimized based on the acoustic response and flow resistance by both simulations and experiments. The results suggest that the whistle with a thin inlet exhibits the best performance at high flow rates, while the whistle with a scale of 0.5 is the most sensitive to low flow rates, making it suitable for pediatric applications.</p><p dir="ltr">In CFD-CAA simulations, the time step typically cannot be too small due to limited computational resources. This constraint results in an aliasing error in spectral analysis. Consequently, an anti-aliasing operation prior to sampling is necessary to eliminate such errors from the acoustic source terms. In the present study, an anti-aliasing filter based on the compact finite difference formulation was designed within a time-domain, compact filter scheme. This filter was directly applied to the Navier-Stokes solver prior to sampling for CAA analysis. A cavity flow case was simulated to validate this mitigation strategy. The results indicate that the artificial spectral peak induced by aliasing error is removed without affecting other signature peaks. The anti-aliasing filter was also applied to more complex cases for predicting the acoustic field of a vortex whistle. The acoustic field around the vortex whistle, with both constant and variable inlet flow rates, was simulated, and the aliasing peak was successfully removed. Although the peak magnitudes decreased slightly due to the filter, the signature frequencies remained unchanged. Thus, the simulation with anti-aliasing operation can predict acoustic features without introducing aliasing errors, even if the time step is not sufficiently small, thereby significantly reducing simulation time.</p><p dir="ltr">In engineering applications, once noise sources are identified, the subsequent concern is noise reduction. An effective strategy for noise reduction involves acoustical absorbing materials to minimize noise emissions from components. Traditionally, experiments in engineering applications have focused on surface treatments to explore noise control techniques. However, the CFD-CAA method commonly assumes smooth and purely reflective wall surfaces. Consequently, there is growing interest in incorporating impedance boundary conditions into the CFD-CAA method. Since impedance boundary conditions are defined in the frequency domain, while CFD-CAA simulations operate in the time domain, direct implementation is not feasible. To address this issue, several methods have been proposed to define time-domain impedance boundary conditions in simulations. In the present study, a wall softness model was implemented in the CFD-CAA method and to examine a vortex whistle featuring an acoustically permeable surface. In simulations, an impedance boundary condition representing the properties of melamine foam was defined over the surface of a cylindrical cavity. The simulation results were validated against experimental data obtained from a vortex whistle with melamine foam. The findings revealed that the impedance of the melamine foam contributed to noise reduction at high frequencies. Additionally, at low airflow rates, the impedance boundary condition enhanced the signal-to-noise ratio for the low-frequency peak, which is advantageous in clinical applications.</p>

This Master's thesis deals with design and a realisation of a device controlling an OLED display, Densitron DD-25664-1A. This display has a resolution of 256 x 64 pixels and allows displaying of 4-bit grayscale. The proposed utility software implements the initialization and termination functions, two sets of fonts { Latin and Greek letters and functions for rendering graphics and text. The result of the project is a device with the controlling software.