<p>Beacon AB has been producing Gobos for some time. A Gobo is a small round sheet used in projectors almost like a slide. It is used mostly in the commercial and entertainment business. Today these Gobos are created by using a film (also called mask). A digital exposure machine called LIOS has been developed to make it possible to create Gobos using direct exposure. This means a film will no longer be necessary and it will also make the process faster and cheaper. </p><p>To be able to use LIOS in the industry a lot of work still has to be done. An image is sent to the display in LIOS. This image comes from a computer connected to LIOS and at the end of the process it will be reproduced on the Gobo. This image can be modified before it is sent to LIOS so that a better result can be achieved in the end. The problem is that once the process is complete the image will be binary, which means halftoning is going to be used. The goal of the research described in this paper is first to test the properties of LIOS, second to create a halftoning method especially designed for those properties. </p><p>The resultof this thesis is an AM (Amplitude Modulated) method that uses a modified threshold matrix. Using this method would not give a satisfying result unless some of the distortions could be corrected somehow. This can however be done using a property available for the display in LIOS. The display can handle grayscales but since etching is used later in the process the final result will be a binary image (only black and white). This means that even though the image will be binary in the end, these grayscales can still be used to improve the result. The equipment that was available when this thesis was done was not fully developed why the grayscales are used to correct distortions. </p><p>The resulting method will most likely be good enough to produce Gobos with a satisfying quality. The method has never been used before and it introduces a new way of making corrections for halftoning. There are still some practical problems left to solve before LIOS can be used to reliably produce Gobos. Using better equipment can solve several of these problems but not all of them.</p>

Beacon AB has been producing Gobos for some time. A Gobo is a small round sheet used in projectors almost like a slide. It is used mostly in the commercial and entertainment business. Today these Gobos are created by using a film (also called mask). A digital exposure machine called LIOS has been developed to make it possible to create Gobos using direct exposure. This means a film will no longer be necessary and it will also make the process faster and cheaper. To be able to use LIOS in the industry a lot of work still has to be done. An image is sent to the display in LIOS. This image comes from a computer connected to LIOS and at the end of the process it will be reproduced on the Gobo. This image can be modified before it is sent to LIOS so that a better result can be achieved in the end. The problem is that once the process is complete the image will be binary, which means halftoning is going to be used. The goal of the research described in this paper is first to test the properties of LIOS, second to create a halftoning method especially designed for those properties. The resultof this thesis is an AM (Amplitude Modulated) method that uses a modified threshold matrix. Using this method would not give a satisfying result unless some of the distortions could be corrected somehow. This can however be done using a property available for the display in LIOS. The display can handle grayscales but since etching is used later in the process the final result will be a binary image (only black and white). This means that even though the image will be binary in the end, these grayscales can still be used to improve the result. The equipment that was available when this thesis was done was not fully developed why the grayscales are used to correct distortions. The resulting method will most likely be good enough to produce Gobos with a satisfying quality. The method has never been used before and it introduces a new way of making corrections for halftoning. There are still some practical problems left to solve before LIOS can be used to reliably produce Gobos. Using better equipment can solve several of these problems but not all of them.

Ray tracing comes together with a tremendous computational cost [1]. Therefore, Keller et al., expressed that possible cost reduction appears when a hybrid rendering pipeline is implemented by combining rasterization and ray tracing, which have already been introduced to the film and game industries. Such a rendering method within Grand Strategy Games (GSG) has been an unexplored task. The standard rendering method of GSG has been rasterization. Implementing hybrid rendering for GSG would allow this niche to follow the continuously developing rendering techniques. Therefore, this thesis examined the advantages and disadvantages of hybrid rendering compared to a path traced pipeline. The study measured different camera angles applied to three GSG-inspired scenes by rendering time and quality according to pixelby-pixel comparison focusing on effects like shadows and reflections. Closeup images have been taken on the rendered scenes to evaluate interesting pieces in the scenes. Steady time performance for all angles was the significant advantage of the hybrid pipeline. The angles at lower grades resulted in an increased difference in shadows and reflections for two out of three scenes. Additionally, the entire pixel-by-pixel comparison did not generate more than ten percent difference for any scene and not more than twelve percent difference on closeup images. Still, differences were noticeable to the eye since the path tracer was superior for developing sharp shadows. The hybrid pipeline generated a massive reflection compared to the path tracer. Since the path tracer was defined as the ground truth, this quantity of reflections was not considered positive. The thesis concludes that a simple hybrid rendering pipeline could be an exciting future for GSG, especially for angles above 67.25◦ . Additionally, improving the sharpness of the shadows for the hybrid rendering pipeline could increase the interest in hybrid rendering for GSG even at angles below 67.25◦ . Some interesting future work is rendering advanced 3D map-based GSG scenes, including more shadows and reflections. Another suggestion is a qualitative analysis of users playing a game with the two rendering pipelines before attending a user study about their possible improved graphical experience and how the game experience has been affected. / Strålspårning kommer tillsammans med en stor beräkningskostnad [1]. Därför har Keller m.fl. uttryckt att kostnaderna kan reduceras genom att implementera en hybridrenderingsmetod baserad på en kombination av rastrering och strålspårning, vilket redan har introducerats till film- och spelindustrin. En sådan renderingsmetod inom Grand Strategy Games (GSG) har dock varit ett outforskat område. Standard renderingsmetoden för GSG har varit rastrering. Implementering av hybridrendering för GSG skulle tillåta denna nisch att följa de ständigt utvecklande renderingsteknikerna. Därför undersöker denna avhandling fördelarna och nackdelarna med hybridrendering jämfört med en renderingspipeline baserad på strålspårning. Studien har mätt olika kameravinklar applicerade på GSG-inspirerade scener mätt med renderingstid och kvalitet enligt pixel-för-pixel-jämförelse och med fokus på effekter som skuggor och reflektioner. Närbilder har tagits på de renderade scenerna för att utvärdera intressanta delar i scenerna. Stabil tidprestanda av samtliga vinklar var den betydande fördelen med hybridpipelinen. Vinklarna vid lägre grader resulterade i ökad differens av skuggor och reflektioner för två av tre scener. Dessutom resulterade hela pixeljämförelsen inte mer än tio procents skillnad för någon av scenerna och inte mer än tolv procents skillnad på närbilderna. Ändå var skillnaderna märkbara för ögat eftersom strålspårningen var överlägsen för att generera skarpa skuggor. Hybridlösningen genererade en stor andel reflektion jämfört med strålspårningen. Eftersom strålspårningen definierades som målbilden var denna mängd reflektioner inte positiva. Avhandlingen drar slutsatsen att en enkel hybridmetod kan vara en spännande framtid för GSG, speciellt för vinklar över 67,25◦ . Dessutom kan en förbättring av skärpan på skuggorna för hybridrenderingen öka intresset för hybridrendering för GSG även vid vinklar under 67,25◦ . Intressanta framtida arbeten är rendering av avancerade GSG scener, som inkluderar fler skuggor och reflektioner. Ett till förslag är kvalitativ analys av användare som spelar ett spel med de två renderingsmetoder följt av användarstudie om deras möjliga förbättrade grafiska upplevelse och om spelupplevelsen har drabbats.

Iridescence is the property that makes colors vary by angle of observation. Technology has made it possible to print with ink that has this anisotropic property. The ink that is used contains microparticles and therefore only specific printing methods can be used, for example screen printing. This comes with new demands on halftones, due to its procedure; dots cannot be too small, and keeping structures should be prioritized. To minimize costs and time, prints should be simulated before sending an order. In this thesis, different methods to halftone for screen printing with iridescent ink are developed. Three existing methods are compared to methods that are developed for this specific cause. The result is presented as a 2D-mask and as an interactive 3D-simulation, using data measured from real ink. Also, properties of iridescence are analyzed to separate it from diffuse colors. An OpenGL simulation tool was developed for simulating halftones on 3D-models. The ink reflectance spectra are represented by polynomials that take as input the wavelength and observation angle. Given an observation angle, a spectrum can be found, which can be converted to RGB and set as the output color in the fragment shader. The program uses an RGB-mask which is the combined masks of the halftone. This is loaded as a texture which indicates what polynomial to use. There is no perfect method that works for all types of images. Images that contain colors similar to the inks benefit from morphological halftoning (enhanced structures) for iridescent areas, or foreground, and hatching (an angle dependant grid pattern) for diffuse areas, or background. Other images, that contain mixed colors as cyan, yellow or magenta, benefit froma hue separation error diffusion, where masks are created by thresholding the hue where the mixed colors are error diffused.The actual prints confirmed the hypothesis that tone reproduction can be of lower priority while structure and depth preservance should be highly prioritized. Iridescent colors can be separated from diffuse colors by thresholding the saturation combined with value, or the lightness of the Lab-representation