Burini, Nino

Kvaliteten af digitale billed- og videosignaler på TV skærme er påvirket af mange faktorer, herunder display-teknologi og kompressions-standard. Præcist kendskab til skærmens og videosignalernes egenskaber kan bruges til at udvikle avancerede algoritmer til at forbedre den visuelle gengivelse af signalerne, særligt i tilfælde af LCD med dynamisk lokal bagbelysning. Denne afhandling viser, at det er muligt at modellere LCD med dynamisk baglys til at udvikle algoritmer, der forbedrer den visuelle kvalitet af 2D og 3D billede, og at videokodnings-artefakter som blokke eller ringinger kan reduceres ved hjælp af post-processing. LCD-skærme med dynamisk lokal bagbelysning modelleres med hensyn til deres vigtigste aspekter, såsom pixel luminans, lysdiusion og perception. Nye algoritmer baseret pa optimering efter modellen præsenteres, udvides og simpliceres for at producere bagbelysning, der har en optimal balance mellem billedkvalitet og strmforbrug. Algoritmerne testes i flere eksperimenter i sammenligning med andre avancerede metoder. En anden model af bagbelyst scanning indføres for at reducere cross-talk i tid-sekventiel stereoskopisk visualisering pa LCD skærme. Cross-talk på et givet luminansniveau minimeres ved at justere de signaler, der styrer bagbelysningen.Quality of digital image and video signals on TV screens is aected by many factors, including the display technology and compression standards. An accurate knowledge of the characteristics of the display andof the video signals can be used to develop advanced algorithms that improve the visual rendition of the signals, particularly in the case of LCDs with dynamic local backlight. This thesis shows that it is possible to model LCDs with dynamic backlight to design algorithms that improve the visual quality of 2D and 3D content, and that digital video coding artifacts like blocking or ringing can be reduced with post-processing. LCD screens with dynamic local backlight are modeled in their main aspects, like pixel luminance, light diusion and light perception. Following the model, novel algorithms based on optimization are presented and extended, then reduced in complexity, to produce backlights that find optimal balance between image quality and power consumption. The algorithms are tested in several experiments in comparison with other State of the Art approaches.Based on the model of backlight dimming, another model of backlight scanning for crosstalk reduction in time-sequential stereoscopic visualization on LCD is introduced. Crosstalk at a given luminance level is minimized by properly adjusting the signals controlling the backlight

Online Research Database In Technology

Processing Decoded Video for Backlight Dimming:Video Quality Enhancement on LCD with Dynamic Local Backlight

http://orbit.dtu.dk/ws/files/57194821/thesisMain_final.pdf

Processing Decoded Video for Backlight Dimming:Video Quality Enhancement on LCD with Dynamic Local Backlight

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Online Research Database In Technology