Virtual Photographic Relighting
Author
Skov-Pedersen, Jakob
Term
10. term
Publication year
2005
Abstract
Denne afhandling undersøger relighting – at ændre belysningen i et enkelt fotografi ved at beregne, hvordan lys opfører sig i scenen. Systemet bruger to input: scenens geometri (3D-form) og et High Dynamic Range (HDR) fotografi, som indeholder et stort spænd af lysstyrker. Metoden består af tre trin. Først estimeres den oprindelige belysning ved hjælp af en global belysningssimulation, som modellerer lysets refleksioner i scenen; dette udføres med enten en ray tracer eller en radiosity-løser, og flere tilgange til håndtering af belysning afprøves. Dernæst bruges den estimerede belysning til at fjerne fotografiets eksisterende lys, så der bliver et billede, der repræsenterer scenens overfladetekstur. Til sidst beregnes en ny belysning og påføres teksturbilledet. Den nye belysning renderes på grafikhardware og bruges til at genbelyse fotoet i realtid, så brugeren interaktivt kan justere lyskilder.
This thesis explores relighting—changing the lighting in a single photograph by computing how light behaves in the scene. The system takes two inputs: the scene’s geometry (3D shape) and a high dynamic range (HDR) photograph that captures a wide range of light intensities. The method has three steps. First, it estimates the original illumination by running a global illumination simulation, which models light bouncing in the scene; this is implemented with either a ray tracer or a radiosity solver, and several approaches to handling lighting are tested. Second, the estimated illumination is used to remove the photo’s existing lighting, leaving an image that represents the scene’s surface texture. Third, new illumination is computed and applied to this texture image. The new lighting is rendered on graphics hardware and used to relight the photo in real time, allowing the user to interactively adjust light sources.
[This abstract was generated with the help of AI]
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