Image-based lighting in integration of computer-generated imagery and live-action for cinematic visual effects

Image-based lighting (IBL), in the context of cinematic visual effects, significantly facilitates the integration of computer-generated imagery (CGI) and live action. Improved global-illumination sampling algorithms and ever-increasing machinery-computing speeds have encouraged the development of IBL techniques adopted by the industry for productions. The techniques have evolved from a conventional approach----consisting of a single environment map projected onto a mathematically infinite sphere to derive diffuse indirect illumination and reflections for computer-graphics (CG) objects----to a more elaborate lighting setup incorporating high dynamic range (HDR) imagery-based set reconstruction to drive both the direct and indirect illumination for addressing spatially aware lighting.;This study presents a systematic research dedicated to the field of IBL. It covers theoretical foundations of IBL-related disciplines and includes a review of real-world IBL practices with designed shots, featuring integration of CGI and live action. The review's purpose is to understand the benefits and limitations of various approaches of generating omnidirectional HDR environment maps in distinct lighting conditions. Additionally, the review examines rendering techniques of IBL for integrating CG objects into background plates of designed shots, in which each shot presents unique challenges in terms of matching the CG lighting to that present in the plates. At the end, the review leads to the proposal for an experimental workflow model that incorporates physically-based set reconstruction and pre-computation of a light-stage style data set. The proposed workflow model addresses issues discussed in the review and achieves interactive lighting design through the aid of image-based relighting. In addition, the proposed workflow model facilitates the process of lighting CG characters using HDR images of real-world lights to enhance the experiences of matching CG lighting to cinematic lighting created on a film set. Two examples are included to demonstrate the efficiency that the proposed workflow achieves and the limitations that current implementation causes.