HDR Light Probe Sequence Resampling for
Realtime Incident Light Field Rendering

Joakim Löw, Anders Ynnerman, Per Larsson and Jonas Unger
Department of Science and Technology, Linköping University
(SCCG 2009)

Real-time rendering: diffuse plane Real-time rendering: diffuse dragon Real-time rendering: glossy dragon
Real-time rendering using captured real world Incident Light Field (ILF) illumination. The real-time performance is achieved by resampling the captured ILF to a 3D grid of spherical harmonic basis functions. The renderings displays: A diffuse plane (left), the Stanford Dragon rendered using a diffuse material (middle), and the dragon rendered using a glossy material (right).


This paper presents a method for resampling a sequence of high dynamic range light probe images into a representation of Incident Light Field(ILF) illumination which enables realtime rendering. The light probe sequences are captured at varying positions in a real world environment using a high dynamic range video camera pointed at a mirror sphere. The sequences are then resampled to a set of radiance maps in a regular three dimensional grid before projection onto spherical harmonics. The capture locations and amount of samples in the original data make it inconvenient for direct use in rendering and resampling is necessary to produce an efficient data structure. Each light probe represents a large set of incident radiance samples from different directions around the capture location. Under the assumption that the spatial volume in which the capture was performed has no internal occlusion, the radiance samples are projected through the volume along their corresponding direction in order to build a new set of radiance maps at selected locations, in this case a three dimensional grid. The resampled data is projected onto a spherical harmonic basis to allow for realtime lighting of synthetic objects inside the incident light field.
Keywords: Image Based Lighting, Incident Light Fields, Spherical harmonics
SCCG 2009 Paper (.pdf) 10.8 Mb
SCCG 2009 Video (.mov) 16.5 Mb (Quicktime)
Related Projects:
Image based lighting project
This project was supported by the Swedish Foundation for Strategic Research through the Strategic Research Center MOVIII.


Jonas Unger 2019