Spectral Image Rendering of Fluorescent Objects Using a Conventional Renderer

Area of Science:

• Computer Graphics
• Computational Imaging
• Optics

Background:

• Simulating fluorescence in computer graphics is challenging due to wavelength-shifting phenomena.
• Existing renderers often lack native support for complex light transport involving fluorescence.
• Accurate rendering of fluorescent objects requires modeling interactions between emitted and reflected light across different wavelengths.

Purpose of the Study:

• To develop a practical spectral image rendering method for fluorescent objects.
• To enable simulation of wavelength-shifting transport in scenes with fluorescent and non-fluorescent surfaces.
• To integrate fluorescence simulation into existing rendering systems lacking native support.

Main Methods:

• Classified incident illumination on fluorescent objects into direct, indirect, and luminescent components.
• Expressed observed radiance as a linear combination of reflection and fluorescence terms.
• Utilized measured Donaldson matrices for wavelength conversion and reused diffuse-reflection shading, implemented within the Mitsuba rendering system.

Main Results:

• The proposed method accurately renders spectral images of fluorescent objects.
• Experimental validation using a physical Cornell Box showed good agreement with direct measurements and an existing fluorescence renderer.
• Demonstrated an extension for non-planar fluorescent objects using sparse emitter discretization.

Conclusions:

• The developed method provides a practical approach for simulating fluorescence in computer graphics.
• It effectively handles wavelength-shifting transport by leveraging existing rendering capabilities and measured optical properties.
• The technique is extendable to complex geometries, improving the realism of virtual scenes containing fluorescent materials.