Efficient light scattering through thin semi-transparent objects

Abstract

This paper concerns real-time rendering of thin semi-transparent objects. An object in this category could be a piece of cloth, eg. a curtain. Semi-transparent objects are visualized most correctly using volume rendering techniques. In general such techniques are, however, intractable for real-time applications. Surface rendering is more efficient, but also inadequate since semi-transparent objects should have a different appearance depending on whether they are front-lit or back-lit. The back-lit side of a curtain, for example, often seems quite transparent while the front-lit side seems brighter and almost opaque. To capture such visual effects in the standard rendering pipeline, Blinn [1982] proposed an efficient local illumination model based on radiative transfer theory. He assumed media of low density, hence, his equations can render media such as clouds, smoke, and dusty surfaces. Our observation is that Chandrasekhar [1960] has derived the same equations from a different set of assumptions. This alternative derivation makes the theory useful for realistic real-time rendering of dense, but thin, semitransparent objects such as cloth. We demonstrate that application of the theory in this new area gives far better results than what is obtainable with a traditional real-time rendering scheme using a constant factor for alpha blending.

Modelling appearance printing : Acquisition and digital reproduction of translucent and goniochromatic materials

“…where µ t and µ s are cosines of transmitted and scattered angles (with regards to the surface normal). This practical solution is based on the intrinsic properties of materials and can be used to efficiently visualise materials with the assumption if single scattering [75].…”

A new system to acquire and restore document shape and content

“…The single-scatter transmission has been well studied in the area of computer graphics. Chandrasekhar's work has been used to create an efficient rendering system for thin semi-transparent objects [Frisvad et al 2005]. Moreover, the area of plant/leaf rendering has been thoroughly studied [Wang et al 2006] [Govaerts et al 1996] [Ganapol et al 1998] with respect to single-scatter transmission.…”

Three-Dimensional Density Estimation of Flame Captured From Multiple Cameras

“…• transparent objects transmit all incoming light [7]. Since the natural world is composed of opaque, semitransparent, and transparent objects, we consider the less studied problem of 3D view synthesis of semitransparent objects, such as flame [8], [9].…”