Subsurface scattering in point-based rendering

November 29, 2010

The Department of Computer Engineering, Sejong University in Korea and ETH Zurich in Switzerland have recently introduced a novel and simple framework for rendering subsurface scattering on surfaces represented by points. This is useful for realistically rendering a cloud of points representing translucent materials such as the human skin. This significant study is reported in Vol. 53, No. 5 of SCIENCE CHINA Information Sciences.

The point-based graphics method for rendering surfaces has gained much attention as an alternative to polygon-based graphic methods because of its simplicity and flexibility. However, current point-based techniques do not provide sufficient rendering quality for translucent materials such as the human skin. The scattering of light inside translucent materials has been extensively studied with polygon-based methods in recent years, but there has been very little focus on point-based rendering.

To accurately simulate subsurface scattering in multilayered materials, two new computation passes are added to the typical three-pass point-based rendering process. These additional passes are shadow map generation and splat-based diffusion. Splat-based diffusion is an efficient way of approximating the light diffusion phenomenon inside a material using splats. The assumption is that the diffusion of light is isotropic; therefore, its effect at a splat can be expressed as a Gaussian distribution applied to the radius of the splat. The overall diffusion effect across the surface is determined by combining the contribution of all the splats.

As the radius of a splat increases in the surface splatting process, the process slows because the number of fragments projected on the screen space has increased. It is notable that even though the number of splats with large radii decreases, the outcome does not change very much because the overlapping area between splats is large. Such observations allow us to reduce the number of splats when the amplitude of the radius is large.

Prof. Choi reported: "Although in this paper we apply the surface splatting with subsurface scattering to human facial skin, our method can be used for various translucent objects such as marble, leaves, and milk by analyzing the scattering of laser or structured light patterns. In the future, we plan to optimize the number of splats required to produce each diffuse color image and to adjust the resolution using perception-based metrics".

One reviewer commented: "This paper made a nice addition to the point-based family by adding the scattering effect". Another reviewer noted "The authors have demonstrated their method for rendering soft and semi-translucent appearances of human skin and their rendering results are quite impressive".
Prof. Choi and her student Kim are affiliated with the Laboratory of Graphics and Virtual Reality at Sejong University and Prof. Gross and Dr. Bickel are affiliated with ETH Zurich and Disney Research Zurich.

This work was supported by the National Research Foundation of Korea (Grant Nos. 2009-0073692 and F01-2009-000-10029-0) and the Swiss National Science Foundation (Grant No. 200021-130379).

See the article: Kim H J, Bickel B, Gross M and Choi "S M. Subsurface scattering using splat-based diffusion in point-based rendering." Sci China Inf Sci, 2010, 53(5): 911-919

Science China Press

Related Human Skin Articles from Brightsurf:

Stretchable 'skin' sensor gives robots human sensation
Cornell University researchers have created a fiber-optic sensor that combines low-cost LEDs and dyes, resulting in a stretchable ''skin'' that detects deformations such as pressure, bending and strain.

Wearable circuits printed directly on human skin
Wearable electronics are getting smaller, more comfortable and increasingly capable of interfacing with the human body.

New tool mimics human skin to allow detailed study of mosquito biting
Scientists have developed a tool for studying the biting behaviour of common pathogen-carrying mosquitoes, according to new research published this week in eLife.

New electronic skin can react to pain like human skin
New pain-sensing prototype mimics the body's near-instant feedback response and reacts to painful sensations with the same lighting speed that nerve signals travel to the brain.

Human-Artificial intelligence collaborations best for skin cancer diagnosis
Artificial intelligence (AI) improved skin cancer diagnostic accuracy when used in collaboration with human clinical checks, an international study including University of Queensland researchers has found.

A deep-learned E-skin decodes complex human motion
A deep-learning powered single-strained electronic skin sensor can capture human motion from a distance.

Creating hairy human skin: Not as easy as you think
For the first time, growing human skin cell capable of growing hair embedded with fat and nerve cells is a reality.

IU researchers grow hairy skin from human stem cells
Building on years of groundbreaking discoveries in stem cell research, scientists from Indiana University School of Medicine and Harvard Medical School have determined how to grow hairy skin using human stem cells--developing one of the most complex skin models in the world.

Hairy, lab-grown human skin cell model could advance hair loss research
A new, hair-sprouting dollop of human skin created in the lab might one day help prevent hair loss.

Skin-to-skin 'kangaroo care' shows important benefits for premature babies
A world-first study led by Monash University has demonstrated significant benefits to a premature baby's heart and brain function when held by the parent in skin-to-skin contact.

Read More: Human Skin News and Human Skin Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to