# US 2013/0155089 A1 · Real-time global illumination rendering system

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- Number: US 2013/0155089 A1
- Document ID: US20130155089A1
- Status: Published application
- Kind: A1
- Application number: 13/693,396
- Filed: 2012-12-04
- Published: 2013-06-20
- Earliest claimed: 2011-12-05
- Assignees: KABUSHIKI KAISHA SQUARE ENIX (also trading as SQUARE ENIX CO., LTD.)
- Inventors: Yusuke TOKUYOSHI; Shinji OGAKI
- Web page: https://patentgrep.com/patent/US20130155089A1

## CPC

- G06T 11/10: Texturing; Colouring; Generation of textures or colours (retouching, inpainting or scratch removal G06T5/77)
- G06T 15/506: {Illumination models}
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL

## Abstract

The present invention provides an artifact-free, real-time global illumination rendering system. Artifact-free, real-time global illumination rendering can be performed by estimating appropriate specular roughness using sampling results and performing shading using the estimated specular roughness.

## Claims

### Claim 1

A shading method comprising:
a sampling step of sampling, by a computer, a path of light reflected at a given object (17) from a virtual light source (15) and reaching a given eye point (20); and
an estimated specular roughness obtaining step of obtaining, by the computer, estimated specular roughness of a surface of the object by obtaining a distribution function for the surface of the object (17) using the path obtained in the sampling step and performing arithmetic processing such that a maximum value of the distribution function is less than or equal to a predetermined value.

### Claim 2 (depends on 1)

The shading method according to claim 1, wherein
the distribution function is a distribution function for specular reflection at an intersection point of the path and the object (17), and
the estimated specular roughness obtaining step is a step of obtaining estimated specular roughness of the surface of the object by determining density of the path and performing arithmetic processing using the determined density of the path such that a maximum value of the distribution function is less than or equal to a predetermined value.

### Claim 3 (depends on 1)

The shading method according to claim 1, wherein
the estimated specular roughness obtaining step includes:
an estimated density calculation step of determining density of the path using the path obtained in the sampling step;
a distribution function obtaining step of obtaining a distribution function for specular reflection at an intersection point of the path and the object (17); and
an estimated specular roughness calculation step of determining estimated specular roughness of the surface of the object by performing arithmetic processing using the density of the path such that a maximum value of the distribution function is less than or equal to a predetermined value.

### Claim 4

A computer graphics system comprising:
a sampling unit (101) for sampling a path of light reflected at a given object (17) from a virtual light source (15) and reaching a given eye point (20); and
an estimated specular roughness obtaining unit (102) that obtains estimated specular roughness of a surface of the object by obtaining a distribution function for the surface of the object (17) using the path obtained by the sampling unit (101) and performing arithmetic processing such that a maximum value of the distribution function is less than or equal to a predetermined value.

### Claim 5 (depends on 4)

The computer graphics system according to claim 4, wherein
the estimated specular roughness obtaining unit (102) includes:
an estimated density calculating unit (112) that determines density of the path using the path obtained by the sampling unit;
a distribution function obtaining unit (113) that obtains a distribution function for specular reflection at an intersection point of the path and the object (17); and
an estimated specular roughness calculating unit (114) that determines estimated specular roughness of the surface of the object by performing arithmetic processing using the density of the path such that a maximum value of the distribution function is less than or equal to a predetermined value.