US 8,411,990 B1 · System and method for decomposing an image into reflectance and shading components

Abstract

Various embodiments of a system and methods for decomposing an image into reflectance and shading components are described. An image decomposition module may represent an image as a product of the reflectance and shading components of the image. Data representing the image may be transformed into an image gradient containing both reflectance and shading component gradients. A normal vector perpendicular to the direction of the reflectance component gradient may be determined, based on a difference between the color channels of the image gradient. The image gradient may be modified according to the normal vector to eliminate the reflectance component gradient. The shading component gradient may be determined from the modified image gradient. The shading component gradient may be transformed into the shading component. The reflectance component may be determined by substituting the shading component into the representation of the image which is a product of the reflectance and shading components.

Claims20

Dependent claims

A method for determining a reflectance component and a shading component of an image, comprising:

transforming image data representative of the image into an image gradient, wherein the image gradient comprises a reflectance component gradient and a shading component gradient;
based on a difference between color channels of the image gradient, determining a normal vector that is perpendicular to the direction of the reflectance component gradient;
modifying the image gradient according to the normal vector;
determining the shading component gradient from the modified image gradient;
determining the shading component of the image from the shading component gradient;
and
determining the reflectance component of the image from the image data and the shading component.

4 more elements

A non-transitory computer-readable storage medium storing program instructions executable on a computer to implement an image decomposition module configured to:

transform image data representative of the image into an image gradient, wherein the image gradient comprises a reflectance component gradient and a shading component gradient;
based on a difference between color channels of the image gradient, determine a normal vector that is perpendicular to the direction of the reflectance component gradient;
modify the image gradient according to the normal vector;
determine the shading component gradient from the modified image gradient;
determine the shading component of the image from the shading component gradient;
and
determine the reflectance component of the image from the image data and the shading component.

4 more elements

A system, comprising:

a memory;
and
one or more processors coupled to the memory, wherein the memory comprises program instructions executable by the one or more processors to implement a image decomposition module configured to:
transform image data representative of the image into an image gradient, wherein the image gradient comprises a reflectance component gradient and a shading component gradient;
based on a difference between color channels of the image gradient, determine a normal vector that is perpendicular to the direction of the reflectance component gradient;
modify the image gradient according to the normal vector;
determine the shading component gradient from the modified image gradient;
determine the shading component of the image from the shading component gradient;
and
determine the reflectance component of the image from the image data and the shading component.

7 more elements

Dependencies are inferred from the claim text.

System and method for decomposing an image into reflectance and shading components

Life of this patent

System and method for decomposing an image into reflectance and shading components

Life of this patent

Abstract

Claims20