Method and apparatus for chromatic adaptation
AssigneeEastman Kodak Company
InventorChristopher J. Edge
Life of this patent
Estimating the term…
Abstract
A method for performing chromatic adaptation includes performing chromatic adaptation wherein corrections to tristimulous values XYZ are maximized in the regions of white and neutral and are minimized in the vicinity of non-neutral regions of colors space via piecewise linear corrections in XYZ. In one embodiment, a selective linear correction is performed using three matrices one for each sector in an RGB color space. In an alternative embodiment, selective color adjustments are made and the adjustments are partitioned for each primary and secondary color.
Claims20
A method for performing chromatic adaptation, comprising:
- performing maximum corrections to tristimulous color values in the vicinity of white and neutral colors;
- performing minimum corrections to tristimulous color values in the vicinity of non-neutral colors;
- wherein said corrections are piecewise linear in a tristimulous color space.
A system, comprising:
- a display;
- and
- a controller coupled to the display, wherein the controller performs
- a chromatic adaptation that yields a color profile for the display wherein:
- XYZ
- →
- adapt
- =
-
- XYZ
- →
- +
- Δ
-
-
- XYZ
- →
-
- (
- RGB
- →
- )
- =
-
- XYZ
- →
- +
- ∑
- i
- =
- 0
- i
- =
- 5
-
- Δ
-
-
- XYZ
- →
- i
-
- (
- 1.0
- -
- f
- corr
-
- (
- RGB
- →
- ,
- i
- )
- )
- =
-
- M
- WP
-
- RGB
- →
- +
- ∑
- i
- =
- 0
- i
- =
- 5
-
- (
- M
- D
-
-
- 50
- -
- M
- WP
- )
-
- RGB
- →
- i
-
- (
- 1.0
- -
- f
- corr
-
- (
- RGB
- →
- ,
- i
- )
- )
- RGB
- →
- i
- =
- (
- 1
- ,
- 0
- ,
- 0
- )
-
-
- for
-
-
- i
- =
- 0
- =
- (
- 0
- ,
- 1
- ,
- 0
- )
-
-
- for
-
-
- i
- =
- 1
- =
- (
- 0
- ,
- 0
- ,
- 1
- )
-
-
- for
-
-
- i
- =
- 2
- =
- (
- 0
- ,
- 1
- ,
- 1
- )
-
-
- for
-
-
- i
- =
- 3
- =
- (
- 1
- ,
- 0
- ,
- 1
- )
-
-
- for
-
-
- i
- =
- 4
- =
- (
- 1
- ,
- 1
- ,
- 0
- )
-
-
- for
-
-
- i
- =
- 5
- where MD50 is a matrix for converting RGB to XYZ for the display set to a white point of D50, and MWP is a matrix for converting RGB to XYZ for the display set to a white point of XYZWP.
A system for performing color adaptation, comprising:
- a memory;
- and
- a processor coupled to the memory, the processor providing color adaptation by:
- performing maximum corrections to tristimulous color values in the vicinity of white and neutral colors;
- performing minimum corrections to tristimulous color values in the vicinity of non-neutral colors;
- and
- wherein said corrections are piecewise linear in the tristimulous color space.
Dependencies are inferred from the claim text.