Harmonizing color selection system and method

• US 6,870,544 B2
• Filed: 01/09/2002
• Issued: 03/22/2005
• Est. Priority Date: 01/10/2001
• Status: Expired due to Term

• Current Assignee: X-Rite Incorporated (Danaher Corporation)
• Original Assignee: X-Rite Incorporated (Danaher Corporation)
• Inventors: Blanchard, Clark E., Haadsma, Richard D.
• Primary Examiner(s): Bella, Matthew C.
• Assistant Examiner(s): CHEN, PO WEI
• Application Number:
  US10/042,840
• Publication Number:
  US 20020089513A1
• Time in Patent Office: 1,168 Days
• Field of Search: 345/589, 345/593, 345/604, 345/605, 345/600
• US Class Current: 345/589
• CPC Class Codes: G01J 3/462 Computing operations in or between colour spaces; Colour management systems
• CPC Class Codes: G01J 3/528 using colour harmony theory
• CPC Class Codes: G06F 3/04845 for image manipulation, e.g. dragging, rotation, expansion or change of colour

Abstract

A system and method for calculating harmonizing colors based on a reference color. In a first embodiment, the invention includes (a) defining a reference color in a uniform color space, (b) converting the hue of the reference color from the uniform color space to an artists color wheel, (c) determining harmonizing colors for the reference color within the artists color wheel, (d) converting the hues of the harmonizing colors from the artists color wheel to the uniform color space, and (e) displaying the harmonizing color information. In a second embodiment, a brown region is defined for colors having red/orange/yellow hues and low chroma values. Additional harmonizing colors are determined when either the reference color or one of the harmonizing colors falls within the brown region.

Claims

1. A method of calculating a harmonizing color comprising:

defining a reference color in a first color space;

converting the reference color from the first color space to a second color space, the second color space having a closer correspondence to the non-linear hue acuity of the human eye than the first color space, said first converting step including a nonlinear conversion;

calculating a harmonizing color within said second color space based on the reference color; and

converting the harmonizing color from the second color space to the first color space, said second converting step including a nonlinear conversion.

2. A method as defined in claim 1 wherein the second color space is the artists color wheel.

3. A method as defined in claim 1 wherein said calculating step comprises calculating a plurality of harmonizing colors.

4. A method of calculating a harmonizing color comprising:

defining a reference color in a first color space having first hue angles;

converting the reference color from the first color space to a second color space having second hue angles, the second hue angles being a nonlinear function of the first hue angles;

calculating a harmonizing color in the second color space as a function of the second hue angle of the reference color; and

converting the harmonizing color from the second color space to the first color space.

5. A method as defined in claim 4 wherein the second color space is an artists color wheel.

6. A method as defined in claim 4 wherein said calculating step comprises calculating a plurality of harmonizing colors.

7. A method of calculating a harmonizing color based upon a reference color, the harmonizing color having a harmonizing chroma and the reference color having a reference chroma and a reference hue, comprising:

defining a brown region within a color space, said brown region having a hue range with hue boundaries and a chroma range with chroma boundaries;

if the reference color is within the brown region, calculating the harmonizing chroma outside of the chroma range; and

if the reference hue is within the hue range and the reference chroma is outside of the chroma range, calculating the harmonizing chroma within the chroma range.

8. A method as defined in claim 7 wherein:

the red hue is 0 degrees;

the hue boundaries are approximately 30 degrees and approximately 120 degrees; and

the chroma boundaries are approximately 4 and 40.

9. A method of calculating harmonizing colors comprising:

defining a brown region within a color space, the brown region being bounded by brown hue angles and brown chroma values;

identifying a reference color within the color space;

calculating a first harmonizing color within the color space as a function of the reference color;

for each first harmonizing color that is within the brown region, calculating a second harmonizing color having the same hue as the first harmonizing color and having a chroma value outside the brown region; and

for each first harmonizing color that is within the brown hue angles but outside the brown chroma values, calculating a second harmonizing color having the same hue as the first harmonizing color and having a chroma value inside the brown region.

10. A method as defined in claim 9 wherein:

the red hue is 0 degrees;

the brown angle boundaries are approximately 30 degrees and approximately 120 degrees; and

the chroma value boundaries are approximately 4 and 40.

11. A method for obtaining harmonizing colors comprising the steps of:

defining a reference color in a uniform color space according to hue, chroma and lightness values;

converting the hue value in the uniform color space to a hue value in a non-uniform color space having a closer correspondence to the nonlinear hue acuity of the human eye;

generating a harmonizing color for the reference color according to a typical color harmonization scheme and defining the harmonizing color in the second color space according to hue, chroma and lightness; and

converting the hue angle of the harmonizing color in the second color space to a hue angle in the uniform color space.

12. A method as defined in claim 11 further including the steps of:

defining a brown range in the second color space with a hue range of H₁ to H₂ and a chroma range of c₁ to c₂;

generating a secondary harmonizing color at the same hue as the reference color or the harmonizing color within the chroma range if the reference color or the harmonizing color is within the hue range and outside the chroma range; and

generating a secondary harmonizing color at the same hue as the reference color or the harmonizing color outside the chroma range if the reference color or the harmonizing color is within the hue range and within the chroma range.

16. A method as defined in claim 11 wherein the non-uniform color space is the artists color wheel.

13. A method of operating a machine to produce harmonizing paint colors comprising the steps of:

receiving a user selection of a reference color;

defining the reference color in a uniform color space;

receiving a user selection of a color harmonization scheme;

converting the reference color in the uniform color space to a non-uniform color space having a closer correspondence to the nonlinear hue acuity of the human eye;

generating one or more harmonizing colors for the reference color within the non-uniform color space according to the color harmonization scheme selected;

converting the harmonizing colors from the non-uniform space to the uniform color space; and

displaying the reference color and the harmonizing colors.

14. A method as defined in claim 13 further including the steps of:

defining a brown range in the non-uniform color space with a hue range of H₁ to H₂ and a chroma range of c₁ to c₂;

generating a secondary harmonizing color at the same hue as the reference color or the harmonizing color within the chroma range if the reference color or the harmonizing color is within the hue range and outside the chroma range; and

generating a secondary harmonizing color at the same hue as the reference color or the harmonizing color outside the chroma range if the reference color or the harmonizing color is within the hue range and within the chroma range.

15. A method as defined in claim 13 further including:

computing paint formulas for the harmonizing colors; and

displaying the paint formulas for the harmonizing colors.

17. A method as defined in claim 13 wherein the second color space is the artists color wheel.