Digital color system and method which provides a visual match across different input and output viewing conditions

• US 5,754,184 A
• Filed: 01/06/1993
• Issued: 05/19/1998
• Est. Priority Date: 01/06/1993
• Status: Expired due to Term

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Ring, Stuart Frederick, Giorgianni, Edward Joseph
• Primary Examiner(s): Jankus, Almis R.
• Application Number:
  US08/002,497
• Time in Patent Office: 1,959 Days
• Field of Search: 395/109, 395/129-133, 395/155, 395/161, 358/164, 358/298, 358/302, 358/443, 358/456, 358/501, 358/505, 358/506, 358/518-521, 358/523, 358/530, 358/531, 358/535, 358/537, 345/154, 345/200, 345/431, 364/526, 364/723, 355/38, 356/421, 382/54, 346/157
• US Class Current: 345/604
• CPC Class Codes: G06T 11/001 Texturing; Colouring; Generation of texture or colour inpainting G06T5/77
• CPC Class Codes: H04N 1/6052 Matching two or more picture signal generators or two or more picture reproducers
• CPC Class Codes: H04N 1/6055 using test pattern analysis
• CPC Class Codes: H04N 1/6088 by viewing conditions, i.e. conditions at picture output
• CPC Class Codes: H04N 1/6094 depending on characteristics of the input medium, e.g. film type, newspaper

Abstract

A color management system that converts or transforms color signals between device dependent color spaces and a device-independent space using reference image viewing conditions for the device-independent space. A device transform converts input color signals of an input image in an input space into device-independent color signals and a visual adaption transform converts the device-independent input color signals into device-independent signals that take into account the input viewing conditions, the reference viewing conditions and adaption characteristics of the human visual system to the standard viewing conditions. This provides intermediate signals which represent device independent corresponding colorimetric values that would be required to visually match the appearance of the input image, as seen in its input viewing conditions under the defined reference viewing conditions of the device independent space. The intermediate signals can then be transformed into output color signals for output, taking into account the reference and output viewing conditions, and the particular color reproduction and gamut capabilities of the output device. The color signals can then be converted into renderable output signals and rendered on the output device. A preview output image for a preview display device can be produced after taking into account the output device characteristics and viewing environment. Transforms for intent and editing, such as sharpening the image or cutting and pasting, can be performed in the intermediate device-independent space and previewed before rendering by the output device.

Claims

1. An apparatus, comprising:

first and second input devices producing color input signals in first and second input device spaces and having first and second predetermined viewing conditions; and

a color management system coupled to said first and second input devices and having a device-independent color space with third predetermined viewing conditions different from the first and second viewing conditions, said management system including means for transforming the color input signals, from the first and second input device spaces into intermediate color signals in the device-independent color space, responsive to a human visual response to the first, second and different third predetermined viewing conditions.

2. An apparatus as recited in claim 1, wherein said human visual response comprises chromatic adaptations.

3. An apparatus, comprising:

first and second output devices producing images responsive to color output signals in first and second output device spaces and having first and second predetermined viewing conditions; and

a color management system coupled to said first and second output devices and having a device-independent color space with third predetermined viewing conditions different from the first and second viewing conditions, said management system including means for transforming independent color space signals into device space output color signals responsive to a human visual response to the first, second and different third predetermined viewing conditions.

4. An apparatus as recited in claim 3, wherein said human visual response comprises chromatic adaptation.

5. An apparatus as recited in claim 3, wherein said output devices have output gamut characteristics and said system includes means for transforming responsive to the output gamut characteristics.

6. An apparatus, comprising:

an input device producing color input signals in an input device space for an input image viewed under first viewing conditions;

an output device producing an output image visually matching the input image under different second viewing conditions from color output signals in an output device space; and

a color management system coupled to said input and output devices, transforming the color input signals into device-independent color signals in a device-independent space, having intermediate space viewing conditions, responsive to the first viewing conditions and the intermediate space viewing conditions, and transforming the device-independent color signals into the color output signals responsive to the intermediate space viewing conditions and the different second viewing conditions.

7. An apparatus as recited in claim 6, wherein said output device has output image gamut characteristics and said management system transforms the independent color signals into the color output signals responsive to the gamut characteristics.