Operator adjustable color image processing

• US 4,972,257 A
• Filed: 04/03/1989
• Issued: 11/20/1990
• Est. Priority Date: 04/03/1989
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Cass, Lee A., Birnbaum, David
• Primary Examiner(s): Britton, Howard W.
• Assistant Examiner(s): VU, KIM Y
• Application Number:
  US07/332,866
• Time in Patent Office: 596 Days
• Field of Search: 358/75, 358/78, 358/80, 358/76
• US Class Current: 358/520
• CPC Class Codes: H04N 1/60 Colour correction or control H04N1/54 takes precedence
• CPC Class Codes: H04N 1/6016 Conversion to subtractive colour signals

Abstract

An operator controllable apparatus which adjusts the color of a copy being reproduced from a multi-colored original document. The original document is scanned and a set of primary color densities therein measured. The measured set of primary color densities is changed to a set of colorimetric coordinates. The operator adjusts the set of colorimetric coordinates so that the copy has the desired hue, saturation and darkness. The operator adjusted set of colorimetric coordinates is transformed into a set of subtractive primary color densities. This set of subtractive primary color densities controls the marking engine to form a copy having the desired hue, saturation and darkness.

Claims

1. A printing system in which the color of a copy being formed from an original document is adjustable, including:

means for scanning the original document and measuring a set of primary color densities therein;

operator controllable means, in communication with said scanning means, for converting the measured set of primary color densities to signals corresponding to a set of operator selected subtractive primary color densities, said converting means comprising first means for changing the measured set of primary color densities to a set of colorimetric coordinates, operator abjustable means, in communication with said changing means, for varying the set of colorimetric coordinates, said varying means varying the set of colorimetric coordinates to adjust independently or in combination with one another darkness, hue or saturation of the set of subtractive primary color densities and second means, in communication with said varying means, for changing the operator abjusted set of colorimetric coordinates to signals corresponding to the set of operator selected subtractive primary color densities; and

a marking engine which receives the signals from said converting means and forms a copy of the original document in response thereto.

2. A printing system according to claim 1, wherein said marking engine includes:

a member adapted to have a latent image recorded thereon;

means, responsive to signals received from said converting means, for recording at least one latent image on said member; and

means for developing the latent image recorded on said member with developer material corresponding to one of the set of operator selected subtractive primary color densities.

3. A printing system according to claim 2, wherein said marking engine includes:

means for transferring the developer material from said member to a copy sheet; and

means for fusing the developer material to the copy sheet.

4. A printing system according to claim 1, wherein said second changing means changes the operator adjusted set of colorimetric coordinates by selected scale factors to generate the signals corresponding to the set of subtractive primary color densities.

5. A printing system according to claim 1, wherein said varying means rotates the set of colorimetric coordinates to adjust the hue of the set of subtractive primary color densities without changing the darkness or saturation of the set of subtractive primary color densities.

6. A printing system according to claim 1, wherein said varying means multiplies the set of colorimetric coordinates by a first set of scale factors to adjust the darkness of the set of subtractive primary color densities without changing the hue or saturation of the set of subtractive primary densities.

7. A printing system according to claim 1, wherein said controlling means multiplies the set of colorimetric coordinates by a second set of scale factors to adjust the saturation of the set of subtractive primary color densities without changing the hue or darkness of the set of subtractive primary color densities.

8. A printing system according to claim 1, wherein said varying means controls the set of colorimetric coordinates to adjust the set of subtractive primary color densities of the copy to correspond to the set of subtractive primary color densities of the original document.