System for calibrating a color display to enable color-matching

• US 5,381,349 A
• Filed: 06/29/1993
• Issued: 01/10/1995
• Est. Priority Date: 06/29/1993
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Company (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Winter, Kirt A., Bockman, Francis E.
• Primary Examiner(s): Voeltz, Emanuel T.
• Assistant Examiner(s): Stamber, Eric W.
• Application Number:
  US08/084,375
• Time in Patent Office: 560 Days
• Field of Search: 348/182, 348/675, 348/179, 348/576, 348/577, 348/651, 358/518, 358/519, 358/520, 364/553, 364/526, 364/571.02, 364/571.04, 364/571.05, 364/571.06, 364/571.07, 364/571.08
• US Class Current: 382/167
• CPC Class Codes: H04N 1/6011 with simulation on a subsidiary picture reproducer H04N1/622 takes precedence; matching two or more picture reproducers H04N1/6052
• CPC Class Codes: H04N 1/622 with simulation on a subsidiary picture reproducer

Abstract

A color display screen displays a calibration color patch and a comparison color patch. The calibration color patch manifests a calibration color of a predetermined intensity, and the comparison color patch manifests a comparison color derived from a user determined input value. The system is controlled by a processor and is responsive to a user'"'"'s indication of a perceived color match between a calibration color patch and a comparison color patch, to determine a transfer function that enables conversion of a value that generated the comparison color to a value assigned to the calibration color. The processor is further responsive to further perceived color matches of first and second color patches with first and second different intensity calibration color patches, respectively, to determine if first and second transfer functions determined for the first and second comparisons are within a transfer function threshold value of each other. If they are, the transfer functions are averaged and employed to calibrate colors transmitted to an attached color printer. If they are not within the transfer function threshold value, an additional comparison test is made. If the resulting transfer function is not within the threshold value, a default color transfer function is substituted.

Claims

1. A system for enabling a user to determine a transfer function of a color display means, said system comprising:

color display means for displaying at least a calibration color patch and a comparison color patch, said calibration color patch manifesting a calibration color of predetermined intensity, said comparison color patch manifesting a user-determined comparison color that matches to a determined binary value;

color intensity variation means for enabling a user to vary an intensity of said comparison color;

memory means for storing a transfer function threshold value; and

processor means for operating said color display means to display said calibration color patch with determined calibration color intensities, and responsive to a user'"'"'s indication of a perceived color match between said calibration color patch and a comparison color patch, to determine a transfer function that enables conversion of a binary value that matches said comparison color to a binary value matching said calibration color, said processor means further responsive to plural user inputs indicating perceived color matches of first and second comparison color patches with first and second different intensity calibration color patches, to determine if first and second transfer functions determined for said first and second comparison color patches are within said transfer function threshold value of each other, and if so, to employ a combination of said first and second transfer functions for calibration of said color display means.

2. The system as recited in claim 1 wherein said combination of said first and second transfer functions is an average of gamma values that describe each transfer function (x.sup.γ

).

3. The system as recited in claim 2 wherein, upon a determination by said processor that transfer functions for said first and second comparison color patches are not within said transfer function threshold value, said processor is caused to determine a third transfer function for a third intensity comparison color patch and to further determine if said first and third transfer functions are within said transfer function threshold value of each other, and if yes, to further determine if said second and third transfer functions are within said transfer function threshold value of each other and, if yes, to average said first, second and third transfer functions for color calibration purposes.

4. The system as recited in claim 3 wherein upon a determination by said processor that said first and third transfer functions are not within said transfer function threshold value, said processor further determines if said second and third transfer function are within said transfer function threshold value, and if yes, averages said second and third transfer functions for for color calibration purposes.

5. The system as recited in claim 4 wherein upon a determination by said processor that said second and third transfer functions are not within said transfer function threshold value, said processor selects a default transfer function for color calibration purposes.

6. The system as recited in claim 5 wherein said system utilizes a determined or default transfer function to calibrate a color for matching to a color printer color, said system determining a transfer function or default transfer function for each primary color.

7. A system for enabling a user to determine a transfer function of a color display means, said system comprising:

color display means for displaying at least a calibration color patch and a comparison color patch, said calibration color patch manifesting a calibration color of predetermined intensity, said comparison color patch manifesting a user-determined comparison color intensity that matches to a binary value;

color intensity variation means for varying said intensity of said comparison color and, as a result, said matching binary value;

memory means for storing a transfer function threshold range; and

processor means for operating said color display means to display a calibration color patch with a first determined calibration color intensity and responsive to a user'"'"'s indication of a perceived color match between said calibration color patch and said comparison color patch, to determine a first transfer function that will enable conversion of a binary value that matches said comparison color to a binary value assigned to said calibration color, said processor means further determining if the first transfer function falls within said transfer function threshold range and, if yes, employing said first transfer function for color calibration.

8. The system as recited in claim 7 wherein upon a determination by said processor means that said transfer function does not fall within said transfer function threshold range, said processor causes a display of a calibration color patch of a second determined calibration color intensity and is further responsive to a user'"'"'s indication of a perceived color match between said calibration color patch of second intensity and said comparison color patch, to determine a second transfer function, said processor then determining if a difference between said first transfer function and second transfer function falls within said transfer function threshold range, and if yes, employing an average of said first transfer function and second transfer function as a resultant transfer function for color calibration purposes.

9. The system as recited in claim 8 wherein said processor means, upon determining that said difference between said first transfer function and second transfer function does not fall within said transfer function threshold range, causes a default transfer function to be selected for further use in calibration of a color intensity.

10. The system as recited in claim 9 wherein said system utilizes a determined or default transfer function to calibrate a color for matching to a color printer color, said system determining a transfer function or default transfer function for each primary color.

11. A system for enabling a user to determine a transfer function of a color display means, said system comprising:

memory means for storing a transfer function threshold range; and

processor means for operating said color display means to display a calibration color patch with a first determined calibration color intensity and responsive to a user'"'"'s indication of a perceived color match between said calibration color intensity and a comparison color intensity of a comparison color patch, to determine a transfer function that will enable conversion of a binary value that resulted in said comparison color intensity to a binary value assigned to said calibration color intensity, said processor means further determining if said transfer function falls within said transfer function threshold range and if yes employing said transfer function.

12. The system as recited in claim 11 wherein said processor means responds to a determination that plural transfer functions are not within said transfer function threshold range, by substituting a default transfer function, said default transfer function enabling conversion of displayed colors to standard color values for control of a connected printer.