Methods and apparatus for calibrating a color display

• US 10,008,180 B2
• Filed: 08/25/2017
• Issued: 06/26/2018
• Est. Priority Date: 04/11/2000
• Status: Active Grant

• Current Assignee: RAH Color Technologies LLC
• Original Assignee: RAH Color Technologies LLC
• Inventors: Holub, Richard A.
• Primary Examiner(s): Martello, Edward
• Application Number:
  US15/686,473
• Publication Number:
  US 20170352326A1
• Time in Patent Office: 305 Days
• Field of Search: None
• CPC Class Codes: G01J 3/506 measuring the colour produced by screens, monitors, displays or CRTs
• CPC Class Codes: G06F 3/14 Digital output to display device ; Cooperation and interconnection of the display device with other functional units
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 2340/06 Colour space transformation
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 2370/045 using multiple communication channels, e.g. parallel and serial
• CPC Class Codes: G09G 5/006 Details of the interface to the display terminal specific for a display terminal using a CRT G09G1/167; using a flat panel G09G3/2096; circuits for interfacing with colour displays G09G5/04
• CPC Class Codes: G09G 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 5/026 Control of mixing and/or overlay of colours in general G09G5/022 and G09G5/024 take precedence

Abstract

Improved methods are provided for calibrating color on a color display coupled to a computer, which are useful for obtaining calibrated data in a virtual proof network for enabling different color devices to render consistent color. Methods involve user interactions with screens on the display to set color display parameters. An apparatus is also provided for calibrating a sensor which may be used for measuring color of a display in one or more of these methods.

Claims

1. An apparatus for digital image reproduction comprising:

a color video display;

one or more processors, wherein at least one of said processors controls said display;

memory storing programs and data, wherein said one or more processors are operable to execute said programs, at least one of said programs controls said display functions, and said data comprise graphical elements providing a user interface enabling control of said apparatus;

a network interface through which at least one of said one or more processors receives digital image data from a web site using a client-server protocol; and

another one of said programs uses one or more of subjective visual judgement or instrumental measurement of ambient illumination in vicinity of said display to adjust the reproduction gamut and white balance of said display to approximate the gamut and neutral balance of colors represented by said digital image data when rendered on said display.

2. The apparatus according to claim 1 further comprising a sensor which provides said instrumental measurement of ambient illumination in vicinity of said display, wherein said another one of said programs uses at least said sensor to provide said instrumental measurement.

3. The apparatus according to claim 2 wherein said sensor is a multi-channel sensor calibrated against a colorimetric reference.

4. The apparatus according to claim 1 wherein said digital image data are one of received in device independent units of color or translated into device independent units of color by one of said programs using at least a multidimensional transform received with said digital image data.

5. The apparatus according to claim 1 wherein said display is calibrated to enable translation of device independent color values to codes for said display that provide improved accuracy of reproduction of said digital image data on said display represented by said device independent color values.

6. The apparatus according to claim 5 wherein said translation provides gamut enlargement of said display to compensate for effects of said ambient illumination.

7. A method of digital image reproduction wherein said method is operable by one or more processors, said method comprising the steps of:

controlling a color video display linked to at least one of said one or more processors, said controlling step further comprising the steps of;

providing a user interface through presentation of graphical elements stored in memory associated with said one or more processors;

rendering on said display, responsive to user interaction with said user interface, digital image data received from a web server using client-server protocols; and

adjusting the reproduction gamut and white balance of said display, using one or more of subjective visual judgement or instrumental measurement of ambient illumination, to approximate the gamut and neutral balance of colors represented in said digital image data when rendered on said display.

8. The method according to claim 7 further comprising the step of measuring the ambient illumination in the vicinity of said display with the aid of a sensor to provide said instrumental measurement.

9. The method according to claim 8 wherein said sensor is a multi-channel sensor, and said method further comprises the step of calibrating said sensor against a colorimetric reference.

10. The method according to claim 7 wherein said digital image data received from said web server is one of in device independent units of color or translated into device independent units of color using at least a multidimensional transform.

11. The method according to claim 7 further comprising the step of calibrating said display to enable translation of device independent color values to codes for said display that provide improved accuracy of reproduction of said digital image data on said display represented by said device independent color values.

12. The method according to claim 11 wherein said translation provides gamut enlargement of said display to compensate for effects of said ambient illumination.

13. A non-transitory, computer-readable medium encoding software executable by one or more processors for digital image reproduction, said software comprising:

one or more programs that control a color video display linked to at least one of said one or more processors, said programs comprising at least;

one or more programs that provide a user interface by displaying graphical elements stored in memory associated with said at least one of said one or more processors;

a program for displaying, responsive to user interaction with said user interface, digital image data received from a web server using client-server protocols; and

a program that adjusts the reproduction gamut and white balance of said display, using one or more of subjective visual judgement or instrumental measurement of ambient illumination, to approximate the gamut and neutral balance of colors represented in said digital image data when rendered by said display.

14. The non-transitory, computer-readable medium according to claim 13 further comprising one or more programs that receive and process said instrumental measurement, said instrumental measurement being in the vicinity of said display and used by said program that adjusts the reproduction gamut and white balance of said display.

15. The non-transitory, computer-readable medium according to claim 14 wherein said instrumental measurement is provided by a multi-channel sensor calibrated against a colorimetric reference.

16. The non-transitory, computer-readable medium according to claim 13 wherein said digital image data are one of received in device independent units of color or translated into device independent units of color by one of said programs using at least a multidimensional transform.

17. The non-transitory, computer-readable medium according to claim 13 wherein said display is calibrated to enable translation of device independent color values to codes of said display that provide improved accuracy of reproduction of said digital image data on said display represented by said device independent color values.

18. The non-transitory, computer-readable medium according to claim 17 wherein said translation provides gamut enlargement of said display to compensate for effects of said ambient illumination.