Visual calibration target set method

• US 6,686,953 B1
• Filed: 03/01/2001
• Issued: 02/03/2004
• Est. Priority Date: 03/01/2000
• Status: Active Grant

• Current Assignee: Joseph Holmes
• Original Assignee: Joseph Holmes
• Inventors: Holmes, Joseph
• Primary Examiner(s): Lee, Michael H.
• Application Number:
  US09/797,897
• Time in Patent Office: 1,069 Days
• Field of Search: H04/N 1.700, H04/N 1.702, 348/179, 348/178, 348/177, 348/180, 348/181, 348/182, 348/183, 348/187, 348/188, 348/806, 348/807, 348/745-747, 348/657, 348/658, 348/674
• US Class Current: 348/179
• CPC Class Codes: H04N 1/6033 using test pattern analysis H04N1/6055 takes precedence
• CPC Class Codes: H04N 17/02 for colour television signals
• CPC Class Codes: H04N 17/04 for receivers

Abstract

A novel process of visual calibration of a computer display or the like in volves adjusting the appearance and relative appearance of targets and su targets displayed on the display. An objective method is provided for determining the precisely optimal brightness setting for CRT displays, which method is also applicable to the setting of the “Black Level” control on some FPDs. A precise method is provided to visually determine conformity of a display'"'"'s tonality to a given standard tone curve, for example a gamma 1.8 curve, which is embodied in one of the preferred calibration target sets. The need to sense and therefore be able to control and to verify the correct gray balance of the entire tone scale of the display is met. The problem of verifying the similarity of the tone curve in the display profile and that of the actual calibration is solved. By converting a preferred RGB gamma target into CIE Lab image data through an ideal display profile of the correct gamma, a new kind of target is taught.

Claims

1. An apparatus for calibrating a display associated with stored LookUp Tables, including:

first means for displaying on said display a first midtone sub-target having a first midtone solid adjacent to a first midtone blended region, said first midtone blended region having a first series of adjacent double rows of substantially black pixels alternating with a first series of single rows of light pixels;

second means for displaying on said display a second dark sub-target having a second dark solid adjacent to a second dark blended region, said second dark blended region having a second series of adjacent double rows of substantially black pixels alternating with a second series of single rows of midtone pixels;

third means for displaying on said display a third light sub-target having a third light solid adjacent to a third light blended region, said third light blended region having a third series of single rows of substantially black pixels alternating with a third series of single rows of midtone pixels and alternating with a third series of single rows of light pixels; and

means for modifying said LookUp Tables responsive to changes in said first, second and third sub-targets.

2. The apparatus of claim 1 wherein:

said first midtone solid is midtone gray and said first series of single rows of light pixels are white,

said second dark solid is dark gray and said second series of single rows of midtone pixels are midtone gray, and

said third light solid is light gray and said third series of single rows of midtone pixels are midtone gray and said third series of single rows of light pixels are white.

3. The apparatus of claim 2 further including:

means for displaying on said display a gray scale, and wherein

said second dark solid is three-quartertone gray and said third light solid is quartertone gray.

4. The apparatus of claim 1 wherein:

said first midtone solid is midtone red and said first series of single rows of light pixels are light red,

said second dark solid is dark red and said second series of single rows of midtone pixels are midtone red, and

said third light solid is light red, said third series of single rows of midtone pixels are midtone red and said third series of single rows of light pixels are light red.

5. The apparatus of claim 4 further including:

means for displaying on said display a fourth lined blended-region-and-solid dark green sub-target;

means for displaying on said display a fifth lined blended-region-and-solid midtone green sub-target;

means for displaying on said display a sixth lined blended-region-and-solid light green sub-target;

means for displaying on said display a seventh lined blended-region-and-solid dark blue sub-target;

means for displaying on said display a eighth lined blended-region-and-solid midtone blue sub-target;

means for displaying on said display a ninth lined blended-region-and-solid light blue sub-target; and

wherein

said means for modifying said LookUp Tables responsive to changes in said first, second and third sub-targets is also responsive to changes in said fourth through ninth sub-targets.

6. The apparatus of claim 1 wherein:

said first midtone solid is midtone green and said first series of single rows of light pixels are light green,

said second dark solid is dark green and said second series of single rows of midtone pixels are midtone green, and

said third light solid is light green, said third series of single rows of midtone pixels are midtone green and said third series of single rows of light pixels are light green.

7. The apparatus of claim 6 further including:

means for displaying on said display a fourth lined blended-region-and-solid dark red sub-target;

means for displaying on-said display a fifth lined blended-region-and-solid midtone red sub-target;

means for displaying on said display a sixth lined blended-region-and-solid light red sub-target;

means for displaying on said display a seventh lined blended-region-and-solid dark blue sub-target;

means for displaying on said display a eighth lined blended-region-and-solid midtone blue sub-target;

means for displaying on said display a ninth lined blended-region-and-solid light blue sub-target; and

wherein

said means for modifying said LookUp Tables responsive to changes in said first, second and third sub targets is also responsive to changes in said fourth through ninth sub-targets.

8. The apparatus of claim 1 wherein:

said first midtone solid is midtone blue and said first series of single rows of light pixels are light blue,

said second dark solid is dark blue and said second series of single rows of midtone pixels are midtone blue, and

said third light solid is light blue, said third series of single rows of midtone pixels are midtone blue and said third series of single rows of light pixels are light blue.

9. The apparatus of claim 8 further including:

means for displaying on said display a fourth lined blended-region-and-solid dark green sub-target;

means for displaying on said display a fifth lined blended-region-and-solid midtone green sub-target;

means for displaying on said display a sixth lined blended-region-and-solid light green sub-target;

means for displaying on said display a seventh lined blended-region-and-solid dark red sub-target;

means for displaying on said display a eighth lined blended-region-and-solid midtone red sub-target;

means for displaying on said display a ninth lined blended-region-and-solid light red sub-target; and

wherein

said means for modifying said LookUp Tables responsive to changes in said first, second and third sub-targets is also responsive to changes in said fourth through ninth sub-targets.

10. An apparatus for calibrating a display associated with stored LookUp Tables, including:

first means for displaying on said display a first blended-region-and-solid midtone sub-target;

second means for displaying on said display a second blended-region-and-solid light sub-target;

third means for displaying on said display a third blended-region-and-solid dark sub target, said third dark sub-target having a third dark solid surrounded by a uniform repeating pattern of between one and three white pixels per first group of twelve pixels, the remainder of said first group of twelve pixels being substantially black pixels;

fourth means for displaying on said display a fourth blended-region-and-solid very dark sub-target, said fourth very dark sub-target having a fourth very dark solid surrounded by a uniform repeating pattern of between one and three midtone gray pixels per second group of twelve pixels, the remainder of said second group of twelve pixels being substantially black pixels; and

means for modifying said LookUp Tables responsive to changes in said first, second, third and fourth sub-targets.

11. An apparatus for calibrating a display including:

means for displaying on said display a first brightness tone solid having a first dark tone;

means for displaying on said display a second brightness tone solid having a second dark tone;

means for displaying on said display a third brightness tone solid having a third dark tone; and

means for calibrating the brightness of said display by adjusting the relative lightnesses of said brightness tone solids until a first visible degree of lightness difference between a first two of said brightness tone solids substantially equals a second visible degree of lightness difference between a second two of said brightness tone solids.

12. The apparatus of claim 11 further including:

means for displaying on said display a fourth brightness tone solid having a fourth dark tone, said first brightness tone solid displayed adjacent to said second brightness tone solid and said third brightness tone solid displayed adjacent to said fourth brightness tone solid,

wherein said means for calibrating said brightness of said display calibrates by adjusting the relative lightnesses of said brightness tone solids until a first visible degree of lightness difference between said first and second brightness tone solids substantially equals a second visible degree of lightness difference between said third and fourth brightness tone solids.

13. The apparatus of claim 12 further including:

overall slider means for controlling the full tone scale on said display;

darks slider means for controlling the dark half of the tone scale on said display;

lights slider means for controlling the light half of the tone scale on said display;

first means for displaying on said display at least one first lined blended-region-and-solid gamma sub-target responsive to adjustments of said overall slider means;

second means for displaying on said display at least one second lined blended-region-and-solid gamma sub-target responsive to adjustments of said darks slider means;

third means for displaying on said display at least one third lined blended-region-and-solid gamma sub-target responsive to adjustments of said lights slider means; and

means for calibrating the gamma of said display responsive to changes in said gamma sub targets occasioned by adjustments to said overall slider means, darks slider means and lights slider means.

14. The apparatus of claim 13 wherein:

the first, second and third displaying means display a total of eight first, second and third lined blended-region-and-solid gamma sub-targets.

15. A system for calibrating a display, including:

a gray balance target produced by said display having at least three blended-region-and-solid gray balance sub-targets and a gray scale;

a brightness target produced by said display having at least a first brightness tone solid having a first dark tone, a second brightness tone solid having a second dark tone, and a third brightness tone solid having a third dark tone;

a gamma target produced by said display having eight lined blended-region-and-solid gamma sub-targets;

at least one target adjustment tool produced by said display; and

a video card having LookUp Tables responsive to changes in said gray balance target, said brightness target and said gamma target.

16. The system of claim 15 wherein:

said gray balance target includes

a first midtone sub-target having a first midtone solid adjacent to a first midtone blended region, said first midtone blended region having a first series of adjacent double rows of substantially black pixels alternating with a first series of single rows of light pixels;

a second dark sub-target having a second dark solid adjacent to a second dark blended region, said second dark blended region having a second series of adjacent double rows of substantially black pixels alternating with a second series of single rows of midtone pixels; and

a third light sub-target having a third light solid adjacent to a third light blended region, said third light blended region having a third series of single rows of substantially black pixels alternating with a third series of single rows of midtone pixels and alternating with a third series of single rows of light pixels.

17. The system of claim 16 wherein:

said first midtone solid is midtone gray and said first series of single rows of light pixels are white,

said second dark solid is dark gray and said second series of single rows of midtone pixels are midtone gray, and

said third light solid is light gray and said third series of single rows of midtone pixels are midtone gray and said third series of single rows of light pixels are white.

18. A method for calibrating a display including the steps of:

providing LookUp Tables associated with said monitor;

providing a first midtone sub-target having a first midtone solid adjacent to a first midtone blended region, said first midtone blended region having a first series of adjacent double rows of substantially black pixels alternating with a first series of single rows of light pixels;

providing a second dark sub-target having a second dark solid adjacent to a second dark blended region, said second dark blended region having a second series of adjacent double rows of substantially black pixels alternating with a second series of single rows of midtone pixels;

providing a third light sub-target having a third light solid adjacent to a third light blended region, said third light blended region having a third series of single rows of substantially black pixels alternating with a third series of single rows of midtone pixels and alternating with a third series of single rows of light pixels;

adjusting the visual appearance of said first midtone sub-target until said first midtone solid appears to blend with said first midtone blended region;

adjusting the visual appearance of said second dark sub-target until said second dark solid appears to blend with second dark blended region;

adjusting the visual appearance of said third light sub-target until said third light solid appears to blend with said third light blended region; and

saving modifications to said LookUp tables which have occurred as a result of any of the preceding steps.

19. The method of claim 18 further including the steps of:

providing a first brightness tone solid having a first dark tone;

providing a second brightness tone solid having a second dark tone;

providing a third brightness tone solid having a third dark tone,

providing a fourth brightness tone solid having a fourth dark tone, said first brightness tone solid displayed adjacent to said second brightness tone solid and said third brightness tone solid displayed adjacent to said fourth brightness tone solid; and

calibrating the brightness of said display by adjusting the relative lightnesses of said brightness tone solids until a first visible degree of lightness difference between said first and second brightness tone solids substantially equals a second visible degree of lightness difference between said third and fourth brightness tone solids.

20. The method of 19 further including the steps of:

providing at least one first lined blended-region-and-solid gamma sub target responsive to adjustments in the full tone scale on said display;

providing at least one second lined blended-region-and-solid gamma sub-target responsive to adjustments in the dark half of the tone scale on said display;

providing at least one third lined blended-region-and-solid gamma sub-target responsive to adjustments in the light half of the tone scale on said display;

adjusting said at least one first lined blended-region-and-solid gamma sub-target until it appears fully blended visually;

adjusting said at least one second lined blended-region-and-solid gamma sub-target until it appears fully blended visually; and

adjusting said at least one third lined blended-region-and-solid gamma sub-target until it appears filly blended visually.

21. An apparatus for calibrating a display associated with stored LookUp Tables, including:

first means for displaying on said display a first midtone sub-target having a first midtone solid adjacent to a first midtone blended region, said first midtone blended region having a first mixture of substantially black pixels and light pixels;

second means for displaying on said display a second blended-region-and-solid dark sub-target;

third means for displaying on said display a third blended-region-and-solid light sub-target;

overall tone means for adjusting said first midtone LookUp Tables responsive to changes in said first midtone sub-target;

dark tone means for adjusting said second dark sub-target and for modifying said LookUp Tables responsive to changes in said second dark sub-target; and

light tone means for adjusting said third light sub-target and for modifying said LookUp Tables responsive to changes in said third light sub-target.

22. The apparatus of claim 21 wherein:

said second dark sub-target has a second dark solid adjacent to a second dark blended region, said second dark blended region having a second mixture of substantially black pixels and midtone pixels, and

said third light sub-target has a third light solid adjacent to a third light blended region, said third light blended region having a third mixture of substantially black pixels, midtone pixels, and light pixels.

23. The apparatus of claim 22 wherein:

said first mixture is of substantially black pixels and white pixels, and

said third mixture is of substantially black pixels, midtone pixels, and white pixels.

24. The apparatus of claim 21 wherein:

said second dark sub-target has a second dark solid adjacent to a second dark blended region, said second dark blended region having a second mixture of substantially black pixels and light pixels, and

said third light sub-target has a third light solid adjacent to a third light blended region, said third light blended region having a third mixture of pixels chosen from the tones black and midtone and of light pixels.

25. The apparatus of claim 24 wherein:

said first mixture is of substantially black pixels and white pixels,

said second mixture is of substantially black pixels and white pixels, and

said third mixture is of pixels chosen from the tones black and midtone and of white pixels.

26. The apparatus of claim 22 further including:

fourth means for displaying on said display a fourth very dark sub-target having a fourth very dark solid adjacent to a fourth very dark blended region, said fourth very dark blended region having a mixture of substantially black pixels and midtone pixels.