Method for radiometric compensated display, corresponding system, apparatus and computer program product

Patent metadata

Field	Value
Publication number	US-2016189673-A1
Application number	US-201514870131-A
Country	US
Kind code	A1
Filing date	Sep 30, 2015
Priority date	Dec 24, 2014
Publication date	Jun 30, 2016
Grant date	—

Abstract

Color signals to be displayed on a colored display surface and having a first gamut in a color space, are subjected to radiometric compensation. An embodiment includes displaying on the colored surface a set of control points of a known color, acquiring via a camera the control points as displayed on the colored surface and evaluating at least one second color gamut of the control points displayed on the colored surface. The second color gamut(s) is/are misaligned with respect to the first color gamut due to the display surface being a colored surface. The method may also include evaluating as an intersection gamut, the misalignment of the second color gamut(s) with respect to the first color gamut, calculating the color transformation operator(s) as a function of the misalignment evaluated, and applying the color transformation operator(s) to the color signals for display on the colored display surface.

First claim

1 - 12 . (canceled)

13 . A radiometric compensation method for displaying on a colored display surface color signals having a first gamut in a color space, the method comprising:
displaying on the colored display surface a set of control points of a known color; acquiring the control points as displayed on the colored display surface, wherein the control points displayed on the colored display surface as acquired have at least one second color gamut which is misaligned with respect to the first color gamut due to the colored display surface being a colored surface; evaluating the misalignment of the at least one second color gamut with respect to the first color gamut; calculating at least one color transformation operator as a function of the misalignment; and applying the at least one color transformation operator to the color signals for display on the colored display surface.

14 . The method of claim 13 , comprising displaying on the colored display surface the color signals to which the color transformation operator has been applied.

15 . The method of claim 13 , wherein the colored display surface is of uniform color and the control points displayed on the colored display surface as acquired have a single second color gamut which is misaligned with respect to the first color gamut; and comprising evaluating the misalignment of the single second color gamut with respect to the first color gamut, calculating as a function of the misalignment a single color transformation operator, and applying the single color transformation operator to the color signals for display on the uniformly colored display surface.

16 . The method of claim 13 , wherein the colored display surface is of non-uniform color and includes areas of different colors and the control points displayed on the colored display surface as acquired have a plurality of second color gamuts which are misaligned with respect to the first color gamut; and comprising evaluating misalignments of the second color gamuts of the plurality with respect to the first color gamut, calculating as a function of the misalignments a plurality of respective transformation operators, and applying the respective color transformation operators to the areas of different colors of the non-uniformly colored display surface.

17 . The method of claim 16 , wherein the colored display surface is of non-uniform color and includes areas of different colors; and comprising evaluating misalignments of the second color gamuts of the plurality with respect to the first color gamut for areas including clustered pixels of the colored surface, the clustering being based on color classes.

18 . The method of claim 13 , comprising:
evaluating the misalignment of the at least one second color gamut with respect to the first color gamut as an intersection gamut therebetween; and calculating the at least one color transformation operator as at least one mapping operator mapping the first gamut to the intersection gamut.

19 . The method of claim 18 , wherein the colored display surface is of non-uniform color and includes areas of different colors; and comprising performing a boosting action of the color signals, by allowing a certain amount of clipping at the intersection gamut.

20 . The method of claim 13 , comprising:
generating a set of lines joining the control points to a middle grey color; sampling each line in the set from the middle grey color by finding a point common to the first gamut and the at least one second gamut displayable on the colored display surface; and calculating the at least one color transformation operator as a transformation matrix from the control points to common points found.

21 . The method of claim 13 , comprising:
converting the color signals for display on the colored display surface to a device-independent XYZ color space; subjecting the color signals converted to the device-independent color space to radiometric compensation as a function of the at least one color transformation operator; and converting the signals subjected to radiometric compensation to conversion from the device-independent color space to a display color space for display on the color display surface.

22 . The method of claim 13 , comprising:
converting the color signals for display on the colored display surface to a perceptually uniform color space as a workspace for the radiometric compensation; subjecting the color signals converted to the perceptually uniform color space to radiometric compensation as a function of the at least one color transformation operator; and converting the color signals subjected to radiometric compensation to conversion from the perceptually uniform color space to a display color space for display on the colored display surface.

23 . An electronic device comprising:
a processor and a memory coupled thereto and configured to perform radiometric compensation for displaying on a colored display surface color signals having a first gamut in a color space by at least
displaying on the colored display surface a set of control points of a known color,
acquiring the control points as displayed on the colored display surface, wherein the control points displayed on the colored display surface as acquired have at least one second color gamut which is misaligned with respect to the first color gamut due to the colored display surface being a colored surface,
evaluating the misalignment of the at least one second color gamut with respect to the first color gamut, calculating at least one color transformation operator as a function of the misalignment, and
applying the at least one color transformation operator to the color signals for display on the colored display surface.

24 . The electronic device of claim 23 , wherein the processor and memory are configured to display on the colored display surface the color signals to which the color transformation operator has been applied.

25 . The electronic device of claim 23 , wherein the colored display surface is of uniform color and the control points displayed on the colored display surface as acquired have a single second color gamut which is misaligned with respect to the first color gamut; and wherein the processor and memory are configured to evaluate the misalignment of the single second color gamut with respect to the first color gamut, calculate as a function of the misalignment a single color transformation operator, and apply the single color transformation operator to the color signals for display on the uniformly colored display surface.

26 . The electronic device of claim 23 , wherein the colored display surface is of non-uniform color and includes areas of different colors and the control points displayed on the colored display surface as acquired have a plurality of second color gamuts which are misaligned with respect to the first color gamut; and wherein the processor and memory are configured to evaluate misalignments of the second color gamuts of the plurality with respect to the first color gamut, calculate as a function of the misalignments a plurality of respective transformation operators, and apply the respective color transformation operators to the areas of different colors of the non-uniformly colored display surface.

27 . The electronic device of claim 23 , wherein the processor and memory are configured to:
evaluate the misalignment of the at least one second color gamut with respect to the first color gamut as an intersection gamut therebetween; and calculate the at least one color transformation operator as at least one mapping operator m

Assignees

• St Microelectronics Srl

Inventors

• Naccari Filippo
• Guarnera Mirko
• Bianco Simone
• Schettini Raimondo

Classifications

• G09G3/002 Primary

  to project the image of a two-dimensional display, such as an array of light emitting or modulating elements or a CRT · CPC title

• H04N23/85

  for matrixing · CPC title

• G09G2320/0242

  Compensation of deficiencies in the appearance of colours · CPC title

• G09G5/02 Primary

  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 title

• G09G2340/06

  Colour space transformation · CPC title