Method of converting signals for multi-primary color display

• US 8,237,747 B2
• Filed: 03/31/2006
• Issued: 08/07/2012
• Est. Priority Date: 04/04/2005
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Belik, Oleg, Cordes, Claus Nico, Hekstra, Gerben Johan
• Primary Examiner(s): MANDEVILLE, JASON M
• Application Number:
  US11/910,472
• Publication Number:
  US 20080252658A1
• Time in Patent Office: 2,321 Days
• Field of Search: 345/690, 345 76- 83, 345 87- 90, 345/694, 345/698, 345/214, 345/36, 345589-593, 345600-605
• US Class Current: 345/690
• CPC Class Codes: H04N 9/67 for matrixing camera processing pipelines for matrixing of colour signals H04N23/85

Abstract

A method is described which converts a three primary color input signal (Cx, Cy, Cz) into N drive signals (P1, . . . , PN) to drive N>3 primary colors of a multi-primary color display (3). The method determines (1) a valid range (VS) wherein the N drive signals (P1, . . . , PN) have valid values by performing the steps of (i) defining 3 functions representing 3 of the drive signals (P1, P2, P3) as a function of the remaining N−3 drive signal(s) (P4, . . . , PN), and (ii) calculating (1) a common range in a space formed by the N−3 drive signal(s) (P4, . . . , PN) wherein each one of the 3 functions has valid values. The method selects (2) a point from the common range to determine the N drive signals (P1, . . . , PN).

Claims

1. A method of converting a three primary color input signal (Cx, Cy, Cz) into N drive signals (P1, . . . , PN) for driving N>

3 primary colors of a multi-primary color display, the display comprising a plurality of pixels with each pixel comprising N sub-pixels and each of the respective N drive signals (P1, . . . , PN) supplied for driving a respective sub-pixel, the method comprises;

determining, via a range circuit, a common range (VS) wherein the N drive signals (P1, . . . , PN) all have valid values in a coordinate system defined by a minimum and maximum drive range and the N−

3 drive signal(s) by performing the steps of (i) defining, via the range circuit, three functions representing three of the drive signals (P1, P2, P3) wherein each of the three functions is a function of the remaining N−

3 drive signal(s) (P4, . . . , PN), (ii) calculating, via the range circuit, the common range (VS) for the N−

3 drive signal(s) in a space formed by the N−

3 drive signal(s) (P4, . . . , PN) wherein each one of the three functions representing three of the drive signals (P1, P2, P3) has valid values in the coordinate system, and (iii) calculating, via the range circuit, border values for the common range (VS),

wherein the three functions are defined by

2. The method as claimed in claim 1, wherein the selecting is performed under a constraint (CON) for at least one aspect of at least one of the three drive signals (P1, P2, P3).

3. The method as claimed in claim 2, wherein the constraint (CON) is that one of the drive signals (P1, P2, P3, P4) is selected to have a minimum possible drive value.

4. The method as claimed in claim 2, wherein the constraint (CON) is a real time constraint determined by at least one of the group of:

a temperature of the display, an amount of ambient light at the display, aging of the display, or a power consumption of the display.

5. The method as claimed in claim 1, wherein N=4, and wherein the three functions are defined by

6. The method as claimed in claim 5, wherein the calculating calculates the common range (VS) on a line formed by the fourth drive signal (P4), and wherein the common range (VS) defines a range wherein each one of the three functions has valid values, wherein the range of valid values includes border values of (i) a lower border value (P4,min) and (ii) a higher border value (P4,max).

7. The method as claimed in claim 6, wherein the calculating of the common range (VS) comprises:

calculating, for each one of the three functions, a lower border value of the fourth drive signal (P4) where a corresponding one of the three functions reaches one of the border values of the valid range, and a higher border value of the fourth drive signal (P4) where the corresponding one of the three functions reaches another border value of the valid range, and

determining the common range (VS) from the respective lower and higher border values calculated for each of the three functions to obtain the respective lower and upper border values (P4,min, P4,max) for the common range (VS).

8. The method as claimed in claim 1, wherein all drive values (P1 to PN) are normalized and wherein valid ranges are defined as the values in the range from zero to one, including its borders.

9. A system for converting a three primary color input signal (Cx, Cy, Cz) into N drive signals (P1, . . . , PN) for driving N>

3 primary colors of a multi-primary color display, the display comprising a plurality of pixels with each pixel comprising N sub-pixels and each of the respective N drive signals (P1, . . . , PN) supplied for driving a respective sub-pixel, the system comprising;

circuit means for determining a common range (VS) wherein the N drive signals (P1, . . . , PN) all have valid values in a coordinate system defined by a minimum and maximum drive range and the N−

3 drive signal(s), wherein the circuit means for determining the common range (VS) comprises (i) circuit means for defining three functions representing three of the drive signals (P1, P2, P3) wherein each of the three functions is a function of the remaining N−

3 drive signal(s) (P4, . . . , PN), (ii) circuit means for calculating the common range (VS) for the N−

3 drive signal(s) in a space formed by the N−

3 drive signal(s) (P4, . . . , PN) wherein each one of the three functions representing three of the drive signals (P1, P2, P3) has valid values in the coordinate system, and (iii) circuit means for calculating border values for the common range (VS),

wherein the three functions are defined by

10. A display apparatus comprising

a signal processing circuit for receiving an image input signal (IV) to supply the primary color input signal (Cx, Cy, Cz),

the system as claimed in claim 9, and

a display device for receiving the N drive signals (P1 to PN).