System and method to generate multiprimary signals

• US 8,305,391 B2
• Filed: 11/27/2006
• Issued: 11/06/2012
• Est. Priority Date: 11/27/2006
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Ramanath, Rajeev, Kempf, Jeffrey Matthew
• Primary Examiner(s): TRAN, MY CHAU T
• Application Number:
  US11/604,599
• Publication Number:
  US 20080122861A1
• Time in Patent Office: 2,171 Days
• Field of Search: 345/55, 345/84, 345/85, 345/87, 345/105, 345/108, 345/581, 345/589, 345/591, 345/593, 345/595
• US Class Current: 345/591
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 3/2044 using dithering
• CPC Class Codes: G09G 3/346 based on modulation of the reflection angle, e.g. micromirrors micromirrors devices per se G02B26/0833
• CPC Class Codes: G09G 5/06 using colour palettes, e.g. look-up tables

Abstract

System and method for generating multiprimary signals with optimization for bit depth for use in display devices. A preferred embodiment comprises converting an input color signal into an output color signal, wherein the number of colors in the output color signal is less than a number of colors used in a display system, when a weighting of the input color signal is less than a specified threshold, and converting the input color signal into an output color signal, wherein the number of colors in the output color signal is equal to the number of colors used in the display system, when the weighting of the input color signal is greater than the specified threshold. The use of fewer colors eliminates low bit depth colors, allowing increased dither quality in dimmer images.

Claims

1. A method for displaying images in a multiprimary display system using N colors, comprising:

receiving a video input signal representation of pixel intensity and hue using M-dimensional color vectors, where M<

N;

determining an input gray scale weighting of the M-dimensional color vectors;

converting the M-dimensional color vectors into (N-K)-dimensional and N-dimensional color vectors >

+M-dimensional color vectors, including;

if the determined weighting is less than a given threshold, converting the M-dimensional color vectors into (N-K)-dimensional color vectors, where (N-K)>

=M, with the weightings of K of the colors set to zero; and

if the determined weighting is greater than the given threshold, converting the M-dimensional color vectors into N-dimensional color vectors using weightings for all of the K colors; and

displaying the image with the N colors using the (N-K)-dimensional and N-dimensional color vectors.

2. The method of claim 1, wherein K>

1; and

converting the M-dimensional color vectors into the (N-K)-dimensional and N-dimensional color vectors further includes;

if the determined weighting is less than a second given threshold which is less than the given threshold, converting the M-dimensional color vectors into N-(K+1)-dimensional color vectors, wherein N-(K+1)>

=M, with the weightings of K+1 of the N colors set to zero; and

if the determined weighting is greater than the second given threshold but less than the given threshold, converting the M-dimensional color vectors into the (N-K)-dimensional color vectors.

3. The method of claim 1, wherein N>

=5 and M=3.

4. The method of claim 3, wherein the M-dimensional color vectors are red, green and blue color vectors.

5. The method of claim 4, wherein the N colors include cyan and yellow.

6. The method of claim 1, wherein converting the M-dimensional color vectors further includes converting the M-dimensional color vectors into intermediate color vectors in an intermediate common connection color space, and converting the intermediate color vectors into the (N-K)-dimensional and N-dimensional color vectors.

7. The method of claim 1, wherein converting the M-dimensional color vectors includes:

storing both (N-K)-dimensional color vectors and N-dimensional color vectors conversions for each of at least some M-dimensional color vectors in memory;

retrieving the (N-K)-dimensional color vectors if the determined weighting is less than the given threshold; and

retrieving the N-dimensional color vectors if the determined weighting is greater than the given threshold.

8. The method of claim 7, wherein the display system includes a controller which calculates the weighting, compares the calculated weighting with the given threshold, and selects retrieval of the (N-K)-dimensional color vectors or the N-dimensional color vectors based on an output of the comparison.

9. The method of claim 8, wherein the display system includes a source of light of the N colors and a spatial light modulator having an array of controllable individual light modulators;

and displaying the image includes modulating the light of the N colors by controlling settings of the individual light modulators using the retrieved (N-K)-dimensional color vectors and N-dimensional color vectors.

10. The method of claim 9, wherein the spatial light modulator is a digital micromirror device having an array of micromirrors having position settings controlled using the retrieved (N-K)-dimensional color vectors and N-dimensional color vectors.

11. The method of claim 1, wherein the display system includes a source of light of the N colors and a spatial light modulator having an array of controllable individual light modulators;

and displaying the image includes modulating the light of the N colors by controlling settings of the individual light modulators using the (N-K)-dimensional color vectors and N-dimensional color vectors.

12. The method of claim 11, wherein the spatial light modulator is a digital micromirror device having an array of micromirrors having position settings controlled using the retrieved (N-K)-dimensional color vectors or N-dimensional color vectors.

13. The method of claim 1, further comprising setting the given threshold empirically between a lower value determined by decreasing the value until dither noise becomes visually objectionable in the displayed image and an upper value determined by increasing the value until a difference between using (N-K)-dimensional color vectors and N-dimensional color vectors becomes visibly noticeable in the displayed image.