Method or apparatus for displaying greyscale or color images from binary images

• US 6,243,072 B1
• Filed: 10/15/1997
• Issued: 06/05/2001
• Est. Priority Date: 07/20/1995
• Status: Expired due to Term

• Current Assignee: RealD Incorporated
• Original Assignee: The Board of Regents of the University of Colorado (University of Colorado System)
• Inventors: McKnight, Douglas J.
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Marc-Coleman, Marthe Y.
• Application Number:
  US08/949,692
• Time in Patent Office: 1,329 Days
• Field of Search: 345/148, 345/89, 345/147, 345/87, 345/84, 345/54, 345/94, 345/88
• US Class Current: 345/690
• CPC Class Codes: G06T 3/40 Scaling of whole images or parts thereof, e.g. expanding or contracting
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• CPC Class Codes: G09G 2300/0814 used for selection purposes, e.g. logical AND for partial update
• CPC Class Codes: G09G 2300/0823 used to establish symmetry in driving, e.g. with polarity inversion
• CPC Class Codes: G09G 2300/0828 forming a digital to analog [D/A] conversion circuit
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0857 Static memory circuit, e.g. flip-flop
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/0266 Reduction of sub-frame artefacts
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/2014 by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/2018 by time modulation using two or more time intervals
• CPC Class Codes: G09G 3/2033 with splitting one or more sub-frames corresponding to the most significant bits into two or more sub-frames
• CPC Class Codes: G09G 3/2037 with specific control of sub-frames corresponding to the least significant bits
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 3/3659 : the addressing of the pixel involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependant on signal of two data electrodes

Abstract

An apparatus and method for improving image quality and in particular to an apparatus and method for converting binary images to grey-scale or color images and displaying those images. The apparatus and method utilize the natural process of integration which occurs when a person views images at sufficiently high rates and involves identifying least significant subframes within a group of subframes and reducing the intensity of those subframes or extending the duration of subframes other than the least significant subframes.

Claims

1. A method for displaying an image on a display with a plurality of pixels, comprising the steps of:

receiving image data comprised of a series of attenuated and unattenuated subframes, wherein the unattenuated subframes are formed by combining precombined subframes;

storing the image data in a plurality of storage elements; and

displaying the image data in the plurality of pixels.

2. The method of claim 1, wherein a first frame rate of the unattenuated subframes is lower than a second frame rate of the pre-combined subframes.

3. The method of claim 1, wherein the unattenuated subframes are binary.

4. The method of claim 1, wherein the attenuated subframes are not binary.

5. The method of claim 1, comprising the further step of:

modulating the attenuated subframes using intensity modulation.

6. The method of claim 1, comprising the further step of:

modulating the attenuated subframes using pulse modulation.

7. The method of claim 1, comprising the further step of:

grouping the unattenuated subframes in unattenuated subframe groups.

8. The method of claim 7, wherein the unattenuated subframe groups for an associated image vary in size with each unattenuated subframe group including 2ⁿ unattenuated subframes, where n is an integer.

9. The method of claim 8, wherein each unattenuated subframe group is associated with a bit of a digital image value.

10. The method of claim 9, wherein the digital image value represents an A/D conversion of the associated image.

11. The method of claim 7, wherein said step of displaying includes sequentially displaying the unattenuated subframes of each unattenuated subframe group.

12. The method of claim 7, wherein said step of displaying includes not sequentially displaying the unattenuated subframes of each unattenuated subframe group.

13. The method of claim 1, wherein said step of displaying includes approximately simultaneously displaying, across the plurality of pixels, each of the attenuated and unattenuated subframes.

14. The method of claim 1, wherein said plurality of storage elements are static.

15. The method of claim 1, wherein said plurality of storage elements are dynamic.

16. The method of claim 1, wherein the display is a liquid crystal display.

17. The method of claim 1, wherein the image is a grey-scale non-color image.

18. The method of claim 1, wherein the image is a grey-scale color image.

19. A method for displaying an image on a display with a plurality of pixels, comprising the steps of:

receiving image data comprised of a series of attenuated and unattenuated subframes;

attenuating the attenuated subframes by approximately a factor of ½

in relation to the unattenuated subframes;

storing the image data in a plurality of storage elements; and

displaying the image data in the plurality of pixels.

20. A method for displaying an image on a display with a plurality of pixels, comprising the steps of:

receiving image data comprised of a series of attenuated and unattenuated subframes;

attenuating the attenuated subframes by approximately a factor of ½

^m in relation to the unattenuated subframes;

storing the image data in a plurality of storage elements; and

displaying the image data in the plurality of pixels.

21. A method for displaying an image on a display with a plurality of pixels, comprising the steps of:

receiving image data to be displayed at a first rate;

subdividing said image data into bit plane subframes;

altering said bit plane subframes into new subframes to be displayed; and

displaying said new subframes in a manner to achieve visual integration, wherein said step of altering said bit plane subframes comprises;

attenuating intensity of lower significant bit subframes to produce attenuated subframes; and

combining unattenuated subframes to yield fewer unattenuated subframes.

22. The method of claim 21, wherein said step of attenuating includes attenuating the intensity of lower significant bit subframes by approximately a factor of ½

in relation to the intensity of unattenuated subframes.

23. The method of claim 21, wherein said step of attenuating includes attenuating the intensity of lower significant bit subframes by approximately a factor of ½

^m in relation to the intensity of unattenuated subframes.

24. The method of claim 21, wherein the display is a liquid crystal display.

25. The method of claim 21, wherein the image is a grey-scale non-color image.

26. The method of claim 21, wherein the image is a grey-scale color image.

27. A method for displaying an image on a display with a plurality of pixels, comprising the steps of:

receiving image data to be displayed at a first rate;

subdividing said image data into bit plane subframes;

altering said bit plane subframes into new subframes to be displayed; and

displaying said new subframes in a manner to achieve visual integration, wherein said step of altering said bit plane subframes comprises;

combining higher significant bit plane subframes to yield fewer bit plane subframes having longer duration.

28. The method of claim 27, wherein the display is a liquid crystal display.

29. The method of claim 27, wherein the image is a grey-scale non-color image.

30. The method of claim 27, wherein the image is a grey-scale color image.