Method and apparatus for displaying grey-scale or color images from binary images

• US 5,767,828 A
• Filed: 07/20/1995
• Issued: 06/16/1998
• Est. Priority Date: 07/20/1995
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: The Board of Regents of the University of Colorado (University of Colorado System)
• Inventors: McKnight, Douglas J.
• Primary Examiner(s): Hjerpe, Richard A.
• Assistant Examiner(s): CHANG, KENT WU
• Application Number:
  US08/505,654
• Time in Patent Office: 1,062 Days
• Field of Search: 345/87, 345/88, 345/89, 345/94, 345/99, 345/84, 345/55
• US Class Current: 345/89
• 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 a grey-scale image on a display unit with a plurality of pixels, comprising the steps of:

receiving a group of image data including pixel location and pixel intensity, said image data to be displayed at a first rate;

arranging said group of image data into bit plane subframes;

attenuating intensity of the least significant unattenuated subframe as well as any previously attenuated subframes to yield attenuated subframes;

combining unattenuated subframes to yield fewer unattenuated subframes; and

displaying said fewer unattenuated subframes and said lower bit subframes on the display unit at a correspondingly reduced rate to achieve visual integration.

2. The method as claimed in claim 1, wherein said receiving step comprises receiving a group of binary images.

3. The method as claimed in claim 1, wherein said attenuating step comprises attenuating intensity of the least significant unattenuated subframe as well as any previously attenuated subframes by approximately 1/2 to yield attenuated subframes.

4. The method as claimed in claim 1, further comprising the step of repeatedly performing said attenuating step and said combining step.

5. The method as claimed in claim 4, wherein said displaying step comprises displaying said unattenuated subframes and said attenuated subframes at a rate of approximately 1/2^m of said first rate, where m'"'"' represents the number of times said attenuating step and said combining step are repeated.

6. The method as claimed in claim 1, wherein said receiving step comprises receiving color image data.

7. The method as claimed in claim 6, wherein said arranging step comprises arranging said color image data into red bit plane subframes, green bit plane subframes, and blue bit plane subframes.

8. The method as claimed in claim 7, wherein said attenuating step comprises attenuating intensity of the least significant unattenuated red bit plane subframe, the least significant unattenuated green bit plane subframe and the least significant blue bit plane subframe as well as any previously attenuated red bit subframes, green bit subframes and blue bit subframes to yield attenuated red bit subframes, green bit subframes and blue bit subframes, respectively.

9. The method as claimed in claim 8, wherein said combining step comprises combining unattenuated red bit subframes to yield fewer unattenuated red bit subframes, combining unattenuated green bit subframes to yield fewer unattenuated green bit subframes, and combining unattenuated blue bit subframes to yield fewer unattentuated blue bit subframes.

10. The method as claimed in claim 9, wherein said displaying step comprises displaying said fewer unattenuated red bit subframes, green bit subframes and blue bit subframes as well as said attenuated red bit subframes, green bit subframes and blue bit subframes at a correspondingly reduced rate to achieve visual integration.

11. The method as claimed in claim 10, where said displaying step comprises interchangeably displaying said fewer red unattenuated subframes, said fewer green unattenuated subframes, said fewer blue unattenuated subframes, said red attenuated subframes, said green attenuated subframes, and said blue attenuated subframes.

12. The method as claimed in claim 6, wherein said displaying step comprises interchangeably displaying said fewer unattenuated subframes and said attenuated subframes while maintaining visual integration thereof regardless of color.

13. The method as claimed in claim 6, wherein said arranging step comprises arranging said color image data into red bit plane subframes;

green bit plane subframes, and blue bit plane subframes.

14. The method as claimed in claim 13, wherein said displaying step comprises interchangeably displaying said fewer subframes regardless of color while maintaining visual integration thereof.

15. The method as claimed in claim 1, wherein said displaying step comprises interchangeably displaying said fewer unattenuated subframes and said attenuated subframes while maintaining visual integration thereof.

16. The method as claimed in claim 15, wherein said receiving step comprises receiving color image data.

17. A method for displaying a grey-scale image on a display unit with a plurality of pixels wherein said grey-scale image can include colored or non-colored images, comprising the steps of:

receiving a group of bit plane subframes to be displayed at a first rate;

attenuating intensity of the least significant unattenuated subframe as well as any previously attenuated subframes to yield attenuated subframes;

combining unattenuated subframes to yield fewer unattenuated subframes; and

displaying said fewer unattenuated subframes and said attenuated subframes on the display unit at a correspondingly reduced rate to achieve visual integration.

18. The method as claimed in claim 17, wherein said combining step comprises combining pairs of unattenuated subframes other than the least significant bit subframes to yield the fewer subframes.

19. The method as claimed in claim 17, wherein said receiving step comprises receiving red bit plane subframes, green bit plane subframes, and blue bit plane subframes.

20. The method as claimed in claim 19, wherein said displaying step comprises interchangeably displaying said fewer unattenuated and attenuated subframes regardless of color while maintaining visual integration thereof.

21. A method for displaying a grey-scale image on a display unit with a plurality of pixels, wherein said grey-scale image can include colored or non-colored images, comprising the steps of:

receiving at least one grey-scale image;

bit slicing said at least one grey-scale image into bit plane subframe;

attenuating intensity of the least significant unattenuated subframe as well as any previously attenuated subframes to yield attenuated subframes;

combining unattenuated subframes to yield fewer unattenuated subframes; and

displaying said fewer unattenuated subframes and said attenuated subframes on the display unit at a correspondingly reduced rate to achieve visual integration.

22. The method as claimed in claim 21, wherein said receiving step comprises receiving at least one grey-scale image comprising at least one grey-scale red image, at least one grey-scale green image and at least one grey-scale blue image.

23. The method as claimed in claim 22, wherein said attenuating step comprises attenuating intensity of the least significant unattenuated subframe which comprises the least significant subframe of said at least one grey-scale red image, the least significant subframe of said at least one grey-scale green image, and the least significant subframe of said at least one grey-scale blue image.

24. A method for displaying a grey-scale image on a display unit with a plurality of pixels, comprising the steps of:

receiving a series of N frames of binary images to be displayed at a rate of approximately 1/t;

arranging the series of N frames of binary images into n groups of m binary subframes, where m is less than or equal to N;

attenuating the output of the least significant subframes within each of said N groups of subframes;

combining pairs of subframes within each of said n groups of m subframes to yield a series of unattenuated subframes;

doubling the duration of the display of the least significant subframes; and

displaying said series of unattenuated subframes and said least significant subframes at a reduced rate of approximately 1/(2t).

25. A method for displaying a grey-scale image on a binary display unit with a plurality of pixels, comprising the steps of:

receiving bit plane subframes;

attenuating intensity of the least significant unattenuated subframe of said bit plane subframes as well as any previously attenuated subframes of said bit plane subframes to yield attenuated subframes;

combining unattenuated subframes to yield fewer unattenuated subframes; and

displaying said fewer unattenuated subframes and said attenuated subframes on at a correspondingly reduced rate to achieve visual integration.