Methods and systems for adaptive dither structures

• US 20050174360A1
• Filed: 02/09/2004
• Published: 08/11/2005
• Est. Priority Date: 02/01/2002
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Daly, Scott J., Feng, Xiao-fan
• Granted Patent: US 7,098,927 B2
• Time in Patent Office: Days
• US Class Current: 345/596
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/2055 the pattern being varied in time
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

Embodiments of the present invention comprise methods and systems for adaptive dither pattern array generation and application.

Claims

1. A method for creating a dither pattern structure, said method comprising:

a. establishing a first multi-dimensional array of dither pattern tiles, said array comprising a first upper horizontal spatial frequency bound, a first lower horizontal frequency bound, a first upper vertical spatial frequency bound, a first lower vertical spatial frequency bound, a first upper temporal frequency bound and a first lower temporal frequency bound;

b. wherein said spatial frequency bounds and said temporal frequency bounds define a high-pass pattern configuration;

c. establishing a second multi-dimensional array of dither pattern tiles, said array comprising a second upper horizontal spatial frequency bound, a second lower horizontal frequency bound, a second upper vertical spatial frequency bound, a second lower vertical spatial frequency bound, a second upper temporal frequency bound and a second lower temporal frequency bound;

d. wherein said second lower temporal frequency bound is lower than said first lower temporal frequency bound; and

e. associating said first multi-dimensional array of dither pattern tiles with a first range of image characteristic values; and

f. associating said second multi-dimensional array of dither pattern tiles with a second range of image characteristic values.

2. A method as described in claim 1 wherein said image characteristic values comprise luminance values.

3. A method as described in claim 1 wherein said image characteristic values comprise localized average luminance values.

4. A method for adaptive processing of a digital image, said method comprising:

a. receiving a digital image;

b. designating a location in said image for application of a dither pattern tile;

c. determining a local image characteristic for that tile location;

d. selecting a first dither pattern tile set from a plurality of dither pattern tile sets wherein said selecting is based on said local image characteristic.

5. A method for adaptive processing of a digital image, said method comprising:

a. dividing a digital image into tile block locations;

b. determining a local luminance characteristic for each of said tile block locations;

c. selecting a dither pattern array from among a plurality of dither pattern arrays wherein each of said arrays is associated with a range of values of said local luminance characteristic.

6. A method for adaptive processing of a digital image, said method comprising:

a. establishing a first multi-dimensional array of dither pattern tiles, said array comprising a first upper horizontal spatial frequency bound, a first lower horizontal frequency bound, a first upper vertical spatial frequency bound, a first lower vertical spatial frequency bound, a first upper temporal frequency bound and a first lower temporal frequency bound;

b. establishing a second multi-dimensional array of dither pattern tiles, said array comprising a second upper horizontal spatial frequency bound, a second lower horizontal frequency bound, a second upper vertical spatial frequency bound, a second lower vertical spatial frequency bound, a second upper temporal frequency bound and a second lower temporal frequency bound, wherein said second lower temporal frequency bound is lower than said first lower temporal frequency bound; and

c. associating said first multi-dimensional array of dither pattern tiles with a first range of local luminance characteristic values; and

d. associating said second multi-dimensional array of dither pattern tiles with a second range of local luminance characteristic values.

e. dividing a digital image into tile block locations;

f. determining a local luminance characteristic for a multiplicity of said tile block locations;

g. selecting a dither pattern tile from said first multi-dimensional array of dither pattern tiles for application on a first set of tile block locations when said first tile block locations have local luminance characteristic values that fall within said first range; and

h. selecting a dither pattern tile from said second multi-dimensional array of dither pattern tiles for application on a second set of tile block locations when said second tile block locations have local luminance characteristic values that fall within said second range.

7. A system for adaptive processing of a digital image, said system comprising:

a. a first multi-dimensional array of dither pattern tiles, said array comprising a first upper horizontal spatial frequency bound, a first lower horizontal frequency bound, a first upper vertical spatial frequency bound, a first lower vertical spatial frequency bound, a first upper temporal frequency bound and a first lower temporal frequency bound, wherein said first multi-dimensional array is associated with a first range of local luminance characteristic values;

b. a second multi-dimensional array of dither pattern tiles, said array comprising a second upper horizontal spatial frequency bound, a second lower horizontal frequency bound, a second upper vertical spatial frequency bound, a second lower vertical spatial frequency bound, a second upper temporal frequency bound and a second lower temporal frequency bound, wherein said second lower temporal frequency bound is lower than said first lower temporal frequency bound, wherein said second multi-dimensional array is associated with a second range of local luminance characteristic values; and

c. a selector for selecting between said first array and said second array based on the local luminance characteristic value for a location in said image.

8. An image display device comprising:

a. image storage for storing an image to be displayed;

b. a dither array storage having contents comprising

i. a first multi-dimensional array of dither pattern tiles, said array comprising a first upper horizontal spatial frequency bound, a first lower horizontal frequency bound, a first upper vertical spatial frequency bound, a first lower vertical spatial frequency bound, a first upper temporal frequency bound and a first lower temporal frequency bound, wherein said first multi-dimensional array is associated with a first range of local luminance characteristic values; and

ii. a second multi-dimensional array of dither pattern tiles, said array comprising a second upper horizontal spatial frequency bound, a second lower horizontal frequency bound, a second upper vertical spatial frequency bound, a second lower vertical spatial frequency bound, a second upper temporal frequency bound and a second lower temporal frequency bound, wherein said second lower temporal frequency bound is lower than said first lower temporal frequency bound, wherein said second multi-dimensional array is associated with a second range of local luminance characteristic values;

c. a processor for determining a local luminance characteristic value for an image location; and

d. a selector for selecting between said first array and said second array based on the local luminance characteristic value for said image location.