Display apparatus

• US 20050104812A1
• Filed: 11/08/2004
• Published: 05/19/2005
• Est. Priority Date: 11/13/2003
• Status: Active Grant

• Current Assignee: Rakuten Group, Inc.
• Original Assignee: Victor Company of Japan Limited (JVC Kenwood Corporation)
• Inventors: Ohshima, Yoshinori
• Granted Patent: US 7,391,391 B2
• Time in Patent Office: Days
• US Class Current: 345/60
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2320/0266 Reduction of sub-frame artefacts
• CPC Class Codes: G09G 2320/0271 Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/2803 Display of gradations G09G3/288 takes precedence

Abstract

A display apparatus divides each frame period of an input image signal into a plurality of subframes and selects the subframes according to a gray-scale level of the input signal, to display a gray-scale image. The display apparatus alternately employs two sets of tables having different gray-scale-level input/output characteristics, to move locations to cause false contours frame by frame, thereby minimizing false contours.

Claims

1. A display apparatus for displaying a gray-scale image by dividing a frame period of an input image signal into subframes having different brightness weights and by selecting at least one of the subframes that provides a brightness weight corresponding to an input gray-scale level specified by the input image signal, comprising:

a table generator configured to generate at least two sets of subframe coding tables having different gray-scale-level input/output characteristics; and

an image processing unit configured to cyclically and alternately employ the at least two sets of subframe coding tables at intervals of one frame, or one pixel, or one frame and one pixel of the input image signal and provide an output image signal having an output gray-scale level corresponding to the input gray-scale level.

2. A display apparatus for displaying a gray-scale image by dividing a frame period of an input image signal into subframes having different brightness weights and by selecting at least one of the subframes that provides a brightness weight corresponding to an input gray-scale level specified by the input image signal, comprising:

a table generator configured to generate at least two sets of subframe coding tables that nonlinearly increase, according to an increase in gray-scale level, the number of subframes to be selected; and

an image processing unit configured to cyclically alternate the at least two sets of subframe coding tables at intervals of one frame, or one pixel, or one frame and one pixel of the input image signal and provide an output image signal having an output gray-scale level corresponding to the input gray-scale level.

3. A display apparatus for displaying a gray-scale image by dividing a frame period of an input image signal into subframes having different brightness weights and by selecting at least one of the subframes that provides a brightness weight corresponding to an input gray-scale level specified by the input image signal, comprising:

a table generator configured to generate at least two sets of subframe coding tables having different gray-scale-level input/output characteristics; and

an image processing unit configured to cyclically and alternately employ the at least two sets of subframe coding tables at intervals of one frame, or one pixel, or one frame and one pixel of the input image signal and provide an output image signal having an output gray-scale level corresponding to the input gray-scale level,

the at least two sets of subframe coding tables generated by the table generator being configured such that a location in a first set of the at least two sets of subframe coding tables where a first of two adjacent output gray-scale levels involves an “

n−

1”

th subframe (“

n”

being an integer equal to or greater than 2 and equal to or smaller than the number of the subframes) as a top subframe among subframes selected for the first output gray-scale level and a second thereof involves an “

n”

th subframe as a top subframe among subframes selected for the second output gray-scale level differs from that in a second set of the at least two sets of subframe coding tables.

4. The display apparatus of claim 3, wherein:

the table generator generates a second set of the at least two sets of subframe coding tables by linearly transforming a first set thereof.

5. A display apparatus for displaying a gray-scale image by dividing a frame period of an input image signal into subframes having different brightness weights and by selecting at least one of the subframes that provides a brightness weight corresponding to an input gray-scale level specified by the input image signal, comprising:

a table generator configured to generate at least two sets of subframe coding tables having different gray-scale-level input/output characteristics; and

an image processing unit configured to cyclically and alternately employ the at least two sets of subframe coding tables at intervals of one frame, or one pixel, or one frame and one pixel of the input image signal and provide an output image signal having an output gray-scale level corresponding to the input gray-scale level,

the at least two sets of subframe coding tables generated by the table generator being configured such that a location in a first set of the at least two sets of subframe coding tables where a first of two adjacent output gray-scale levels involves an “

n−

1”

th subframe (“

n”

being an integer equal to or greater than 2 and equal to or smaller than the number of the subframes) as a top subframe among subframes selected for the first output gray-scale level and a second thereof involves an “

n”

th subframe as a top subframe among subframes selected for the second output gray-scale level corresponds to an intermediate location of a range of a second set of the at least two sets of subframe coding tables in which one of “

n−

1”

th and “

n”

th subframes continuously serves as a top subframe among selected subframes.

6. The display apparatus of claim 5, wherein:

the table generator generates a second set of the at least two sets of subframe coding tables by linearly transforming a first set thereof.

7. A display apparatus for displaying a gray-scale image by dividing a frame period of an input image signal into subframes having different brightness weights and by selecting at least one of the subframes that provides a brightness weight corresponding to an input gray-scale level specified by the input image signal, comprising:

a table generator configured to generate at least two sets of subframe coding tables having different gray-scale-level input/output characteristics; and

an image processing unit configured to cyclically and alternately employ the at least two sets of subframe coding tables at intervals of one frame, or one pixel, or one frame and one pixel of the input image signal and provide an output image signal having an output gray-scale level corresponding to the input gray-scale level,

the at least two sets of subframe coding tables generated by the table generator being configured such that a location in a first set of the at least two sets of subframe coding tables where a first of two adjacent output gray-scale levels involves an “

n−

1”

th subframe (“

n”

being an integer equal to or greater than 2 and equal to or smaller than the number of the subframes) as a top subframe among subframes selected for the first output gray-scale level and a second thereof involves an “

n”

th subframe as a top subframe among subframes selected for the second output gray-scale level corresponds to an intermediate location of a range of a second set of the at least two sets of subframe coding tables in which an “

m”

th subframe (“

m”

being one of “

n−

1” and

“

n”

) continuously serves as a top subframe among selected subframes and in which a “

k”

th subframe (“

k”

being equal to or greater than 1 and equal to or smaller than “

m−

1”

) is continuously unselected.

8. The display apparatus of claim 7, wherein:

the table generator generates a second set of the at least two sets of subframe coding tables by linearly transforming a first set thereof.

9. A display apparatus for displaying a gray-scale image by dividing a frame period of an input image signal into subframes having different brightness weights and by selecting at least one of the subframes that provides a brightness weight corresponding to an input gray-scale level specified by the input image signal, comprising:

a table generator configured to generate at least two sets of subframe coding tables having different gray-scale-level input/output characteristics; and

an image processing unit configured to cyclically and alternately employ the at least two sets of subframe coding tables at intervals of one frame, or one pixel, or one frame and one pixel of the input image signal and provide an output image signal having an output gray-scale level corresponding to the input gray-scale level,

the at least two sets of subframe coding tables generated by the table generator being configured such that a location in a first set of the at least two sets of subframe coding tables where a first of two adjacent output gray-scale levels involves an “

n−

1”

th subframe (“

n”

being an integer equal to or greater than 2 and equal to or smaller than the number of the subframes) as a top subframe among subframes selected for the first output gray-scale level and a second thereof involves an “

n”

th subframe as a top subframe among subframes selected for the second output gray-scale level corresponds to an intermediate location of a range of a second set of the at least two sets of subframe coding tables in which an “

m”

th subframe (“

m”

being one of “

n−

1” and

“

n”

) continuously serves as a top subframe among selected subframes and in which a “

k”

th subframe (“

k”

being equal to or greater than 1 and equal to or smaller than “

m−

1”

) is continuously selected.

10. The display apparatus of claim 9, wherein:

the table generator generates a second set of the at least two sets of subframe coding tables by linearly transforming a first set thereof.