DATA CONVERTING CIRCUIT AND DISPLAY APPARATUS USING THE SAME

• US 20070153021A1
• Filed: 01/05/2007
• Published: 07/05/2007
• Est. Priority Date: 01/05/2006
• Status: Abandoned Application

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Inventors: UMEDA, Kengo, Hori, Yoshihiko
• Application Number:
  US11/620,285
• Publication Number:
  US 20070153021A1
• Time in Patent Office: Days
• US Class Current: 345/600
• 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 2340/0428 Gradation resolution change
• CPC Class Codes: G09G 3/2007 Display of intermediate tones

Abstract

In a data converting circuit, an approximation calculation circuit calculates an approximation value of an output to input data by using an n-th order equation (n is an integer equal to or more than one). An error reducing circuit generates an error correction value by using a multiplication factor determined based on the input data. An addition section adds the approximation value and the error correction value and outputs an addition result.

Claims

1. A data converting circuit comprising:

an approximation calculation circuit configured to calculate an approximation value of an output to input data by using an n-th order equation (n is an integer equal to or more than one);

an error reducing circuit configured to generate an error correction value by using a multiplication factor determined based on said input data; and

an addition section configured to add said approximation value and said error correction value and outputs an addition result.

2. The data converting circuit according to claim 1, further comprising:

a look up table (LUT) configured to store data of a plurality of control points and said multiplication factor to a specific region predetermined to said input data,

wherein said approximation calculation circuit refers to said LUT based on said input data to read out the data of said plurality of control points, and calculates said approximation value to said input data by carrying out an approximation calculation using said n-th order equation and the data of said plurality of control points, and

said error reducing circuit calculates a basic correction value from an error approximation equation based on said input data and determines said error correction value from said multiplication factor outputted from said LUT and said basic correction value.

3. The data converting circuit according to claim 2, wherein said error reducing circuit holds said error approximation equation which is determined based on predetermined lower bits of said input data.

4. The data converting circuit according to claim 2, wherein a plurality of regions are set and one of said plurality of regions is selected as said specific region based on said input data, and

said n-th order equation and said error approximation equation are different for every region.

5. The data converting circuit according to claim 2, wherein said n-th order equation is a secondary equation,

said plurality of control points are three of a start point, a middle point, and an end point, and

said error approximation equation is a function which is convex in an upper direction between said start point and said middle point and convex in a lower direction between said middle point and said end point.

6. The data converting circuit according to claim 2, wherein said n-th order equation is a secondary equation,

said plurality of control points are three of a start point, a middle point, and an end point, and

said error approximation equation is a function which is convex in a lower direction between said start point and said middle point and convex in an upper direction between said middle point and said end point.

7. The data converting circuit according to claim 2, wherein said n-th order equation is a primary equation,

said plurality of control points are two of a start point, and an end point, and

said error approximation equation is a function which is convex in an upper direction between said start point and said end point.

8. The data converting circuit according to claim 2, wherein said n-th order equation is a primary equation,

said plurality of control points are two of a start point, and an end point, and

said error approximation equation is a function which is convex in a lower direction between said start point and said end point.

9. A data converting circuit comprising:

an approximation calculation circuit configured to calculate an approximation value of an output to input data by using an n-th order equation (n is an integer equal to or more than one) in response to input of said input data;

an error reducing circuit configured to generate an error correction value from a preset error approximation equation based on said input data in response to input of said input data; and

an addition section configured to add said approximation value and said error correction value and outputs an addition result.

10. The data converting circuit according to claim 9, further comprising:

a look up table (LUT) configured to store data of a plurality of control points and said multiplication factor to a specific region predetermined to said input data,

wherein said approximation calculation circuit refers to said LUT based on said input data to read out the data of said plurality of control points, and calculates said approximation value to said input data by carrying out an approximation calculation using said n-th order equation and the data of said plurality of control points, and

said error reducing circuit calculates a basic correction value from said error approximation equation for said specific region based on said input data and determines said error correction value from said multiplication factor outputted from said LUT and said basic correction value.

11. The data converting circuit according to claim 10, wherein said error reducing circuit holds said error approximation equation which is determined based on predetermined lower bits of said input data.

12. The data converting circuit according to claim 10, wherein a plurality of regions are set,

one of said plurality of regions is selected as said specific region based on said input data, and

said n-th order equation and said error approximation equation are different for every region.

13. A data converting circuit which converts an input data showing gradation data of an input digital video data for each of pixels into an output data to output to a display panel, comprising:

an approximation calculation circuit configured to calculate an approximation value to input data by using an n-th order equation (n is an integer equal to or more than one) which approximates an input/output characteristic of said display panel;

an error reducing circuit configured to generate an error correction value to said input data; and

an adding section configured to add said approximation value from said approximation calculation circuit and said error correction value from said error reducing circuit and to output an addition result.

14. The data converting circuit according to claim 13, further comprising:

a look up table (LUT) configured to store data of a plurality of control points and said multiplication factor for a specific region predetermined to said input data,

wherein said approximation calculation circuit refers to said LUT based on said input gradation data to read out the data of said plurality of control points, and calculates said approximation value to said input gradation data by carrying out an approximation calculation using said n-th order equation and the data of said plurality of control points, and

said error reducing circuit calculates a basic correction value from an error approximation equation for said specific region based on said input gradation data and determines said error correction value from said multiplication factor outputted from said LUT and said basis correction value.

15. The data converting circuit according to claim 14, wherein said n-th order equation is a secondary equation,

said plurality of control points are three of a start point, a middle point, and an end point, and

said error approximation equation is a function which is convex in an upper direction between said start point and said middle point and convex in a lower direction between said middle point and said end point.

16. The data converting circuit according to claim 14, wherein said n-th order equation is a secondary equation,

said plurality of control points are three of a start point, a middle point, and an end point, and

said error approximation equation is a function which is convex in a lower direction between said start point and said middle point and convex in an upper direction between said middle point and said end point.

17. The data converting circuit according to claim 14, wherein said n-th order equation is a primary equation,

said plurality of control points are two of a start point, and an end point, and

said error approximation equation is a function which is convex in an upper direction between said start point and said end point.

18. The data converting circuit according to claim 14, wherein said n-th order equation is a primary equation,

said plurality of control points are two of a start point, and an end point, and

said error approximation equation is a function which is convex in a lower direction between said start point and said end point.

19. A display apparatus comprising:

a display panel;

a holding section configured to hold a gradation data of each of pixels of said digital video data for one line of said display panel; and

a data converting circuit,

wherein said data converting circuit comprises;

an approximation calculation circuit configured to calculate an approximation value of an output to input data by using-an n-th order equation (n is an integer equal to or more than one);

an error reducing circuit configured to generate an error correction value by using a multiplication factor determined based on said input data; and

an addition section configured to add said approximation value and said error correction value and outputs an addition result,

said n-th order equation expresses γ

correction,

said data converting circuit outputs said output data by carrying out said γ

correction to said input data, and

said display panel is driven based on said output data.

20. The display apparatus according to claim 19, wherein said data converting circuit further comprises:

a look up table (LUT) configured to store data of a plurality of control points and said multiplication factor to a specific region predetermined to said input data,

wherein said approximation calculation circuit refers to said LUT based on said input data to read out the data of said plurality of control points, and calculates said approximation value to said input data by carrying out an approximation calculation using said n-th order equation and the data of said plurality of control points, and

said error reducing circuit calculates a basic correction value from an error approximation equation based on said input data and determines said error correction value from said multiplication factor outputted from said LUT and said basic correction value.