Resolution conversion system and method

• US 6,587,602 B2
• Filed: 03/19/2002
• Issued: 07/01/2003
• Est. Priority Date: 04/14/1995
• Status: Expired due to Term

• Current Assignee: Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Hitachi, Ltd., Hitachi Device Engineering Co., Ltd. (Japan Display Incorporated)
• Inventors: Koizumi, Hiroyuki, Watanabe, Youichi, Wakisawa, Shinji, Kasai, Naruhiko, Sato, Hiroko
• Primary Examiner(s): Mariam, Daniel G.
• Application Number:
  US10/099,951
• Publication Number:
  US 20020097921A1
• Time in Patent Office: 469 Days
• Field of Search: 382/237, 382/293, 382/298, 382/299, 382/300, 345/660, 345/667, 345/670, 345/671, 348/561, 348/581, 348/582, 348/704, 358/445, 358/451, 358/525, 708/208
• US Class Current: 382/298
• CPC Class Codes: G06T 3/4007 based on interpolation, e.g. bilinear interpolation image demosaicing G06T3/4015; edge-driven or edge-based scaling G06T3/403
• CPC Class Codes: G09G 2340/0407 Resolution change, inclusive of the use of different resolutions for different screen areas
• CPC Class Codes: G09G 2340/0414 Vertical resolution change
• CPC Class Codes: G09G 2340/0421 Horizontal resolution change
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 5/00 Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators image data processing or generation, in general G06T
• CPC Class Codes: G09G 5/26 for modifying the character dimensions, e.g. double width, double height
• CPC Class Codes: G09G 5/391 Resolution modifying circuits, e.g. variable screen formats
• CPC Class Codes: H04N 5/14 Picture signal circuitry for video frequency region cameras or camera modules comprising electronic image sensors, or control thereof H04N23/00
• CPC Class Codes: H04N 7/01 Conversion of standards , e.g. involving analogue television standards or digital television standards processed at pixel level

Abstract

There is disclosed a resolution conversion apparatus for converting an original digital image into a digital image having a different number of pixels in accordance with an instructed conversion magnification factor. In the apparatus, a determination circuit determines the number of pixels to be interpolated in each block of the original image and positions where they are interpolated in accordance with the conversion magnification factor. The block includes a predetermined number of pixels of the original image. A converted image generation circuit generates pixel data for the interpolation pixels at the positions where they are interpolated in accordance with a predetermined interpolation equation whose coefficients are determined with the positions and data values of the pixels in the block, and combines the pixel data for the digital original image and the generated pixel data to output a converted digital image. The interpolation equation includes spline functions and Bezier functions.

Claims

1. A display device that interpolates inputted original image data and displays converted image data thus interpolated, comprising:

a display unit that displays said converted image data;

an image processing unit that generates an interpolation pixel based on said original image data, inserts said interpolation pixel into said original image data, and generates said converted image data; and

a display control unit that outputs said converted image data to said display unit, wherein,

said image processing unit determines a gray-scale level of at least one interpolation pixel to be inserted between two pixels of said original image data, said gray-scale level having a value larger than a value on a straight line connecting values of gray-scale level of said two pixels of said original image data.

2. A display device according to claim 1, wherein,

when a difference between the values of gray-scale level of said two pixels of said original image data is larger than a threshold value, said gray-scale level of said at least one interpolation pixel has a value larger than said value on the straight line, and

when a difference between the values of gray-scale level of said two pixels of said original image data is not larger than said threshold value, said gray-scale level of said at least one interpolation pixel has a value on the straight line.

3. A display device according to claim 1, wherein,

said gray-scale level of said at least one interpolation pixel has a value on a spline curve or a cubic Bezier curve that connects the values of gray-scale level of said two pixels of said original image data.

4. A display device according to claim 1, wherein,

said converted image data comprises image data that has been converted by enlarging said original image data.

5. A display device according to claim 4, wherein,

said image processing unit determines a number of said interpolation pixel to be generated and at least one position where said interpolation pixel is inserted based on an enlargement factor for enlargement conversion.

6. A display device according to claim 5, wherein,

said image processing unit determines the number of said interpolation pixel to be generated based on a table defining a relationship between said enlargement factor and the number of said interpolation pixel to be generated.

7. A display device according to claim 1, further comprising a memory that stores said converted image data, wherein,

said display control unit reads out said converted image data from said memory and outputs said converted image data thus read out to said display unit.

8. A display device according to claim 1, wherein, said image processing unit includes:

a horizontal direction image processing unit that inserts said interpolation pixel in a line direction of said original image data by a line unit, so as to generate said converted image data by line unit, and

a vertical direction image processing unit that inserts said interpolation pixel by a line unit in a vertical direction of said converted image data by a line unit, so as to generate said converted image data.

9. A display device according to claim 1, wherein,

a resolution of said display unit is larger than a resolution of said original image data.

10. A display device that interpolates inputted original image data and displays converted image data thus interpolated, comprising:

a display unit that displays said converted image data;

an image processing unit that generates an interpolation pixel based on said original image data, inserts said interpolation pixel into said original image data, and generates said converted image data; and

,

a display control unit that outputs said converted image data to said display unit, wherein,

said image processing unit determines a luminance of at least one interpolation pixel to be inserted between two pixels of said original image data, said luminance having a value larger than a value on a straight line connecting values of luminance of said two pixels of said original image data.

11. A display device that interpolates inputted original image data and displays converted image data thus interpolated, comprising:

a display unit that displays said converted image data;

an image processing unit that generates an interpolation pixel based on said original image data, inserts said interpolation pixel into said original image data, and generates said converted image data; and

,

a display control unit that outputs said converted image data to said display unit, wherein,

said image processing unit determines a gray-scale level of at least one interpolation pixel to be inserted between two pixels of said original image data, said gray-scale level having a value smaller than a value on a straight line connecting values of gray-scale level of said two pixels of said original image data.

12. A display device according to claim 11, wherein,

when a difference between the values of gray-scale level of said two pixels of said original image data is larger than a threshold value, said gray-scale level of said at least one interpolation pixel has a value smaller than said values on the straight line, and

when a difference between the values of gray-scale level of said two pixels of said original image data is not larger than said threshold value, said gray-scale level of said at least one interpolation pixel has a value on the straight line.

13. A display device according to claim 11, wherein,

said gray-scale level of said at least one interpolation pixel has a value on a spline curve or a cubic Bezier curve that connects that values of gray-scale level of said two pixels of said original image data.

14. A display device according to claim 11, wherein,

said converted image data comprises image data that has been converted by enlarging said original image data.

15. A display device according to claim 14, wherein,

said image processing unit determines a number of said interpolation pixel to be generated and at least one position where said interpolation pixel is inserted based on an enlargement factor for enlargement conversion.

16. A display device according to claim 15, wherein,

said image processing unit determines the number of said interpolation pixel to be generated based on a table defining a relationship between said enlargement factor and said interpolation pixel to be generated.

17. A display device according to claim 11, further comprising a memory that stores said converted image data, wherein,

said display control unit reads out said converted image data from said memory and outputs said converted image data thus read out to said display unit.

18. A display device according to claim 11, wherein,

said image processing unit includes:

a horizontal direction image processing unit that inserts said interpolation pixel in a line direction of said original image data by a line unit, so as to generate said converted image data by line unit, and

a vertical direction image processing unit that inserts said interpolation pixel by a line unit in a vertical direction of said converted image data by a line unit, so as to generate said converted image.

19. A display device according to claim 11, wherein,

a resolution of said display unit is larger than the resolution of said original image data.

20. A display device that interpolates inputted original image data and displays converted image data thus interpolated, comprising:

a display unit that displays said converted image data;

an image processing unit that generates an interpolation pixel based on said original image data, inserts said interpolation pixel into said original image data, and generates said converted image data; and

a display control unit that outputs said converted image data to said display unit, wherein,

said image processing unit determines a luminance of at least one interpolation pixel to be inserted between two pixels of said original image data, said luminance having a value smaller than a value on a straight line connecting values of luminance of said two pixels of said original image data.

21. A display device that interpolates original image data and displays converted image data thus interpolated, the display device comprising:

a display unit that displays said converted image data;

an image processing unit that generates an interpolation pixel based on said original image data, inserts said interpolation pixel into said original image data, and generates said converted image data; and

a display control unit that outputs said converted image data to said display unit, wherein,

said image processing unit determines, based on two pixels of said original image data, reference values of said interpolation pixel to be inserted between said two pixels of said original image data, and

a value of said interpolation pixel is selected so as to be inserted between said two pixels of said original image data, out of said reference values, in accordance with a function, which is set in such a manner that at least one gray-scale value of said interpolation pixel has a value larger than values on a straight line connecting said two pixels of said original image data, in a graph having pixel locations on a horizontal axis and gray-scale values on a vertical axis.

22. The display device according to claim 21, wherein said image processing unit comprises:

a subtractor for calculating a difference between said two pixels of said original image data;

a shifter for multiplying said difference by a predetermined rate;

an adder for adding a value obtained as a result of said multiplying, to one of said two pixels of said original image data, so as to decide reference values of said interpolation pixel; and

a selector for selecting a value of said interpolation pixel, so as to be inserted between said two pixels of said original image data, out of said reference values, in accordance with a function, which is set in such a manner that at least one gray-scale value of said interpolation pixel has a value larger than values on a straight line connecting to said two pixels of said original image data, on a graph having pixel locations in a horizontal axis and gray-scale values on a vertical axis.