Method for resizing an image using the inverse discrete cosine transform

• US 20040091157A1
• Filed: 10/24/2003
• Published: 05/13/2004
• Est. Priority Date: 10/25/2002
• Status: Active Grant

• Current Assignee: Humax Company Limited
• Original Assignee: Humax Company Limited
• Inventors: Kang, Jung Yong
• Granted Patent: US 7,421,152 B2
• Time in Patent Office: Days
• US Class Current: 382/233
• CPC Class Codes: H04N 19/117 Filters, e.g. for pre-processing or post-processing sub-band filter banks H04N19/635
• CPC Class Codes: H04N 19/16 for a given display mode, e.g. for interlaced or progressive display mode
• CPC Class Codes: H04N 19/48 using compressed domain processing techniques other than decoding, e.g. modification of transform coefficients, variable length coding [VLC] data or run-length data motion estimation in a transform domain H04N19/547; processing of decoded motion vectors H04N19/513
• CPC Class Codes: H04N 19/86 involving reduction of coding artifacts, e.g. of blockiness
• CPC Class Codes: H04N 5/2628 Alteration of picture size, shape, position or orientation, e.g. zooming, rotation, rolling, perspective, translation
• CPC Class Codes: H04N 7/012 Conversion between an interlaced and a progressive signal for graphics images G09G2310/0229

Abstract

A method and apparatus are provided for resizing an image using an inverse discrete cosine transform (IDCT). A macro block of an original source image is enlarged to an arbitrary size using the inverse discrete cosine transform after the encoding type of the macro block is converted so that the macro block and the original source image have the same encoding type. Consequently, the original source image is always enlarged naturally in a digital video apparatus such as a digital broadcast receiver or an HD-TV.

Claims

1. A method for resizing an image using an inverse discrete cosine transform (IDCT), the method comprising the steps of:

(a) checking an encoding type of an original source image and an encoding type of a discrete cosine transformed macro block;

(b) converting the encoding type of said macro block into a frame type or a field type if the checked two encoding types are different; and

(c) enlarging said converted macro block using the inverse discrete cosine transform.

2. The method as set forth in claim 1, wherein in said step (a), the encoding type of said original source image is identified as either a field type or a frame type by using at least progressive_sequence information or picture_structure information.

3. The method as set forth in claim 1, wherein in said step (a), the encoding type of said macro block is identified as either a field type or a frame type by using DCT_type information contained in a header of said macro block.

4. The method as set forth in claim 1, wherein said step (b) converts the encoding type of said macro block so that the encoding type of said macro block coincides with the encoding type of said original source image, if the checked two encoding types are different.

5. The method as set forth in claim 1, further comprising the step of:

(d) enlarging said macro block using the inverse discrete cosine transform without converting the encoding type of said macro block if the checked two encoding types are identical.

6. The method as set forth in claim 1, wherein said original source image is received through a digital broadcast.

7. The method as set forth in claim 1, wherein said original source image is reproduced from an optical disk.

8. The method as set forth in claim 1, wherein if the encoding type of said original source image is a frame type and the encoding type of said macro block is a field type, then said step (b) converts the encoding type of said macro block from the field type into a frame type.

9. The method as set forth in claim 1, wherein if the encoding type of said original source image is a field type and the encoding type of said macro block is a frame type, then said step (b) converts the encoding type of said macro block from the frame type into a field type.

10. An apparatus for resizing an image using an inverse discrete cosine transform (IDCT), the apparatus comprising:

detecting means for detecting an encoding type of a macro block;

converting means for converting the encoding type of said macro block to either a field type or a frame type;

control means for detecting an encoding type of an original source image, and controlling said converting means depending upon the detected encoding type of said macro block and the detected encoding type of said original source image; and

enlarging means for enlarging said macro block received from said converting means using the inverse discrete cosine transform.

11. The apparatus as set forth in claim 10, wherein said detecting means identifies the encoding type of said macro block as either a field type or a frame type by examining DCT_type information contained in a header of said macro block.

12. The apparatus as set forth in claim 10, wherein said control means identifies the encoding type of said original source image as either a field type or a frame type by examining at least progressive_sequence information or picture_structure information.

13. The apparatus as set forth in claim 10, wherein said control means controls said converting means so that the encoding type of said macro block is converted into the encoding type of said original source image, if the encoding types of said macro block and said original source image are different.

14. The apparatus as set forth in claim 10, wherein said enlarging means enlarges said macro block using the inverse discrete cosine transform without converting the encoding type of said macro block if the detected two encoding types are identical.

15. The apparatus as set forth in claim 10, wherein said original source image is received through a digital broadcast.

16. The apparatus as set forth in claim 10, wherein said original source image is reproduced from an optical disk.

17. The apparatus as set forth in claim 10, wherein if the encoding type of said original source image is a frame type and the encoding type of said macro block is a field type, then said converting means converts the encoding type of said macro block from the field type into a frame type.

18. The apparatus as set forth in claim 10, wherein if the encoding type of said original source image is a field type and the encoding type of said macro block is a frame type, then said converting means converts the encoding type of said macro block from the frame type into a field type.

19. An apparatus for resizing an image using an inverse discrete cosine transform (IDCT), the apparatus comprising:

(a) means for checking an encoding type of an original source image and an encoding type of a discrete cosine transformed macro block;

(b) means for converting the encoding type of said macro block into a frame type or a field type if the checked two encoding types are different; and

(c) means for enlarging said converted macro block using the inverse discrete cosine transform.

20. The apparatus as set forth in claim 19, wherein said (b) means converts the encoding type of said macro block so that the encoding type of said macro block coincides with the encoding type of said original source image, if the checked two encoding types are different.