Method for resizing an image using the inverse discrete cosine transform

• US 7,421,152 B2
• Filed: 10/24/2003
• Issued: 09/02/2008
• Est. Priority Date: 10/25/2002
• Status: Active Grant

• Current Assignee: Humax Company Limited
• Original Assignee: Humax Company Limited
• Inventors: Kang, Jung Yong
• Primary Examiner(s): Bella, Matthew C.
• Assistant Examiner(s): CHU, RANDOLPH I
• Application Number:
  US10/691,561
• Publication Number:
  US 20040091157A1
• Time in Patent Office: 1,775 Days
• Field of Search: 382/298, 382/250
• US Class Current: 382/298
• 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 discrete cosine transformed macro blocks;

(b) selectively converting the encoding type of said macro blocks so that the encoding type of said macro blocks coincides with the encoding type of said original source image, only if the checked two encoding types are different;

(c) selectively using the inverse discrete cosine transform to enlarge said converted macro blocks and macro blocks that have not been converted; and

(d) merging the enlarged macro blocks to thereby enlarge the original source image.

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 original source image is received through a digital broadcast.

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

6. 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.

7. 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.

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

detecting means for detecting an encoding type of macro blocks;

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

control means for detecting an encoding type of an original source image, and selectively controlling said converting means so that the encoding type of said macro blocks is converted into the encoding type of said original source image, only if the encoding types of said macro blocks and said original source image are different;

enlarging means for selectively using the inverse discrete cosine transform to enlarge said macro blocks received from said converting means and macro blocks that have not been converted; and

merging means for merging the enlarged macro blocks to thereby enlarge the original source image.

9. The apparatus as set forth in claim 8, 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.

10. The apparatus as set forth in claim 8, 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.

11. The apparatus as set forth in claim 8, wherein said original source image is received through a digital broadcast.

12. The apparatus as set forth in claim 8, wherein said original source image is reproduced from an optical disk.

13. The apparatus as set forth in claim 8, 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.

14. The apparatus as set forth in claim 8, 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.

15. 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 discrete cosine transformed macro blocks;

(b) means for selectively converting the encoding type of said macro blocks so that the encoding type of said macro blocks coincides with the encoding type of said original source image, only if the checked two encoding types are different; and

(c) means for selectively using the inverse discrete cosine transform to enlarge said converted macro blocks and macro blocks that have not been converted; and

(d) means for merging the enlarged macro blocks to thereby enlarge the original source image.