Resolution conversion upon hierarchical coding and decoding

• US 8,369,636 B2
• Filed: 03/30/2011
• Issued: 02/05/2013
• Est. Priority Date: 10/24/2002
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Owada, Mitsuru
• Primary Examiner(s): Chu, Randolph I
• Application Number:
  US13/076,045
• Publication Number:
  US 20110176738A1
• Time in Patent Office: 678 Days
• Field of Search: None
• US Class Current: 382/240
• CPC Class Codes: G06T 9/00 Image coding bandwidth or redundancy reduction for static pictures H04N1/41; coding or decoding of static colour picture signals H04N1/64; methods or arrangements for coding, decoding, compressing or decompressing digital video signals H04N19/00
• CPC Class Codes: H04N 19/132 Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
• CPC Class Codes: H04N 19/134 characterised by the element, parameter or criterion affecting or controlling the adaptive coding
• CPC Class Codes: H04N 19/187 the unit being a scalable video layer
• CPC Class Codes: H04N 19/44 Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• CPC Class Codes: H04N 19/59 involving spatial sub-sampling or interpolation, e.g. alteration of picture size or resolution
• CPC Class Codes: H04N 19/635 characterised by filter definition or implementation details

Abstract

In a decoding method of decoding encoded image data which has been hierarchically encoded in advance, a size of an image to be outputted is determined, and then the encoded image data is decoded up to a layer of hierarchy which is at least one layer more than a minimum number of layer/layers of hierarchy necessary to acquire an image of the determined size.

Claims

1. A decoding method of decoding encoded image data which has been hierarchically encoded by subband coding in advance, comprising:

determining a layer of hierarchy up to which the encoded image data is to be decoded;

decoding the encoded image data up to the determined layer;

judging whether or not the determined layer corresponds to a highest layer of hierarchy of the encoded image data; and

restraining, when the determined layer does not correspond to the highest layer, a frequency component, which corresponds to alias occurred by the subband coding, of the decoded image data after being decoded up to the determined layer.

3. The decoding method according to claim 1, wherein an encoding method uses an orthogonal mirror filter.

5. The decoding method according to claim 1, wherein an encoding method is a discrete wavelet transform method.

2. A decoding method of decoding encoded image data which has been hierarchically encoded by subband coding in advance, comprising:

inputting encoded image data from external;

determining a layer of hierarchy up to which the encoded image data is to be decoded;

decoding the encoded image data up to the determined layer;

judging whether or not all layers of hierarchy of the encoded image data have been decoded; and

restraining, when all the layers of hierarchy have not been decoded, a frequency component, which corresponds to alias occurred by the subband coding, of the decoded image data after being decoded up to the determined layer.

4. The decoding method according to claim 2, wherein an encoding method uses an orthogonal mirror filter.

6. The decoding method according to claim 2, wherein an encoding method is a discrete wavelet transform method.

7. A decoding apparatus for decoding encoded image data which has been hierarchically encoded by subband coding in advance, comprising:

a determination unit that determines a layer of hierarchy up to which the encoded image data is to be decoded;

a decoder which decodes the encoded image data up to the determined layer;

a judging unit that judges whether or not the determined layer corresponds to a highest layer of hierarchy of the encoded image data; and

a restraining unit that restrains, when the determined hierarchy does not correspond to the highest layer, a frequency component, which corresponds to alias occurred by the subband coding, of the decoded image data after being decoded up to the determined layer.

9. The decoding apparatus according to claim 7, wherein an encoding method uses an orthogonal mirror filter.

11. The decoding apparatus according to claim 7, wherein an encoding method is a discrete wavelet transform method.

8. A decoding apparatus for decoding encoded image data which has been hierarchically encoded by subband coding in advance, comprising:

an input unit that inputs encoded image data from external;

a determination unit that determines a layer of hierarchy up to which the encoded image data is to be decoded;

a decoder that decodes the encoded image data up to the determined layer;

a judging unit that judges whether or not all layers of hierarchy of the encoded image data have been decoded; and

a restraining unit that restrains, when all the layers of hierarchy have not been decoded, a frequency component, which corresponds to alias occurred by the subband coding, of the decoded image data after being decoded up to the determined layer.

10. The decoding apparatus according to claim 8, wherein an encoding method uses an orthogonal mirror filter.

12. The decoding apparatus according to claim 8, wherein an encoding method is a discrete wavelet transform method.

13. A decoding method of decoding encoded image data which has been hierarchically encoded by subband coding in advance, comprising:

decoding all of the encoded image data;

judging whether or not the encoded image data was obtained as a result of encoding all layers of hierarchy; and

restraining, when all the layers of hierarchy have not been encoded, a frequency component, which corresponds to alias occurred by the subband coding, of the decoded image data after all of the encoded image data are decoded.

14. The decoding method according to claim 13, wherein an encoding method uses an orthogonal mirror filter.

15. The decoding method according to claim 13, wherein an encoding method is a discrete wavelet transform method.

16. A decoding apparatus for decoding encoded image data which has been hierarchically encoded by subband coding in advance, comprising:

a decoder that decodes all of the encoded image data;

a judging unit which judges whether or not the encoded image data was obtained as a result of encoding all layers of hierarchy; and

a restraining unit that restrains, when all the layers of hierarchy have not been encoded, a frequency component, which corresponds to alias occurred by the subband coding, of the decoded image data after all of the encoded image data are decoded.

17. The decoding apparatus according to claim 16, wherein an encoding method uses an orthogonal mirror filter.

18. The decoding apparatus according to claim 16, wherein an encoding method is a discrete wavelet transform method.