RESOLUTION CONVERSION UPON HIERARCHICAL CODING AND DECODING

• US 20090245671A1
• Filed: 06/09/2009
• Published: 10/01/2009
• 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
• Granted Patent: US 7,933,460 B2
• Time in Patent Office: Days
• 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

1-23. -23. (canceled)

24. An encoding method of hierarchically encoding an image, comprising:

restraining a frequency component which causes alias of an image signal of the image at the time of separating the image signal into layers of hierarchy; and

separating the restrained image signal into layers of hierarchy.

25. The encoding method according to claim 24, wherein said restraining includes:

restraining a high frequency component of the input image signal; and

restraining a low frequency component of the input image signal.

26. The encoding method according to claim 25, wherein a low pass filter is used in said restraining of the high frequency component, and an output from said low pass filter is subtracted from the input image signal in said restraining of the low frequency component.

27. The encoding method according to claim 25, wherein a high pass filter is used in said restraining of the low frequency component, and an output from the high pass filter is subtracted from the input image signal in said restraining of the high frequency component.

28. The encoding method according to claim 25, wherein a low pass filter is used in said restraining of the high frequency component, and a high pass filter is used in said restraining of the low frequency component.

29. The encoding method according to claim 25, repeating said restraining and said separating for an image signal obtained by separating the image signal whose high frequency component is restrained.

30. The encoding method according to claim 26, wherein a filter is used in said separating, and a passband of the low pass filter is narrower than a passband of the filter used in said separating.

31. The encoding method according to claim 28, wherein a filter is used in said separating, and a passband of the low pass filter is narrower than a passband of the filter used in said separating.

32. The encoding method according to claim 27, wherein a filter is used in said separating, and a passband of the high pass filter is narrower than a passband of the filter used in said separating.

33. The encoding method according to claim 28, wherein a filter is used in said separating, and a passband of the high pass filter is narrower than a passband of the filter used in said separating.

34. The encoding method according to claim 25, wherein in said restraining of a high frequency component and a low frequency component, at least either one of a horizontal component and a vertical component of the image signal is restrained.

37. The encoding method according to claim 24, wherein an encoding method conforms to JPEG2000.

52. A storage medium, readable by an information processing apparatus, storing a program including program codes capable of realizing the encoding method according to claim 24, the program being executable by the information processing apparatus.

35-36. -36. (canceled)

38. An encoding apparatus for hierarchically encoding an image, comprising:

a frequency restraining unit that restrains a frequency component which causes alias of an image signal of the image at the time of separating the image signal into layers of hierarchy; and

a separating unit that separates the image signal restrained by said frequency restraining unit into layers of hierarchy.

39. The encoding apparatus according to claim 38, wherein said frequency restraining unit comprises:

a first restraining unit which restrains a high frequency component of the input image signal; and

a second restraining unit that restrains a low frequency component of the input image signal.

40. The encoding apparatus according to claim 39, wherein said first restraining unit is a low pass filter, and said second restraining unit is a subtractor which subtracts the image signal restrained by said first restraining unit from the input image signal.

41. The encoding apparatus according to claim 39, wherein said second restraining unit is a high pass filter, and said first restraining unit is a subtractor which subtracts the image signal restrained by said second restraining unit from the input image signal.

42. The encoding apparatus according to claim 39, wherein said first restraining unit is a low pass filter, and said second restraining unit is a high pass filter.

43. The encoding apparatus according to claim 39, wherein said frequency restraining unit and said separating unit recursively perform processes on an image signal obtained by separating by said separating unit the image signal restrained by said first restraining unit.

44. The encoding apparatus according to claim 40, wherein said separating unit includes a filter, and a passband of the low pass filter is narrower than the passband of the filter of the separating unit.

45. The encoding apparatus according to claim 42, wherein said separating unit includes a filter, and a passband of the low pass filter is narrower than the passband of the filter of the separating unit.

46. The encoding apparatus according to claim 41, wherein said separating unit includes a filter, and a passband of the high pass filter is narrower than the passband of the filter of the separating unit.

47. The encoding apparatus according to claim 41, wherein said separating unit includes a filter, and a passband of the high pass filter is narrower than the passband of the filter of the separating unit.

48. The encoding method according to claim 39, wherein said first and second restraining unit restrain at least either one of a horizontal component and a vertical component of the image.

51. The encoding apparatus according to claim 38, wherein an encoding method conforms to JPEG2000.

49-50. -50. (canceled)

53-85. -85. (canceled)