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Title:
画素値を抽出する方法および装置
Document Type and Number:
Japanese Patent JP4515534
Kind Code:
B2
Abstract:
The luminance and chrominance values of pixels encoded according to MPEG or JPEG encoding are extracted using a forward discrete cosine transform (DCT). The forward DCT used in MPEG encoding is analyzed to derive a set of equations which directly relate a pixel value in an encoded image to one or more of the DCT coefficients obtained via the forward DCT transform in the usual image encoding process. These predetermined equations are used to allow for extremely fast and computationally efficient extraction of pixel values directly from the DCT coefficients of an encoded pixel block, without having to undergo an inverse DCT transform. Original images from MPEG and JPEG encoded versions may be extracted in a fast and efficient manner.

Inventors:
Jean Min Jean
Lee Kung Shu
Application Number:
JP2009239212A
Publication Date:
August 04, 2010
Filing Date:
October 16, 2009
Export Citation:
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Assignee:
BRITISH TELECOMMUNICATIONS PUBLIC LIMITED COMPANY
International Classes:
H04N19/625; G06F17/14; G06T9/00; H03M7/30; H04N1/41
Attorney, Agent or Firm:
Takehiko Suzue
Kurata Masatoshi
Satoshi Kono
Makoto Nakamura
Yoshihiro Fukuhara
Takashi Mine
Toshio Shirane
Sadao Muramatsu
Nobuhisa Nogawa
Kocho Chojiro
Naoki Kono
Katsu Sunagawa
Katsumura Hiro
Shoji Kawai
Tatsushi Sato
Takashi Okada
Mihoko Horiuchi
Takenori Masanori
Takuzo Ichihara
Yamashita Gen



 
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