Title:
【発明の名称】画像の圧縮及び伸張
Document Type and Number:
Japanese Patent JP2002531973
Kind Code:
A
Abstract:
This invention relates to systems and methods for increasing image compression. The systems and methods are improvements applicable to encoder/decoders which compress images by, inter alia, transforming non-overlapping independent blocks of pixels into a frequency domain and then quantizing the resulting frequency domain coefficients. The invention achieves increased compression by predicting low frequency coefficients of a block from, preferably, the average intensities, or zero frequency coefficients, of the block and its adjacent blocks. In an encoder, the low frequency coefficients are predicted, are then subtracted from the actual transform coefficients, and the difference coefficients are transmitted to a decoder. In the decoder, the low frequency coefficients are again predicted, are added to the received difference coefficients, and the resulting actual transform coefficients are used to reconstruct an image.
Inventors:
Racket, Albert E
Application Number:
JP2000585827A
Publication Date:
September 24, 2002
Filing Date:
November 18, 1999
Export Citation:
Assignee:
Konin Krekka Philips Electronics NV
International Classes:
H04N7/32; G06T9/00; H03M7/30; H03M7/36; H03M7/40; H04N1/41; H04N7/50; H04N19/593; (IPC1-7): H04N1/41; H03M7/30; H03M7/36; H03M7/40; H04N7/32
Attorney, Agent or Firm:
Tadahiko Ito