Image analysis – Image enhancement or restoration – Variable threshold – gain – or slice level
Patent
1997-11-06
1998-10-06
Johns, Andrew W.
Image analysis
Image enhancement or restoration
Variable threshold, gain, or slice level
382232, 382239, 382251, 358430, 358433, G06K 938, G06K 936, H04N 1417, H04N 1415
Patent
active
058189742
ABSTRACT:
An image coding apparatus wherein an image signal including a locally high signal can be coded efficiently with minimized distortion by adaptively performing quantization for each subblock. An input image signal is divided into a plurality of subband signals by a subband division section. The subband signals from the subband division section are each divided into a plurality of subblocks by a subblock division section. In a classification section, a subband signal is classified, for each of the subblocks from the subblock division section, in terms of a feature parameter of an image, for example, a dynamic range, and a class index is outputted. In a quantization section, a quantizer is changed over for each subblock in response to the class index from the classification section. Each subblock is coded with a necessary minimum number of bits. The bit number is multiplexed with a code. Accordingly, the code can be decoded by referring to the bit number.
REFERENCES:
patent: 4802232 (1989-01-01), Altes
patent: 4920426 (1990-04-01), Hatori et al.
patent: 5086488 (1992-02-01), Kato et al.
patent: 5301242 (1994-04-01), Gonzales et al.
patent: 5307177 (1994-04-01), Shibata etal.
patent: 5392362 (1995-02-01), Kimura et al.
patent: 5394473 (1995-02-01), Davidson
patent: 5414527 (1995-05-01), Koshi et al.
patent: 5442399 (1995-08-01), Asamura et al.
patent: 5444800 (1995-08-01), Kim
"Sub-Band Coding of Images", John W. Woods et al., IEEE Transactions on Acoustics, Speech, and Signal Processing, 34(5):1278-1288 (1986).
Kamizawa Koh
Kimura Shun-ichi
Koshi Yutaka
Davis Monica S.
Fuji 'Xerox Co., Ltd.
Johns Andrew W.
LandOfFree
Image coding apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Image coding apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image coding apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-87984