Image analysis – Image compression or coding – Lossless compression
Patent
1998-07-15
2000-09-12
Boudreau, Leo H.
Image analysis
Image compression or coding
Lossless compression
382239, 382251, 348405, 348419, 3582612, G06K 936
Patent
active
061189030
ABSTRACT:
A DCT based lossy compression method for compressing a digitized image composed of a matrix of image samples to provide a compressed image which satisfies a predefined bit budget. The digitized image is first sub-divided into blocks (e.g. of size 8.times.8 pixels). A discrete cosine transform (DCT) comprising a set of DCT coefficients is then derived for each block. A quantization table is selected from a set of quantization tables and, using the selected table, the coefficients of each DCT are quantized. A zero-value index, corresponding to the average number of zero value quantized DCT coefficients per DCT, is determined. A predicted zero-value index is calculated using said predefined bit budget and a quantization table selected from said set of tables using the determined index and the predicted index. Using that selected table, the unquantized coefficients of the DCTs are re-quantized and the requantized coefficients compressed using run-length encoding and Huffman encoding.
REFERENCES:
patent: 5025482 (1991-06-01), Murakami et al.
patent: 5086488 (1992-02-01), Kato et al.
patent: 5142380 (1992-08-01), Sakagami et al.
patent: 5333211 (1994-07-01), Kanda et al.
patent: 5333212 (1994-07-01), Ligtenberg
patent: 5473376 (1995-12-01), Auyeung
patent: 5629780 (1997-05-01), Watson
patent: 5654760 (1997-08-01), Ohtsuki
patent: 5710595 (1998-01-01), Hang et al.
patent: 5790195 (1998-08-01), Ohsawa
patent: 5835149 (1998-11-01), Astle
patent: 5926569 (1999-07-01), Nickerson
PCT International Search Report.
Finnish Official Action.
"The JPEG Still Picture Compression Standard" Communications of the ACM, Wallace, G.K., Apr. 1991, pp. 1-17.
CCITT Recommendation T.81, "Digital Compression and Coding of Continuous-Tone Still Images--Requirements and Guidelines", Annex K, pp. 143-182.
Boudreau Leo H.
Nokia Mobile Phones Ltd.
Sherali Ishrat
LandOfFree
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