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LOSSY COMPRESSION AND PROGRESSIVE DECOMPRESSION OF MIXED RASTER CONTENT LAYERS USING WAVELETS BASED COMPRESSION

IP.com Disclosure Number: IPCOM000027875D
Original Publication Date: 2001-Jun-30
Included in the Prior Art Database: 2004-Apr-09
Document File: 2 page(s) / 92K

Publishing Venue

Xerox Disclosure Journal

Abstract

Disclosed is a coding algorithm that uses wavelet-based compression to provide both lossy and lossless compression in the same codestream. The advantage of this approach is that compression ratio, and subsequently Mixed Raster Content (MRC) image file size can be precisely controlled, and that MRC can be easily combined with the JPEG 2000 standard.

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XEROX DISCLOSURE JOURNAL

LOSSY COMPRESSION AND PROGRESSIVE DECOMPRESSION OF MIXED RASTER CONTENT LAYERS USING WAVELETS BASED COMPRESSION
Vladimir Misic
Robert R. Buckley

Proposed Classification
U. S. C1. 382/233 Int. C1. G06k 009/42

Disclosed is a coding algorithm that uses wavelet-based compression to provide both lossy and lossless compression in the same codestream. The advantage of this approach is that compression ratio, and subsequently Mixed Raster Content (MRC) image file size can be precisely controlled, and that MRC can be easily combined with the JPEG 2000 standard.

The algorithm starts with the same binary mask as traditional MRC encoders, but then converts it to a multi-level signal that is compressed using JPEG 2000. The compressed mask is decompressed and processed at the encoder and decoder to create a graylevel mask that is used at the encoder to segment the MRC background and foreground layers and at the decoder to recombine them to produce the final image.

In the existing MRC model, mask compression is lossless resulting in the inability to precisely control the size of the compressed file. The approach disclosed here enables controlling that size to one one hundredth (l/lOO) bit per pixel (bpp) using lossy ("gray") compression of binary (black and white) mask layer.

Lossless compression schemes need all of the compressed data to be read (downloaded) prior to reconstruction of the complete image plane. However, some applications do not require high resolution for the best print quality image. Using JPEG 2000 as a compressor, that problem is inherently solved, s...