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Browse Prior Art Database

Conversion Between CCITT GIV Modified Modified READ (Mmr) and IBM MMR

IP.com Disclosure Number: IPCOM000037300D
Original Publication Date: 1989-Dec-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Inoue, K: AUTHOR [+2]

Abstract

A program is disclosed that performs conversion of image data between CCITT GIV Modified Modified READ (MMR) and IBM MMR. The primary means is insertion or deletion of the horizontal mode flags used in Modified READ (MR) two-dimensional encoding.

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Conversion Between CCITT GIV Modified Modified READ (Mmr) and IBM MMR

A program is disclosed that performs conversion of image data between CCITT GIV Modified Modified READ (MMR) and IBM MMR. The primary means is insertion or deletion of the horizontal mode flags used in Modified READ (MR) two-dimensional encoding.

In the IBM MMR compression algorithm the first line of an image is encoded by using the same one-dimensional code table as that used in the Modified Huffman (MH) algorithm, to which are attached a prefix code called one- dimensional End Of Line (EOL) and a suffix code called two-dimensional EOL. The following lines are encoded by using the two- dimensional encoding used in the MR algorithm, with a K value of infinity. A sequence of six one-dimensional EOL codes marks the end of the image.

In the CCITT GIV MMR compression algorithm the MR two-dimensional encoding with an infinite K value is used from the first line, assuming a virtual all- white reference line above the first line. A code called End Of Facsimile Block (EOFB) is placed at the end. It is noted here that, when the reference line is all white, all but at most the last three changing elements are encoded by using the horizontal mode of MR compression. This is because there is only one virtual changing element on the reference line at its right end. From the definition of MR horizontal mode encoding, it follows that the result is the same as data produced by the MH algorithm, except that a ho...