Browse Prior Art Database

Video Data Compaction

IP.com Disclosure Number: IPCOM000076563D
Original Publication Date: 1972-Mar-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 3 page(s) / 57K

Publishing Venue

IBM

Related People

Ii, LB: AUTHOR

Abstract

The video data compaction (VDC) process is an encode/decode algorithm, which reduces the digital sampling of a high quality line-scan picture image to a 1-bit code. It's advantages are (a) reduced storage for a line-scan picture image in which the total storage in bits is equal to the number of samples per line multiplied by the number of lines, (b) the digital remoting bandwidth is the sample bandwidth for 1 bit, and (c) a simple encode/decode method is employed for reproduction of the original picture image.

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Video Data Compaction

The video data compaction (VDC) process is an encode/decode algorithm, which reduces the digital sampling of a high quality line-scan picture image to a 1-bit code. It's advantages are (a) reduced storage for a line-scan picture image in which the total storage in bits is equal to the number of samples per line multiplied by the number of lines, (b) the digital remoting bandwidth is the sample bandwidth for 1 bit, and (c) a simple encode/decode method is employed for reproduction of the original picture image.

The sample resolution depends on the image to be reproduced. The coding for the VCD is a visual cell in which certain conditions are established:
1) Each cell consists of two samples.
2) The samples within a cell cannot go from a (+) tone to

a (-) tone without going through a zero tonal change.
3) A maximum tonal change in a cell having a SIGN change of

(+) or (-) is one tone.

A picture to be encoded consists of a specified number of cells per line and a specified number of lines. A cell consists of two samples in which each sample is coded as either (1) or (0). The coding for the VDC considers the cyclic storage or transfer of each cell as either: (a) DATA, or (b) SIGN and DATA. The decoding of each cell generates the sample tones as delta variations to the previous cell tones. A base TONE REGISTER (TR) and SIGN REGISTER (SR) in the DECODER provide, respectively, a running accumulation for both the full TONAL range of the picture image as well as the SIGN of the latest tone change. The cell coding for two samples is either (00), (01), (10), or (11), for which the cell code provides the following meaning to the DECODER and ENCODER:

(Image Omitted)

The DECODER functions to: (a) store the sample input in a BUFFER REGISTER, (b) count the cells decoded, (c) count the lines decoded, (d) provide cell sequence clocking, (e) decode and set the SR, (f) decode and increment/decrement or inhibit the TR, and (g) provide a digital/analog output in the form of a video stream for delta-tone changes of the line-scan image. A flow chart for the DECODER process is illustrated in Fig. 1.

The START of the decode process presets the LINE COUNTER (LC) and CELL COUNTER (CC) for the number of picture elements. The TR is preset to an initial count, and the starting sign for the SR is preset to (01). Decoding of succeeding cells provides incrementing/decrementing or inhibiting of the TR with the SR either remaining the same, or being updated with a new sign code. The SR is forced with a sign update for either codes (01) or (10). A (00) cell code inhibits changing the TR and SR. A (11) cell code is only data and uses the existing SR code.

The ENCODER functions to format the line-scan video into 1-bit samples for either remoting or storage. Each cell is made up of an odd/even sample, in which the coding of the present cell is related to the coding of the previous cell.

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The delta-tone change for each processed cell in...