公开(公告)号：US3833900A

公开(公告)日：1974-09-03

申请号：US28189572

申请日：1972-08-18

Applicant: IBM

Inventor： BAHL L ,  BARNEA D ,  KOBAYASHI H

IPC: H03M7/30 ,  G06T9/00 ,  H03M7/32 ,  H04B14/06 ,  H04N1/417 ,  H04L3/00

CPC classification number: G06T9/005 ,  H04N1/4175

Abstract: A data compaction system wherein segmented binary data that has redundancy between segments is compacted by means of differential run-length encoding. For compaction of document digitized data, the segments represent lines on the document. Black image points on the document which are represented by a ''''1'''' are coded relative to the position of a 1 appearing in the line above the one being coded. The differential distance between binary 1 bit positions on successive lines are coded in accordance with a compaction code. Codewords having a small number of bits are used for small differentials.

Abstract translation: 数据压缩系统，其中在段之间具有冗余度的分段二进制数据通过差分游程编码来压缩。 为了压缩文档数字化数据，这些段表示文档上的行。 由“1”表示的文档上的黑色图像点相对于出现在正被编码的行上方的1的位置被编码。 根据压实码对连续行上的二进制1位位置之间的差分距离进行编码。 具有少量位的码流用于小差分。

公开(公告)号：US3769453A

公开(公告)日：1973-10-30

申请号：US3769453D

申请日：1972-08-17

Applicant: IBM

Inventor： BAHL L ,  BARNEA D ,  GROSSMAN D ,  KOBAYASHI H

IPC: H04B1/66 ,  H03M7/46 ,  H04L25/48 ,  H04N1/40 ,  H04N1/417 ,  H04N7/12

CPC classification number: H04N1/417 ,  H03M7/46

Abstract: A system for compacting digital data by means of prediction error coding. Prediction for each unknown bit is a function of previous detected levels in the data stream. A plurality of n-bit up-down counters, each associated with one of the possible states of prediction for an unknown bit, is utilized to arrive at a prediction of the level of the unknown bit. If the value found in the up-down counter is above a pre-specified level, a prediction will be made that the unknown bit is a one, otherwise, the prediction is zero. The predictor code output signals are summed modulo 2 with the actual signal value of the predicted bit in order to develop a prediction error pattern having a sparsity of ones. This error pattern is adaptable to run-length coding. After each prediction, the appropriate up-down counter is incremented or decremented depending on the actual value of the data bit that has been predicted so as to make future predictions adaptive to the previously coded data stream. The number of stages n is small so that the counters which control the predictions quickly adapt to changes in the nature of the actual information stream.

Abstract translation: 一种用于通过预测误差编码压缩数字数据的系统。 每个未知位的预测是数据流中以前检测到的电平的函数。 利用与未知位的预测的可能状态之一相关联的多个n位向上 - 向上计数器来得到未知位的电平的预测。 如果在递增计数器中找到的值高于预先设定的电平，则预测未知位为1，否则为0。