Data compression apparatus

摘要

Correlation between data in two adjacent scan lines is sensed. When the degree of correlation is above a predetermined value the data is compressed by means of two dimensional compression. When the degree of correlation is below the predetermined value the data is compressed by means of one dimensional compression. Typically, both the one and two dimensional compression systems are based on run length encoding. After a predetermined number of scan lines have been compressed by two dimensional compression, one scan line may be compressed by one dimensional compression to prevent accumulation of error.