Manipulation of graphics image data.

摘要

Data compression, resolution and coding efficiency of graphic text or line image data is achieved by eliminating transitions between gray levels at edges in an image, converting all gray levels to a common value to achieve a 3 level representation of the image, and reversibly converting the 3 level representation to a bilevel double resolution representation by increasing the data sampling rate and therefore allowing the use of two level data compression techniques. A high resoluton display or printed output may be obtained from the bilevel multiresolution representation,