摘要 |
<p>The present invention provides a method for compressing image data. The method first detects (Fig. 10) a pattern in a first subset of the image data, where the second subset being collocated to a second subset. If no pattern is detected, then a text mode context model (Fig. 3) is selected. If a pattern is detected (810 - 826), then the period of the pattern is detected and a pattern mode context model (Fig. 4, Fig. 8) is selected. The pattern mode context model (Fig. 4, Fig. 8) has a width (801) directly related to the period of the pattern detected. An arithmetic compressor compresses (1116) the second subset using the selected context model.</p> |