摘要 |
A predictive function expressed by a dot matrix is applied to binary image data and an object dot is converted into, e.g., white data so as to increase the number of white data. A run length coding is performed on the image data where the number of the white data is increased, thus compression is performed on the image data at high compression rate. When expanded, the compressed image data is expanded by run length decoding. A reverse prediction is performed by using the predictive function, thus, original image data is obtained. <IMAGE> |