Method of enlarging and processing image data

摘要

In obtaining image data of an enlargement factor alpha by which the image data is enlarged and processed by multiplication with a non-integer number, the image data are firstly contracted and processed to a contraction factor beta = alpha / gamma , wherein gamma is an integer satisfying alpha < gamma . Then, the contraction-processed image data are subjected to pseudo half tone processing. Thereafter, the pseudo half tone processed image data are enlarged and processed by a factor gamma times. The contraction factor beta is selected as a value equal to or more than 50%. Thereby, even for an enlargement factor which requires multiplication by a non-integer number, visual image quality is upgraded, processing data amount is reduced and memory capacity is lowered, thus resulting in a lower cost.