| 摘要 |
PURPOSE:To make a picture natural in its observation by converting an N picture element into a picture element of a halftone level specified by predetermined gradation number. CONSTITUTION:In the case of reduction rate of 1/N, the number of gradation of a halftone level is (N+1). Picture arrangement d, e are obtained by converting 4 notice picture elements a1, a1', a2, a2' in the original picture into one of 5 gradations including white level based on a conversion table and on a conversion table of other algorithm. Thus, the apparent resolution attended with mixture of the halftone picture element is improved and even a repetitive pattern such as thin lines or the like is recognized as a natural picture element according to human visual sense. |
