| 摘要 |
PURPOSE:To perform efficient picture processings without raising considerably the cost by dividing an N-level picture and assigning a certain value to each picture element in each unit area and multiplying a different weight coefficient in accordance with this value to restore a half-tone picture. CONSTITUTION:Unit areas are provided on the N-level picture, and each unit area is 2X2, and a certain value is assigned to each picture element in each area. A different weight coefficient is multiplied in accordance with this value, and the half-tone picture is obtained from the total sum of values of individual picture elements of each unit area. When an M-level picture is restored in a unit area U1, numerical value 2 is obtained in the first row in the area U1 by counting and numerical value 2 is obtained in the second row by counting, and density restored value 4 is obtained in accordance with a rule of restoration. With respect to an area U2, numerical value 3 is obtained in the first row by counting and numerical value 2 is obtained in the second row by counting, and density restored value 5 is obtained. Density values are restored in all unit areas hereafter to restore the M-level picture. Since weight coefficients are used in this manner when the half-tone picture is restored from the N-level picture, efficient picture processings are performed without raising considerably the cost.
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