PURPOSE: To produce a reduced image having the reduced omission of the linear information on characters by allocating the high density value to the small number of black dots.
CONSTITUTION: A black dot number calculating device 103 inputs a reduction coefficient 104 and defines the value of the coefficient 104 as (n). Then the device 103 reads the dot data 102 on a rectangular area having an (n × n) size out of the original bit map data 101 and calculates the black dots included in the rectangular area to output the black dot number 105. Then a density converting device 112 inputs the number 105 and the coefficient 104, retrieves a density conversion table 111 corresponding to the coefficient 104 out of a density conversion table group 110, and converts the number 105 into the density value 107 based on the table 111 to output the value 107. In the table 111, the high density value is allocated to the small number of black dots. Thus, it is possible to obtain a reduced image that has the reduce omission of the linear information on characters.
MIYABE YOSHIYUKI
OTSU TAKASHI
