PURPOSE: To reproduce smooth and high definition pseudo intermediate tone picture by deciding a black picture element density of several gradation density levels of a reproduced picture in response to the density level of an original picture and deciding the picture element arrangement of the black density level of the reproduced picture in response to the density level change of the original picture.
CONSTITUTION: An original picture signal is read in a picture element R11 of a scanning window Wr of a redistribution storage means 2 and a picture element O11 of a scanning window Wo of a sequencing storage means 4, and a sum S(=Sm+en) of a picture signal level sum Sm of four photoelectric picture elements R00, R01, R10, R11 of the scanning window Wr of the redistribution storage means 2 and a distribution error en caused in one preceding picture element is calculated. A maximum value C of the picture signal is divided by an output gradation number (n-1) of an n-level to obtain a picture signal level Cn, which is used as a distributed value, and the distribution number M and a residue A of the value Cn obtained from the total sum S are obtained, the residue A is compared with a half value picture signal level Cn/2 to control the distribution number of the value Cn to decrease the distribution error en. Thus, a smooth reproduced picture is obtained.
KANAMORI KATSUHIRO
KAWAKAMI HIDEHIKO
KODERA HIROAKI
