Patent ID: 6954556

Claim:
A smoothing method comprising the steps of: (a) extracting an evaluation window including a target pixel of a multi-value image data in which tone is represented by a multi-value in units of pixels; (b) judging black and white of the target pixel according to a predetermined rule, and binarizing pixel data within the evaluation window; and (c) generating a binary correction value based on collating binarized pixel data within the evaluation window and a look-up table which stores patterns in vicinities of the target pixel, converting the binary correction value to a multi-value correction value with reference to an original multi-value image data, and outputting a multi-value correction signal in which the binary correction value is converted into a multi-value correction value, wherein step (c) sets a portion where a dot is to remain after correction is to a value of an original data and a portion where the dot is to be deleted to an intermediate value between the target pixel and an adjacent dot if the target pixel is judged as being black, and sets a portion which becomes a background portion to the value of the original data and sets a portion where the dot is to be added to an intermediate value between the target pixel and an adjacent dot if the target pixel is judged as being white.