Patent ID: 8532379

Claim:
An image processing apparatus comprising a programmed processor, the programmed processor having a plurality of sections, comprising: a pixel value conversion section which performs binarization processing to binarize a pixel value of a target pixel in multi-valued image data based on a predetermined threshold to output the binarized pixel value as an output value; an isolated point determination section which determines whether or not the target pixel is an isolated point; a feedback calculation section which calculates one or more feedback values obtained by multiplying one or more binarized pixel values of one or more processed pixels adjacent to the target pixel by a predetermined feedback coefficient; a feedback addition section which adds the one or more feedback values calculated by the feedback calculation section to the pixel value of the target pixel before binarization by the pixel value conversion section; an error diffusion section which diffuses a difference between the pixel value of the target pixel binarized by the pixel value conversion section and the pixel value of the target pixel before addition by the feedback addition section as an error to one or more pixel values of one or more unprocessed pixels adjacent to the target pixel; and an error subtraction section which subtracts the error diffused by the error diffusion section from the pixel value of the target pixel before the addition by the feedback addition section, wherein the isolated point determination section determines whether or not the target pixel is in a highlight portion, determines whether or not the target pixel is the isolated point when the isolated point determination section determines that the target pixel is in the highlight portion, and determines that the target pixel is an isolated point when all of the pixel values of one or more processed pixels arranged in predetermined adjacent positions with respect to the target pixel are 0, and when the output value of the target pixel is a maximum value, and the pixel value conversion section sets an output value of a predetermined adjacent pixel adjacent to the target pixel determined to be the isolated point to a predetermined forced output value excluding 0.