An image data processing apparatus having pixel density conversion and error diffusion function (Image Having the Pixel Density Conversion and Error Diffusion functions)

摘要

An object of the present invention is to provide an image data processing apparatus capable of performing pixel density conversion and error diffusion without increasing the memory capacity. The halftone part 7 calculates the error data of each pixel stored in the error memory 8 according to the conversion ratio of the pixel density in the pixel density conversion part 4 with respect to the multivalued data of the input one line of the pixel do. If the conversion ratio of the pixel density is equal to or smaller than "1", the halftone processing unit 7 calculates the error data for each pixel and stores the result of the calculation in the error memory 8. On the other hand, when the conversion ratio of the pixel density exceeds " 1 ", the intermediate gradation section 7 calculates an error average for each adjacent two input pixels and stores the result of the calculation in the error memory 8.