Pixel density conversion and processing

An image processing apparatus comprising:

• an input means for inputting binary image data;
• a conversion means for converting the input binary image data to multi-level image data;
• and
• a binarization means for binarizing the multi-level image data,
• wherein said binarization means includes a correction means for correcting error data generated when the multi-level image data is binarized, and
• wherein said conversion means converts the binary image data into the multi-level image data by a linear interpolation method.

A pixel density converting apparatus for converting a pixel density of binary image in which a pseudo-half-tone-processed image and characters or line drawings are present, said apparatus comprising:

• an operation means for operating on a tone or luminance of a pixel to be converted from binary data of a predetermined original pixel in the binary image and a positional relation between the original pixel and the pixel to be converted;
• a first binarization means for binarizing the tone or luminance of the converted pixel which is the operation results while correcting a quantizing error generated when surrounding the pixels have been binarized;
• a second binarization means for conducting a binarization without correcting the quantizing error;
• and
• a binarization selection means for selecting either of said first and second binarization means on the basis of determination as to whether or not an image area is a pseudo-half-tone-processed image area.

A pixel density converting apparatus for converting a pixel density of a binary image, comprising:

• an operation means for operating on a tone or luminance of a pixel to be converted form a binary data of a predetermined original pixel in the binary image and a positional relation between the original pixel and the pixel to be converted;
• a first binarization means for binarizing the tone or luminance of the converted pixel which is the operation results while correcting a quantizing error generated when surrounding pixels have been binarized;
• a second binarization means for conducting binarization without correcting the quantizing error;
• and
• a binarization selection means for selecting either of the first and second binarization means.