Image processing device, image processing method, and computer program

An image processing method, comprising:

• storing an input image;
• generating an inverted image, the inverted image corresponding to a predetermined part of the input image;
• generating a target image, by combining the inverted image and the input image;
• quantizing the target image in accordance with the error diffusion method;
• extracting an output image from the quantized target image, the output image corresponding to the input image;
• and
• outputting the output image extracted by the image extractor;
• wherein a target image generator generates the target image including at least one of a first inverted image and a second inverted image,
• the first inverted image being an image axially symmetrical to the input image, the axis being defined by a start point of the quantization and a direction in which the quantization proceeds, the first inverted image having a length (or a width) of a-line, a being a predetermined positive integer;
• and
• the second inverted image being an image axially symmetrical to the input image, the axis being defined by a start point of the quantization and a direction orthogonal to a direction in which the quantization proceeds, the second inverted image having a length (or a width) of b-line, b being a predetermined positive integer.

A computer readable storage medium storing a program causing a computer device to execute a process, the process comprising:

• an input image;
• generating an inverted image, the inverted image corresponding to a predetermined part of the input image;
• generating a target image, by combing the inverted image and the input image;
• quantizing the target image in accordance with the error diffusion method;
• extracting an output image from the quantized target image, the output image corresponding to the input image;
• and
• outputting the output image extracted by the image extractor;
• wherein the target image including at least one of a first inverted image and a second inverted image,
• the first inverted image being an image axially symmetrical to the input image, the axis being defined by a start point of the quantization and a direction in which the quantization proceeds, the first inverted image having a length (or a width) of a-line, a being a predetermined positive integer;
• and
• the second inverted image being an image axially symmetrical to the input image, the axis being defined by a start point of the quantization and a direction orthogonal to a direction in which the quantization proceeds, the second inverted image having a length (or a width) of b-line, b being a predetermined positive integer.