Image processing apparatus, image processing method and storage medium storing image processing program

An image processing apparatus to perform an image quality improving process for an original color image data, comprising:

• a target color selecting unit that selects two target colors C1 and C2 for each local region of a plurality of local regions of the original color image data, the local region being a 2×2 pixel block having four pixel locations, the target color C1 being a pixel color of a first single pixel in the local region, each first single pixel of each local region being in a same first pixel location, and the target color C2 being a pixel color of a second single pixel in the local region, each second single pixel of each local region being in a same second pixel location, the first and second pixel locations being different, so that the two target colors C and C2 are selected from the first and second pixel locations and the target color selecting unit does not select, for each local region, colors from any other pixel location than the first and second pixel locations;
• a sorting unit that categorizes the local region based on a layout of the target colors selected by the target color selecting unit;
• a processing unit that performs, based on the target colors C1 and C2, an image quality improving process corresponding to a result of the categorizing performed by the sorting unit;
• an enhancing unit that performs at least one of an antialiasing process and an antialiasing-enlarging process as the image quality improving process for the original color image data;
• and
• a controller for controlling the processing of the target color selecting unit, the sorting unit and the processing unit,
• wherein the target color selecting unit selects the two target colors C1 and C2 for each local region independently of selecting two target colors C1 and C2 for any of the remaining local region or regions, and
• the original color image data is formed of image pixels, the image pixels containing more than two different colors.

An image processing method to perform an enlarging process for an original color image data, comprising using a hardware controller to perform the steps of:

• selecting two target colors C1 and C2 for each local region of a plurality of local regions of the original color image data, the local region being a 2×2 pixel block having four pixel locations, the target color C1 being a pixel color of a first single pixel in the local region, each first single pixel of each local region being in a same first pixel location, and the target color C2 being a pixel color of a second single pixel in the local region, each second single pixel of each local region being in a same second pixel location, the first and second pixel locations being different, so that the two target colors C1 and C2 are selected from the first and second pixel locations;
• not selecting, for each local region, colors from any other pixel location than the first and second pixel locations;
• categorizing the local region based on a layout of the selected target colors;
• determining pixel values after enlargement from the target colors C1 and C2 in accordance with a result of the categorizing;
• enlarging the original color image data based on the determined pixel values, and
• performing at least one of an antialiasing process and an antialiasing-enlarging process as an image quality improving process for the original color image data,
• wherein the selecting two target colors C1 and C2 for each local region is performed independently of selecting two target colors C1 and C2 for any of the remaining local region or regions, and
• the original color image data is formed of image pixels, the image pixels containing more than two different colors.

An image processing method to perform an image quality improving process for an original color image data, comprising using a hardware controller to perform the steps of:

• selecting two target colors C1 and C2 for each local region of a plurality of local regions of the original color image data, the local region being a 2×2 pixel block having four pixel locations, the target color C1 being a pixel color of a first single pixel in the local region, each first single pixel of each local region being in a same first pixel location, and the target color C2 being a pixel color of a second single pixel in the local region, each second single pixel of each local region being in a same second pixel location, the first and second pixel locations being different, so that the two target colors C1 and C2 are selected from the first and second pixel locations;
• not selecting, for each local region, colors from any other pixel location than the first and second pixel locations;
• categorizing the local region based on a layout of the selected target colors;
• performing an image quality improving process on the original color image data resulting in an image with improved image quality, the image quality improving process corresponding to a result of the categorizing based on the target colors C1 and C2;
• and
• performing at least one of an antialiasing process and an antialiasing-enlarging process as the image quality improving process for the original color image data,
• wherein the selecting two target colors C1 and C2 for each local region is performed independently of selecting two target colors C1 and C2 for any of the remaining local region or regions, and
• the original color image data is formed of image pixels, the image pixels containing more than two different colors.

A storage medium readable by a computer, the storage medium storing a program of instructions executable by the computer to perform a function for enlarging an original color image data, the function comprising using a hardware controller to perform the steps of:

• selecting two target colors C1 and C2 for each local region of a plurality of local regions of the original color image data, the local region being a 2×2 pixel block having four pixel locations, the target color C1 being a pixel color of a first single pixel in the local region, each first single pixel of each local region being in a same first pixel location, and the target color C2 being a pixel color of a second single pixel in the local region, each second single pixel of each local region being in a same second pixel location, the first and second pixel locations being different, so that the two target colors C1 and C2 are selected from the first and second pixel locations;
• not selecting, for each local region, colors from any other pixel location than the first and second pixel locations;
• categorizing the local region based on a layout of the selected target colors;
• determining pixel values after enlargement from the target colors C1 and C2 in accordance with a result of the categorizing;
• enlarging the original color image data based on the determined pixel values;
• and
• performing at least one of an antialiasing process and an antialiasing-enlarging process as the image quality improving process for the original color image data,
• wherein the selecting two target colors C1 and C2 for each local region is performed independently of selecting two target colors C1 and C2 for any of the remaining local region or regions, and
• the original color image data is formed of image pixels, the image pixels containing more than two different colors.