Method and apparatus to enhance digital image quality

A computer-readable recording medium encoded with computer instructions executable by a computer to perform thereby a method of improving a quality of a document image comprising pixels with a predetermined resolution and obtained by scanning a script comprising a combination of a background, a text, and an image, the method comprising:

• updating history information regarding color data and a pixel type of a concerned pixel using previous history information of the concerned pixel;
• determining a block feature type of the concerned pixel using the pixel type and the updated history information of the concerned pixel;
• determining a type of an area to which the concerned pixel belongs based on a second type of a second area to which a first neighboring pixel in a left direction of the concerned pixel belongs, a third type of a third area to which a second neighboring pixel in a line above the concerned pixel belongs, the pixel type of the concerned pixel, and the determined block feature type;
• and
• performing different image quality enhancing processes on the concerned pixel based on the determined area type.

A digital image quality improving apparatus to improve a quality of a document image comprising pixels with a predetermined resolution and obtained by scanning a script comprising a combination of a background, a text, and an image, the apparatus comprising:

• a history information updating unit that updates history information regarding color data and a pixel type of a concerned pixel using previous history information of the concerned pixel;
• a block feature type detecting unit that determines a block feature type of the concerned pixel using the pixel type and updated history information of the concerned pixel;
• an area type determining unit that determines a type of an area to which the concerned pixel belongs depending on a type of an area to which a neighboring pixel in a left direction of the concerned pixel belongs, the pixel type of the concerned pixel, a type of an area to which a neighboring pixel in a line above the concerned pixel belongs, and the block feature type of the concerned pixel provided by the block feature type detecting unit;
• and
• an image quality enhancing unit that enhances an image quality of the concerned pixel to different degrees according to the area type determined by the area type determining unit.

A method of enhancing digital image quality of a document image comprising pixels with a predetermined resolution, the method comprising:

• converting color data of a concerned pixel;
• updating history information according to a pixel type of the concerned pixel;
• determining a block feature type of the concerned pixel;
• determining a type of an area to which the concerned pixel belongs;
• and
• enhancing image quality of each determined type of area.

A digital image quality improving apparatus to improve a quality of a document image comprising pixels with a predetermined resolution and obtained by scanning a script comprising a combination of a background, a text, and an image, the apparatus comprising:

• a history information updating unit that updates history information according to a pixel type of a concerned pixel;
• a block feature type detecting unit that determines a block feature type of the concerned pixel;
• an area type determining unit that determines a type of an area to which the concerned pixel belongs;
• and
• an image quality enhancing unit that enhances an image quality of the concerned pixel to different degrees according to the area type determined by the area type determining unit.

A computer-readable recording medium encoded with computer instructions executable by a computer to perform thereby a method of improving a quality of a document image comprising pixels with a predetermined resolution and obtained by scanning a script comprising a combination of a background, a text, and an image, the method comprising:

• converting color data of a concerned pixel;
• updating history information according to a pixel type of the concerned pixel;
• determining a block feature type of the concerned pixel;
• determining a type of an area to which the concerned pixel belongs;
• and
• enhancing image quality of each determined type of area.

A digital image processing apparatus comprising:

• a pixel type determining unit to classify a concerned pixel into a first pixel type and a second pixel type;
• a history information updating unit to maintain a first history value of a number of contiguous pixels of the first pixel type and a second history value of a number of contiguous pixels of the second pixel type;
• a block feature determining system to reclassify the concerned pixel according to the first history value and the second history value;
• an area type determining system to determine an image enhancement process to apply to the reclassified concerned pixel;
• and
• an image enhancement unit to apply the enhancement process to the reclassified concerned pixel.

A digital image processing method comprising:

• classifying a concerned pixel into a first pixel type and a second pixel type;
• updating a first history value if the concerned pixel is of the first pixel type and updating a second history value if the concerned pixel is of the second pixel type;
• reclassifying the concerned pixel according to the first history value and the second history value;
• and
• applying an image enhancement process according to a pixel type of the reclassified concerned pixel.