Colour correcting foreground colours for visual quality improvement

A computer readable storage medium having a computer program recorded thereon, the program being executable by computer apparatus to modifying colours of text extracted from an image of a document page to improve visual quality, said document image comprising text and image regions of various colours, the program comprising:

• code for dividing the document image into a plurality of connected components, the connected components comprising pixels of similar colour that are closely spatially located, and selecting from said image a plurality of the connected components that represent text;
• code for grouping said plurality of text connected components to form a logical structure grouping of said page comprising one or more text blocks wherein each said text block represents a text line or paragraph;
• code for forming one or more logically consistent colour sets for each said text block based on the colours of said connected components in said text block, wherein said logically consistent colour sets represent all text of visually similar colour of the corresponding text line or paragraph;
• and
• code for applying colour enhancement to said logically consistent colour sets to enhance visual quality and correct image defects in the document image.

Computer apparatus comprising a processor, a memory, an input for a document image and an output for a modified document images, said memory having a computer program recorded therein, the program being executable by the processor to modify colours of text extracted from the document image, said document image comprising text and image regions of various colours, the program comprising:

• code for dividing the document image into a plurality of connected components, the connected components comprising pixels of similar colour that are closely spatially located, and selecting from said image a plurality of the connected components that represent text;
• code for grouping said plurality of text connected components to form a logical structure grouping of said page comprising one or more text blocks wherein each said text block represents a text line or paragraph;
• code for forming one or more logically consistent colour sets for each said text block based on the colours of said connected components in said text block, wherein said logically consistent colour sets represent all text of visually similar colour of the corresponding text line or paragraph;
• and
• code for applying colour enhancement to said logically consistent colour sets to enhance visual quality and correct image defects in the document image to form the modified document image.