Canon Kabushiki Kaisha

Trevor Lee McDonell

Yu-Ling Chen

Ping Liu

A method () is disclosed for modifying colors of text extracted from an image of a document page to improve visual quality. The document image comprises text and image regions of various colors. The method divides () the document image into a plurality of connected components, the connected components comprising pixels of similar color that are closely spatially located, and selects from the image a plurality of the connected components that represent text. The plurality of text connected components are grouped 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. One or more logically consistent color sets are then formed () for each text block based on the colors of the connected components in the text block. The logically consistent color sets represent all text of visually similar color of the corresponding text line or paragraph. The method then applies color enhancement () to the logically consistent color sets to enhance visual quality and correct image defects in the document image.

Colour correcting foreground colours for visual quality improvement

A method of text extraction in color compound documents is described. The method connects similarly colored pixels of an image of a color compound document into connected components (CCs); classifies each CC as either text or non-text; refines the text CC classification for each text CC using global color context statistics; groups text CCs into text blocks; recovers misclassified non-text CCs into a nearby text block; and removes extraneous CCs from each text block using local color context statistics to thereby provide the extracted text in the text blocks. Also described is a method of locating graphics objects in a color compound document image.

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Ingleburn, Australia

Trevor Lee McDonell