A color image input from a document image inputting unit is converted into a gray-scale image by a brightness image extracting unit. The gray-scale image is then converted into an image having a higher resolution according to the resolution of the original gray-scale image. When this conversion is performed,...http://www.google.fr/patents/US6347156?utm_source=gb-gplus-shareBrevet US6347156 - Device, method and storage medium for recognizing a document image
Device, method and storage medium for recognizing a document image
