Method and apparatus to correct distortion of document copies

A method for correcting distortion in an image of a scanned document, comprising:

• placing a reference pattern on a page;
• obtaining an image of said page containing printed information at least a portion of which is distorted;
• detecting said reference pattern in the image indicative of the distortion;
• computing an amount of the distortion in said image by analyzing the detected reference pattern;
• and
• correcting the distortion in said image based on the amount of distortion computed in said computing step,
• wherein said placing step includes:
• attaching a plurality of strips of material at predetermined locations and predetermined orientations to said page, one of said strips of material containing said reference pattern and another of said strips containing a second reference pattern, said obtaining step including scanning said page containing said plurality of strips of material into a memory.

A distortion correction processor adapted for use with a digital imaging device, said distortion correction processor comprising:

• an optical recognition unit which locates a reference pattern on a page in the form of a strip of material having a predetermined location and predetermined orientation in a document image;
• a distortion computation unit which determines an amount of the distortion in said image by analyzing said reference pattern;
• and
• a bitmap processor which corrects the distortion in said image based on the amount of distortion computed by the distortion computation unit.

A digital imaging system, comprising:

• a document having a strip of material containing a reference pattern at a predetermined location and predetermined orientation on a page of said document;
• an optical scanner which scans said document to obtain an image, said image containing distortion resulting from curvature of said document on a support surface of said optical scanner;
• a distortion correction processor which receives said image from said optical scanner, said distortion correction processor including:
• (a) an optical recognition unit which locates said reference pattern in said image,
• (b) a distortion computation unit which determines an amount of the distortion in said image by analyzing said reference pattern,
• (c) a bitmap processor which corrects the distortion in said image based on the amount of distortion computed by the distortion computation unit;
• and
• an output unit for outputting the corrected image to an output device.