Removing Background Color from Blueprints

摘要

A blueprint is a type of paper-based reproduction. For almostrna century blueprint was the only low cost process available forrncopying drawings. Despite today this technology has been largelyrnsuperseded by digital printing, it is still being used in emergingrncountries. When making copies of those documents, the coloredrnbackground often makes difficult reading the information in thernscanned plot. Hence, having an accurate way to transform thernbackground to white enhances the look of the plot, plus saves inkrnwhen printing. This paper introduces an algorithm for removingrnthe background color from a blueprint scanned image, comprisingrnprocessing the image in a colorimetric space by determining therncolorimetric values of the background color of the image,rncomputing a linear chromatic adaptation transform forrntransforming the background-color colorimetric values to valuesrnof a target white point, and applying the computed chromaticrnadaptation transformation to the image.