Land Map Images Binarization Based on Distance Transform and Adaptive Threshold

This work presents a binarization technique of map document images. It exploits an amalgam of global and local threshold approaches best suited for binarization of document images with complex background and overlapping objects in the foreground like maps. The proposed approach uses Distance Transform (DT) and Adaptive threshold. Initially a rough estimate of the map background is done using Distance Transform (DT). This is followed by an adaptive threshold operation to extract the foreground. The efficacy and accuracy of the proposed technique are also compared, using ICDAR 2009 -- DIBCO (Document Image Binarization Contest) evaluation parameters, with other algorithms already reported in the literature.