Efficient skew estimation and correction algorithm for document images

摘要

In this paper, we propose a fast skew estimation and correction algorithm for English and Korean documents based on a BAG (Block Adjacency Graph) representation. BAG is one of the most efficient data structures for extracting various information concerning connected components; the image rotation for skew correction is performed rapidly using the block information in the BAG. The proposed skew estimation algorithm uses a coarse/refine strategy based on the Hough transformation of connected components in the image. The skew correction algorithm then generates a non-skew image by rotating the blocks, rather than the individual pixels. An experiment using 2016 images from various English and Korean documents demonstrates how the proposed method is superior to conventional ones.