Projection Methods Require Black Border Removal

Abstract—A persistent flaw in the evaluation of page segmentation algorithms is examined. Index Terms—X-Y tree, page segmentation, layout analysis. Ç A detailed comparative evaluation of six page segmentation methods, reported recently by Shafait et al. [1], follows the experimental protocol of an earlier study by Mao and Kanungo [2] that purported to show that recursive X-Y cut (RXYC) segmentation is much more error-prone than competitive methods, even on isothetic layouts. It does not, however, require much experimentation or reflection to discover that all pixel-projection methods (for either segmentation or skew determination) require removing any black background introduced by optical scanning. We reported good results for RXYC segmentation in 1992 [3], from which Shafait et al. extracted the algorithm, and added to th