Document page decomposition by the bounding-box project

This paper describes a method for extracting words, textlines and text blocks by analyzing the spatial configuration of bounding boxes of connected component on a given document image. The basic idea is that connected components of black pixels can be used as computational units in document image analysis. In this paper, the problem of extracting words, textlines and text blocks is viewed as a clustering problem in the 2-dimensional discrete domain. Our main strategy is that profiling analysis is utilized to measure horizontal or vertical gaps of (groups of) components during the process of image segmentation. For this purpose, we compute the smallest rectangular box, called the bounding box, which circumscribes a connected component. Those boxes are projected horizontally and/or vertically, and local and global projection profiles are analyzed for word, textline and text-block segmentation. In the last step of segmentation, the document decomposition hierarchy is produced from these segmented objects.