Experimental tool for generating ground truths for skewed page images
Oleg G. Okun, Ari Vesanen, Matti Pietikäinen · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2000
We describe a new tool called GROTTO to generate ground truths for skewed page images, which can be used for performance evaluation of page segmentation algorithms. Some of these algorithms are claimed to be more or less insensitive to skew. However, this fact is usually only supported by a visual comparison of what one obtains and what one should obtain. As a result, the evaluation is both subjective, that is, prone to errors and tedious. Our tool allows users to quickly and easily produce many sufficiently accurate ground truths that can be employed in practice and therefore it facilitates automatic performance evaluation. The main idea is to utilize the ground truths available for upright images, that is, for those without skew, and the concept of the representative square in order to produce the ground truths for skewed images. The usefulness of our tool is demonstrated through a number of experiments described.