Document image restoration - For document images scanned from bound volumes -

Abstract

When one scans a document page from a thick bound volume, perspective distortion is a common problem due to the curvature of the page to be scanned. This results in two kinds of distortion in the scanned document images: (1) Photometric distortion: shade along the spine of the book (2) Geometric distortion: warping in the shade area. The distortion in the document images introduces problems not only for fast and painless human reading, but also for document image analysis, understanding and recognition. In this thesis, we first propose two novel restoration approaches to tackle the above distortion problems: Approach 1: Document image restoration based on 2D document image processing Approach 2: Document image restoration based on 3D document shape discovery We then evaluate the restoration results by comparing the OCR performance on the original document image and the corresponding restored images by different methods respectively, and compare the two approaches by discussing two issues: effectiveness and efficiency.