Bodin Dresevic

20.4: Displaced Filtering for Patterned Displays

This paper describes the filtering used in Microsoft ClearType. ClearType is a software system than enhances the resolution and readability of fonts on displays that contain a repeating pattern of addressable colored sub-pixels. The filtering in ClearType is based on a perceptual model of human vision. The perceptual model leads to an optimization technique for finding the best output values. The results of the optimization can be approximated by pre-filtering each color channel of an input image and then sampling each filtered color image at the spatial locations of the same colored sub-pixels in the display. We refer to this filtering followed by displaced sampling as RGB decimation. RGB decimation eliminates the phase error caused by standard anti-aliasing. A further approximation of the optimal filter yields RGB decimation with displaced box filters. Fourier analysis demonstrates that both the optimization technique and the displaced box filter suppress frequencies that contribute most to color fringing in unfiltered displaced sampling.

Setting up a competition framework for the evaluation of structure extraction from OCR-ed books

This paper describes the setup of the Book Structure Extraction competition run at ICDAR 2009. The goal of the competition was to evaluate and compare automatic techniques for deriving structure information from digitized books, which could then be used to aid navigation inside the books. More specifically, the task that participants faced was to construct hyperlinked tables of contents for a collection of 1,000 digitized books. This paper describes the setup of the competition and its challenges. It introduces and discusses the book collection used in the task, the collaborative construction of the ground truth, the evaluation measures, and the evaluation results. The paper also introduces a data set to be used freely for research evaluation purposes.

Book Layout Analysis: TOC Structure Extraction Engine

Scanned then OCRed documents usually lack detailed layout and structural information. We present a book specific layout analysis system used to extract TOC structure information from the scanned and OCRed books. This system was used for navigation purposes by the live books search project. We provide labeling scheme for the TOC sections of the books, high level overview for the book layout analysis system, as well as TOC Structure Extraction Engine. In the end we present accuracy measurements of this system on a representative test set.