Braille document parameters estimation for optical character recognition

Abstract

There is a significant need for a system to recognize Braille documents in order to preserve them and make them available to a larger group of visually impaired people. We introduce a high-adaptive Braille documents parameters estimation method to automatically determine the skewness, indentations, and spacing in both vertical and horizontal directions. The key element in determining the skewness of the images is based on Radon transform, which is generated from the integral of a function over straight lines, and is nicely applied in this case since Braille documents are highly directional. We demonstrate the effectiveness of skewness correction as well as the accuracy of indentation and spacing in both orientations. The proposed algorithm is an essential component of character recognition of Braille document discussed in this paper. © 2008 Springer Berlin Heidelberg.