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We present a structural analysis method for the recognition of on-line handwritten mathematical expressions based on a minimum spanning tree construction and symbol dominance. The method handles some layout irregularities frequently found in on-line handwritten formula recognition systems, like symbol overlapping and association of arguments of sum-like(More)
This paper presents E-Chalk, a software system which transforms a large touch sensitive screen into a smart teaching tool. The instructor writes on the screen using a special stylus and the software emulates a classical chalkboard. The lecturer can paste images to the board, can send queries to remote web services, can activate a computer algebra system,(More)
In this article, we present a system for the recognition of on-line handwritten mathematical formulas which is used in the electronic chalkboard (E-chalk), a multimedia system for distance-teaching. We discuss the classification of symbols and the construction of the tree of spatial relationships among them. The classification is based on support vector(More)
This paper introduces a novel binarization method based on the concept of transition pixel, a generalization of edge pixels. Such pixels are characterized by extreme transition values computed using pixel-intensity differences in a small neighborhood. We show how to adjust the threshold of several binary threshold methods which compute gray-intensity(More)
This paper presents a system that maps classroom lectures directly into web based education lessons. In the classroom, the lecturer writes on a wide, pen sensitive display. The system tracks all actions and makes it possible for the lecture to be replayed from the web any time. The remote viewer can follow the progress of the lecture: Audio, the creation of(More)
1. INTRODUCTION Using conventional authoring systems, the ratio of production time versus duration of the produced learning unit is typically a two to three digit number. Generally, this is not economically viable, especially as content of university lectures changes quickly. A cause for this tremendous effort is that traditional teaching know-how does not(More)
The transition method for image binarization is based on the concept of t-transition pixels, a generalization of edge pixels, and t-transition sets. We introduce a novel unsupervised thresholding for unimodal histograms to estimate the transition sets. We also present dilation and incidence transition operators to refine the transition set. Afterward, we(More)
This article introduces the new version of our system for the recognition of on-line handwritten mathematical expressions. The previous version was capable to recognize the most common mathematical expressions, such as expressions of calculus, following the usual mathematical conventions. This version improves and extends our technique, allowing the(More)
This article presents a system that maps classroom lectures directly into web based education lessons. In the classroom, the lecturer writes on a wide, pen sensitive display. The system tracks all actions and makes it possible for the lecture to be replayed from the web any time. The remote viewer can follow the progress of the lecture: Audio, the creation(More)