Text Skew Detection Using Combined Entropy Algorithm

Darko Brodić, Zoran N. Milivojevic

Abstract


This paper proposes the algorithm for text skew estimation based on the combined entropy calculation. The method consists of three steps. In the first step, it calculates the horizontal and vertical projection profiles. In the second step, the horizontal and vertical entropy for the rough angles is calculated. In the last step, the horizontal and vertical entropy calculation for the smooth angles is performed. The calculated entropy creates the two cost functions: horizontal and vertical. The position where each of cost functions has an absolute minimum represents horizontal and vertical estimated text skew angle. In the last step, it estimates the text skew angle as a mean of horizontal and vertical estimated text skew angles. The functionality, correctness and robustness of the proposed algorithm is investigated by the experiment. which is based on DISEC'13 document database. The obtained results and promising. They confirm that the method correctly estimates text skew angle.

DOI: http://dx.doi.org/10.5755/j01.itc.46.3.15797


Keywords


algorithm; document image processing; entropy; optical character recognition, text skew

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