Effect of text orientation to OCR error and anti-skew of text using projective transform technique

In this paper, text orientation which affects to OCR output error together with corresponding correction technique was examined. In case of text oriented in 3D or tilted manner, conventional anti-skew technique such as Hough or Radon transform could fail and a technique of Projective transform is proposed. To illustrate the effectiveness of the technique, Arial and OCR-A extended font types had been tested by manipulating in both 2D and 3D orientations. The tested results from MATLAB and OCR freeware showed that OCR accuracy is sensitive to text orientation and the proposed technique can do anti-skew image of text from 2D scene which mapped from 3D object orientation.