Comparison of vertical projection profile, moment-based and initial skew rate algorithm for text skew estimation

Abstract

This paper makes analysis and evaluation of vertical projection profile, moment-based and initial skew rate algorithm for the text skew. Among these three methods, the initial skew rate method is newly developed, while moment-based is adapted compared to its initial version. The vertical projection profile method is used in its native form, which is widely accepted for text skew estimation. The comparison is based on the experiment which includes testing of the algorithm with a dataset that consist of the printed text image samples. These image samples are given in the resolution of 25, 50 and 300 dpi. Tested algorithms obtain different skew accuracy for different resolution of text images. At the end, the moment-based method has the smallest accuracy declination, which demonstrates its benefit over the other two methods. Furthermore, this contributes to its robustness in applications, which use low resolution images.