A study on three dimensional rotation-free character recognition and rotation angle estimation of characters

This paper addresses the problem of recognizing rotated characters in scene and estimating the rotation angle using Weighted Direction Code Histogram (WDCH) and Modified Quadratic Discriminant Function (MQDF). In our previous paper [1], we proposed a rotation-free character recognition method and confirmed the feasibility of real world application. We also applied our method to scene analysis to detect surface normal from written characters by estimating rotation angle of the characters. In this research, we evaluate how precisely our proposed method can estimate rotation angle by comparing obtained result by 3D digitizer.