A Fast Skew Correction Technique for Camera Captured Business Card Images

Abstract

Performance of an Optical Character Recognition engine may be affected if the images are skewed and distorted due to perspective projection. In this paper, a computationally efficient skew correction technique has been presented for extracted text regions from business card images. The skew angle is estimated by analyzing the bottom and/or top profiles (height/depth from a horizontal base line) of a text region. After rejecting some of the profile elements based on mean and mean deviation, three reference profile elements are chosen from which we get three skew angles. The average is considered as the computed skew angle. Besides being faster, it has an applicable accuracy and the effect of perspective distortion is made normalized. It is observed from the experiment that the average deviation of the skew corrected text lines, from the ground truth data, is within ±3 degree while the average processing time is between 17-110 milliseconds for 0.45-3.0 mega pixel images.