Enhancement of uneven lighting text image using line-based Empirical Mode Decomposition

Non-uniform light distribution problems often arise in the text images taken by digital camera. In this paper, we propose a novel technique for text image uneven lighting removal using Empirical Mode Decomposition (EMD). The EMD is local, adaptive and useful for analyzing non-linear and non-stationary signals. In this method, we decompose images by EMD and get the background level locally and adaptively. This algorithm can enhance local contrast in the image while removing shadows for black-and-white text images. In addition, this work can be very helpful for text recognition. The experimental results show that the proposed approach can effectively enhance text images more readable under uneven lighting.