A data hiding scheme based on multidirectional line encoding and integer wavelet transform

Abstract

An effective image steganography scheme can make a good compromise among embedding capacity, imperceptibility, security and robustness. This paper presents a novel data hiding method based on multidirectional line encoding (MDLE) and integer wavelet transform (IWT). It can get a good result in those indicators simultaneously. The method firstly uses the IWT instead of the DWT to achieve accurate extraction of secret bits. The four wavelet sub-bands are divided into non-overlapping 3 ×3 coefficient blocks which are exploited as embedding regions. Secondly, the MDLE method based on the 3×3 block model is proposed. The center coefficient of the block is paired with surrounding coefficients in eight directions to embed n-bit secret data respectively, which improves the utilization of coefficients and ensures the change value of coefficient in one direction not to exceed 2n−1, thereby embedding capacity is increased and good imperceptibility is obtained. Finally, a simple edge detection method is proposed and applied to the low frequency approximation sub-band to embed more secret data in edge blocks in order to further enhance the embedding capacity. The experimental results show that the proposed method is not only superior in terms of embedding capacity and image quality than previous methods, but also secure to steganalysis and robust to attacks.