Reversible Data Hiding in Encrypted Images Based on Block-Wise Multi-Predictor

Abstract

Reversible data hiding of encrypted images (RDHEI) is a technology where after the original image is encrypted with a key, secret data can be embedded in the encrypted image without knowing the information of the original image. In recent years, RDHEI has attracted much attention due to its security and effectiveness, and many RDHEI methods have been proposed. However, the capacity of embedded data is still not high enough. In this paper, a high-capacity RDHEI algorithm based on block-wise multi-predictor, and improved Huffman coding is proposed. First, the original image is divided into non-overlapping blocks. To better exploit the spatial correlation of the original image, 16 prediction models are used to predict the current pixel value from the neighboring pixels. All the pixels in one block use the same prediction model. The improved Huffman encoding is used to compress the prediction error image and the optimal prediction model determined by the sum of the absolute prediction errors, which makes more room for data embedding. The experimental results show that our method is superior to some of the latest algorithms in terms of achieving a higher embedding capacity.