Reversible Data Hiding Algorithm with High Imperceptibility Based on Histogram Shifting

Abstract

Histogram shifting based reversible data hiding (RDH) algorithm embeds the secret messages into the peak point (with the highest frequency) in the image histogram. Using RDH however results in the number of peak points in the histogram to drop by half of its original quantity, thus results in depression of the image histogram. This significantly affects the imperceptibility of the secret message. To address this issue, in this paper we propose an RDH algorithm with high imperceptibility in which the embedding point (the grayscale value corresponds to the pixels embedded secret message) in the image histogram is selected based on the length of the secret message and the specific pixels to embed the secret message are chosen by taking into account the value of their adjacent pixels. The adjustment made to the quantity of embedding point and its surrounding points in the histogram causes the number of pixels to have a smooth transition around the embedding point in the histogram. This significantly enhances imperceptibility. Experimental results confirm the effectiveness of the proposed algorithm.