A new method of reversible data hiding based on compressed gray level histogram shifting

Abstract

Histogram shifting is one of the most useful techniques of Reversible Data Hiding (RDH). In histogram shifting based data hiding technique, lower distortion and improved capacity can be achieved. In this paper, a new method of reversible data hiding based on compressed gray level histogram shifting has been proposed which provides a high capacity of data hiding and also maintains a good image quality. In the proposed technique of data hiding, the range of the image pixel values is compressed by taking the square root of these pixel values. Considering the rounded pixel values increases the amount of peak pixel and thus also increases the data hiding capacity greatly. After data insertion, pixel values are squared and round values of the pixels are considered to form the image. At the receiver the hidden data is extracted and the actual cover image is regained by following the reverse technique of data insertion. The proposed scheme has been applied to various images to check its generality. The bit-rate and PSNR value obtained by the proposed method have been compared to a reference method and it was found that the proposed method provides a higher capacity than the reference method but PSNR value is a little bit lower in some cases.