Reversible data hiding with enhancing contrast and preserving brightness in medical image

With the development of telemedicine and medical sharing, private information which stored in the cloud may be disclosed. In order to protect the private information of patients and improve the quality of medical image further, there are some researches of reversible data hiding (RDH) based on contrast enhancement in medical image. However, the existing methods may cause the embedded medical image to be over-enhanced when increasing the embedding capacity. With the intention of protecting the medical image stored on a semi -trusted server, a novel reversible data hiding with enhancing contrast and preserving brightness is proposed in this paper. The proposed algorithm separates medical image into regions of interest (ROI) and regions of non-interest (NROI) firstly. Then through pre-processing the bins in the histogram of ROI regions to get better contrast stretching effect. Thereafter, stretch the contrast of ROI region and embed secret message with brightness preservation. Experimental results show that the proposed method can not only enhance the ROI region's contrast but also preserve the brightness of the embedded images when compared with traditional methods.