关键词: 可逆数据隐藏, 直方图平移, 对比度增强, 医学图像

Abstract: Reversible data hiding is a kind of information hiding technique that can exactly recover the original image after data extraction from the image with hidden data. Due to this property, it has been widely used in the areas of medical, remote sensing and military. This paper proposes a reversible data hiding algorithm based on histogram shifting, which can alleviate the visual distortion caused by an existing reversible data hiding algorithm, and reversibly hide the patient information into the contrast-enhanced image. According to the characteristics of pixel distribution in medical images, the pre-processing is improved to adaptively choose the optimal intervals and the method of maximum classes square error is used to separate the background and the foreground. In the information hiding procedure, the contrast of the region of interest can be gradually enhanced. Furthermore, the original image can be exactly recovered when needed. The experimental results on two sets of medical images show that the proposed algorithm can effectively reduce the visual distortions that may be caused by the previous algorithm, while the contrast enhancement effects can be achieved with considerable hiding rates.

Key words: reversible data hiding, histogram shifting, contrast enhancement, medical image