Abstract: In the data hiding algorithm based on reversible integer transform, the traditional method obtains the values by calculating the differences between the upper left pixel and the remaining pixel of block. The proposed method obtains the values by using the median of a block instead of the upper left pixel, so that the stego image achieves lower distortion. Further, employing priority hidden data in the smooth regions can significantly improve the signal to noise ratio of stego image. It compares the similar reversible data hiding schemes, and the experimental results show that the proposed scheme achieves better visual quality with the same embedded capacity and demonstrate the effectiveness of the proposed algorithm.

Key words:  reversible data hiding, block median, difference expansion, reversible integer transform

摘要： 在基于可逆整数变换的数据隐藏算法中，传统的方法利用左上角像素值与块中其他像素值得到差值。提出的方法利用块中值与块中其他像素值得到差值，差值变小，从而使得藏密图像失真降低。同时该方法采用在平滑区域优先嵌入数据的策略，使藏密图像的信噪比显著提高。将该方法与类似的方法进行实验比较，结果表明提出方法在嵌入相同数据量时确实具有更好的隐蔽性，并且隐密数据和原宿主图像均能从隐藏图像无损恢复，验证了提出算法的有效性。

关键词: 可逆数据隐藏, 块中值, 差值扩展, 可逆整数变换