Recently, several reversible data hiding (RDH) techniques based on pixel value ordering (PVO) have been proposed that precisely embed the secret data into cover images. As the neighboring pixels in smooth images are highly correlated, these methods perform better for smooth images but achieve comparatively low performance for roughly textured images. In many application domains like satellite imagery, the cover images are not always smooth. So, the performance of existing PVO based methods for roughly textured images needs to be improved. In this paper, we propose a novel RDH method based on PVO that is specially designed for improving the hiding performance in roughly textured images. In the proposed method, a segmentation scheme is used to cluster the pixels into different segments based on their intensity values. The segmentation ensures that the pixels in each segment are highly correlated to each other and each segment is divided into non-overlapping blocks of size \( 2 \times 2 \) where a block can hide at most two data bits in the smallest and the largest valued pixel. The size of the block is further extended by \( 2 \times 1 \) pixels if the complexity level of the block is ‘0’. The proposed method results in an increase in the hiding capacity as well as the visual quality of the stego images as the correlation of each block is increased which in turn limits the number of shifted pixels. The experimental results also prove the superiority of the proposed method against the existing PVO based RDH methods.

最近，已经提出了几种基于像素值排序（PVO）的可逆数据隐藏（RDH）技术，这些技术可将秘密数据精确地嵌入到封面图像中。由于平滑图像中的相邻像素高度相关，因此这些方法对平滑图像的性能更好，但对粗纹理图像的性能却相对较低。在许多应用领域（如卫星图像）中，封面图像并不总是很平滑。因此，需要改进现有的基于PVO的粗纹理图像方法的性能。在本文中，我们提出了一种新的基于PVO的RDH方法，该方法是专门为提高粗糙纹理图像的隐藏性能而设计的。在提出的方法中，分割方案用于基于像素的强度值将像素聚类为不同的片段。\（2 \ times 2 \），其中一个块最多可以在最小和最大值的像素中隐藏两个数据位。如果块的复杂度为“ 0” ，则将块的大小进一步扩展\（2 × 1 \）像素。由于每个块的相关性增加，因此所提出的方法导致隐身能力的增加以及隐身图像的视觉质量的提高，这反过来又限制了移位像素的数量。实验结果也证明了该方法相对于现有的基于PVO的RDH方法的优越性。