Reversible data hiding (RDH) plays a significant role in the field of information security which allows safe transmission of secret data inside a cover media. Additionally, RDH allows extraction of secret data and lossless recovery of the cover media at the decoding end which makes it applicable for the applications like medical imaging and military services. In recent years, variety of RDH techniques such as lossless compression, histogram shifting, difference expansion, prediction error expansion and pixel value ordering (PVO) have been proposed. Among all of them, PVO is one of the most researched RDH techniques as it provides high-fidelity images with decent data hiding capacity. So, to thoroughly understand the evolution of PVO based RDH schemes along with their advantages and disadvantages, this paper presents a comprehensive study of all the existing PVO based RDH schemes with an aim to provide research guidance to the researchers who are interested to work in the field of PVO based reversible data hiding. For this, the working of PVO based schemes is discussed and explained by using suitable examples. Additionally, the challenges being faced by reversible data hiding technique for increasing the data hiding capacity along with image quality, are comprehensively presented. Furthermore, comparative analysis of different PVO-based RDH scheme (after categorizing them based on their working style) using two key parameters—embedding capacity and marked image quality, is presented.

可逆数据隐藏（RDH）在信息安全领域中发挥着重要作用，它允许在封面媒体内部安全传输秘密数据。此外，RDH允许提取秘密数据并在解码端无损恢复封面媒体，这使其可用于医学成像和军事服务等应用。近年来，已经提出了各种RDH技术，例如无损压缩，直方图移位，差异扩展，预测误差扩展和像素值排序（PVO）。其中，PVO是RDH技术中研究最多的技术之一，因为它可以提供具有良好数据隐藏能力的高保真图像。因此，要彻底了解基于PVO的RDH方案的发展以及它们的优缺点，本文对现有的所有基于PVO的RDH方案进行了全面的研究，旨在为有兴趣在基于PVO的可逆数据隐藏领域工作的研究人员提供研究指导。为此，通过使用合适的示例来讨论和解释基于PVO的方案的工作。此外，全面介绍了可逆数据隐藏技术所面临的挑战，这些技术用于提高数据隐藏能力以及图像质量。此外，提出了使用两个关键参数（嵌入能力和标记图像质量）对不同的基于PVO的RDH方案进行比较分析（根据其工作方式分类后）。