Histogram shifting is an effective manner to achieve reversible watermarking, which works by shifting pixels between the peak point and its nearest zero point in histogram to make room for watermark embedding. However, once zero point is absent, the algorithm suffers from overflowing problem. Even though some works attempt to deal with this risk by introducing auxiliary information, such as a location map, they occupy a lot of embedding capacity inevitably. In this article, in order to deal with overflowing problem efficiently, we propose a border following–based reversible watermarking algorithm for images. With the help of border following algorithm and pre-processing, available regions with at least one zero point are recognized to embed watermark so that auxiliary information is not needed any more. And the algorithm utilized also ensures the same border can be re-recognized from the watermarked image without error, thus the correctness is also guaranteed. The performance of the proposed algorithm is evaluated using classic image datasets in this area, and the results not only validate the effectiveness of the proposed algorithm but also indicate its advantages compared with the classic histogram shifting–based reversible watermarking algorithm as well as the state of the art.

中文翻译：

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基于边界跟随的抗直方图溢出图像可逆水印算法

直方图移位是实现可逆水印的一种有效方式，它通过在直方图中的峰值点与其最近的零点之间移动像素来为水印嵌入腾出空间。然而，一旦没有零点，算法就会出现溢出问题。尽管一些作品试图通过引入辅助信息（例如位置图）来应对这种风险，但它们不可避免地会占用大量嵌入容量。在本文中，为了有效地处理溢出问题，我们提出了一种基于边界跟随的图像可逆水印算法。借助边界跟随算法和预处理，识别至少有一个零点的可用区域来嵌入水印，从而不再需要辅助信息。并且所采用的算法也保证了从水印图像中可以无误地重新识别出相同的边界，从而也保证了正确性。使用该领域的经典图像数据集对所提出算法的性能进行了评估，结果不仅验证了所提出算法的有效性，而且表明了与经典的基于直方图移位的可逆水印算法相比的优势，以及艺术。