顾及地形特征的DEM脆弱水印完整性认证算法

针对目前DEM完整性认证的需求,以及相关认证方法的欠缺,基于脆弱水印技术提出了一种充分顾及DEM地形特征的完整性认证算法.本文对DEM数据进行特征分析,进而提出与其相适应的脆弱水印技术的特殊要求.为了减少水印嵌入对载体数据的影响,在脆弱水印嵌入过程中,首先,提取DEM数据特征线,并依此将数据分为特征区域和非特征区域2部分;然后,根据特征区域的栅格数和水印序列段生成脆弱水印,并以LSB位平面替换的方法,将水印信息嵌入到非特征区域部分.在完整性认证过程中,同样提取DEM数据的特征区域,将重新生成的水印信息与提取的水印信息进行对比,从而判断数据的完整性.算法实验结果表明,其能有效认证DEM数据的完整性,对数据影响较小,且算法安全性和适用性较强.

A Fragile Watermarking Algorithm for Integrity Authentication of DEM Based on the Terrain Feature

Considering the necessity of integrity certification and the lack of certification methods for DEM, an integrity certification algorithm based on fragile watermarking for DEM was proposed, which had fully taken the terrain features into account. The characteristic of DEM data is analyzed in order to propose the special requirements of the fragile watermarking technology. To reduce the impact of watermarked data, in the process of fragile watermark embedding, based on the feature lines extracted from the original DEM data, the data was firstly divided into two different parts: the feature region and non-feature region. Secondly, the fragile watermarking information was generated according to the number of raster in feature region and watermarking sequence segments, and then it was embedded into the non-feature region by LSB-based method. In the integrity certification process, the same feature region was extracted from DEM data, and the regenerated watermark information was compared with the extracted one in order to determine the integrity of the data. Finally, experiments using the proposed algorithms were presented. Experimental results show that the presented algorithm not only is able to effectively certificate the integrity of DEM data, but also has little influence on the data accuracy. In addition, the algorithm has high security and suitability.