定位篡改区域的二维矢量地图脆弱水印算法研究

Due to the development of Internet and geo-information processing technology, 2D vector maps are not only being widely applied in varied fields of national economy, but also facing increased risk of being illegally tampered and transferred. Fragile watermarking is viewed as an effective way to authenticate data integrity and locate tampered data. Currently, research on 2D vector map fragile watermarking is mainly focused on locating tampered vertex groups or feature groups. These schemes cannot accurately locate all the regions influenced by tampering. Once these tampered regions identified as untampered have been used, very serious or even catastrophic consequences may be caused. However, few works have been done on locating tampered regions with high accuracy. To solve the tampered region localization problem in 2D vector map fragile watermarking schemes, this project will focus on developing 2D vector map fragile watermarking schemes that locate tampered regions with high accuracy, by proposing adaptive data unit division methods, data unit localization information design and storing methods, and information hiding methods with high embedding capacity. The 2D vector map fragile watermarking schemes proposed in this project are expected to have high tampered region localization ability, and meet the requirements of different application scenarios for precision distortion control and tolerance for normal operations. Results of this project will provide new theory and implementation schemes for 2D vector map fragile watermarking, which will push forward the timely and reliable application of 2D vector maps.

因特网和地理信息处理技术的发展，推动了二维矢量地图在国民经济各领域的广泛应用，同时，也加剧了二维矢量地图非法篡改、传播的危险。脆弱水印算法是认证数据完整性和定位篡改的有效方法。目前二维矢量地图脆弱水印算法的成果以定位篡改顶点分组、图元分组为主，还不能准确定位篡改影响的所有区域。这些未能定位到的篡改区域一旦使用，将会带来极其严重甚至灾难性后果。当前二维矢量地图脆弱水印算法在准确定位篡改区域方面的工作还非常少。为此，针对二维矢量地图脆弱水印算法的篡改区域定位问题，本项目将通过提出自适应数据单元划分策略、数据单元定位信息构建和存储策略、高嵌入容量的信息隐藏算法，设计以准确定位篡改区域为目标的二维矢量地图脆弱水印算法,以获得高篡改区域定位能力，同时满足不同应用场景对精度扰动控制和容忍常规操作的需求。本项目将形成二维矢量地图脆弱水印的新型理论与实现机制，研究成果将有力推动二维矢量地图的及时可靠应用。

脆弱水印算法是认证数据完整性和定位篡改的有效方法。通过定位发生篡改的数据，有效使用没有被篡改的数据，能够避免重新传输数据造成的时间与资源的浪费。将脆弱水印算法应用于地理信息系统的基础数据即二维矢量地图时，如何准确定位篡改影响的所有区域是其面临的重要挑战。本项目研究了以准确定位篡改区域为主要目标的二维矢量地图脆弱水印算法，通过提出自适应数据单元划分策略、数据单元定位信息构建和存储策略、高嵌入容量的信息隐藏算法，设计了定位篡改区域的脆弱水印算法框架，并实现了定位篡改区域的脆弱水印算法。具体地，我们基于模拟退火方法，提出了优化的数据单元划分方法；设计了数据单元和其关联数据单元间的一一映射方法，并依据数据单元最小外接矩形和其关联数据单元间的位置关系，构建了不同应用场景的数据单元定位信息；提出了基于归一化顶点的可逆信息隐藏方法、保持顶点方向关系的可逆信息隐藏方法和保持图元拓扑关系的可逆信息隐藏方法；实现了定位篡改区域的可逆脆弱水印算法和容忍旋转、缩放、平移的脆弱水印算法。我们提出的脆弱水印算法有较高的篡改区域定位能力，能够满足不同应用场景对有效控制精度扰动和容忍一定程度常规操作的需求，从而为二维矢量地图的及时可靠应用提供强有力的技术支持和保障。