【作者】 闫娜；

【导师】 周卫；

【作者基本信息】 南京师范大学 ， 地图学与地理信息系统， 2013， 硕士

【摘要】 数字正射影像图(DOM)是对航空或航天相片进行数字微分纠正和镶嵌,按一定图幅范围裁剪生成的数字正射影像集。它是同时具有地图几何精度和影像特征的图像,具有精度高、信息丰富、直观逼真、获取快捷等优点。随着DOM数据的广泛使用,其安全保护问题日益突出。本文针对DOM数据的安全保护问题,基于DOM数据结构特征和几何精度脱密模型的研究,构建了DOM几何精度脱密与恢复模型,在此基础上设计并实现了脱密误差控制算法和DOM几何精度脱密与恢复算法,最后进行了系统实现与验证。论文主要研究内容与结论如下：(1)DOM脱密模型研究。本文在分析DOM数据模型、脱密模型与算法需求的基础上,研究了几何精度脱密模型。利用多项式曲面拟合模型并基于共线方程,构建了DOM几何精度脱密模型,基于共线方程的逆方程构建了DOM几何精度的恢复模型。(2)脱密误差控制算法研究。确定模型参数与误差两者关系是保证数据按照相应指标进行几何精度脱密的关键问题,本文针对构建的混合模型中线性与非线性部分分别进行了脱密误差控制研究,并考虑密钥的安全性,研究并实现了参数的加密算法生成密钥,实现了脱密的误差控制和密钥生成。(3)DOM脱密与恢复算法研究。DOM脱密与恢复过程主要包括新建数据、坐标转换和像素重采样,本文根据DOM数据的结构特征,新建数据时添加一个波段用于存储脱密过程中生成的高程信息,并基于脱密误差控制算法生成的密钥进行坐标转换和像素重采样,完成DOM数据脱密与恢复。(4)DOM脱密系统实现。系统对上述研究成果进行了验证和实现,主要包括密钥生成、DOM脱密、DOM恢复等功能,通过密钥生成完成脱密误差控制过程,根据密钥实现DOM脱密与恢复过程。本文研究的DOM几何精度混合脱密模型,在保证数据拓扑关系基本不发生改变的前提下,根据密钥可对DOM数据进行脱密,脱密后的数据依据密钥可进行恢复。本方法具有随机性、渐变性、可逆性等特点,提高了DOM栅格数据脱密的可靠性,完善了地理信息安全保护的理论与方法体系。更多还原

【Abstract】 Digital orthoimage map (DOM) is the orthoimage data which applies digital elevation models to correct and inlay digital images, according to map sheet, clipping and generating.DOM combines the geometric qualities of a map and the image characteristics of an aerial photograph, has the advantages of high-accuracy, informative, intuitive, and can be got easily and quickly. As widely used, the safety protection of DOM has been brought to the front. This paper aim at security of DOM data, built decipherment and restoration model of DOM, based on the data structure characteristics of DOM and the researches of decipherment model of geometric accuracy, and then design and realize the algorithm of decipherment error control and decipherment and restoration algorithm of DOM. Finally complete decipherment system.The main content and conclusions are as follows:(1) Research about decipherment features and models for DOM.Based on analysis of data model and decipherment model about DOM data, together with requirement of the algorithm, this paper studied decipherment model about geometric accuracy of data. Using polynomial curve fitting model, decipherment model of geometric accuracy for DOM is constructed based on collinearity equation. Restoration model of geometric accuracy for DOM is constructed based on inverse formula of collinearity equation.(2) Research about algorithm of error control for deciphermentInvestigating the relationship between model parameters and errors is the key link for decipherment model about geometric accuracy. Considering the security of key, this paper researched error control about decipherment of the linear part and the non-linear part in mixed model, which realized the generation of keys by encryption algorithm of parameters, as well as error control and generation of keys for decipherment.(3) Research about decipherment and restoration algorithm for DOMDecipherment and restoration of DOM mainly including data creating, coordinate transformation, and pixel resampling. This paper added elevation information generated during decipherment progressed in band storage according to the data structure of DOM, and conducted coordinate transformation, and pixel resampling based on the key generated by algorithm of error control for decipherment, finally completed decipherment and restoration of DOM.(4) Realization of decipherment system for DOMWith the main modules of key generation, decipherment of DOM, and restoration of DOM, the system verified and implemented the research results above, realized the error control process though key generation, and completed decipherment and restoration of DOM data through the key.This paper reachered on decipherment model and algorithm of geometric accuracy for DOM.Decipherment of DOM raster data according to the security key was completed on the premise of topological relationship unchanged, and deciphered data could be restored by means of the security key. This method had the characteristics of randomness, gradual change and reversibility. It improved reliability of decipherment of DOM raster data, and perfected the theories and methods system about geographic information security.更多还原