Research On Decipherment Model And Algorithm Of Geometric Accuracy For DOM

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.