Research On Digital Watermarking Algorithm Oriented To Geometric Attacks For BIM Model

As an important data source and mapping result,BIM model is widely used in engineering design,construction and urban planning.With the rapid development of Internet technology and big data era,the opening environment also breeds illegal activities and threats the data security lifecycle.It is extremely urgent to use effective means for protecting BIM model omnidirectional.In many technology,making security protocols only restrain human behavior,not protect data security.Entrusting to a professional institution or agent only is rely on people's subjectivity,and cannot use the technically to protect the BIM model copyright Therefore,it is significant to provide copyright protection for BIM model in the process of data sharing.As a frontier of information security technology,digital watermarking technology integrates with BIM model and provides full comprehensive and effective copyright protection in the whole of data life cycle.Using this method avoiding data security relying on the people subjective behavior mode and encryption and decryption not applying in data distribution.The integration of digital watermarking technology and BIM model will realize copyright authentication,leak tracking and post-event investigation of BIM model in each stage of data use.It will provide a more flexible and reliable security guarantee BIM model security mechanism.Different from point cloud model and the mesh model,BIM models have more apply in the Engineering design and fine micro analysis,which has the characteristic of high precision,low redundancy,diverse file formats,consistent and automatic data update and materialization.At present,research on digital watermarking of BIM model is nearly blank all over the world.The existing digital watermarking technology based on 3D model is generally oriented to 3D mesh model and 3D point cloud model.Based on this model feature,the 3d model watermarking robust watermarking algorithm and zero algorithm cannot be directly applied to the materialized BIM model.In order to solve the problem of copyright protection for BIM data during the process of data transfer and sharing,the paper focuses on the digital watermarking model and algorithm for BIM data.The main research contents and conclusions are as follows:(1)Based on the integrated platforms,technologies and application scenarios of BIM and 3DGIS.Analyze the security problems of BIM model in the transmission and sharing,the existing ensure,BIM model feature,attacking mode,and evaluation.Thus,this paper proposes two digital watermarking modeling of BIM including zero watermarking frame model and reversible watermark frame model,which will provide theoretical basis for watermarking algorithm construction.(2)For the characteristic of high precision and less reduction,analyze the properties and characteristics of different watermarking techniques,a BIM model watermarking algorithm based on the distance partition and BIM zero model is proposed.At first,the pseudo-random sequence watermarking information is generated by the key code.After that,in the stage of watermarking embedding,the watermarking information is embedded by modulating the distance value between the benchmark,and the proposed distance partitioning method is used to increase the robustness of rotation and transmission.The experiment shows that the zero-watermarking algorithm has excellent robustness to transmission,rotation and Model fineness changes.It is significant for BIM model in copyright protection.(3)For BIM model zero watermarking needing the participation of third party authority and the cumbersome of watermarking detection,the BIM model reversible watermarking algorithm based on the BIM reversible model,difference and quantization modulation is proposed.The proposed reversible algorithm modulates the difference value when embedding the watermarking information,the method will improve capacity and imperceptibility.The experiment shows that,using the difference in the watermarking embedding stage will effectively resist the attack of translation.At the same time,establishing the synchronization between remainder in quantization modulation and the watermarking information,it will increasingly resist the attack of deleting points randomly and cropping.At the same time,The BIM model reversible watermarking algorithm does not compromise the data accuracy,which can reach to 10-12,which will solve the security issues in the data transmission and sharing.