Research On Digital Watermarking Algorithm Oriented To Screen Capture Process For Remote Sensing Image

Remote Sensing data,one of the sources of geospatial information,has the characteristics of large information capacity,high update speed and accuracy.It is widely used in territory,surveying and mapping,environment and other fields.Remote sensing data sharing can effectively improve the utilization of data and give full play to the application value of data.However,its data security problems have also become increasingly prominent.In recent years,with the popularization of "4G"technology and the continuous improvement of camera technology,mobile phones and digital cameras have been widely used.The screen captures are more common.For example,in the process of distribution of confidential remote sensing images,it is difficult to protect the copyright if a person who is exposed to confidential data leaks the data through a screen capture.How to protect data copyright against screen capture is a problem that needs to be solved.In addition,for the suspected leak data that cannot be obtained directly,it can also be screened for evidence.Therefore,it is urgent to study the security technology for the screen capture process to protect the data security of remote sensing image.As a kind of information security technology,digital watermarking technology uses a specific algorithm to hide the watermark information in the original data to determine the copyright owner,track the infringement behaviors,content authentication and data source.Digital watermarking technology can effectively deter and track the leakers,it provides a feasible technical method for the protection of remote sensing images.In this paper,the digital watermarking algorithm for remote sensing images facing the screen capture process is studied by analyzing the screen capture process and using QR code technology.The main research work and conclusions are as follows:(1)Describe the digital watermark attack methods and watermark related evaluation indicators of remote sensing image,and establish a theoretical basis for designing and measuring watermarking algorithms against screen capture attacks.Analyze the impact of screen capture process on remote sensing images,and summarize the types of attacks.After that,a correction scheme and an example for the screen capture process are proposed.It will provide technical support for watermark information detection.(2)For the limited watermark bearing capacity of the screen-image algorithm,the QR code is used as the watermark information,and its advantages are discussed from the aspects of watermark information capacity,embedded data volume,and anti-attack capability.After that,the QR code watermark information is structurally analyzed,and a QR code preprocessing method is proposed and verified experimentally.The experimental results show that QR code can express more content with less data.Its strong self-correction and preprocessing method can increase the anti-attack ability and reduce the embedded data amount of watermark information.(3)According to the type of damage attacks caused by the screen capture process,and selecting the invariant features by analyzing the characteristics of the DCT domain coefficients,a digital watermarking algorithm for remote sensing image based on QR Code and DCT invariant features is proposed.The algorithm uses the DCT invariant features mapping method to determine the watermark information embedding position,and embeds the watermark information into the block DCT low-frequency DC coefficients in a parity-quantized manner.Experiments show that the algorithm can effectively resist the single attack caused by the screen capture process such as JPEG compression,noise,filtering,blur and so on.It establishes the foundation to against the screen capture attacks.(4)In order to resist multiple kinds of compound attacks during the screen capture process,the watermark information is encoded and converted,and combined with a circular angle template watermark,a digital watermarking algorithm based on QR Code and circular angle template is proposed.The algorithm replaces the binary sequence watermark information with the circular angle periodic pattern watermark,and the watermark information is embedded with the JND value of the remote sensing image.Before the watermark information detection,Harris corner detection and perspective transformation are used to preprocess the detected data.In the process of watermark information detection,the knowledge of image morphology is introduced,and the watermark information is obtained by detecting the angle information of the template watermark.Experiments show that the algorithm can detect the watermark information from the screen photos and can resist the screen capture process attacks effectively.At the same time,it has strong robustness against attacks such as JPEG compression,scaling,color adjustment,rotation,and other image common attacks.