The rapid development in the information technology field has introduced digital watermark technologies as a solution to prevent unauthorized copying and redistribution of data.This article introduces a self-embedded ...The rapid development in the information technology field has introduced digital watermark technologies as a solution to prevent unauthorized copying and redistribution of data.This article introduces a self-embedded image verification and integrity scheme.The images are firstly split into dedicated segments of the same block sizes.Then,different Analytic Beta-Wavelet(ABW)orthogonal filters are utilized for embedding a self-segment watermark for image segment using a predefined method.ABW orthogonal filter coefficients are estimated to improve image reconstruction under different block sizes.We conduct a comparative study comparing the watermarked images using three kinds of ABW filters for block sizes 64×64,128×128,and 256×256.We embed the watermark using the ABW-based image watermarking method in the 2-level middle frequency sub-bands of the ABW digital image coefficients.The imperceptibility and robustness of the ABW-based image watermarking method image is evaluated based on the Peak Signal to Noise Ratio(PSNR)and Correlation coefficient values.From the implementation results,we came to know that this ABW-based image watermarking method can withstand many image manipulations compared to other existing methods.展开更多
The extended Empirical CODE Orbit Model(ECOM2)is widely used for Precise Orbit Determination(POD)of the BeiDou-3 Satellite Navigation System(BDS-3).However,Satellite Laser Ranging(SLR)residuals for BDS-3 satellites wi...The extended Empirical CODE Orbit Model(ECOM2)is widely used for Precise Orbit Determination(POD)of the BeiDou-3 Satellite Navigation System(BDS-3).However,Satellite Laser Ranging(SLR)residuals for BDS-3 satellites with Space Vehicle Numbers(SVNs)C223(Pseudo Random Noise(PRN)code C45)and C222(PRN C46)show systematic biases at high|β|angles.These satellites carry international Medium Earth Orbit Satellite-based Search and Rescue(MEOSAR)payloads.To address the SLR residual anomalies,this study proposes a set of POD strategies that integrate the Adjustable Box-Wing(ABW)Solar Radiation Pressure(SRP)model with ECOM2.Two ABW models were developed,incorporating the MEOSAR payload on either the+X or−X side of the satellite,accounting for self-shadowing effects.Analysis of model parameters and SRP accelerations from both ECOM2 and ABW models reveals that ECOM2 misrepresents B-direction accelerations.The ABW-estimated daily SRP accelerations can serve as a priori accelerations,used jointly with ECOM2,and without the concern of a priori model degradation due to environmental or property changes.The proposed strategies eliminate the SLR residual anomalies,resulting in the orbits with an SLR residual Standard Deviation(STD)improved from 7.8 cm in the ECOM2 solutions to 3 cm,representing an improvement of approximately 65%.The mean orbit Day boundary discontinuity(DBD)is approximately 2.7 cm,comparable to that of the ECOM2 solutions,and the 6-12 h orbit prediction accuracies in the 1-Dimensional(1-D)direction are improved from 4.6 cm in the ECOM2 solutions to 4.1 cm,showing an improvement of approximately 11%.The proposed strategies significantly improve SLR residuals,with mounting the MEOSAR payload on the−X side producing a better mean SLR residual.Additionally,to simultaneously satisfy the demand for simplified deployment,two a priori models employing truncated Fourier series formulations were also derived.Finally,we recommend one of these strategies for daily POD products.展开更多
基金This research was funded by Deanship of Scientific Research,Taif University Researches Supporting Project number(TURSP-2020/216),Taif University,Taif,Saudi Arabia.
文摘The rapid development in the information technology field has introduced digital watermark technologies as a solution to prevent unauthorized copying and redistribution of data.This article introduces a self-embedded image verification and integrity scheme.The images are firstly split into dedicated segments of the same block sizes.Then,different Analytic Beta-Wavelet(ABW)orthogonal filters are utilized for embedding a self-segment watermark for image segment using a predefined method.ABW orthogonal filter coefficients are estimated to improve image reconstruction under different block sizes.We conduct a comparative study comparing the watermarked images using three kinds of ABW filters for block sizes 64×64,128×128,and 256×256.We embed the watermark using the ABW-based image watermarking method in the 2-level middle frequency sub-bands of the ABW digital image coefficients.The imperceptibility and robustness of the ABW-based image watermarking method image is evaluated based on the Peak Signal to Noise Ratio(PSNR)and Correlation coefficient values.From the implementation results,we came to know that this ABW-based image watermarking method can withstand many image manipulations compared to other existing methods.
基金supported by the Natural Science Foundation of China(grant number 42374025)Natural Science Basic Research Program of Shaanxi(grant number 2019 JC-20)+2 种基金Key R&D Program of Shaanxi Province(grant number 2022ZDLSF07-12,2022 KW-09,2021LLRH-06)Innovation Capability Support Program of Shaanxi(grant number 2021TD-03)the Fundamental Research Funds for the Central Universities,CHD(grant number 300102264719,300102263401,300102261301).
文摘The extended Empirical CODE Orbit Model(ECOM2)is widely used for Precise Orbit Determination(POD)of the BeiDou-3 Satellite Navigation System(BDS-3).However,Satellite Laser Ranging(SLR)residuals for BDS-3 satellites with Space Vehicle Numbers(SVNs)C223(Pseudo Random Noise(PRN)code C45)and C222(PRN C46)show systematic biases at high|β|angles.These satellites carry international Medium Earth Orbit Satellite-based Search and Rescue(MEOSAR)payloads.To address the SLR residual anomalies,this study proposes a set of POD strategies that integrate the Adjustable Box-Wing(ABW)Solar Radiation Pressure(SRP)model with ECOM2.Two ABW models were developed,incorporating the MEOSAR payload on either the+X or−X side of the satellite,accounting for self-shadowing effects.Analysis of model parameters and SRP accelerations from both ECOM2 and ABW models reveals that ECOM2 misrepresents B-direction accelerations.The ABW-estimated daily SRP accelerations can serve as a priori accelerations,used jointly with ECOM2,and without the concern of a priori model degradation due to environmental or property changes.The proposed strategies eliminate the SLR residual anomalies,resulting in the orbits with an SLR residual Standard Deviation(STD)improved from 7.8 cm in the ECOM2 solutions to 3 cm,representing an improvement of approximately 65%.The mean orbit Day boundary discontinuity(DBD)is approximately 2.7 cm,comparable to that of the ECOM2 solutions,and the 6-12 h orbit prediction accuracies in the 1-Dimensional(1-D)direction are improved from 4.6 cm in the ECOM2 solutions to 4.1 cm,showing an improvement of approximately 11%.The proposed strategies significantly improve SLR residuals,with mounting the MEOSAR payload on the−X side producing a better mean SLR residual.Additionally,to simultaneously satisfy the demand for simplified deployment,two a priori models employing truncated Fourier series formulations were also derived.Finally,we recommend one of these strategies for daily POD products.
